WO2013018860A1 - 炭素繊維の製造方法、および炭素繊維 - Google Patents
炭素繊維の製造方法、および炭素繊維 Download PDFInfo
- Publication number
- WO2013018860A1 WO2013018860A1 PCT/JP2012/069682 JP2012069682W WO2013018860A1 WO 2013018860 A1 WO2013018860 A1 WO 2013018860A1 JP 2012069682 W JP2012069682 W JP 2012069682W WO 2013018860 A1 WO2013018860 A1 WO 2013018860A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- carbon fiber
- fiber bundle
- ozone solution
- ozone
- solution
- Prior art date
Links
- 229920000049 Carbon (fiber) Polymers 0.000 title claims abstract description 466
- 239000004917 carbon fiber Substances 0.000 title claims abstract description 466
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 447
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 49
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims abstract description 318
- 238000004381 surface treatment Methods 0.000 claims abstract description 127
- 239000000835 fiber Substances 0.000 claims abstract description 123
- 239000007788 liquid Substances 0.000 claims abstract description 18
- 239000002904 solvent Substances 0.000 claims abstract description 10
- 238000011282 treatment Methods 0.000 claims description 87
- 238000000034 method Methods 0.000 claims description 71
- 239000012530 fluid Substances 0.000 claims description 69
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 9
- 238000002484 cyclic voltammetry Methods 0.000 claims description 9
- 229910052799 carbon Inorganic materials 0.000 claims description 5
- 238000007380 fibre production Methods 0.000 claims description 4
- 239000000243 solution Substances 0.000 description 232
- 239000003570 air Substances 0.000 description 37
- 229920005989 resin Polymers 0.000 description 35
- 239000011347 resin Substances 0.000 description 35
- 239000011159 matrix material Substances 0.000 description 33
- 230000003647 oxidation Effects 0.000 description 22
- 238000007254 oxidation reaction Methods 0.000 description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 21
- 239000012298 atmosphere Substances 0.000 description 17
- 238000005259 measurement Methods 0.000 description 16
- 239000002131 composite material Substances 0.000 description 15
- 239000002243 precursor Substances 0.000 description 14
- 238000003763 carbonization Methods 0.000 description 13
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 12
- 238000011156 evaluation Methods 0.000 description 12
- 239000001301 oxygen Substances 0.000 description 12
- 229910052760 oxygen Inorganic materials 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 11
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 11
- 239000007789 gas Substances 0.000 description 9
- 238000004513 sizing Methods 0.000 description 9
- 238000005452 bending Methods 0.000 description 8
- 125000000524 functional group Chemical group 0.000 description 8
- 239000008151 electrolyte solution Substances 0.000 description 7
- 238000004140 cleaning Methods 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- 229910052757 nitrogen Inorganic materials 0.000 description 6
- 239000012299 nitrogen atmosphere Substances 0.000 description 6
- 230000001590 oxidative effect Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 239000000123 paper Substances 0.000 description 5
- 238000009656 pre-carbonization Methods 0.000 description 5
- 238000005406 washing Methods 0.000 description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 229910021607 Silver chloride Inorganic materials 0.000 description 4
- 238000009835 boiling Methods 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000035699 permeability Effects 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 4
- 229920002972 Acrylic fiber Polymers 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 239000003822 epoxy resin Substances 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- 229920002239 polyacrylonitrile Polymers 0.000 description 3
- 229920000647 polyepoxide Polymers 0.000 description 3
- 238000011144 upstream manufacturing Methods 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 239000004925 Acrylic resin Substances 0.000 description 2
- 229920000178 Acrylic resin Polymers 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229920002430 Fibre-reinforced plastic Polymers 0.000 description 2
- 229920000297 Rayon Polymers 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000011825 aerospace material Substances 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 230000005587 bubbling Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 239000011151 fibre-reinforced plastic Substances 0.000 description 2
- 239000012770 industrial material Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 239000011087 paperboard Substances 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920005668 polycarbonate resin Polymers 0.000 description 1
- 239000004431 polycarbonate resin Substances 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 239000009719 polyimide resin Substances 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000010526 radical polymerization reaction Methods 0.000 description 1
- 239000002964 rayon Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 229920006337 unsaturated polyester resin Polymers 0.000 description 1
- 229920001567 vinyl ester resin Polymers 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F11/00—Chemical after-treatment of artificial filaments or the like during manufacture
- D01F11/10—Chemical after-treatment of artificial filaments or the like during manufacture of carbon
- D01F11/12—Chemical after-treatment of artificial filaments or the like during manufacture of carbon with inorganic substances ; Intercalation
- D01F11/122—Oxygen, oxygen-generating compounds
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
- D06M11/32—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with oxygen, ozone, ozonides, oxides, hydroxides or percompounds; Salts derived from anions with an amphoteric element-oxygen bond
- D06M11/34—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with oxygen, ozone, ozonides, oxides, hydroxides or percompounds; Salts derived from anions with an amphoteric element-oxygen bond with oxygen, ozone or ozonides
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M23/00—Treatment of fibres, threads, yarns, fabrics or fibrous goods made from such materials, characterised by the process
- D06M23/06—Processes in which the treating agent is dispersed in a gas, e.g. aerosols
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M2101/00—Chemical constitution of the fibres, threads, yarns, fabrics or fibrous goods made from such materials, to be treated
- D06M2101/40—Fibres of carbon
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M2200/00—Functionality of the treatment composition and/or properties imparted to the textile material
- D06M2200/50—Modified hand or grip properties; Softening compositions
Definitions
- the present invention relates to a carbon fiber manufacturing method and carbon fiber. This application claims priority based on Japanese Patent Application No. 2011-169273 for which it applied to Japan on August 02, 2011, and uses the content here.
- carbon fibers have excellent mechanical strength, they are extremely useful as industrial materials such as aerospace materials, sports materials, leisure materials, and pressure vessels, and the demand for carbon fibers is expanding. In the future, it is expected to be used in a wider range of fields.
- carbon fibers are produced by firing a carbon fiber precursor fiber bundle in which precursor fibers (precursor fibers) of carbon fibers such as polyacrylonitrile fibers are bundled.
- precursor fibers precursor fibers
- polyacrylonitrile fibers are bundled.
- a heat treatment flame-proofing treatment
- the obtained flame-proof fiber bundle is nitrogen or the like.
- a carbon fiber is obtained by heat treatment (pre-carbonization treatment and carbonization treatment) in a carbonization furnace filled with an inert atmosphere. Carbon fiber is not usually used as it is, but is molded as a composite material in combination with a matrix resin and used for various applications.
- the carbon fiber after heat treatment in an inert atmosphere is usually subjected to a surface treatment for modifying the surface of the carbon fiber, and further subjected to a sizing treatment to wet the matrix fiber. , Affinity and adhesion are improved.
- liquid phase oxidation treatment such as electrolytic oxidation treatment and chemical solution oxidation treatment, and gas phase oxidation treatment are known. It is considered that by subjecting the surface of the carbon fiber to an oxidation treatment, an oxygen-containing functional group is formed on the surface of the fiber, and wettability, affinity, and adhesion to the matrix resin are improved.
- the oxidized carbon fiber is usually put into a dryer or the like, dried, and then sized with a sizing agent.
- electrolytic oxidation treatment is chemical oxidation treatment from the standpoint of ease of treatment, ease of control of treatment conditions, ease of introduction of oxygen-containing functional groups onto the carbon fiber surface, and the like. This is a more practical and effective surface treatment method than gas phase oxidation treatment.
- Patent Document 1 discloses that carbon fiber is immersed or transported in an ozone solution in which ozone is dissolved. And a method for treating the surface of the carbon fiber is disclosed.
- the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a carbon fiber manufacturing method and a carbon fiber capable of obtaining a carbon fiber excellent in adhesiveness with a matrix resin.
- the present invention has the following aspects.
- An ozone solution in which ozone is dissolved in a solvent is ejected from a fluid outlet toward a carbon fiber bundle, and the ozone solution is passed between the single fibers of the carbon fiber bundle so as to contact the surface of the single fiber.
- the manufacturing method of carbon fiber which has the surface treatment process of surface-treating carbon fiber with an ozone solution.
- tensile_strength of the carbon fiber bundle at the time of the said ozone solution contacting the single fiber surface is 0.3 kg or more and 1.8 kg or less per 12000 number of single fibers Method.
- the manufacturing method of carbon fiber as described in any one of. (6) The shape of the fluid jet port is rectangular, the longitudinal direction of the fluid jet port is the width direction of the carbon fiber bundle, and the length of the fluid jet port in the longitudinal direction is equal to or greater than the width of the carbon fiber bundle.
- the method for producing a carbon fiber according to any one of (1) to (5).
- the surface treatment is performed on the carbon fiber bundle transported on the liquid surface of the ozone treatment tank in which the moisture content is 40% or less and the ozone solution is stored.
- (1) to (8) The manufacturing method of the carbon fiber as described in any one.
- (11) The carbon fiber production method according to any one of (1) to (10), wherein an ozone concentration of the ozone solution is 10 mg / L or more and 120 mg / L or less.
- a carbon fiber excellent in adhesiveness with a matrix resin can be obtained. Moreover, the carbon fiber of this invention is excellent in adhesiveness with a matrix resin.
- an ozone solution in which ozone is dissolved in a solvent is ejected from a fluid ejection port toward a carbon fiber bundle, and the ozone solution is passed between the single fibers of the carbon fiber bundle.
- the carbon fiber has a surface treatment step for surface treatment with an ozone solution.
- the ozone solution may be ejected toward the stationary carbon fiber bundle or may be ejected toward the carbon fiber bundle to be transported, but is transported from the viewpoint that the ozone solution can be ejected uniformly. It is preferable to eject toward the carbon fiber bundle.
- a carbon fiber manufactured with an untreated surface or a commercially available carbon fiber with an untreated surface is prepared, and when necessary, a container containing an ozone solution is prepared.
- Surface treatment may be performed by conveying these carbon fiber bundles, or surface treatment may be performed by continuously conveying the carbon fiber bundles into an ozone solution after a baking treatment (carbonization treatment) described later. . If it is the latter operation method, since carbon fiber can be manufactured continuously, productivity can be improved more.
- FIG. 1 is a front view schematically showing an example of a surface treatment apparatus for treating the surface of carbon fiber
- FIG. 2 is a plan view of the surface treatment apparatus shown in FIG.
- the surface treatment apparatus 10 of this example includes an ozone treatment tank 12 that stores an ozone solution 11, a first free roll 14 a that guides a carbon fiber bundle 13 to be conveyed into the ozone treatment tank 12, and a carbon fiber bundle 13.
- the second free roll 14b led outside the ozone treatment tank 12, contact means 15 for bringing the ozone solution 11 into contact with the carbon fiber bundle 13, and a circulation pump 16 for circulating the ozone solution 11 are provided.
- the ozone solution 11 and the circulation pump 16, and the pipe 15a and the suction pipe 16a described later are omitted.
- the ozone solution 11 is a solution in which ozone is dissolved in a solvent.
- the ozone solution 11 is obtained, for example, by dissolving ozone gas generated from an ozone generator (not shown) in a solvent by an ozone gas dissolving device (not shown).
- a solvent for dissolving ozone water, a solution used for liquid phase oxidation, and the like can be mentioned. Among them, water is preferable, and pure water with reduced impurities such as distilled water and deionized water is particularly preferable.
- Commercially available ozone generators and ozone gas dissolving devices can be used.
- the ozone treatment tank 12 stores the ozone solution 11 supplied from an ozone gas dissolving device (not shown).
- the first free roll 14 a guides the conveyed carbon fiber bundle 13 into the ozone treatment tank 12.
- the second free roll 14 b guides the carbon fiber bundle 13 that has been surface-treated by contact with the ozone solution 11 to the outside of the ozone treatment tank 12.
- the contact means 15 makes the ozone solution 11 contact the carbon fiber bundle 13.
- the contact means 15 of this example is provided below the ozone treatment tank 12, and includes a pipe 15a and four branch pipes 15b branched from the pipe 15a.
- the pipe 15 a is arranged so that its longitudinal direction is parallel to the conveying direction of the carbon fiber bundle 13, one end is connected to the circulation pump 16, and the ozone solution 11 is supplied by the circulation pump 16.
- the branch pipe 15b is a long pipe, and as shown in FIG. 2, the longitudinal direction thereof is perpendicular to the longitudinal direction of the pipe 15a (that is, the longitudinal direction of the branch pipe 15b and the conveying direction of the carbon fiber bundle 13). So that they are orthogonal to each other). Further, the branch pipe 15b has a rectangular fluid jet port 15c on the upper side thereof along the longitudinal direction of the branch pipe 15b (that is, the longitudinal direction of the fluid jet port 15c is the width direction of the carbon fiber bundle 13). ) The ozone solution 11 formed and supplied to the branch pipe 15b through the pipe 15a is ejected from the fluid ejection port 15c toward the carbon fiber bundle 13 conveyed in the ozone treatment tank 12. Yes. It is preferable that the length of the fluid jet port in the longitudinal direction is not less than the width of the carbon fiber bundle.
- the circulation pump 16 sucks the ozone solution 11 in the ozone treatment tank 12 through the suction pipe 16 a and supplies it to the pipe 15 a of the contact means 15.
- the carbon fiber bundle 13 is placed in the ozone treatment tank 12 filled with the ozone solution 11 via the first free roll 14a. 11 is immersed. Then, the ozone solution 11 is ejected from the fluid ejection port 15c of the contact means 15 toward the carbon fiber bundle 13 conveyed in the ozone solution, specifically in a direction crossing the conveyance direction of the carbon fiber bundle 13. The ozone solution 11 is passed between the single fibers of the carbon fiber bundle 13 and brought into contact with the surface of the single fibers.
- the moving direction F of the ozone solution 11 at this time is a direction orthogonal to the conveying direction of the carbon fiber bundle 13 and upward (that is, a direction from the lower side to the upper side of the carbon fiber bundle 13 in the horizontal state).
- the carbon fiber bundle 13 that has been surface-treated by the contact with the ozone solution 11 is guided out of the ozone solution 11 in the ozone treatment tank 12 by the second free roll 14b.
- the ozone solution 11 If the ozone solution 11 is ejected in a direction intersecting with the conveying direction of the carbon fiber bundle 13, the ozone solution 11 can easily pass between the single fibers of the carbon fiber bundle 13, and the ozone solution reaches the inside of the carbon fiber bundle 13. 11 becomes easy to diffuse.
- the ozone solution 11 diffuses to the inside of the carbon fiber bundle 13, the number of oxygen-containing functional groups on the surface tends to increase uniformly to the inside of the carbon fiber bundle 13, and the carbon fiber surface-treated according to the present invention.
- the moving direction of the ozone solution is a direction in which the ozone solution ejected from the fluid ejection port or the ozone solution that naturally falls flows.
- the lower limit of the dissolved ozone concentration (hereinafter referred to as “ozone concentration”) in the ozone solution is preferably 10 mg / L or more, more preferably 20 mg / L or more, more preferably 30 mg / L from the viewpoint of efficiently performing the carbon fiber surface treatment. L or more is more preferable.
- the upper limit value of the dissolved ozone concentration is preferably 120 mg / L or less, more preferably 80 mg / L or less, and further preferably 50 mg / L or less from the viewpoint of the production cost of the ozone solution.
- the ozone concentration can be adjusted by the ozone gas concentration or the ozone solution temperature. For example, if the concentration of ozone gas is increased or the ozone solution temperature is decreased, the ozone concentration tends to increase.
- the treatment temperature at the surface treatment of the carbon fiber is not particularly limited, but as the treatment temperature increases, ozone (O 3 ) dissolved in the solution changes to oxygen (O 2 ), or ozone is converted into ozone. There is a tendency that the efficiency of the surface treatment is lowered by being discharged from the solution to the outside air. Therefore, the ozone solution temperature is preferably 0 to 40 ° C, more preferably 5 to 25 ° C.
- the number of times that the ozone solution 11 is jetted from the fluid jet port 15c toward the carbon fiber bundle 13 and is brought into contact with the surface of the single fiber is preferably 1 to 4 times.
- the number of times of contact of the ozone solution 11 by ejection to the carbon fiber bundle 13 is zero (that is, when the ozone solution 11 is not ejected toward the carbon fiber bundle 13)
- the ozone solution 11 diffuses to the inside of the carbon fiber bundle 13. It becomes difficult.
- the surface treatment is not sufficiently performed up to the single fiber inside the carbon fiber bundle 13, and the adhesion between the carbon fiber and the matrix resin is lowered.
- the number of contacts is preferably 4 times or less.
- the number of times of contact means the number of times that the ozone solution is ejected at an arbitrary position of the carbon fiber bundle 13 and the ozone solution is passed between the single fibers, and the surface treatment device 10 shown in FIG.
- the number of contacts is four. That is, the number of branch pipes 15b is equal to the number of contacts.
- the ozone solution 11 is ejected from the fluid ejection port 15c of the contact means 15 toward the carbon fiber bundle 13 conveyed through the ozone solution 11 in the ozone treatment tank 12.
- the moving ozone solution 11 is brought into contact with the carbon fiber bundle 13, and the ejection speed of the ozone solution 11 at this time is preferably 0.20 m / second or more and 2.0 m / second or less, and preferably 0.25 m / second or more. 1.0 m / sec or less is more preferable.
- the ejection speed is 0.20 m / sec or more, the ozone solution 11 easily passes between the single fibers of the carbon fiber bundle 13, so that the ozone solution 11 is sufficiently easily diffused into the carbon fiber bundle 13. As a result, it is easy to obtain good adhesion between the surface-treated carbon fiber and the matrix resin.
- the ejection speed is 2.0 m / second or less, it is possible to suppress the ozone solution 11 from coming into strong contact with the carbon fiber, to reduce the occurrence of fuzzing, and to suppress the deterioration of process passability.
- the ejection speed of the ozone solution 11 can be controlled by adjusting the pump pressure of the circulation pump 16 and the like.
- the distance is not particularly limited as long as it can reach the carbon fiber bundle 13 and can pass between the single fibers.
- the lower limit value of the distance from the fluid ejection port 15 c to the carbon fiber bundle 13 is not particularly limited as long as the branch pipe 15 b does not hinder the conveyance of the carbon fiber bundle 13.
- the tension of the carbon fiber bundle 13 when the ozone solution 11 contacts the surface of the single fiber is preferably 0.3 kg or more and 1.8 kg or less, more preferably 0.4 kg or more and 1.5 kg or less per 12,000 single fibers. . If the tension is 0.3 kg or more, since the tension is extremely low, it is easy to suppress the deterioration of the processability of the continuously produced carbon fiber due to the dispersion of the fiber bundle. On the other hand, if the tension is 1.8 kg or less, the ozone solution is sufficiently easily diffused into the carbon fiber bundle 13. As a result, good adhesion between the surface-treated carbon fiber and the matrix resin can be obtained.
- the carbon fiber bundle 13 is conveyed in the ozone solution 11, and the ozone solution 11 is ejected from the fluid ejection port 15c toward the carbon fiber bundle 13 during that time.
- the time (holding time) for holding the carbon fiber bundle 13 in the ozone solution 11 depends on the ozone concentration, it cannot be determined unconditionally.
- the ozone concentration is within the above range, 0.1 second or more 60 Seconds or less are preferred.
- the holding time is 0.1 seconds or more, the carbon fiber can be sufficiently surface-treated.
- productivity can be maintained.
- the holding time is more preferably 1 second or longer, further preferably 10 seconds or longer, and particularly preferably 30 seconds or longer.
- the holding time is more preferably 50 seconds or less from the viewpoint of productivity.
- the ozone solution can be uniformly contacted with the surface of the single fiber of the carbon fiber bundle having a large number of single fibers, and the carbon fiber can be more uniformly surface-treated, specifically, the number of single fibers.
- the ozone solution can be uniformly contacted with the surface of the single fiber of the carbon fiber bundle having 10,000 or more and 60000 or less. If the number of single fibers is 60000 or less, the ozone solution easily passes between the single fibers.
- the lower limit of the number of single fibers of the carbon fiber bundle is preferably 12,000 or more, more preferably 18000 or more, and further preferably 25,000 or more from the viewpoint of productivity.
- the upper limit value of the number of single fibers of the carbon fiber bundle is preferably 40000 or less, more preferably 30000 or less from the viewpoint of the uniformity of the surface treatment.
- the surface treatment method can make the ozone solution uniformly contact the surface of the single fibers of the carbon fiber bundle.
- the target carbon fiber can be obtained by a method other than the surface treatment method (for example, a conventional surface treatment method).
- the surface treatment method described above is suitable when the number of single fibers is as large as 10,000 or more.
- the method of setting the number of single fibers of the carbon fiber bundle within the above range is not particularly limited. For example, a method using a precursor fiber having a high tow volume as a starting material, a plurality of precursor fibers having a low tow volume, And a method of combining yarns with
- oxygen-containing functional groups are introduced to the surface of carbon fiber in the same manner as surface treatment by a conventional method such as electrolytic oxidation treatment.
- Examples of a method for confirming that the carbon fiber has been surface-treated include a method of measuring a current value (ipa value) flowing per unit area of the carbon fiber.
- the ipa value is an index of the surface characteristics of the carbon fiber, and the higher the ipa value, the greater the surface area of the carbon fiber, which means that the surface treatment has been performed. Therefore, when the ipa value is increased, the adhesion with the matrix resin is improved due to the anchor effect that the adhesion area between the carbon fiber and the matrix resin is increased.
- the ipa value of the carbon fiber can be determined by the cyclic voltammetry method disclosed in, for example, Japanese Patent Application Laid-Open No. 60-246864.
- the cyclic voltammetry method referred to in the present invention is a method of measuring the relationship between the current and the electrode potential (voltage) using carbon fiber as the working electrode in an analyzer comprising a potentiostat and a function generator. That is.
- a 5 mass% phosphoric acid aqueous solution is used to adjust the pH to 3, and a solution from which dissolved oxygen is removed by bubbling nitrogen is prepared.
- An Ag / AgCl electrode as a reference electrode, a platinum electrode having a sufficient surface area as a counter electrode, and carbon fiber as a working electrode are inserted into this solution, and the current and electrode potential of the carbon fiber are measured.
- the potential operation range is -0.2 to 0.8 V
- the potential operation speed is 2 mV / sec
- a potential-current curve is drawn with an XY recorder, swept three or more times
- Ag / With respect to the AgCl electrode the current is read with the potential at +0.4 V as a standard, and the ipa value is calculated according to the following formula (1).
- “sample length” is the length in the longitudinal direction of the carbon fiber used for the working electrode
- weight per unit is the weight per unit length of the carbon fiber used for the working electrode. That is.
- ipa value [ ⁇ A / cm 2 ] current value [ ⁇ A] / sample length [cm] ⁇ ⁇ 4 ⁇ ⁇ weight per unit area [g / cm] ⁇ number of single fibers / density [g / cm 3 ] ⁇ 1/2. 1)
- an ozone solution is attached to the surface of the surface-treated carbon fiber.
- the ozone solution adhering to the surface of the carbon fiber can be removed by putting the carbon fiber into a dryer and drying it.
- the temperature in the dryer can be set lower than in the case of the electrolytic oxidation treatment.
- the temperature in the dryer can be set in accordance with the boiling point of water, so that a relatively low temperature dryer can be used. Therefore, an increase in manufacturing cost can be suppressed.
- the ozone solution is ejected in a direction intersecting the transport direction of the carbon fiber bundle transported in the ozone solution, and the ozone solution passes between the single fibers of the carbon fiber bundle. Therefore, the ozone solution easily diffuses into the carbon fiber bundle.
- the ozone solution diffuses into the carbon fiber bundle, the number of oxygen-containing functional groups on the surface of the carbon fiber increases, so the carbon fiber surface-treated by the above-described carbon fiber surface treatment method is used as a composite material. When it does, it will become excellent in adhesiveness with a matrix resin.
- the carbon fiber surface treatment method does not use an electrolytic solution used for electrolytic oxidation treatment, and the carbon fiber is surface treated, there is no need to perform a cleaning step after the surface treatment. Moreover, it is not necessary to prepare an electrolytic solution that takes more time than preparation of an ozone solution. Therefore, the manufacturing apparatus can be downsized, the productivity can be improved, and the increase in manufacturing cost can be suppressed. Furthermore, since it is not necessary to provide a cleaning step in the above-described carbon fiber surface treatment method, there is no need to drain the cleaning waste liquid generated in the cleaning step. Furthermore, when the ozone solution used for the surface treatment is drained, if there is a storage tank, the ozone concentration is lowered to a harmless level by simply leaving it for several hours.
- the operation of the surface treatment itself is simple, and the surface treatment can be performed without using an expensive electrode. Therefore, since the productivity is improved, it is possible to obtain the same surface treatment effect as when the surface treatment is performed by a method such as a conventional electrolytic oxidation treatment while reducing the manufacturing cost. Moreover, according to the carbon fiber surface treatment method described above, a carbon fiber having an ipa value measured by a cyclic voltammetry method of 0.10 ⁇ A / cm 2 or more can be easily obtained.
- the surface treatment method of carbon fiber is not limited to the method mentioned above.
- the ozone treatment tank 12 is filled with the ozone solution 11 as shown in FIG. 1, but the ozone treatment tank 12 is filled with the ozone solution 11 like the surface treatment apparatus 20 shown in FIG. 3, for example. It does not have to be. That is, in FIG.
- the ozone solution 11 is ejected toward the carbon fiber bundle 13 while the carbon fiber bundle 13 is immersed in the ozone solution 11, but the ozone solution 11 is ejected toward the carbon fiber bundle 13, If the ozone solution 11 is passed between the single fibers of the carbon fiber bundle 13 and brought into contact with the surface of the single fiber, the carbon fiber bundle 13 is brought into contact with the ozone solution 11 without being immersed in the ozone solution 11 as shown in FIG.
- the surface treatment is performed in a shorter time when the carbon fiber bundle 13 conveyed on the liquid surface of the ozone treatment tank 12 is subjected to surface treatment. The reason for this is as follows.
- the carbon fiber bundle 13 is not immersed in the ozone solution 11, that is, the carbon fiber bundle 13 conveyed on the liquid surface of the ozone treatment tank 12 has a moisture content as compared with the carbon fiber bundle 13 conveyed in the ozone solution 11. Low. Therefore, until the ozone solution 11 reaches the inside of the carbon fiber bundle 13, the ozone solution 11 comes into contact with the surface of the single fiber more effectively and uniformly, and the number of oxygen-containing functional groups on the surface is likely to increase. Become. Therefore, when the carbon fiber obtained by subjecting the carbon fiber bundle 13 conveyed on the liquid surface of the ozone treatment tank 12 to the surface treatment is used as a composite material, the adhesion with the matrix resin is further improved.
- the method of performing the surface treatment on the carbon fiber bundle 13 conveyed on the liquid surface of the ozone treatment tank 12 is not limited to the method using the surface treatment apparatus 20 shown in FIG.
- the ozone solution 11 passes between the single fibers of the carbon fiber bundle 13
- the ozone solution moving in a direction parallel to the conveying direction of the carbon fiber bundle 13 is brought into contact with the carbon fiber. May be.
- FIGS. 4, 7, and 8 are front views schematically showing another example of the surface treatment apparatus for treating the surface of the carbon fiber
- FIG. 5 is a plan view of the surface treatment apparatus shown in FIG. 6 is a partial perspective view of the surface treatment apparatus shown in FIG.
- the ozone solution 11, the pipe 15a, the circulation pump 16, and the suction pipe 16a are omitted.
- the ozone treatment tank 12, the first free roll 14a, the second free roll 14b, the pipe 15a, the collision plate 15e, the circulation pump 16, and the suction pipe 16a are omitted.
- the surface treatment apparatus 30 shown in FIGS. 4 to 8 includes a rectifying plate 15d installed on the liquid surface of the ozone treatment tank 12 and an upper portion of the fluid outlet 15c of the branch pipe 15b, an upper portion of the rectifying plate 15d, and a carbon fiber. It further includes a collision plate 15e installed at a position facing the fluid ejection port 15c across the bundle 13. The number of times that the ozone solution 11 is ejected from the fluid ejection port 15c toward the carbon fiber bundle 13 and is brought into contact with the surface of the single fiber (number of times of contact) is 4 in FIG. 4 and 2 in FIGS.
- the rectifying plate 15 d moves the ozone solution 11 after passing between the single fibers of the carbon fiber bundle 13 in a direction parallel to the conveying direction of the carbon fiber bundle 13.
- the rectifying plate 15d in this example includes a bottom plate 152d provided with a rectangular hole 151d at a position located directly above the fluid ejection port 15c, a vertical plate attached to the bottom plate 152d, and There are two side plates 153d facing each other, and the bottom plate 152d and the side plate 153d form a bowl-shaped flow path through which the ozone solution 11 flows.
- the rectifying plate 15d in which the bottom plate 152d and the side plate 153d form a channel is also referred to as “a rectifying plate having a channel”.
- the length of the flow path of the rectifying plate 15d is preferably 150 mm or more. If it is 150 mm or more, when used as a surface-treated composite material, the adhesion to the matrix resin is further improved.
- the upper limit of the length of the flow path is not particularly limited, but if it is too long, the equipment becomes large and takes up space, so 500 mm or less is preferable.
- the length of the flow path is more preferably 200 mm or more and 400 mm or less. Further, the length of the flow path is appropriately set according to the conveyance speed of the carbon fiber bundle 13, but specifically, the time during which the ozone solution 11 stays in the flow path (stay time) is 1 second or more. Thus, it is preferable to adjust the length of the flow path.
- the staying time is 1 second or longer, a sufficient holding time with the carbon fiber bundle 13 can be secured, so that the adhesion to the matrix resin is further improved when used as a surface-treated composite material.
- the upper limit of the staying time is not particularly limited, but a longer staying time leads to an increase in the size of the facility, and is preferably 10 seconds or less.
- the staying time is more preferably 3 seconds or more and 8 seconds or less.
- the length of the flow path is equal to the length of the side where the bottom plate 152d and the side plate 153d contact each other.
- the collision plate 15 e changes the moving direction of the ozone solution 11 after passing between the single fibers of the carbon fiber bundle 13 in a direction parallel to the conveying direction of the carbon fiber bundle 13.
- the shape and size of the collision plate 15e are not particularly limited as long as the surface of the collision plate 15e on which the ozone solution 11 collides is larger than the cross-sectional area of the fluid ejection port 15c.
- the carbon fiber bundle 13 is conveyed on the liquid surface of the ozone treatment tank 12 while passing through the flow path of the rectifying plate 15d.
- the ozone solution 11 ejected from the fluid ejection port 15c toward the carbon fiber bundle 13 reaches the carbon fiber bundle 13 through the hole 151d of the bottom plate 152d of the rectifying plate 15d and passes between the single fibers.
- the ozone solution 11 after passing between the single fibers naturally falls, flows through the flow path of the rectifying plate 15d, and is discharged from both ends of the rectifying plate 15d to the ozone treatment tank 12.
- the moving direction of the ozone solution 11 flowing through the flow path of the rectifying plate 15 d is parallel to the conveying direction of the carbon fiber bundle 13.
- the collision plate 15e is installed at a position opposite to the fluid jet port 15c with the carbon fiber bundle 13 interposed therebetween, the ozone solution 11 after passing between the single fibers of the carbon fiber bundle 13 is applied to the collision plate 15e. By colliding, the moving direction of the ozone solution 11 can be easily changed to a direction parallel to the conveying direction of the carbon fiber bundle 13.
- the fluid jet outlet The amount of ozone solution 11 ejected per unit time from 15c (hereinafter, simply referred to as “the amount of ozone solution ejected”) is the mass of the carbon fiber bundle passing per unit time over the fluid ejection port 15c. 40 times or more is preferable.
- a general carbon fiber has a density of 1.7 g / cm 3 or more and 1.9 g / cm 3 or less, and by supplying 40 equivalents of an ozone solution having a specific gravity of about 1.0 g / cm 3.
- the ejection amount of the ozone solution 11 is 40 times or more the mass of the carbon fiber bundle 13, it is considered that the ozone solution 11 can sufficiently contact the carbon fiber bundle.
- the upper limit of the ejection amount of the ozone solution 11 is not particularly limited. However, if the amount of the ozone solution 11 ejected from the fluid ejection port 15c is too large, the ejection speed increases and the ozone solution 11 comes into strong contact with the carbon fiber. Tends to occur, and the process passability tends to decrease.
- the ejection speed of the ozone solution 11 can be suppressed even if the ejection amount of the ozone solution 11 is increased, but increasing the ejection amount of the ozone solution 11 leads to an increase in production cost. Therefore, it is preferable that the upper limit value of the ejection amount of the ozone solution 11 is 300 times or less with respect to the mass of the carbon fiber bundle passing per unit time on the fluid ejection port 15c. In particular, when the ejection speed of the ozone solution 11 is 0.20 m / second or more and 2.0 m / second or less, it is preferable that the ejection amount of the ozone solution 11 be within the above range.
- the air resistance of the carbon fiber bundle 13 to be surface-treated is 100 seconds or more and 700. It is preferable that it is below second. If the air permeation resistance is 100 seconds or more, tow cracks are unlikely to occur and the convergence is easily maintained. On the other hand, if the air resistance is 700 seconds or less, the convergence is not too strong, and the ozone solution easily comes into contact with the inside of the carbon fiber bundle.
- the air permeability resistance is more preferably 100 seconds or more and 300 seconds or less.
- the air resistance of the carbon fiber bundle 13 is preferably such that the air resistance of the carbon fiber bundle 13 immediately before the ozone solution 11 comes into contact with at least the first ejection is within the above range, and the number of times of contact is 2 or more. In this case, it is more preferable that each air resistance of the carbon fiber bundle 13 immediately before the ozone solution 11 comes into contact with each ejection is within the above range.
- the air resistance refers to the air permeability test method for paper and paperboard measured according to JIS P 8117: 2009 (ISO 5636-5: 2003).
- a carbon fiber bundle is used instead of paper, and the air resistance is determined by measurement according to JIS P 8117: 2009.
- the water content of the carbon fiber bundle 13 to be surface-treated is preferably 40% or less. If the water content is 40% or less, the ozone solution 11 comes into contact with the surface of the single fiber more effectively and uniformly until the ozone solution 11 reaches the inside of the carbon fiber bundle 13, and the oxygen content on the surface is contained. The number of functional groups increases. Therefore, when the obtained carbon fiber is used as a composite material, the adhesion with the matrix resin is further improved.
- the moisture content of the carbon fiber bundle 13 is preferably at least within the above-mentioned range, so that the moisture content of the carbon fiber bundle 13 immediately before the ozone solution 11 comes into contact with the first ejection is more than twice. It is more preferable that each moisture content of the carbon fiber bundle 13 immediately before the ozone solution 11 comes into contact with the spray is within the above range.
- the moisture content of the carbon fiber bundle 13 just before the ozone solution 11 contacts by jetting is 0%. is there.
- the moisture content of the carbon fiber bundle 13 immediately after contact with the ozone solution 11 is 100%, when the number of times of contact is two or more, the moisture content of the carbon fiber bundle 13 is reduced as follows, for example. It is preferable. As shown in FIG. 7, an air blow 17 is installed between the two rectifying plates 15d, and air is blown from the air blow 17 to the carbon fiber bundle 13 that has passed through the flow path of the downstream rectifying plate 15d.
- the ozone solution 11 is removed from the carbon fiber bundle 13 until the moisture content is reached. Further, as shown in FIG. 8, a nip roll 18 is installed between the two rectifying plates 15d, and the carbon fiber bundle 13 that has passed through the flow path of the downstream rectifying plate 15d is sandwiched between the nip rolls 18 to obtain a desired moisture content. The ozone solution 11 is removed from the carbon fiber bundle 13 until. A flat roll may be used instead of the nip roll 18.
- the carbon fiber surface treatment method is not limited to the method using the surface treatment apparatuses 10, 20, and 30 shown in FIGS.
- the ejection direction F of the ozone solution 11 is orthogonal to the transport direction of the carbon fiber bundle 13, but it must be parallel to the transport direction of the carbon fiber bundle 13, that is, in parallel.
- the ejection direction F is not limited to the orthogonal direction.
- the orthogonal direction is particularly preferable in that the ozone solution easily passes between the single fibers of the carbon fiber bundle.
- the ejection direction of the ozone solution 11 is upward (ie, the direction from the lower side to the upper side of the carbon fiber bundle 13 in the horizontal state), but downward (ie, from the upper side to the lower side of the carbon fiber bundle 13). Direction to the side).
- the ozone solution 11 is ejected from the fluid ejection port 15c of the contact means 15.
- the ozone solution is naturally dropped from the upper side to the lower side of the carbon fiber bundle to contact the carbon fiber. You may let them.
- the fluid jet port 15c of the contact means 15 shown in FIGS. 1 to 8 is rectangular, the shape of the fluid jet port 15c is not particularly limited.
- the branch pipe 15b of the contact means 15 may not be long.
- the number of carbon fiber bundles 13 may be one, two, or three as shown in FIGS. 2, 5, and 6, or four or more.
- the method for producing carbon fiber of the present invention includes a surface treatment step for surface-treating the carbon fiber.
- Examples of the method for surface treating carbon fibers include the above-described surface treatment methods for carbon fibers.
- the carbon fiber to be surface-treated is obtained by firing a precursor fiber (precursor fiber) of carbon fiber.
- a precursor fiber precursor fiber
- the firing method for example, a method in which a carbon fiber precursor fiber bundle obtained by bundling carbon fiber precursor fibers is subjected to flame resistance treatment in a flame resistant furnace, and then pre-carbonization treatment and carbonization treatment in a carbonization furnace is used. it can.
- the precursor fiber include polyacrylonitrile fiber, pitch fiber, and rayon fiber, and polyacrylonitrile fiber is preferably used from the balance of cost and performance.
- the carbon fiber precursor fiber bundle is put into a flameproofing furnace and flameproofed.
- An oxidizing atmosphere of 200 to 300 ° C. circulates in the flameproofing furnace, and the carbon fiber precursor fiber bundle is flameproofed while being conveyed in the oxidizing atmosphere.
- the flow of the oxidizing atmosphere circulating in the flameproofing furnace may be in a parallel direction or a vertical direction with respect to the fiber to be processed, and is not particularly limited.
- known oxidizing atmospheres such as air, oxygen and nitrogen dioxide can be adopted, but air is preferable from the viewpoint of economy.
- the time required for flameproofing the carbon fiber precursor fiber bundle is preferably 30 to 100 minutes and more preferably 45 to 80 minutes from the viewpoint of improving the productivity and performance of the carbon fibers. If the time required for the flameproofing treatment is less than 30 minutes, the flameproofing reaction may be insufficient or it may be easily spotted, resulting in fuzz and bundle breakage in the subsequent carbonization process, resulting in productivity. May decrease. On the other hand, if the time required for the flameproofing treatment exceeds 100 minutes, it is necessary to increase the size of the flameproofing device or to reduce the flameproofing processing speed, resulting in a reduction in productivity.
- the carbon fiber subjected to the flame resistance treatment is put into a first carbonization furnace and pre-carbonization treatment is performed.
- An inert atmosphere having a temperature of 300 to 800 ° C. circulates in the first carbonization furnace, and the carbon fiber subjected to flame resistance treatment is pre-carbonized while being conveyed in the inert atmosphere.
- the flow of the inert atmosphere which circulates in the 1st carbonization furnace may be a parallel direction with respect to the to-be-processed fiber conveyed, or a perpendicular direction, and is not specifically limited.
- a known inert atmosphere such as nitrogen, argon, or helium can be adopted, but nitrogen is desirable from the viewpoint of economy.
- the carbon fiber that has been pre-carbonized is put into a second carbonization furnace and carbonized.
- An inert atmosphere having a maximum temperature of 1000 to 2500 ° C. circulates in the second carbonization furnace, and the carbon fiber subjected to the pre-carbonization treatment is carbonized while being conveyed in the inert atmosphere. Is done.
- the flow of the inert atmosphere which circulates in the 2nd carbonization furnace may be a parallel direction with respect to the to-be-processed fiber conveyed, or a perpendicular direction, and is not specifically limited.
- the inert atmosphere can be selected from the known inert atmospheres exemplified above, but nitrogen is desirable from the viewpoint of economy.
- the carbon fiber thus obtained is surface-treated by the above-described carbon fiber surface treatment method.
- the surface-treated carbon fiber may be sized with a sizing agent as necessary.
- the type of the sizing agent is not particularly limited as long as desired characteristics can be obtained, and examples thereof include a sizing agent mainly composed of an epoxy resin, a polyether resin, an epoxy-modified polyurethane resin, and a polyester resin. A known method can be used as the sizing method.
- the carbon fiber manufacturing method causes the ozone solution to be ejected from the fluid ejection port toward the carbon fiber bundle, and the ozone solution is allowed to pass between the single fibers of the carbon fiber bundle so that the surface of the single fiber is obtained. It has the surface treatment process which surface-treats carbon fiber with an ozone solution by making it contact. Accordingly, the ozone solution is easily diffused into the carbon fiber bundle. When the ozone solution diffuses into the carbon fiber bundle, the number of oxygen-containing functional groups on the surface of the carbon fiber increases, so that a carbon fiber excellent in adhesiveness to the matrix resin can be obtained.
- the surface-treated carbon fiber obtained by the carbon fiber production method of the present invention has an ipa value measured by a cyclic voltammetry method of 0.10 ⁇ A / cm 2 or more, and 0.12 ⁇ A / cm 2 or more. preferable.
- the ipa value is an index of the surface property of the carbon fiber bundle, and the higher the ipa value, the more surface treatment is performed. If the ipa value is 0.10 ⁇ A / cm 2 or more, it means that the surface treatment (oxidation) has been sufficiently performed, and when used as a composite material, the adhesion to the matrix resin is good, and sufficient bending strength is obtained. A composite material having is obtained.
- the upper limit value of the ipa value is not particularly limited.
- the carbon fiber of the present invention is combined with a matrix resin, molded as a composite material, and used for various applications.
- matrix resin for example, an epoxy resin, a polyimide resin, a polycarbonate resin, the acrylic resin which is a radical polymerization type resin, a vinyl ester resin, an unsaturated polyester resin, a thermoplastic acrylic resin, a phenol resin etc. are mentioned, for example.
- the application of the composite material using the carbon fiber of the present invention is not particularly limited, and can be used for a wide range of applications such as aerospace materials, sports and leisure materials, and industrial materials such as pressure vessels.
- ⁇ Measurement and evaluation method> (Measurement of jet velocity) The ejection speed of the ozone solution was obtained by collecting the amount of water per minute ejected from the fluid ejection port, obtaining its mass, and dividing the mass by the cross-sectional area of the fluid ejection port.
- the air resistance of the carbon fiber bundle was measured as follows. First, a carbon fiber bundle immediately before contacting with an ozone solution is collected by ejection from a fluid outlet located at the most downstream side, and paper and paperboard are measured according to JIS P 8117: 2009 (ISO 5636-5: 2003). Referring to the air permeability test method, the air resistance was determined using a carbon fiber bundle instead of paper.
- the strand strength and strand elastic modulus of the surface-treated carbon fiber were determined by measuring the tensile properties of the epoxy resin-impregnated strand according to ASTM D4018.
- the ipa value of the surface-treated carbon fiber was determined by the cyclic voltammetry method as follows.
- an analyzer (“HZ-3000 AUTOMATIC POLARIZATION SYSTEM” manufactured by Hokuto Denko Co., Ltd.) composed of a potentiostat and a function generator was used.
- a 5 mass% phosphoric acid aqueous solution was used to adjust the pH to 3, and a solution in which dissolved oxygen was removed by bubbling nitrogen was prepared.
- An Ag / AgCl electrode as a reference electrode, a platinum electrode having a sufficient surface area as a counter electrode, and a surface-treated carbon fiber as a working electrode are inserted into this solution, and the carbon fiber current and electrode are analyzed using the above analyzer.
- the potential was measured.
- the potential operation range was -0.2 to 0.8 V, and the potential operation speed was 2 mV / sec. Draw a potential-current curve with an XY recorder and sweep it three or more times.
- sample length is the length in the longitudinal direction of the carbon fiber used for the working electrode
- weight per unit is the weight per unit length of the carbon fiber used for the working electrode. That is.
- ipa value [ ⁇ A / cm 2 ] current value [ ⁇ A] / sample length [cm] ⁇ ⁇ 4 ⁇ ⁇ weight per unit area [g / cm] ⁇ number of single fibers / density [g / cm 3 ] ⁇ 1/2. 1)
- a fiber reinforced plastic plate (thickness of plate) having a carbon fiber content of 60% by using surface-treated carbon fibers and an epoxy resin (“# 350” manufactured by Mitsubishi Rayon Co., Ltd.) as a matrix resin. : 2 mm).
- vertical direction with respect to a fiber direction was measured by the 3 point
- Example 1 An acrylic fiber having a single fiber fineness of 1.2 dtex and a single fiber number of 12,000 is subjected to a heat treatment (flame resistance treatment) at an elongation rate of -6.0% and a temperature of 220 ° C. to 260 ° C. until completion of the flame resistance. Flame resistant fibers were obtained. This flameproof fiber is pre-carbonized in a nitrogen atmosphere at 700 ° C. with an elongation of + 3%, and subsequently carbonized in a nitrogen atmosphere of 1250 ° C. with an elongation of ⁇ 4.2%, thereby obtaining an untreated carbon fiber. It was. The obtained untreated carbon fiber was surface-treated as follows using the surface treatment apparatus 10 shown in FIG.
- the ozone solution 11 is prepared by aeration of ozone gas generated from an ozone generator (manufactured by Sumitomo Precision Industries, Ltd.) into pure water and adjusting the ozone concentration in the pure water to 30 mg / L. It was prepared by dissolving in pure water. The ozone concentration was measured using an ozone concentration sensor (dissolved ozone measurement type).
- the carbon fiber bundle 13 is immersed in the ozone treatment tank 12 filled with the ozone solution 11 having an ozone concentration of 30 mg / L via the first free roll 14a, and the inside of the ozone treatment tank 12 is being conveyed at a conveyance speed of 3 m / min.
- the ozone solution 11 was ejected from the fluid ejection port 15 c of the contact means 15 toward the carbon fiber bundle 13, and the ozone solution 11 was passed between the single fibers of the carbon fiber bundle 13 to contact the single fiber surface.
- the moving direction F of the ozone solution 11 was orthogonal to the conveying direction of the carbon fiber bundle 13 and upward.
- the ozone solution 11 is ejected from the fluid ejection port 15c toward the carbon fiber bundle 13 and brought into contact with the surface of the single fiber (number of times of contact) four times, the ejection speed of the ozone solution 11 is 0.42 m / second, ozone
- the tension per 12,000 single fibers of the carbon fiber bundle 13 is 0.4 kg, and the ozone with respect to the mass of the carbon fiber bundle 13 passing per unit time on the fluid jet port 15c.
- the ejection amount per unit time of the solution 11 was 208 times, and the time (holding time) for holding the carbon fiber bundle 13 in the ozone solution 11 was 45 seconds.
- the distance from the fluid jet port 15c to the carbon fiber bundle 13 was set to 5 cm.
- the holding time in the case of surface-treating the carbon fiber bundle 13 using the surface treatment apparatus 10 shown in FIG. 1 is the time during which the carbon fiber bundle 13 is conveyed in the ozone solution 11 in the ozone treatment tank 12. It is.
- the carbon fiber bundle 13 is guided out of the ozone treatment tank 12 by the second free roll 14b, it is dried at 150 ° C. for 0.5 minutes to remove the ozone solution adhering to the surface of the carbon fiber, and further sizing Treatment was performed to obtain a surface-treated carbon fiber.
- the moisture content and air resistance of the carbon fiber bundle immediately before the ozone solution was contacted by the first ejection were measured.
- the strand strength, strand elastic modulus, and ipa value of the surface-treated carbon fiber were measured to evaluate the adhesion.
- Examples 2 and 3 Except for changing the tension per 12,000 single fibers as shown in Table 1, surface treatment of carbon fibers was performed in the same manner as in Example 1, and various measurements and evaluations were performed. The results are shown in Table 1.
- Acrylic fibers having a single fiber fineness of 1.0 dtex and a single fiber number of 60000 were subjected to a heat treatment (flame-proofing treatment) at an elongation rate of -6.0% and a temperature of 220 to 260 ° C. Flame resistant fibers were obtained.
- This flameproofed fiber is pre-carbonized in a nitrogen atmosphere at 700 ° C. with an elongation of + 3%, and then carbonized in a nitrogen atmosphere of 1350 ° C. with an elongation of ⁇ 4.2% to obtain an untreated carbon fiber. It was.
- Example 5 Various measurements and evaluations were performed in the same manner as in Example 1 except that the surface treatment apparatus 30 shown in FIG. 4 was used instead of the surface treatment apparatus 10 shown in FIG. The results are shown in Table 1.
- Carbon is used by using the first free roll 14a and the second free roll 14b so that the carbon fiber bundle 13 is conveyed on the liquid surface of the ozone treatment tank 12 in which the ozone solution 11 having an ozone concentration of 30 mg / L is stored.
- the fiber bundle 13 was passed through the flow path of the rectifying plate 15d.
- the ozone solution 11 was ejected from the fluid ejection port 15c of the contact means 15 toward the carbon fiber bundle 13 being conveyed (passing) through the flow path of the rectifying plate 15d at a conveyance speed of 8 m / min.
- the ejected ozone solution 11 reached the carbon fiber bundle 13 through the hole 151d of the bottom plate 152d of the rectifying plate 15d, and passed between the single fibers to contact the surface of the single fibers. Further, the ozone solution 11 after passing between the single fibers collides with the collision plate 15 e, changes the moving direction of the ozone solution 11 to a direction parallel to the conveying direction of the carbon fiber bundle 13, and comes into contact with the carbon fiber bundle 13. While flowing through the flow path of the rectifying plate 15d, it was discharged from both ends of the rectifying plate 15d to the ozone treatment tank 12.
- the moving direction F of the ozone solution 11 is orthogonal to the conveying direction of the carbon fiber bundle 13 and upward, and the moving direction F of the ozone solution 11 flowing through the flow path of the rectifying plate 15d is the conveying direction of the carbon fiber bundle 13.
- the moving direction F of the ozone solution 11 flowing through the flow path from the downstream end of the rectifying plate 15d to the hole 151d is the opposite direction to the conveying direction of the carbon fiber bundle 13, and the upstream side of the rectifying plate 15d from the hole 151d
- the moving direction F of the ozone solution 11 flowing through the flow path to the end is the same as the conveying direction of the carbon fiber bundle 13.
- the ozone solution 11 is ejected from the fluid ejection port 15c toward the carbon fiber bundle 13 and brought into contact with the surface of the single fiber (number of times of contact) four times, the ejection speed of the ozone solution 11 is 0.42 m / second, ozone
- the tension per 12,000 single fibers of the carbon fiber bundle 13 is 0.4 kg, and the ozone with respect to the mass of the carbon fiber bundle 13 passing per unit time on the fluid jet port 15c.
- the ejection amount per unit time of the solution 11 was 78 times, and the time (holding time) for holding the carbon fiber bundle 13 in the ozone solution 11 was 2.3 seconds.
- the holding time when the carbon fiber bundle 13 is surface-treated using the surface treatment apparatus 30 shown in FIG. 4 is the total time for the carbon fiber bundle 13 to pass through the flow paths of the four rectifying plates 15d.
- Example 6> In place of the surface treatment device 30 shown in FIG. 4, the surface treatment device 30 shown in FIG. 7 is used, and the ozone solution 11 is ejected from the fluid ejection port 15 c toward the carbon fiber bundle 13 to be brought into contact with the single fiber surface ( The number of times of contact) is twice, the amount of the ozone solution 11 ejected per unit time is 40 times the mass of the carbon fiber bundle 13 passing per unit time on the fluid ejection port 15c, and the carbon fiber bundle 13 is held in the ozone solution 11.
- the time (holding time) is 1.2 seconds, and two rectifications are made until the carbon fiber bundle 13 that has passed through the flow path of the downstream rectifying plate 15d moves to the flow path of the upstream rectifying plate 15d.
- Carbon was applied in the same manner as in Example 5 except that air was blown from the air blow 17 installed between the plates 15d to the carbon fiber bundle 13 at a flow rate of 150 L / min to remove the ozone solution 11 from the carbon fiber bundle 13.
- Fiber Surface treatment was carried out. About the obtained carbon fiber, it carried out similarly to Example 1, and performed various measurement and evaluation. The results are shown in Table 1.
- the holding time in the case of surface-treating the carbon fiber bundle 13 using the surface treatment apparatus 30 shown in FIG. 7 is the total time for the carbon fiber bundle 13 to pass through the flow paths of the two rectifying plates 15d.
- Example 7 In place of the surface treatment device 30 shown in FIG. 4, the surface treatment device 30 shown in FIG. 8 is used, and the ozone solution 11 is ejected from the fluid ejection port 15 c toward the carbon fiber bundle 13 to be brought into contact with the single fiber surface ( The number of times of contact) is twice, the amount of the ozone solution 11 ejected per unit time is 40 times the mass of the carbon fiber bundle 13 passing per unit time on the fluid ejection port 15c, and the carbon fiber bundle 13 is held in the ozone solution 11.
- the time (holding time) is 1.2 seconds, and two rectifications are made until the carbon fiber bundle 13 that has passed through the flow path of the downstream rectifying plate 15d moves to the flow path of the upstream rectifying plate 15d.
- Carbon was obtained in the same manner as in Example 6 except that the carbon fiber bundle 13 was sandwiched with a nip roll 18 having a diameter of 100 mm installed between the plates 15d at a pressure of 0.2 MPa, and the ozone solution 11 was removed from the carbon fiber bundle 13. It was subjected to a surface treatment of Wei. About the obtained carbon fiber, it carried out similarly to Example 1, and performed various measurement and evaluation. The results are shown in Table 1.
- the holding time in the case of surface-treating the carbon fiber bundle 13 using the surface treatment apparatus 30 shown in FIG. 8 is the total time for the carbon fiber bundle 13 to pass through the flow paths of the two rectifying plates 15d.
- Example 1 Using untreated carbon fiber as the anode, electrolytic oxidation treatment was performed at 30 coulomb / g in an 8% by mass nitric acid aqueous solution. Next, the aqueous nitric acid solution was removed by washing with pure water, dried at 400 ° C. for 0.5 minutes, and then subjected to sizing treatment to obtain a surface-treated carbon fiber. Various measurements and evaluations were performed on the surface-treated carbon fibers in the same manner as in Example 1. The results are shown in Table 1.
- This flameproof fiber is pre-carbonized in a nitrogen atmosphere at 700 ° C. with an elongation of + 3%, and subsequently carbonized in a nitrogen atmosphere of 1250 ° C. with an elongation of ⁇ 4.2%, thereby obtaining an untreated carbon fiber. It was.
- the carbon fiber was subjected to a surface treatment in the same manner as in Comparative Example 1 except that the obtained untreated carbon fiber was used. About the obtained carbon fiber, it carried out similarly to Example 1, and performed various measurement and evaluation. The results are shown in Table 1.
- Example 5 obtained ipa value and bending strength comparable to the carbon fiber surface-treated in Example 1. From this result, it was shown that if the current plate is installed, the surface treatment can be sufficiently performed even under the condition that the treatment speed (that is, the conveyance speed of the carbon fiber bundle) is increased and the productivity is increased.
- the treatment speed that is, the conveyance speed of the carbon fiber bundle
- Example 6 the carbon fiber bundle immediately after passing through the air blow was sampled and the moisture content and the air resistance were measured. The water content was 35%, and the air resistance was 410 seconds. there were.
- Example 7 the carbon fiber bundle immediately after passing through the nip roll was collected and the moisture content and the air resistance were measured. The water content was 20% and the air resistance was 310 seconds. It was. In this way, before the ozone solution is brought into contact with the carbon fiber bundle by the second ejection, the excess ozone solution is removed from the carbon fiber bundle using an air blow or a nip roll, so that the number of times of contact is four. The same surface treatment effect as in Example 5 was obtained. From this result, it was shown that the surface treatment of the carbon fiber can be efficiently performed by controlling the water content and the air resistance of the carbon fiber bundle to be surface-treated.
- the carbon fibers of Comparative Examples 1 and 2 subjected to surface treatment by contacting an ozone solution moving in a direction parallel to the conveying direction of the carbon fiber bundle with the carbon fibers have an ipa value as compared with Examples 1 to 7. It was low. Moreover, bending strength was low and it was inferior to adhesiveness with matrix resin. This is probably because the surface treatment was insufficient because the ozone solution was difficult to diffuse into the carbon fiber bundle 13.
- Reference Example 2 is an example in which an ozone solution moving in a direction parallel to the conveying direction of the carbon fiber bundle was brought into contact with the carbon fiber and surface-treated. However, since the number of single fibers is as small as 6000, it is a comparative example.
- the method of surface treatment by contacting the carbon solution with an ozone solution that moves in a direction parallel to the conveying direction of the carbon fiber bundle has 10,000 single fibers. It is not suitable for surface treatment of more than one carbon fiber bundle.
- the present invention can obtain the same surface treatment effect as the surface treatment by the conventional electrolytic oxidation method (Reference Example 1). Therefore, if it is this invention, since the carbon fiber excellent in adhesiveness with a matrix resin can be obtained and a washing
- the present invention is particularly suitable for surface treatment of a carbon fiber bundle having a large number of single fibers (specifically, the number of single fibers is 10,000 or more).
- Examples 8 to 18> Using the surface treatment apparatus 20 shown in FIG. 3, the ozone treatment tank 12 is not filled with the ozone solution 11, the carbon fiber bundle 13 is not immersed in the ozone solution 11, and the ozone concentration and the surface-treated carbon fiber bundle are treated. Number of single fibers, transport speed of carbon fiber bundles, number of contacts (ie, number of branch pipes 15b), jet speed of ozone solution 11, tension per 12,000 single fibers, passing over fluid jet 15c per unit time Except that the amount of ejection per unit time of the ozone solution 11 with respect to the mass of the carbon fiber bundle 13 to be performed and the condition of the time (holding time) for holding the carbon fiber bundle 13 in the ozone solution 11 were changed as shown in Table 2.
- the surface treatment of the carbon fiber was performed in the same manner as in Example 1, and the ipa value was measured. The results are shown in Table 2.
- the contact time of the carbon fiber bundle 13 with the ozone solution 11 is ejected from the fluid ejection port 15c of each branch pipe 15b. This is the total time for which the ozone solution 11 is in contact with the carbon fiber bundle 13.
- each carbon fiber surface-treated in Examples 8 to 18 without immersing the carbon fiber in an ozone solution was each carbon fiber surface-treated in Comparative Examples 1 and 2, The ipa value was increased as compared with the untreated carbon fiber (Comparative Example 3). This means that the carbon fiber has been sufficiently surface treated.
- the carbon fiber bundle immediately before contact with the ozone solution was collected by jetting from the fluid jet port located on the most downstream side, and the moisture content and air permeability resistance were measured. The water content was 0% and the air resistance was 200 seconds.
- a carbon fiber excellent in adhesiveness with a matrix resin can be obtained. Moreover, the carbon fiber of this invention is excellent in adhesiveness with a matrix resin.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Inorganic Chemistry (AREA)
- Organic Chemistry (AREA)
- Dispersion Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
- Inorganic Fibers (AREA)
Abstract
Description
本願は、2011年08月02日に、日本に出願された特願2011-169273号、に基づき優先権を主張し、その内容をここに援用する。
一般に、炭素繊維は、ポリアクリロニトリル系繊維などの炭素繊維の前駆体繊維(プレカーサー繊維)を束ねた炭素繊維前駆体繊維束を焼成して製造される。具体的には、炭素繊維前駆体繊維束を酸化性雰囲気で満たした耐炎化炉で加熱処理(耐炎化処理)して耐炎化繊維束を得た後、得られた耐炎化繊維束を窒素などの不活性雰囲気で満たした炭素化炉で加熱処理(前炭素化処理および炭素化処理)することによって炭素繊維を得る。
炭素繊維は、通常、そのままでは利用されず、マトリックス樹脂との組み合わせによる複合材料として成型され、様々な用途に利用される。
このため、通常、不活性雰囲気中で加熱処理した後の炭素繊維には炭素繊維の表面を改質するための表面処理が施され、更にはサイジング処理が施されることによりマトリックス樹脂との濡れ性、親和性、接着性を向上させている。
これらの酸化処理の中でも、特に電解酸化処理は、その処理のしやすさ、処理条件制御の容易さ、炭素繊維表面への酸素含有官能基の導入のしやすさなどの見地から、薬液酸化処理や気相酸化処理よりも実用的、かつ効果的な表面処理方法である。
また、洗浄後の炭素繊維を乾燥させる際には、洗浄しきれずに残存する電解液を考慮して、電解液に用いる溶剤の沸点と同程度、あるいは沸点よりも高温にて乾燥させる必要があった。電解液には、通常、硫酸や硝酸などが用いられているので、これらの沸点と同程度の温度に設定できる高温の乾燥機が必要であり、製造コストが増加しやすかった。
さらに、電解酸化処理に用いた電解液をそのまま排水すると環境に負荷がかかるため、排水するには環境に負荷がかからないように中和処理などの廃液処理を行う必要があり、生産性が低下し、製造コストが増加しやすかった。電解酸化処理後の炭素繊維を洗浄した洗浄廃液には電解液が含まれているので、該洗浄廃液を排水する場合も同様である。
(1) オゾンが溶媒に溶存したオゾン溶液を、流体噴出口から炭素繊維束に向かって噴出させ、前記オゾン溶液を炭素繊維束の単繊維間に通過させて単繊維表面に接触させることにより、炭素繊維をオゾン溶液で表面処理する表面処理工程を有する、炭素繊維の製造方法。
(2) 前記オゾン溶液が単繊維表面に接触する際の炭素繊維束の張力が、単繊維数12000本当たり0.3kg以上1.8kg以下である、前記(1)に記載の炭素繊維の製造方法。
(3) 前記炭素繊維束をオゾン溶液中に0.1秒以上60秒以下保持する、前記(1)または(2)に記載の炭素繊維の製造方法。
(4) 搬送される炭素繊維束の搬送方向に対して交差する方向にオゾン溶液を噴出させ、かつ、オゾン溶液の単位時間当たりの噴出量を流体噴出口上または流体噴出口下を単位時間当たりに通過する炭素繊維束の質量に対して40倍以上300倍以下とし、オゾン溶液の噴出速度を0.20m/秒以上2.0m/秒以下とする、前記(1)~(3)のいずれか一項に記載の炭素繊維の製造方法。
(5) 前記流体噴出口から炭素繊維束に向かってオゾン溶液を噴出させて単繊維表面に接触させる回数を1回以上4回以下とする、前記(1)~(4)のいずれか一項に記載の炭素繊維の製造方法。
(6) 前記流体噴出口の形状が矩形であり、該流体噴出口の長手方向が炭素繊維束の幅方向であり、かつ流体噴出口の長手方向の長さが炭素繊維束の幅以上である、前記(1)~(5)のいずれか一項に記載の炭素繊維の製造方法。
(7) オゾン溶液が貯留されているオゾン処理槽の液面上を搬送される炭素繊維束を挟んで前記流体噴出口と対向する位置に衝突板を設置し、流体噴出口から噴出させたオゾン溶液を炭素繊維束の単繊維間に通過させた後に、衝突板に衝突させる、前記(1)~(6)のいずれか一項に記載の炭素繊維の製造方法。
(8) JIS P 8117:2009に準じて測定される透気抵抗度が100秒以上700秒以下であり、かつオゾン溶液が貯留されているオゾン処理槽の液面上を搬送される炭素繊維束に前記表面処理を施す、前記(1)~(7)のいずれか一項に記載の炭素繊維の製造方法。
(9) 含水率が40%以下であり、かつオゾン溶液が貯留されているオゾン処理槽の液面上を搬送される炭素繊維束に前記表面処理を施す、前記(1)~(8)のいずれか一項に記載の炭素繊維の製造方法。
(10) オゾン溶液中を搬送される前記炭素繊維束に前記表面処理を施す、前記(1)~(6)のいずれか一項に記載の炭素繊維の製造方法。
(11) 前記オゾン溶液のオゾン濃度が10mg/L以上120mg/L以下である、前記(1)~(10)のいずれか一項に記載の炭素繊維の製造方法。
(12) 前記炭素繊維束の単繊維数が10000本以上60000本以下である、前記(1)~(11)のいずれか一項に記載の炭素繊維の製造方法。
(13) サイクリックボルタンメトリー法により測定される、単位面積当たりに流れる電流値(ipa値)が0.10μA/cm2以上である炭素繊維を得る、前記(1)~(12)のいずれか一項に記載の炭素繊維の製造方法。
(14) 前記(1)~(13)のいずれか一項に記載の炭素繊維の製造方法により得られた、表面処理された炭素繊維であって、サイクリックボルタンメトリー法により測定される、単位面積当たりに流れる電流値(ipa値)が0.10μA/cm2以上である、炭素繊維。
また、本発明の炭素繊維は、マトリックス樹脂との接着性に優れる。
本発明の炭素繊維の製造方法は、オゾンが溶媒に溶存したオゾン溶液を、流体噴出口から炭素繊維束に向かって噴出させ、前記オゾン溶液を炭素繊維束の単繊維間に通過させて単繊維表面に接触させることにより、炭素繊維をオゾン溶液で表面処理する表面処理工程を有する。
オゾン溶液は、静止している炭素繊維束に向かって噴出させてもよいし、搬送される炭素繊維束に向かって噴出させてもよいが、均一にオゾン溶液を噴出できる観点から、搬送される炭素繊維束に向かって噴出させることが好ましい。
以下、搬送される炭素繊維束に向かってオゾン溶液を噴出させる場合を例に挙げて、炭素繊維をオゾン溶液で表面処理する方法(炭素繊維の表面処理方法)の一例について、図1、2を参照しながら説明する。なお、後述の図3~8において、図1、2と同じ構成要素には同じ符号を付して、その説明を省略する。
図1は、炭素繊維の表面を処理する表面処理装置の一例を模式的に示す正面図であり、図2は図1に示す表面処理装置の平面図である。この例の表面処理装置10は、オゾン溶液11を貯留するオゾン処理槽12と、搬送される炭素繊維束13をオゾン処理槽12の中に導く第1のフリーロール14aと、炭素繊維束13をオゾン処理槽12の外に導く第2のフリーロール14bと、オゾン溶液11を炭素繊維束13に接触させる接触手段15と、オゾン溶液11を循環させる循環ポンプ16とを具備して構成される。
なお、図2においてオゾン溶液11および循環ポンプ16と、後述するパイプ15aと吸引パイプ16aは省略する。
オゾンを溶解させる溶媒としては、水、液相酸化に使用される溶液などが挙げられるが、中でも水が好ましく、特に蒸留水や脱イオン水などの不純物質を少なくした純水が好ましい。
オゾン発生器やオゾンガス溶解装置としては、市販のものを用いることができる。
第1のフリーロール14aは、搬送される炭素繊維束13をオゾン処理槽12の中に導くものである。
第2のフリーロール14bは、オゾン溶液11の接触により表面処理された炭素繊維束13をオゾン処理槽12の外に導くものである。
パイプ15aは、その長手方向が炭素繊維束13の搬送方向と平行になるように配置され、かつ、一端が循環ポンプ16に接続され、循環ポンプ16によりオゾン溶液11が供給される。
流体噴出口の長手方向の長さは、炭素繊維束の幅以上であることが好ましい。
ついで、オゾン溶液11の接触により表面処理された炭素繊維束13を第2のフリーロール14bによってオゾン処理槽12のオゾン溶液11外に導く。
なお、本発明においてオゾン溶液の移動方向とは、流体噴出口から噴出したオゾン溶液または自然落下したオゾン溶液が流れる方向のことである。
オゾン濃度は、オゾンガス濃度やオゾン溶液温度などによって調整できる。例えば、オゾンガスの濃度を高くしたり、オゾン溶液温度を低くしたりすれば、オゾン濃度は高くなる傾向にある。
なお、本発明において接触回数とは、炭素繊維束13の任意の箇所においてオゾン溶液を噴出させて、オゾン溶液を単繊維間に通過させる回数のことであり、図1に示す表面処理装置10を用いる場合、接触回数は4回である。すなわち、分岐管15bの数と接触回数は等しい。
オゾン溶液11の噴出速度は、循環ポンプ16のポンプ圧などを調節することで制御できる。
炭素繊維束の単繊維数を上記範囲内とする方法としては特に制限されないが、例えばトウボリュームの多い前駆体繊維を出発物質として用いる方法、トウボリュームの少ない前駆体繊維を複数、焼成工程の途中で合糸する方法などが挙げられる。
電位操作範囲は-0.2~0.8Vとし、電位操作速度は2mV/secとし、X-Yリコーダーにより電位-電流曲線を描き、3回以上掃引させ、曲線が安定した段階で、Ag/AgCl電極に対して、+0.4Vでの電位を標準にとって電流を読み取り、下記式(1)に従ってipa値を算出する。なお、式(1)において、「試料長」とは作動電極に用いた炭素繊維の長手方向の長さであり、「目付」とは作動電極に用いた炭素繊維の単位長さ当たりの重さのことである。
ipa値[μA/cm2]=電流値[μA]/試料長[cm]×{4π×目付[g/cm]×単繊維数/密度[g/cm3] }1/2 ・・・(1)
さらに、上述した炭素繊維の表面処理方法では洗浄工程を設ける必要がないので、洗浄工程で生じる洗浄廃液を排水する必要もない。さらに、表面処理に用いたオゾン溶液を排水する場合には、貯留槽があれば数時間放置するだけで無害なレベルまでオゾン濃度が低下する。貯留槽が無い場合には、オゾン溶液を活性炭処理などしてオゾンを活性炭に吸収させる程度の簡便な操作を行えばよい。従って、表面処理にオゾン溶液を用いることで、排水の際に環境への負荷を低減するのと共に、中和処理に比べて排水の手間がかかりにくいので生産性が向上して、製造コストの増加を抑制できる。
また、上述した炭素繊維の表面処理方法によれば、サイクリックボルタンメトリー法により測定されるipa値が0.10μA/cm2以上である炭素繊維が容易に得られる。
なお、炭素繊維の表面処理方法は、上述した方法に限定されない。例えば上述した方法では、図1に示すようにオゾン処理槽12がオゾン溶液11で満たされているが、例えば図3に示す表面処理装置20のようにオゾン処理槽12はオゾン溶液11で満たされていなくてもよい。すなわち、図1では炭素繊維束13をオゾン溶液11に浸漬させた状態でオゾン溶液11を炭素繊維束13に向かって噴出させているが、炭素繊維束13に向かってオゾン溶液11を噴出させ、該オゾン溶液11を炭素繊維束13の単繊維間に通過させて単繊維表面に接触させれば、図3に示すように炭素繊維束13をオゾン溶液11に浸漬させずにオゾン溶液11に接触させる(すなわち、オゾン処理槽12の液面上を搬送される炭素繊維束13に表面処理を施す)方が、より短時間で表面処理がなされる。かかる理由は以下の通りである。
ここで、図4、7、8は炭素繊維の表面を処理する表面処理装置の他の例を模式的に示す正面式図であり、図5は図4に示す表面処理装置の平面図であり、図6は図4に示す表面処理装置の部分斜視図である。
なお、図5においてオゾン溶液11、パイプ15a、循環ポンプ16、および吸引パイプ16aは省略する。また図6においてオゾン処理槽12、第1のフリーロール14a、第2のフリーロール14b、パイプ15a、衝突板15e、循環ポンプ16、および吸引パイプ16aは省略する。
流体噴出口15cから炭素繊維束13に向かってオゾン溶液11を噴出させて単繊維表面に接触させる回数(接触回数)は、図4が4回であり、図7、8が2回である。
なお、本発明においては、底板152dと側板153dとで流路を形成している整流板15dを「流路を有する整流板」ともいう。
また、流路の長さは、炭素繊維束13の搬送速度に応じて適宜設定されるが、具体的には、オゾン溶液11が流路内に滞在する時間(滞在時間)が1秒以上となるように、流路の長さを調節するのが好ましい。滞在時間が1秒以上であれば、炭素繊維束13との保持時間を十分に確保できるので、表面処理された複合材料として使用した際に、マトリックス樹脂との接着性がより向上する。滞在時間の上限は特に制限されないが、滞在時間が長くなることは設備の大型化に繋がるため、10秒以下が好ましい。滞在時間は3秒以上8秒以下がより好ましい。
なお、流路の長さは、底板152dと側板153dとが互いに接する辺の長さと等しい。
衝突板15eの形状や大きさについては、衝突板15eのオゾン溶液11が衝突する面が、流体噴出口15cの断面積よりも大きければ、特に制限されない。
また、衝突板15eが、炭素繊維束13を挟んで流体噴出口15cの対向する位置に設置されているので、炭素繊維束13の単繊維間を通過した後のオゾン溶液11を衝突板15eに衝突させて、オゾン溶液11の移動方向を炭素繊維束13の搬送方向に対して平行方向に容易に変えることができる。
例えば、一般的な炭素繊維の密度は1.7g/cm3以上1.9g/cm3以下であり、これに対し、比重約1.0g/cm3のオゾン溶液を40等量供給することで、流体噴出口上を通過する炭素繊維束に対し約100倍の体積を有するオゾン溶液が供給される計算となる。よって、オゾン溶液11の噴出量が炭素繊維束13の質量の40倍以上であれば、オゾン溶液11が炭素繊維束に十分に接触できると考えられる。オゾン溶液11の噴出量の上限は特に制限されないが、流体噴出口15cから噴出するオゾン溶液11の量が多すぎると、噴出速度が速くなり、炭素繊維にオゾン溶液11が強く接触するため、毛羽立ちが発生しやすくなり、工程通過性が低下する傾向にある。流体噴出口15cの形状を変更することにより、オゾン溶液11の噴出量を増加させても噴出速度を抑えることはできるが、オゾン溶液11の噴出量を増やすことは生産コストの増加に繋がる。従って、オゾン溶液11の噴出量の上限値は、流体噴出口15c上を単位時間当たりに通過する炭素繊維束の質量に対して300倍以下とすることが好ましい。特に、オゾン溶液11の噴出速度が0.20m/秒以上2.0m/秒以下である場合、オゾン溶液11の噴出量を上記範囲内とすることが好ましい。
炭素繊維束13の透気抵抗度は、少なくとも最初の噴出によりオゾン溶液11が接触する直前の炭素繊維束13の透気抵抗度が上記範囲内であることが好ましく、接触回数が2回以上の場合は各回の噴出によりオゾン溶液11が接触する直前の炭素繊維束13の各透気抵抗度が上記範囲内であることがより好ましい。
炭素繊維束13の含水率は、少なくとも最初の噴出によりオゾン溶液11が接触する直前の炭素繊維束13の含水率が上記範囲内であることが好ましく、接触回数が2回以上の場合は各回の噴出によりオゾン溶液11が接触する直前の炭素繊維束13の各含水率が上記範囲内であることがより好ましい。
また、オゾン溶液11が接触した直後の炭素繊維束13の含水率は100%となるため、接触回数が2回以上の場合は、例えば以下のようにして炭素繊維束13の含水率を低下させることが好ましい。
図7に示すように、2つの整流板15dの間にエアーブロー17を設置し、下流側の整流板15dの流路を通過した炭素繊維束13にエアーブロー17からエアーを吹き付けて、所望の含水率になるまで炭素繊維束13からオゾン溶液11を取り除く。
また、図8に示すように、2つの整流板15dの間にニップロール18を設置し、下流側の整流板15dの流路を通過した炭素繊維束13をニップロール18で挟んで、所望の含水率になるまで炭素繊維束13からオゾン溶液11を取り除く。ニップロール18に代えてフラットロールを用いてもよい。
まず、流体噴出口からの噴出によりオゾン溶液が接触する直前の炭素繊維束を採取し、蒸気乾燥機により105℃で1時間、水分を蒸発させて乾燥させる。乾燥前の炭素繊維束の質量(W1)、および乾燥後の炭素繊維束の質量(W2)を測定し、下記式(2)により含水率を求める。
含水率[質量%]={(W1-W2)/W2}×100 ・・・(2)
図1~8ではオゾン溶液11の噴出方向Fを、炭素繊維束13の搬送方向に対して直交方向としているが、炭素繊維束13の搬送方向に対して交差すれば、すなわち、平行方向でなければ、噴出方向Fは直交方向に限定されない。ただし、オゾン溶液が炭素繊維束の単繊維間を通過しやすい点で、直交方向が特に好ましい。
また、図1~8ではオゾン溶液11の噴出方向を上向き(すなわち、水平状態の炭素繊維束13の下側から上側へ向かう方向)としているが、下向き(すなわち、炭素繊維束13の上側から下側へ向かう方向)でもよい。ただし、図1~8に示すように、オゾン溶液11の噴出方向Fを上向きすることで、下向きの場合よりも大気中に移動させるために噴出速度が速くなるため、好ましい。
また、図1~8に示す接触手段15の流体噴出口15cは矩形状であるが、流体噴出口15cの形状については特に限定されない。さらに、接触手段15の分岐管15bは長尺でなくてもよい。また、炭素繊維束13の本数は1本でもよいし、2本でもよいし、図2、5、6に示すように3本でもよいし、4本以上でもよいが、複数の炭素繊維束13を並行して搬送させ、一度に表面処理する場合は、図1~8に示すように矩形状の流体噴出口15cが形成された長尺な分岐管15bからオゾン溶液11を噴出させるのが好ましい。この場合、複数の炭素繊維束13の配列方向と、分岐管15bの長手方向が平行になるため、移動するオゾン溶液に全ての炭素繊維束を均一に接触させることができる。
本発明の炭素繊維の製造方法は、炭素繊維を表面処理する表面処理工程を有する。
炭素繊維を表面処理する方法としては、上述した炭素繊維の表面処理方法が挙げられる。
前駆体繊維としては、例えば、ポリアクリロニトリル系繊維、ピッチ系繊維、レーヨン系繊維が挙げられるが、コストと性能のバランスから、好ましくはポリアクリロニトリル系繊維が用いられる。
酸化性雰囲気としては、空気、酸素、二酸化窒素など、公知の酸化性雰囲気を採用できるが、経済性の面から空気が好ましい。
不活性雰囲気としては、窒素、アルゴン、ヘリウムなど公知の不活性雰囲気を採用できるが、経済性の面から窒素が望ましい。
不活性雰囲気としては、先に例示した公知の不活性雰囲気の中から選択して用いることができるが、経済性の面から窒素が望ましい。
また、本発明においては、必要に応じて、表面処理された炭素繊維をサイジング剤でサイジング処理してもよい。サイジング処理することで、繊維の集束性が高まり取り扱い性が向上すると共に、マトリックス樹脂との接着性も向上する。サイジング剤の種類としては、所望の特性を得ることができれば特に限定されないが、例えば、エポキシ樹脂、ポリエーテル樹脂、エポキシ変性ポリウレタン樹脂、ポリエステル樹脂を主成分としたサイジング剤が挙げられる。
サイジング処理の方法としては、公知の方法を用いることができる。
本発明の炭素繊維の製造方法により得られた、表面処理された炭素繊維は、サイクリックボルタンメトリー法により測定されるipa値が0.10μA/cm2以上であり、0.12μA/cm2以上が好ましい。上述したように、ipa値は炭素繊維束の表面特性の指標であり、ipa値が高くなるほど表面処理がなされていることを意味する。ipa値が0.10μA/cm2以上であれば、表面処理(酸化)が十分に行われたこと意味し、複合材料として使用した際にマトリックス樹脂との接着性が良好となり、十分な曲げ強度を有する複合材料が得られる。
ipa値の上限値については特に制限されない。
各例における測定・評価方法については、下記の方法により実施した。
(噴出速度の測定)
オゾン溶液の噴出速度は、流体噴出口から噴出する1分間当たりの水量を採取し、その質量を求め、その質量を流体噴出口の断面積で割って求めた。
炭素繊維束の含水率は、以下のようにして測定した。
まず、最下流に位置する流体噴出口からの噴出によりオゾン溶液が接触する直前の炭素繊維束を採取し、蒸気乾燥機により105℃で1時間、水分を蒸発させて乾燥させた。乾燥前の炭素繊維束の質量(W1)、および乾燥後の炭素繊維束の質量(W2)を測定し、下記式(2)により含水率を求めた。
含水率[質量%]={(W1-W2)/W2}×100 ・・・(2)
炭素繊維束の透気抵抗度は、以下のようにして測定した。
まず、最下流に位置する流体噴出口からの噴出によりオゾン溶液が接触する直前の炭素繊維束を採取し、JIS P 8117:2009(ISO 5636-5:2003)に準じて測定される紙および板紙の透気度試験方法を参考にし、紙の代わりに炭素繊維束を使用して透気抵抗度を求めた。
表面処理された炭素繊維のストランド強度およびストランド弾性率は、ASTM D4018に準拠し、エポキシ樹脂含浸ストランドの引張物性を測定することで求めた。
表面処理された炭素繊維のipa値は、サイクリックボルタンメトリー法により、以下のようにして求めた。なお、測定装置として、ポテンシオスタットとファンクションゼネレータとからなる分析装置(北斗電工株式会社製「HZ-3000 AUTOMATIC POLARIZATION SYSTEM」)を用いた。
電位操作範囲は-0.2~0.8Vとし、電位操作速度は2mV/secとした。X-Yリコーダーにより電位-電流曲線を描き、3回以上掃引させ、曲線が安定した段階で、Ag/AgCl電極に対して、+0.4Vでの電位を標準にとって電流を読み取り、下記式(1)に従ってipa値を算出した。なお、式(1)において、「試料長」とは作動電極に用いた炭素繊維の長手方向の長さであり、「目付」とは作動電極に用いた炭素繊維の単位長さ当たりの重さのことである。
ipa値[μA/cm2]=電流値[μA]/試料長[cm]×{4π×目付[g/cm]×単繊維数/密度[g/cm3] }1/2 ・・・(1)
表面処理された炭素繊維と、マトリックス樹脂としてエポキシ樹脂(三菱レイヨン株式会社製、「#350」)とを用いて、炭素繊維の含有量が体積含有率60%である繊維強化プラスチック板材(板厚:2mm)を製造した。
得られた繊維強化プラスチック板材について、ASTM D790に準拠して3点曲げショートビーム法により、繊維方向に対して直角方向の曲げ強度(FS90°) を測定した。なお、曲げ強度が高いほど、炭素繊維とマトリックス樹脂の接着性に優れることを意味する。
単繊維繊度1.2dtex、単繊維数12000本のアクリル繊維を、耐炎化を終えるまでの伸長率を-6.0%、温度を220℃~260℃として加熱処理(耐炎化処理)を施し、耐炎化繊維を得た。この耐炎化繊維を700℃の窒素雰囲気中、伸長率を+3%として前炭素化し、続いて1250℃の窒素雰囲気中、伸長率を-4.2%として炭素化し、未処理の炭素繊維を得た。
得られた未処理の炭素繊維を、図1に示す表面処理装置10を用いて以下のようにして表面処理した。
なお、オゾン溶液11は、オゾン発生器(住友精密工業株式会社製)より発生したオゾンガスを純水中に曝気させ、純水中のオゾン濃度が30mg/Lになるように調整しながら、オゾンガスを純水に溶解させて調製した。オゾン濃度は、オゾン濃度センサー(溶存オゾン測定タイプ)を用いて測定した。
なお、オゾン溶液11の移動方向Fを炭素繊維束13の搬送方向に対して直交方向、かつ上向きとした。
また、流体噴出口15cから炭素繊維束13に向かってオゾン溶液11を噴出させて単繊維表面に接触させる回数(接触回数)を4回、オゾン溶液11の噴出速度を0.42m/秒、オゾン溶液11が単繊維表面に接触する際の、炭素繊維束13の単繊維数12000本当たりの張力を0.4kg、流体噴出口15c上を単位時間当たりに通過する炭素繊維束13の質量に対するオゾン溶液11の単位時間当たりの噴出量を208倍、オゾン溶液11に炭素繊維束13を保持する時間(保持時間)を45秒とした。また、流体噴出口15cから炭素繊維束13までの距離を5cmとした。
なお、図1に示す表面処理装置10を用いて炭素繊維束13を表面処理する場合の保持時間とは、炭素繊維束13がオゾン処理槽12のオゾン溶液11中を搬送されている間の時間である。
最初の噴出によりオゾン溶液が接触する直前の炭素繊維束の含水率および透気抵抗度を測定した。また、表面処理された炭素繊維のストランド強度、ストランド弾性率、ipa値を測定し、接着性を評価した。これらの結果を表1に示す。
単繊維数12000本当たりの張力を表1に示すように変更した以外は、実施例1と同様にして炭素繊維の表面処理を行い、各種測定・評価を行った。結果を表1に示す。
単繊維繊度1.0dtex、単繊維数60000本のアクリル繊維を、耐炎化を終えるまでの伸長率を-6.0%、温度を220℃~260℃として加熱処理(耐炎化処理)を施し、耐炎化繊維を得た。この耐炎化繊維を700℃の窒素雰囲気中、伸長率を+3%として前炭素化し、続いて1350℃の窒素雰囲気中、伸長率を-4.2%として炭素化し、未処理の炭素繊維を得た。
得られた未処理の炭素繊維を用い、流体噴出口15c上を単位時間当たりに通過する炭素繊維束13の質量に対するオゾン溶液11の単位時間当たりの噴出量を52倍とした以外は、実施例1と同様にして炭素繊維の表面処理を行い、各種測定・評価を行った。結果を表1に示す。
図1に示す表面処理装置10に代えて、図4に示す表面処理装置30を用い、以下のようにして表面処理した以外は、実施例1と同様にして、各種測定・評価を行った。結果を表1に示す。
なお、オゾン溶液11の移動方向Fを炭素繊維束13の搬送方向に対して直交方向、かつ上向きとし、整流板15dの流路を流れるオゾン溶液11の移動方向Fを炭素繊維束13の搬送方向に対して平行方向とした。ただし、整流板15dの下流側の端部から孔151dまでの流路を流れるオゾン溶液11の移動方向Fは炭素繊維束13の搬送方向と逆方向であり、孔151dから整流板15d上流側の端部までの流路を流れるオゾン溶液11の移動方向Fは炭素繊維束13の搬送方向と同方向である。
なお、図4に示す表面処理装置30を用いて炭素繊維束13を表面処理する場合の保持時間とは、炭素繊維束13が4つの整流板15dの流路を通過する時間の合計である。
図4に示す表面処理装置30に代えて、図7に示す表面処理装置30を用い、流体噴出口15cから炭素繊維束13に向かってオゾン溶液11を噴出させて単繊維表面に接触させる回数(接触回数)を2回、流体噴出口15c上を単位時間当たりに通過する炭素繊維束13の質量に対するオゾン溶液11の単位時間当たりの噴出量を40倍、オゾン溶液11に炭素繊維束13を保持する時間(保持時間)を1.2秒とし、下流側の整流板15dの流路を通過した炭素繊維束13が上流側の整流板15dの流路に移動するまでの間に、2つの整流板15dの間に設置されたエアーブロー17から炭素繊維束13にエアーを150L/分の流速で吹き付けて、炭素繊維束13からオゾン溶液11を取り除いた以外は、実施例5と同様にして炭素繊維の表面処理を行った。得られた炭素繊維について、実施例1と同様にして各種測定・評価を行った。結果を表1に示す。
なお、図7に示す表面処理装置30を用いて炭素繊維束13を表面処理する場合の保持時間とは、炭素繊維束13が2つの整流板15dの流路を通過する時間の合計である。
図4に示す表面処理装置30に代えて、図8に示す表面処理装置30を用い、流体噴出口15cから炭素繊維束13に向かってオゾン溶液11を噴出させて単繊維表面に接触させる回数(接触回数)を2回、流体噴出口15c上を単位時間当たりに通過する炭素繊維束13の質量に対するオゾン溶液11の単位時間当たりの噴出量を40倍、オゾン溶液11に炭素繊維束13を保持する時間(保持時間)を1.2秒とし、下流側の整流板15dの流路を通過した炭素繊維束13が上流側の整流板15dの流路に移動するまでの間に、2つの整流板15dの間に設置された直径100mmのニップロール18で炭素繊維束13を0.2MPaの圧力で挟んで、炭素繊維束13からオゾン溶液11を取り除いた以外は、実施例6と同様にして炭素繊維の表面処理を行った。得られた炭素繊維について、実施例1と同様にして各種測定・評価を行った。結果を表1に示す。
なお、図8に示す表面処理装置30を用いて炭素繊維束13を表面処理する場合の保持時間とは、炭素繊維束13が2つの整流板15dの流路を通過する時間の合計である。
図9に示す表面処理装置40を用い、炭素繊維束の搬送方向に対して平行かつ反対方向に移動するオゾン溶液11を炭素繊維に接触させ、かつ単繊維数12000本当たりの張力を表1に示すように変更した以外は、実施例1と同様にして炭素繊維の表面処理を行い、各種測定・評価を行った。結果を表1に示す。
なお、図9中の符号「14c」は第3のフリーロールである。また、図9において図1と同じ構成要素には同じ符号を付して、その説明を省略する。
未処理の炭素繊維について、実施例1と同様にして各種測定・評価を行った。結果を表1に示す。
未処理の炭素繊維を陽極として用い、8質量%の硝酸水溶液中、30クーロン/gで電解酸化処理を行った。次いで、純水で洗浄して硝酸水溶液を除去し、400℃で0.5分乾燥させた後、サイジング処理を行って、表面処理された炭素繊維を得た。
表面処理された炭素繊維について、実施例1と同様にして各種測定・評価を行った。結果を表1に示す。
単繊維繊度1.2dtex、単繊維数6000本のアクリル繊維を、耐炎化を終えるまでの伸長率を-6.0%、温度を220℃~260℃として加熱処理を施し、耐炎化繊維を得た。この耐炎化繊維を700℃の窒素雰囲気中、伸長率を+3%として前炭素化し、続いて1250℃の窒素雰囲気中、伸長率を-4.2%として炭素化し、未処理の炭素繊維を得た。
得られた未処理の炭素繊維を用いた以外は、比較例1と同様にして炭素繊維の表面処理を行った。得られた炭素繊維について、実施例1と同様にして各種測定・評価を行った。結果を表1に示す。
一方、実施例7の場合、ニップロールを通過した直後の炭素繊維束を採取し、含水率および透気抵抗度を測定したところ、含水率は20%であり、透気抵抗度は310秒であった。
このように、2回目の噴出によりオゾン溶液を炭素繊維束に接触させる前に、エアーブローやニップロールを用いて炭素繊維束から余分なオゾン溶液を取り除くことで、接触回数が4回の場合の実施例5と同程度の表面処理効果が得られた。この結果より、表面処理される炭素繊維束の含水率や透気抵抗度を制御することで、炭素繊維の表面処理を効率よく行えることが示された。
なお、参考例2は、炭素繊維束の搬送方向に対して平行方向に移動するオゾン溶液を炭素繊維に接触させて表面処理した例であるが、単繊維数が6000本と少ないため、比較例1、2に比べてipa値や曲げ強度が高かった。しかし、比較例1、2の結果からも明らかなように、炭素繊維束の搬送方向に対して平行方向に移動するオゾン溶液を炭素繊維に接触させて表面処理する方法は、単繊維数が10000本以上の炭素繊維束を表面処理する場合には不向きである。
また、本発明は、単繊維数が多い(具体的には単繊維数が10000本以上の)炭素繊維束を表面処理する場合に、特に好適である。
図3に示す表面処理装置20を用い、オゾン溶液11でオゾン処理槽12を満たさず、オゾン溶液11に炭素繊維束13を浸漬させずに、かつ、オゾン濃度、表面処理される炭素繊維束の単繊維数、炭素繊維束の搬送速度、接触回数(すなわち、分岐管15bの数)、オゾン溶液11の噴出速度、単繊維数12000本当たりの張力、流体噴出口15c上を単位時間当たりに通過する炭素繊維束13の質量に対するオゾン溶液11の単位時間当たりの噴出量、オゾン溶液11に炭素繊維束13を保持する時間(保持時間)の条件を表2に示すように変更した以外は、実施例1と同様にして炭素繊維の表面処理を行い、ipa値を測定した。結果を表2に示す。
なお、図3に示す表面処理装置20を用いて炭素繊維束13を表面処理する場合の、炭素繊維束13のオゾン溶液11との接触時間とは、各分岐管15bの流体噴出口15cから噴出されたオゾン溶液11が炭素繊維束13と接触する時間の合計である。
なお、実施例8~18において、最下流に位置する流体噴出口からの噴出によりオゾン溶液が接触する直前の炭素繊維束を採取し、含水率および透気抵抗度を測定したところ、いずれの場合も含水率は0%であり、透気抵抗度は200秒であった。
また、本発明の炭素繊維は、マトリックス樹脂との接着性に優れる。
11 オゾン溶液
12 オゾン処理槽
13 炭素繊維束
14a 第1のフリーロール
14b 第2のフリーロール
14c 第3のフリーロール
15 接触手段
15a パイプ
15b 分岐管
15c 流体噴出口
15d 整流板
151d 孔
152d 底板
153d 側板
15e 衝突板
16 循環ポンプ
16a 吸引パイプ
17 エアーブロー
18 ニップロール
F オゾン溶液の移動方向
Claims (14)
- オゾンが溶媒に溶存したオゾン溶液を、流体噴出口から炭素繊維束に向かって噴出させ、前記オゾン溶液を炭素繊維束の単繊維間に通過させて単繊維表面に接触させることにより、炭素繊維をオゾン溶液で表面処理する表面処理工程を有する、炭素繊維の製造方法。
- 前記オゾン溶液が単繊維表面に接触する際の炭素繊維束の張力が、単繊維数12000本当たり0.3kg以上1.8kg以下である、請求項1に記載の炭素繊維の製造方法。
- 前記炭素繊維束をオゾン溶液中に0.1秒以上60秒以下保持する、請求項1または2に記載の炭素繊維の製造方法。
- 搬送される炭素繊維束の搬送方向に対して交差する方向にオゾン溶液を噴出させ、かつ、オゾン溶液の単位時間当たりの噴出量を流体噴出口上または流体噴出口下を単位時間当たりに通過する炭素繊維束の質量に対して40倍以上300倍以下とし、オゾン溶液の噴出速度を0.20m/秒以上2.0m/秒以下とする、請求項1~3のいずれか一項に記載の炭素繊維の製造方法。
- 前記流体噴出口から炭素繊維束に向かってオゾン溶液を噴出させて単繊維表面に接触させる回数を1回以上4回以下とする、請求項1~4のいずれか一項に記載の炭素繊維の製造方法。
- 前記流体噴出口の形状が矩形であり、該流体噴出口の長手方向が炭素繊維束の幅方向であり、かつ流体噴出口の長手方向の長さが炭素繊維束の幅以上である、請求項1~5のいずれか一項に記載の炭素繊維の製造方法。
- オゾン溶液が貯留されているオゾン処理槽の液面上を搬送される炭素繊維束を挟んで前記流体噴出口と対向する位置に衝突板を設置し、流体噴出口から噴出させたオゾン溶液を炭素繊維束の単繊維間に通過させた後に、衝突板に衝突させる、請求項1~6のいずれか一項に記載の炭素繊維の製造方法。
- JIS P 8117:2009に準じて測定される透気抵抗度が100秒以上700秒以下であり、かつオゾン溶液が貯留されているオゾン処理槽の液面上を搬送される炭素繊維束に前記表面処理を施す、請求項1~7のいずれか一項に記載の炭素繊維の製造方法。
- 含水率が40%以下であり、かつオゾン溶液が貯留されているオゾン処理槽の液面上を搬送される炭素繊維束に前記表面処理を施す、請求項1~8のいずれか一項に記載の炭素繊維の製造方法。
- オゾン溶液中を搬送される前記炭素繊維束に前記表面処理を施す、請求項1~6のいずれか一項に記載の炭素繊維の製造方法。
- 前記オゾン溶液のオゾン濃度が10mg/L以上120mg/L以下である、請求項1~10のいずれか一項に記載の炭素繊維の製造方法。
- 前記炭素繊維束の単繊維数が10000本以上60000本以下である、請求項1~11のいずれか一項に記載の炭素繊維の製造方法。
- サイクリックボルタンメトリー法により測定される、単位面積当たりに流れる電流値(ipa値)が0.10μA/cm2以上である炭素繊維を得る、請求項1~12のいずれか一項に記載の炭素繊維の製造方法。
- 請求項1~13のいずれか一項に記載の炭素繊維の製造方法により得られた、表面処理された炭素繊維であって、
サイクリックボルタンメトリー法により測定される、単位面積当たりに流れる電流値(ipa値)が0.10μA/cm2以上である、炭素繊維。
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP12819766.2A EP2740837B1 (en) | 2011-08-02 | 2012-08-02 | Carbon fiber manufacturing method |
CN201280038436.9A CN103717799B (zh) | 2011-08-02 | 2012-08-02 | 碳纤维的制造方法以及碳纤维 |
JP2012538901A JP5439603B2 (ja) | 2011-08-02 | 2012-08-02 | 炭素繊維の製造方法、および炭素繊維 |
KR1020147000755A KR101497286B1 (ko) | 2011-08-02 | 2012-08-02 | 탄소 섬유의 제조 방법 및 탄소 섬유 |
US14/235,494 US9796590B2 (en) | 2011-08-02 | 2012-08-02 | Carbon fiber manufacturing method and carbon fiber |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2011-169273 | 2011-08-02 | ||
JP2011169273 | 2011-08-02 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2013018860A1 true WO2013018860A1 (ja) | 2013-02-07 |
Family
ID=47629377
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2012/069682 WO2013018860A1 (ja) | 2011-08-02 | 2012-08-02 | 炭素繊維の製造方法、および炭素繊維 |
Country Status (8)
Country | Link |
---|---|
US (1) | US9796590B2 (ja) |
EP (1) | EP2740837B1 (ja) |
JP (1) | JP5439603B2 (ja) |
KR (1) | KR101497286B1 (ja) |
CN (1) | CN103717799B (ja) |
HU (1) | HUE033064T2 (ja) |
TW (1) | TWI500832B (ja) |
WO (1) | WO2013018860A1 (ja) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2016078258A (ja) * | 2014-10-10 | 2016-05-16 | 倉敷紡績株式会社 | 繊維強化樹脂用繊維シート及びこれを用いた成形体 |
JP2018056083A (ja) * | 2016-09-30 | 2018-04-05 | 株式会社イーツーラボ | プラズマ表面処理方法、プラズマ表面処理装置およびプラズマ表面処理システム |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN108026690B (zh) * | 2015-09-30 | 2024-01-23 | 帝人株式会社 | 沥青系极细碳纤维 |
KR101864512B1 (ko) | 2016-12-20 | 2018-06-04 | 전인권 | 탄소섬유의 제조방법. |
KR102147418B1 (ko) * | 2018-04-27 | 2020-08-24 | 주식회사 엘지화학 | 탄소섬유 제조용 전구체 섬유의 안정화 방법 및 이를 이용한 탄소섬유의 제조방법 |
CN111041583B (zh) * | 2019-12-26 | 2021-07-30 | 兰州蓝星纤维有限公司 | 一种大丝束pan基碳纤维原丝传质传热装置及方法 |
CN116753736B (zh) * | 2023-08-22 | 2023-10-20 | 吉林市神舟炭纤维有限责任公司 | 一种碳纤维丝氧化炉通风管道 |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60246864A (ja) | 1984-05-18 | 1985-12-06 | 三菱レイヨン株式会社 | 炭素繊維の製造法 |
JPS62263375A (ja) * | 1986-05-12 | 1987-11-16 | 三菱レイヨン株式会社 | 炭素繊維の表面処理方法 |
JPH1072762A (ja) * | 1996-08-23 | 1998-03-17 | Oshima Kikai Kk | オゾンによる繊維の改質加工法 |
JP2000154460A (ja) * | 1998-11-17 | 2000-06-06 | Toho Rayon Co Ltd | 炭素繊維の表面処理方法および装置 |
JP2001164460A (ja) * | 1999-09-30 | 2001-06-19 | Kurabo Ind Ltd | 獣毛繊維の改質方法 |
JP2001207377A (ja) * | 2000-01-28 | 2001-08-03 | Toho Rayon Co Ltd | 表面改質された炭素繊維 |
JP2012031559A (ja) * | 2010-07-05 | 2012-02-16 | Taiyo Nippon Sanso Corp | 酸化処理方法及び酸化処理装置 |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2161273B (en) | 1984-05-18 | 1988-04-13 | Mitsubishi Rayon Co | Testing carbon fibre |
US7094451B2 (en) * | 1999-04-07 | 2006-08-22 | Board Of Trustees Of Michigan State University | Chemical functionalization of material surfaces using optical energy and chemicals |
JP2001169273A (ja) | 1999-12-06 | 2001-06-22 | Sharp Corp | カラーテレビドアホン装置 |
JP4338729B2 (ja) * | 2006-10-16 | 2009-10-07 | 三菱レイヨン株式会社 | 液流処理装置および繊維処理装置 |
JP5191322B2 (ja) * | 2007-09-06 | 2013-05-08 | 三菱レイヨン株式会社 | 炭素繊維の表面処理方法 |
TWI406301B (zh) * | 2008-11-24 | 2013-08-21 | Hanwha Chemical Corp | 具有碳複合物之高導電性樹脂組合物 |
-
2012
- 2012-08-02 EP EP12819766.2A patent/EP2740837B1/en not_active Not-in-force
- 2012-08-02 JP JP2012538901A patent/JP5439603B2/ja not_active Expired - Fee Related
- 2012-08-02 CN CN201280038436.9A patent/CN103717799B/zh not_active Expired - Fee Related
- 2012-08-02 WO PCT/JP2012/069682 patent/WO2013018860A1/ja active Application Filing
- 2012-08-02 US US14/235,494 patent/US9796590B2/en not_active Expired - Fee Related
- 2012-08-02 KR KR1020147000755A patent/KR101497286B1/ko not_active IP Right Cessation
- 2012-08-02 HU HUE12819766A patent/HUE033064T2/hu unknown
- 2012-08-03 TW TW101128075A patent/TWI500832B/zh not_active IP Right Cessation
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60246864A (ja) | 1984-05-18 | 1985-12-06 | 三菱レイヨン株式会社 | 炭素繊維の製造法 |
JPS62263375A (ja) * | 1986-05-12 | 1987-11-16 | 三菱レイヨン株式会社 | 炭素繊維の表面処理方法 |
JPH1072762A (ja) * | 1996-08-23 | 1998-03-17 | Oshima Kikai Kk | オゾンによる繊維の改質加工法 |
JP2000154460A (ja) * | 1998-11-17 | 2000-06-06 | Toho Rayon Co Ltd | 炭素繊維の表面処理方法および装置 |
JP2001164460A (ja) * | 1999-09-30 | 2001-06-19 | Kurabo Ind Ltd | 獣毛繊維の改質方法 |
JP2001207377A (ja) * | 2000-01-28 | 2001-08-03 | Toho Rayon Co Ltd | 表面改質された炭素繊維 |
JP2012031559A (ja) * | 2010-07-05 | 2012-02-16 | Taiyo Nippon Sanso Corp | 酸化処理方法及び酸化処理装置 |
Non-Patent Citations (1)
Title |
---|
See also references of EP2740837A4 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2016078258A (ja) * | 2014-10-10 | 2016-05-16 | 倉敷紡績株式会社 | 繊維強化樹脂用繊維シート及びこれを用いた成形体 |
JP2018056083A (ja) * | 2016-09-30 | 2018-04-05 | 株式会社イーツーラボ | プラズマ表面処理方法、プラズマ表面処理装置およびプラズマ表面処理システム |
Also Published As
Publication number | Publication date |
---|---|
TW201311966A (zh) | 2013-03-16 |
EP2740837A4 (en) | 2014-07-23 |
JPWO2013018860A1 (ja) | 2015-03-05 |
CN103717799B (zh) | 2016-01-20 |
CN103717799A (zh) | 2014-04-09 |
TWI500832B (zh) | 2015-09-21 |
KR101497286B1 (ko) | 2015-02-27 |
HUE033064T2 (hu) | 2017-11-28 |
US20140234199A1 (en) | 2014-08-21 |
EP2740837B1 (en) | 2017-01-04 |
JP5439603B2 (ja) | 2014-03-12 |
KR20140012211A (ko) | 2014-01-29 |
US9796590B2 (en) | 2017-10-24 |
EP2740837A1 (en) | 2014-06-11 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5439603B2 (ja) | 炭素繊維の製造方法、および炭素繊維 | |
CN105484012B (zh) | 一种聚丙烯腈碳纤维表面处理方法及装置 | |
EP3208376B1 (en) | Sizing agent-coated carbon fiber bundle, method for manufacturing same, prepreg, and carbon fiber-reinforced composite material | |
US20170335507A1 (en) | Surface-treated carbon fiber, surface-treated carbon fiber strand, and manufacturing method therefor | |
CN106120200B (zh) | 一种单面羊毛织物的亲水、抗静电整理装置及整理方法 | |
JP5191322B2 (ja) | 炭素繊維の表面処理方法 | |
JP5682139B2 (ja) | 炭素繊維束 | |
CN101824742A (zh) | 一种中高强度碳纤维的表面处理方法及设备 | |
JP4023226B2 (ja) | 炭素繊維束の処理方法 | |
JP2014152401A (ja) | 耐久制電撥水性ポリエステル繊維布帛及びその製造方法 | |
JP6216509B2 (ja) | サイジング剤付着炭素繊維束及びその製造方法並びにこのサイジング剤付着炭素繊維束を用いる圧力容器の製造方法 | |
JP2013049941A (ja) | 耐久制電撥水性ポリアミド繊維布帛及びその製造方法 | |
JP2015137444A (ja) | 炭素繊維束の表面処理方法、炭素繊維束の製造方法、及び炭素繊維。 | |
JP4624571B2 (ja) | 炭素繊維前駆体糸条の製造方法 | |
JP2009242971A (ja) | 圧縮強度に優れる炭素繊維及びその製造方法 | |
JP2014118659A (ja) | 炭素繊維束の表面処理装置及び炭素繊維束の表面処理方法 | |
JP6520787B2 (ja) | アクリル系前駆体繊維束の製造方法および炭素繊維の製造方法 | |
JP5455408B2 (ja) | ポリアクリロニトリル系炭素繊維及びその製造方法 | |
JP4547969B2 (ja) | 温水洗浄装置、及びこれを用いた炭素繊維束の処理方法 | |
JP2023125227A (ja) | 炭素繊維束及びその製造方法 | |
WO2021149656A1 (ja) | サイジング剤塗布炭素繊維束およびその製造方法 | |
JP2007023458A (ja) | 難燃性混紡糸 | |
JP2023010616A (ja) | サイジング剤含有炭素繊維束およびその製造方法 | |
JP4446817B2 (ja) | アクリル系炭素繊維前駆体繊維束の製造方法 | |
JP2023037536A (ja) | サイジング剤付着繊維束及びその製造方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
ENP | Entry into the national phase |
Ref document number: 2012538901 Country of ref document: JP Kind code of ref document: A |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 12819766 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 20147000755 Country of ref document: KR Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 14235494 Country of ref document: US |
|
REEP | Request for entry into the european phase |
Ref document number: 2012819766 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2012819766 Country of ref document: EP |
|
NENP | Non-entry into the national phase |
Ref country code: DE |