WO2023188835A1 - 一方向コンポジット、スパーキャップおよび風車ブレード - Google Patents

一方向コンポジット、スパーキャップおよび風車ブレード Download PDF

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Publication number
WO2023188835A1
WO2023188835A1 PCT/JP2023/003947 JP2023003947W WO2023188835A1 WO 2023188835 A1 WO2023188835 A1 WO 2023188835A1 JP 2023003947 W JP2023003947 W JP 2023003947W WO 2023188835 A1 WO2023188835 A1 WO 2023188835A1
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Prior art keywords
fiber
unidirectional composite
carbon
carbon fiber
carbon fibers
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PCT/JP2023/003947
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English (en)
French (fr)
Japanese (ja)
Inventor
野口知久
奥田治己
水田久文
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Toray Industries Inc
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Toray Industries Inc
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Priority to JP2023511792A priority Critical patent/JPWO2023188835A1/ja
Priority to US18/847,709 priority patent/US20250215853A1/en
Priority to CN202380028420.8A priority patent/CN118891147A/zh
Priority to EP23778871.6A priority patent/EP4502365A4/en
Publication of WO2023188835A1 publication Critical patent/WO2023188835A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D1/00—Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06—Rotors
    • F03D1/065—Rotors characterised by their construction elements
    • F03D1/0675—Rotors characterised by their construction elements of the blades
    • F03D1/0679—Load carrying structures, e.g. beams
    • F03D1/0681—Spar caps
    • 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
    • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
    • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
    • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
    • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
    • D01F9/20—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products
    • D01F9/21—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D01F9/22—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyacrylonitriles
    • D01F9/225—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyacrylonitriles from stabilised polyacrylonitriles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/40—Shaping or impregnating by compression not applied
    • B29C70/50—Shaping or impregnating by compression not applied for producing articles of indefinite length, e.g. prepregs, sheet moulding compounds [SMC] or cross moulding compounds [XMC]
    • B29C70/52—Pultrusion, i.e. forming and compressing by continuously pulling through a die
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D99/00—Subject matter not provided for in other groups of this subclass
    • B29D99/0025—Producing blades or the like, e.g. blades for turbines, propellers, or wings
    • B29D99/0028—Producing blades or the like, e.g. blades for turbines, propellers, or wings hollow blades
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/24—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs
    • C08J5/241—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs using inorganic fibres
    • C08J5/243—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs using inorganic fibres using carbon fibres
    • 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
    • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
    • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
    • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
    • D—TEXTILES; PAPER
    • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
    • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
    • D02G3/00—Yarns or threads, e.g. fancy yarns; Processes or apparatus for the production thereof, not otherwise provided for
    • D02G3/22—Yarns or threads characterised by constructional features, e.g. blending, filament/fibre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D1/00—Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06—Rotors
    • F03D1/065—Rotors characterised by their construction elements
    • F03D1/0675—Rotors characterised by their construction elements of the blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/06—Fibrous reinforcements only
    • B29C70/10—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/06—Fibrous reinforcements only
    • B29C70/10—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres
    • B29C70/16—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres using fibres of substantial or continuous length
    • B29C70/20—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres using fibres of substantial or continuous length oriented in a single direction, e.g. roofing or other parallel fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • B29C70/545—Perforating, cutting or machining during or after moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2063/00—Use of EP, i.e. epoxy resins or derivatives thereof, as moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
    • B29K2105/08—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of continuous length, e.g. cords, rovings, mats, fabrics, strands or yarns
    • B29K2105/0872—Prepregs
    • B29K2105/0881—Prepregs unidirectional
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2307/00—Use of elements other than metals as reinforcement
    • B29K2307/04—Carbon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/08—Blades for rotors, stators, fans, turbines or the like, e.g. screw propellers
    • B29L2031/082—Blades, e.g. for helicopters
    • B29L2031/085—Wind turbine blades
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2363/00—Characterised by the use of epoxy resins; Derivatives of epoxy resins
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2280/00—Materials; Properties thereof
    • F05B2280/60—Properties or characteristics given to material by treatment or manufacturing
    • F05B2280/6003—Composites; e.g. fibre-reinforced
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction

Definitions

  • the present invention relates to a unidirectional composite containing unidirectionally aligned carbon fibers that is highly resistant to cracking along the fiber axis of the carbon fibers and has a high modulus of elasticity.
  • Carbon fiber which has low specific gravity and excellent mechanical properties, has been used more and more widely in recent years, and the requirements for it have become more diverse and sophisticated.
  • the forms in which carbon fibers are used vary depending on the application, and are used in various forms from continuous fibers to discontinuous fibers. Unidirectional composites, especially pultrusion molded products, are one of the typical usage forms. Carbon fibers are arranged in one direction, impregnated with resin, and hardened, so they exhibit excellent mechanical properties in the direction of carbon fiber orientation. do.
  • Patent Document 1 proposes a method of increasing the straightness of reinforcing fibers by performing pultrusion while applying tension while repeating opening and closing.
  • Patent Document 2 proposes a structure in which an inner portion and an outer portion of a wind turbine blade can be bolted together at a connection region installed in a thick wall portion.
  • Patent Document 3 proposes a method that uses a pultruded product with grooves in the span direction to give the pultruded product lateral flexibility and make it possible to match the curvature of the wind turbine blade shape.
  • Patent Document 4 proposes a method of obtaining carbon fibers that have both high elastic modulus and high compressive strength by controlling the crystalline state of carbon fibers by adding twist or the like in the carbonization process.
  • Patent Document 2 proposes a structure in which the inner and outer parts of the wind turbine blade can be bolted together at a connection area installed in a thick wall part, but a similar structure is proposed on a spar cap using a carbon fiber pultruded product.
  • Patent Document 3 proposes a method of using a pultruded product having grooves in the span direction to give the pultruded product lateral flexibility and make it possible to match the curvature of the wind turbine blade shape.
  • the curvature of the windmill blade type is large, cracks may occur along the fiber axis direction of the carbon fibers. The inventors believe that these problems are caused by the fact that carbon fibers are highly uniaxially oriented in conventional pultruded products, making them less resistant to cracking along the fiber axis. This was discovered through a study.
  • Patent Document 4 proposes a method of obtaining carbon fibers that have both high elastic modulus and high compressive strength by controlling the crystalline state of carbon fibers by adding twist during the carbonization process, but carbonization It has been revealed that carbon fibers obtained by twisting in the process retain undulations due to the effects of twisting, which may reduce the straightness of the reinforcing fibers.
  • the problem to be solved by the present invention is to provide carbon fibers with high resistance to cracks along the fiber axis, easy to avoid damage in post-processing required to accommodate larger wind turbine blades, and high elasticity modulus.
  • the objective is to provide a unidirectional composite with high
  • the present invention is as follows.
  • [1] A unidirectional composite containing carbon fibers and a matrix resin, in which the fiber axis fluctuation width is 1.5 ⁇ m or more when a single fiber of the carbon fibers is observed at a linear distance of 1 mm from the side.
  • [2] The unidirectional composite according to [1], wherein the average value of the helical pitch of the fiber axes of the carbon fibers is 5.50 cm or less.
  • R average value of the distance between single fibers of the carbon fibers included in the unidirectional composite
  • D fluctuation width of the fiber axis of the carbon fibers
  • the carbon fiber includes both carbon fibers in which the fiber axis of the single fiber has a right-handed helix, and carbon fibers in which the fiber axis of the single fiber has a left-handed helix.
  • Unidirectional composite as described.
  • the number of carbon fiber bundles made of carbon fibers whose single fiber fiber axis has a right-handed helix is N A (pieces)
  • the number of carbon fiber bundles made of carbon fibers whose fiber axis has a left-handed helix is N A (pieces).
  • the unidirectional composite according to [7], wherein the ratio N A /(N A +N B ) is 0.4 to 0.6, where N B (bonds).
  • Carbon fiber bundles made of carbon fibers whose single fiber fiber axes have a right-handed helix and carbon fiber bundles made of carbon fibers whose single fiber fiber axes have a left-handed helix are alternately arranged in the width direction of a unidirectional composite.
  • the unidirectional composite of the present invention is produced by untwisting a twisted yarn with a large number of twists, and by effectively controlling the fluctuation width of the fiber axis of a carbon fiber single fiber. It is a unidirectional composite with high modulus and high resistance to cracking along the fiber axis.
  • FIG. 1 is a schematic diagram showing a method for evaluating the fluctuation width of the fiber axis.
  • FIG. 2 is a schematic diagram showing a method for evaluating the helical pitch of a single fiber.
  • FIG. 3 is a schematic diagram showing how to obtain the average value of the distance between single fibers of carbon fibers included in a unidirectional composite.
  • FIG. 4 is a schematic diagram showing how to determine the area of the resin-rich portion when there is no carbon fiber inside.
  • FIG. 5 is a schematic diagram showing how to determine the area of the resin-rich portion when there are carbon fibers inside.
  • FIG. 6 is a schematic diagram showing a method for evaluating crack resistance along the fiber axis of carbon fiber.
  • FIG. 7 is a schematic diagram showing the helical direction of carbon fiber during pultrusion molding.
  • carbon fiber is used in a broad sense including carbon fiber bundles and carbon fiber single fibers.
  • a carbon fiber bundle refers to a bundle of multiple carbon fiber single fibers (for clarity, carbon fiber single fibers are sometimes simply referred to as “single fibers”).
  • the unidirectional composite of the present invention includes carbon fibers and a matrix resin, and the unidirectional composite has a fiber axis fluctuation width of 1.5 ⁇ m or more when a single fiber of the carbon fiber is observed from the side within a linear distance of 1 mm. It is a composite. To determine whether the fluctuation width is 1.5 ⁇ m or more, first, if a unidirectional composite is manufactured using a carbon fiber bundle, single fibers are taken out from the carbon fiber bundle to be fed and the method described below is performed. It can be easily confirmed by observation.
  • the fluctuation width of the present invention is measured by observing a carbon fiber single fiber from a direction perpendicular to the fiber axis direction in an environment where no stress other than gravity is applied.
  • the fiber axis direction and orthogonal direction are defined as follows. A straight line connecting two points 1,000 ⁇ m apart in a projected image of a carbon fiber single fiber placed on a horizontal plane on a horizontal plane is the virtual fiber axis at the observation point, and the vertical direction is a direction perpendicular to the fiber axis direction. . That is, the fluctuation width is approximately measured in the projected image.
  • the fluctuation width is determined by arbitrarily selecting the center in the thickness direction of the single carbon fiber 1 observed as a contact point A, and then placing the carbon fiber 1 mm (1,000 ⁇ m) away in a straight line from there.
  • the center of the fiber single fiber 1 in the thickness direction is the contact point B
  • Y 0 ⁇ m
  • the residual ⁇ Y is obtained by subtracting the minimum value Ymin ( ⁇ m) from the maximum value Ymax ( ⁇ m) among the values of the Y coordinate through which the center in the thickness direction of the single fiber passes. ( ⁇ m).
  • the fluctuation width is measured for 50 randomly selected individual fibers, and the average value is used.
  • the fluctuation width can be interpreted as a parameter indicating the twist strength of the carbon fibers used in the unidirectional composite, and the larger the fluctuation width, the stronger the twist.
  • the fluctuation width is preferably 3.0 ⁇ m or more, more preferably 4.0 ⁇ m or more, and even more preferably 4.5 ⁇ m or more.
  • the upper limit of the fluctuation width there is no particular limit to the upper limit of the fluctuation width, but in order to obtain carbon fibers with a large fluctuation width, it is necessary to twist the fibers strongly. , it may be necessary to reduce the manufacturing speed, so from the viewpoint of productivity, it is preferably less than 30 ⁇ m.
  • the average value of the helical pitch of the fiber axes of the carbon fibers is 5.50 cm or less.
  • the helical pitch of the fiber axis of a single fiber is a morphological characteristic of the fiber axis that correlates with the twist strength of the twisted yarn.
  • twisted yarn is obtained by processing a carbon fiber bundle in a twisted state when manufacturing it, but the twisted form may be retained in the carbon fiber bundle obtained in this way. .
  • the state in which the twisted form is maintained refers to a state in which the twist is not removed from the carbon fiber bundle even if the carbon fiber bundle is cut to form a free end.
  • the single carbon fiber bundle that makes up the carbon fiber bundle is Since the fiber axes of the fibers are originally straight, the twists are naturally resolved starting from the free ends due to the high rigidity of carbon fibers.
  • a carbon fiber bundle in which the twisted form is maintained is particularly likely to be obtained when the fiber is subjected to a twisted state during the carbonization process.
  • the fiber axis of the single fiber draws a "spiral".
  • the helical pitch refers to the distance that the helix travels in the fiber axis direction during one revolution.
  • the average value of the helical pitch refers to the average value of the helical pitch evaluated by taking out a plurality of carbon fiber single fibers included in the unidirectional composite, and the detailed evaluation method will be described later.
  • the fact that the average value of the helical pitch is 5.50 cm or less indicates that the carbon fiber bundle was processed with sufficient twist strength when manufacturing the carbon fiber bundle, and the carbon fiber with the large fluctuation width As a result, the number of times that adjacent single fibers of carbon fibers intertwine with each other can be increased, and the resistance to cracks along the fiber axis of carbon fibers can be increased.
  • the average value of the helical pitch is more preferably 4.50 cm or less, particularly preferably 3.50 cm or less.
  • there is no particular restriction on the upper limit of the helical pitch but in order to obtain carbon fibers with a large helical pitch, it is necessary to twist the fibers strongly. , it may be necessary to reduce the manufacturing speed, so from the viewpoint of productivity, it is more preferably 1.00 cm or more.
  • Z twist and S twist which are general technical terms expressing the direction of twist, correspond to right-handed and left-handed helical directions of single fibers, respectively. That is, the Z-twist twisted yarn consists of single fibers in which the helical direction of the fiber axis is a right-handed twist, and the S-twist twisted yarn consists of a single fiber in which the helical direction of the fiber axis is a left-handed twist.
  • the unidirectional composite can be made of carbon fiber having a right-handed spiral fiber axis as a single fiber, and a carbon fiber having a left-handed spiral fiber axis as a single fiber.
  • right-handed carbon fiber carbon fibers in which the fiber axis of the single fiber has a right-handed helix
  • left-handed carbon fibers By mixing and using fibers (hereinafter sometimes abbreviated as left-handed carbon fibers), it is possible to increase the number of times that adjacent single fibers of carbon fibers intertwine with each other. It is possible to suppress warping of the unidirectional composite while increasing crack resistance.
  • both right-handed carbon fibers and left-handed carbon fibers are included, it depends on whether a unidirectional composite is produced directly from the carbon fiber bundle or an intermediate base material for obtaining a unidirectional composite is produced. , can be easily confirmed by observing the carbon fiber bundle being fed.
  • the fed carbon fiber bundle is cut to form a free end, and the twist is recovered from the free end in the direction of the twist originally held by the carbon fiber bundle. Therefore, if the direction of the recovered twist is the Z-twist direction, the helical axis of the fiber axis is right-handed, and if the direction of the recovered twist is the S-twist direction, the helical direction of the fiber axis is left-handed. Randomly check the number of carbon fibers ranging from a few to all of them, and when you see carbon fiber bundles with right-handed helical directions of the fiber axes and left-handed carbon fiber bundles with left-handed helical directions of the fiber axes, you can identify right-handed carbon fiber bundles. It can be determined that it is a unidirectional composite containing fibers and left-handed carbon fibers.
  • the unidirectional composite of the present invention preferably includes both a carbon fiber bundle made of right-handed carbon fibers and a carbon fiber bundle made of left-handed carbon fibers.
  • the ratio N A /( N A +N B ) is preferably 0.4 to 0.6.
  • ratio fA such a ratio is also referred to as ratio fA for convenience.
  • This ratio f A is calculated based on the number of carbon fiber bundles. For example, when the ratio f A is 0.4, it means that the composite is made at a ratio of 4 right-handed carbon fiber bundles to 6 left-handed carbon fiber bundles.
  • the ratio N A /( NA + N B ) is 0.4 to 0 in both of the two divided pieces. .6 is preferred.
  • the ratio N A /( NA + N B ) in both of the two fragments after splitting, by setting the ratio N A /( NA + N B ) in the range of 0.4 to 0.6, the right-handed carbon fiber and the left-handed carbon fiber in the unidirectional composite are separated. This makes it easier for the fibers to come into contact with each other, increasing the number of times that single fibers intertwine with each other, making it easier to increase crack resistance and suppress warping of the unidirectional composite.
  • the ratio of N A /( NA + N B ) is 0.4 to 0.6 in each of the four divided pieces. It is more preferable to do so.
  • the ratio N A /(N A +N B ) in the range of 0.4 to 0.6 in any of the four fragments after division, it becomes easier to further increase crack resistance, and warping of the unidirectional composite is also reduced. Easier to suppress.
  • the width of the unidirectional composite is 50 mm or more, when the unidirectional composite is equally divided into 2 n parts in the width direction (n is a natural number) until the width of the unidirectional composite after division becomes 10 mm or more and 20 mm or less,
  • the ratio N A /(N A +N B ) of any of the 2 n fragments after division is preferably 0.4 to 0.6.
  • the unidirectional composite of the present invention is preferably in the form of a long plate, and the long side direction in a cross section perpendicular to the fiber direction is the width direction, and the short side direction is the thickness direction.
  • the cross section is square, that is, if it is a unidirectional composite in the form of a regular square prism, the direction of any one side is the width direction.
  • the unidirectional composite of the present invention includes both a carbon fiber bundle consisting of right-handed carbon fibers and a carbon fiber bundle consisting of left-handed carbon fibers
  • the right-handed carbon fiber bundle and the left-handed carbon fiber bundle are unidirectional. Preferably, they are arranged alternately in the width direction of the composite. Because right-handed carbon fiber bundles and left-handed carbon fiber bundles are arranged alternately in the width direction, right-handed carbon fibers and left-handed carbon fibers easily come into contact with each other in the unidirectional composite, and the single fibers become entangled with each other. Since it becomes possible to increase the number of times, it becomes easier to improve crack resistance and to suppress warping of the unidirectional composite.
  • the unidirectional composite of the present invention preferably has a carbon fiber volume content of 60% by volume or more. As the volume content of carbon fibers increases, the number of times that adjacent single fibers of carbon fibers intertwine with each other can be increased, and the resistance to cracks along the fiber axis of carbon fibers can be increased.
  • the volume content of carbon fiber is more preferably 65% by volume or more. If the volume content of carbon fiber is increased, the pulling force during pultrusion will increase, which may cause fluffing and make the process difficult, so the volume content of carbon fiber should be 80% by volume or less. is even more preferable.
  • the average value of the distance between single fibers of carbon fibers included in the unidirectional composite is R ( ⁇ m)
  • the fluctuation width of the fiber axis of the carbon fibers is D ( ⁇ m)
  • the following formula is used: It is preferable that (1) is satisfied. 2.0 ⁇ D ⁇ R ⁇ 35.0...Formula (1)
  • D ⁇ R is an index indicating the ease with which adjacent single fibers of carbon fibers intertwine with each other, and the larger the value, the higher the crack resistance can be.
  • D ⁇ R is 3.5 or more. Furthermore, from the perspective of increasing the resistance to cracks along the fiber axis of carbon fibers, there is no particular upper limit for D ⁇ R, but in order to increase D ⁇ R, it is simple to increase the fluctuation width D. It is necessary to reduce the average value R of the inter-fiber distances, or both. In order to increase the fluctuation width D, it is necessary to apply strong twisting, and in order to decrease the average value R of the distance between single fibers, it is necessary to increase the volume content of carbon fibers, which makes D ⁇ R too large. Since this may significantly reduce productivity, it is preferably 35.0 or less. D ⁇ R is more preferably 15.0 or less, particularly preferably 10.0 or less.
  • the carbon fiber bundles are contained in the matrix resin with a twist of 10 turns/m or less.
  • the number of twists of the carbon fiber bundle is 10 turns/m or less, the single fibers included in adjacent carbon fiber bundles are likely to become entangled with each other, and crack resistance can be improved. More preferably, it is 5 turns/m or less.
  • the unidirectional composite of the present invention in a cut plane perpendicular to the fiber direction of the unidirectional composite, when the cross-sectional area of the carbon fiber bundle included in the unidirectional composite is X (mm 2 ), 3% or more of X
  • the resin-rich portion refers to a portion that does not contain carbon fibers and is composed only of resin.
  • the fact that there is substantially no resin-rich portion having an area of 3% or more of the cross-sectional area is repeated three times on an arbitrary cut surface, and no resin-rich portion having an area of 3% or more of the cross-sectional area X of the carbon fiber bundle is present in any of the observations.
  • the tensile modulus of the unidirectional composite is 150 GPa or more.
  • the tensile modulus of the unidirectional composite is more preferably 200 GPa or more, particularly preferably 240 GPa or more. From the perspective of improving rigidity, there is no particular upper limit for the tensile modulus of a unidirectional composite, but if the tensile modulus of carbon fiber is increased with the aim of improving the tensile modulus of a unidirectional composite, the tensile strength will decrease and fuzz will occur. It is even more preferred that the tensile modulus of the unidirectional composite is less than 500 GPa, particularly preferably less than 400 GPa.
  • Examples of the unidirectional composite of the present invention include a pultrusion molded product, a unidirectional prepreg molded product, a filament-wound molded product, etc., and a pultrusion molded product or a composite having an average diameter of carbon fiber single fibers of 6.0 ⁇ m or less.
  • it is a directional prepreg molded product.
  • the unidirectional composite of the present invention is preferably a pultrusion product that can be efficiently manufactured into the same shape in the longitudinal direction from the viewpoint of efficiency in manufacturing large-sized members.
  • the unidirectional composite of the present invention is a unidirectional prepreg molded product from the viewpoint of suitability for manufacturing members with complex shapes, and in order to satisfy the dimensional stability often required for complex shapes, It is preferable that the average value of the single fiber diameter of the carbon fibers is 6.0 ⁇ m or less.
  • the unidirectional composites when manufacturing a member using the unidirectional composite of the present invention, may be bonded together and integrated, or a nonwoven fabric or fabric may be laminated between the unidirectional composites and then resin They may be integrated by impregnating and curing. Furthermore, a different isotropic composite or the like may be adhered to the unidirectional composite of the present invention.
  • thermosetting resins vinyl ester resin, epoxy resin, unsaturated polyester resin, acrylic resin, etc. can be used.
  • thermoplastic resin polyamide resin, polyester resin, polycarbonate resin, polyphenylene sulfide resin, polyether sulfone resin, polyether ether ketone resin, etc. can be used.
  • the spar cap of the present invention is preferably a spar cap comprising the unidirectional composite of the present invention.
  • a spar cap with high resistance to cracking along the fiber axis of carbon fibers and high elastic modulus can be obtained.
  • a spar cap is a reinforcing material that makes up a spar used in wind turbine blades, airplane wings, ship masts, etc., and is often used to increase the strength and elastic modulus of the structure. Therefore, a spar cap with high strength and elastic modulus is preferably used because it has a large reinforcing effect. Further, since cracks may occur in the spar cap, the reinforcing effect may be weakened, so a spar cap with high resistance to cracks is preferably used.
  • the spar cap of the present invention may contain only the unidirectional composite of the present invention, or may contain the unidirectional composite of the present invention and other unidirectional composites or isotropic composites.
  • the spar cap of the present invention may include one in which unidirectional composites are bonded together and integrated, or a nonwoven fabric or fabric is laminated between two unidirectional composites and then impregnated with resin. It may also include those that have been integrated by being cured.
  • the wind turbine blade of the present invention preferably includes the spar cap of the present invention.
  • Larger wind turbine blades are preferably used because the larger the wind turbine blades, the greater the amount of power generated by wind power generation, but damage may occur during post-processing required to accommodate larger wind turbine blades.
  • the spar cap of the present invention it is possible to obtain a wind turbine blade that can easily avoid damage during post-processing required to accommodate larger sizes.
  • the wind turbine blade of the present invention may include only the spar cap of the present invention, or may include the spar cap of the present invention and other spar caps.
  • the spar cap of the present invention may be used only in areas that are prone to cracking or deformation.
  • the twisted yarn used in the unidirectional composite of the present invention can be obtained, for example, by the method described in JP-A-2014-141761 or the method described in WO 19/203088. You can effectively increase the degree of crystal orientation by passing through the carbonization process while applying high tension while twisting, or you can increase the degree of crystal orientation by applying twist but keeping the tension to the minimum required. It may also be a high-quality carbon fiber bundle with less breakage. What is important is that by adopting the configuration of the unidirectional composite of the present invention, a unidirectional composite with high elastic modulus and high resistance to cracking along the fiber axis of carbon fibers can be effectively obtained.
  • the tensile modulus of carbon fiber is determined according to the resin-impregnated strand test method of JIS R7608:2004 according to the following procedure. However, when the carbon fiber has twist, it is evaluated after being untwisted by applying the same number of twists of opposite rotation as the number of twists.
  • As the curing conditions normal pressure, temperature of 125° C., and time of 30 minutes are used. Ten carbon fiber strands are measured, and the average value is taken as the tensile modulus. Note that the strain range when calculating the tensile modulus is 0.1 to 0.6%.
  • ⁇ Number of twists of carbon fiber bundle The number of twists (turns/m) of a carbon fiber bundle is determined by pulling out the carbon fiber bundle to be measured by 1 m, twisting one end with the longitudinal direction of the fiber bundle as the rotation axis, and dividing the number of twists by 1 until the twist is completely removed. Calculate. The number of twists is counted with 360 degrees as one revolution. You can visually determine whether the twist is completely gone, or if it is difficult to follow visually, insert a thin, rigid needle such as a cultured needle into the carbon fiber bundle and trace it in the longitudinal direction of the carbon fiber bundle. By doing so, you can determine if there is a slight amount of twist remaining and make fine adjustments.
  • ⁇ Fluctuation width of carbon fiber fiber axis Fifty single fibers are randomly sampled from the carbon fiber bundle used in the unidirectional composite. If it is difficult to obtain a carbon fiber bundle that has already been pultruded and has not yet been manufactured into a unidirectional composite, a rectangle with a length of 1 cm is cut from an arbitrary position of the unidirectional composite in the fiber orientation direction. If the width in the direction perpendicular to the fiber direction is 5 cm or more, it is cut out as a rectangle with a length of 1 cm and a width of 5 cm.
  • the unidirectional composite cut into a rectangular shape was placed in an electric furnace in a nitrogen atmosphere set at a temperature of 450°C to burn off the matrix resin, and then the remaining carbon fiber bundle aggregate was placed in a 50 mL glass container with a lid. After shaking the single fibers up and down 50 times to mix the single fibers well, 50 single fibers of carbon fibers were randomly sampled from among the single fibers.
  • a carbon fiber single fiber to be evaluated has a length of 1 to 5 mm, and is placed on copy paper. If the single fibers stick to the copy paper due to static electricity, remove the static electricity using a standard method before doing so. Observe using an optical microscope from the vertical direction of the paper surface and obtain an image. The magnification of the objective lens of the optical microscope is 10 times. The image is saved in jpg format of 2592 pixels horizontally by 1944 pixels vertically.
  • the acquired image is loaded into the open source image processing software "ImageJ", and any point on the fiber axis is designated as point A, and a point on the fiber axis 1,000 ⁇ m away from point A is designated as point B. do.
  • "Bilinear Interpolation” is selected as the interpolation algorithm during rotation, and the image is rotated so that point A and point B are horizontal.
  • skeletonization is performed to extract the fiber axis as a curve with a width of 1 pixel. At this time, if dust or the like is attached to the fiber surface, the fiber axis may branch, but side chains other than the fiber axis are ignored.
  • the residual difference ⁇ Y ( ⁇ m) obtained by subtracting the minimum value Ymin from the maximum value Ymax is read and used as the fluctuation width of the evaluated single fiber.
  • the fluctuation widths evaluated for 50 different single fibers are averaged and used as the fluctuation width in the present invention.
  • a carbon fiber single fiber to be measured is cut out to a length of 10 ⁇ 0.5 cm, and placed on copy paper spread on a horizontal table. If the single fibers stick to the copy paper due to static electricity, remove the static electricity using a standard method. If the single fibers stick to the copy paper and do not separate when the copy paper on which the monofilaments are placed are turned upside down, the static electricity removal is insufficient, so additional static electricity is removed. Visual observation is made from the normal direction of the single fibers and parallel to the paper surface, and the distance between the points where the single fibers contact the copy paper is measured.
  • the helical pitch is 3.0 cm
  • the copy paper is contacted at three contact points A, B, and C, as illustrated in FIG. Therefore, in this case, the distance AB and the distance BC are measured, and the average value (3.0 cm) is taken as the helical pitch of the fiber axis of the single fiber.
  • the unidirectional composite cut into a rectangular shape was placed in an electric furnace in a nitrogen atmosphere set at a temperature of 450°C to burn off the matrix resin, and then 50 single fibers were randomly collected from the remaining aggregate of carbon fiber bundles. do.
  • the helical pitch of the fiber axes of the obtained single fibers is evaluated by the method described above, and the evaluation values of the helical pitches are averaged to calculate the average value of the pitch of the fiber axes of the carbon fiber bundle.
  • the average value of the helical pitch is rounded to the second decimal place.
  • the helical direction of the fiber axis of a single fiber is identified by visual observation not from the normal direction of the single fiber but from the fiber axis direction.
  • Right-handed winding refers to the direction in which the watch moves toward the back of the dial when rotated clockwise, and is also called Z-winding.
  • Left-handed winding is the opposite, and is also called S-winding.
  • a unidirectional composite contains carbon fibers with different helical directions of the fiber axes>
  • a rectangular parallelepiped with a length of 13 cm is cut out from an arbitrary position of the unidirectional composite in the fiber orientation direction.
  • the unidirectional composite cut into a rectangular parallelepiped was placed in an electric furnace in a nitrogen atmosphere set at a temperature of 450°C to burn off the matrix resin, and then 50 single fibers were randomly collected from the remaining carbon fiber bundle aggregate. do.
  • the helical direction of the fiber axis is evaluated by the method described above.
  • three or more single fibers each have a right-handed spiral direction and three or more single fibers have a left-handed spiral direction, carbon fibers having a right-handed spiral fiber axis, and a unidirectional composite including carbon fibers having a left-handed helix.
  • a of carbon fiber bundles consisting of single fibers whose fiber axes have a right-handed helical direction First, a rectangular parallelepiped with a length of 13 cm is cut out from an arbitrary position of the unidirectional composite in the fiber orientation direction. The unidirectional composite cut into rectangular parallelepipeds was placed in an electric furnace in a nitrogen atmosphere set at a temperature of 450°C to burn off the matrix resin, and the remaining carbon fiber bundles were visually confirmed to reveal individual carbon fibers. Identify fiber bundles. Next, three single fibers are collected from each carbon fiber bundle, and the helical direction of the fiber axis is evaluated by the method described above. For a certain carbon fiber bundle, the helical direction of the carbon fiber bundle as a whole is determined by majority vote based on the evaluation results of the helical direction of the fiber axes of three single fibers taken from the carbon fiber bundle.
  • the helical direction of the fiber axes of such a carbon fiber bundle is right-handed. (i.e., a carbon fiber bundle consisting of single fibers in which the helical direction of the fiber axis is clockwise).
  • the number of carbon fiber bundles made of single fibers whose fiber axes have a right-handed helix is N A (pieces)
  • the number of carbon fiber bundles made of single fibers whose fiber axes have a left-handed helix is N B (pieces).
  • the ratio N A /(N A +N B ) is calculated, and this is taken as the abundance ratio f A of carbon fiber bundles made of single fibers whose fiber axes have a right-handed helical direction.
  • f A of the two fragments after dividing a unidirectional composite into two evenly in the width direction f A of the four fragments after dividing when dividing the unidirectional composite into four evenly in the width direction, and the unidirectional composite after dividing
  • fA of the 2n pieces after dividing the unidirectional composite into 2n pieces evenly in the width direction n is a natural number
  • a carbon fiber bundle is also cut when splitting the unidirectional composite, measure the weight of the cut carbon fiber bundle, and if the weight is 70% or more of the uncut carbon fiber bundle, one carbon fiber bundle, 0.5 carbon fiber bundles if the weight is 30% or more and less than 70% of the weight of the uncut carbon fiber bundle, 0 carbon fiber bundle if the weight is less than 30% of the weight of the uncut carbon fiber bundle Counted as a carbon fiber bundle.
  • the helical direction of the carbon fiber bundle as a whole is determined by majority vote based on the evaluation results of the helical direction of the fiber axes of three single fibers taken from the carbon fiber bundle.
  • the positions of right-handed carbon fiber bundles and left-handed carbon fiber bundles we can determine whether carbon fiber bundles with different helical directions of the fiber axes are arranged alternately in the width direction of the unidirectional composite. judge.
  • ⁇ Volume content of carbon fiber in unidirectional composite First, a rectangle with a length of 13 cm is cut out from an arbitrary position of the unidirectional composite in the fiber orientation direction. If the width in the direction perpendicular to the fiber direction is 5 cm or more, it is cut out as a rectangle with a length of 13 cm and a width of 5 cm. After measuring the mass of the unidirectional composite cut into a rectangle, the matrix resin was burned off in an electric furnace with a nitrogen atmosphere set at a temperature of 450°C, and the mass of the resulting carbon fiber was measured. The mass content W f of carbon fibers in the directional composite is determined.
  • the density ⁇ c of the unidirectional composite was determined by the plastic density test method of JIS K7112:1999, and the density ⁇ f of the carbon fiber obtained by burning off the matrix resin was determined by JIS R7603:1999. Determine the density of carbon fiber according to the test method.
  • volume content V f of carbon fibers is calculated according to the following formula.
  • V f W f ⁇ ( ⁇ c ⁇ ⁇ f ) ⁇ Average value of single fiber diameter of carbon fiber> Evaluation is made by observing a single carbon fiber using a scanning electron microscope (SEM). The number of single fibers to be evaluated is 50, and the average value thereof is taken as the average value of the single fiber diameter. In the Examples and Comparative Examples of the present invention, observations were made using SEM "S-4800" manufactured by Hitachi High-Technologies.
  • ⁇ Average value of distance between single fibers of carbon fibers included in unidirectional composite> A cross section perpendicular to the fiber direction of the unidirectional composite is shown in FIG. As shown in Figure 3, the calculated value of the distance between the carbon fibers in the unidirectional composite is calculated based on the assumption that the carbon fibers 4 are dispersed at equal distances from each other in the unidirectional composite. The average value R of the distance between single fibers of the fibers was determined by the following procedure.
  • the positive length L obtained by connecting the centers of the single fibers 4 of each carbon fiber is It will be shown as a structure with triangles as repeating units.
  • L r ⁇ 200 ⁇ ( ⁇ 3 ⁇ V f ) ⁇ 0.5 .
  • ⁇ Number of single fibers included in carbon fiber bundle> First, a rectangular parallelepiped with a length of 13 cm is cut out from an arbitrary position of the unidirectional composite in the fiber orientation direction. The unidirectional composite cut into rectangular parallelepipeds is placed in an electric furnace with a nitrogen atmosphere set at a temperature of 450°C to burn off the matrix resin, and the remaining carbon fiber bundle aggregates are visually checked to determine individual carbon fibers. The bundles are identified and evaluated by observing the carbon fiber bundles with an SEM. The number of carbon fiber bundles to be evaluated is three, and the average value thereof is taken as the number of single fibers included in the carbon fiber bundle. The number of single fibers is determined in units of 1,000. In the Examples and Comparative Examples of the present invention, observations were made using a scanning electron microscope (SEM) "S-4800" manufactured by Hitachi High-Technologies.
  • SEM scanning electron microscope
  • ⁇ Cross-sectional area of carbon fiber bundle included in unidirectional composite> Using the average value of the single fiber diameters of the carbon fibers obtained by the method described above, the cross-sectional area of the single carbon fibers is determined assuming that the single fibers are perfectly circular. The cross-sectional area of the carbon fiber bundle contained in the unidirectional composite is determined by multiplying the cross-sectional area of the obtained single fiber by the number of single fibers contained in the carbon fiber bundle obtained by the method described above.
  • ⁇ Evaluation that there is substantially no resin-rich part having an area of 3% or more of the cross-sectional area X of the carbon fiber bundle in the unidirectional composite First, a unidirectional composite is cut perpendicular to the fiber direction to obtain a cut surface with a width of 20 mm and a thickness of 1 mm, and then the cross section is observed with a laser microscope. Next, using the cross-sectional area of the carbon fiber bundle obtained in the above method, calculate the area that is 3% of the cross-sectional area of the carbon fiber bundle, and then evaluate whether there is a resin-rich part with the same area or more. did.
  • the area of the resin-rich portion 7 is determined by using a laser microscope to confirm the presence or absence of the resin-rich portion 7, which is composed almost only of resin. It was obtained by subtracting the area of the carbon fiber single fiber 6 contained in the area obtained by connecting the center points. Note that parts where the distance between the single fiber diameters of the carbon fibers is greater than or equal to the average value are considered to be continuous resin-rich parts, and parts where the distance between the single fiber diameters of the carbon fibers remains less than the average value are considered to be resin-rich parts.
  • the carbon fiber single fibers 6 surrounding the area of the resin-rich portion 7 were determined by assuming that the resin-rich portion 7 is discontinuous.
  • the area of the resin-rich portion 7 was calculated by subtracting the area surrounded by the internal carbon fiber single fibers 6 and the area of the internal carbon fiber single fibers 6.
  • ⁇ Tensile modulus of unidirectional composite The tensile modulus of the unidirectional composite is determined according to JIS K7164:2005. Ten test pieces cut out from the unidirectional composite were measured, and the average value was taken as the tensile modulus. Note that the strain range when calculating the tensile modulus is 0.1 to 0.6%.
  • evaluation sample 8 is obtained by cutting the unidirectional composite into a piece of 100 mm in the fiber axis direction D, 20 mm in the direction perpendicular to the fiber axis, and 1 mm in the thickness direction.
  • two pliers each having a width of 12 mm are held in both hands, and the pliers grip the evaluation sample 8 at two locations on the pliers gripping portion 9 (width: 12 mm, length: 5 mm).
  • the evaluation sample 8 was bent for 1 second in a direction perpendicular to the fiber axis direction D so that the gripping parts formed a 90 degree angle with each other, and the fiber axis direction of the carbon fiber was bent. After forming a crack E along D, the angle is returned to 0 degrees.
  • the pliers gripping portion 9 is gripped with a chuck and pulled at a crosshead speed of 2 mm/min in a direction perpendicular to the fiber axis direction D, and crack resistance is evaluated using the following criteria.
  • a tensile tester "5565 Model Universal Tester" manufactured by INSTRON was used.
  • Flame-resistant fiber production example 2 In flame-resistant fiber production example 1, except that the single fiber fineness of the carbon fiber precursor fiber bundle was set to 0.8 dtex and that the carbon fiber precursor fiber bundle was doubled into four fibers to make the number of single fibers 12,000. A flame-resistant fiber bundle was obtained in the same manner.
  • Flame-resistant fiber production example 3 A flame-resistant fiber bundle was obtained in the same manner as in Flame-resistant fiber production example 1, except that the single fiber fineness of the carbon fiber precursor fiber bundle was set to 0.8 dtex.
  • an uncured epoxy resin composition containing an epoxy resin containing a curing agent and a curing accelerator is used, and carbon fiber bundles aligned in one direction are passed through a resin impregnation tank to form the epoxy resin.
  • the central part in the molding direction is passed through a rectangular hole-shaped mold with a width of 20 mm and a thickness of 1 mm heated to 180°C to harden it.
  • a pultrusion molded product was obtained by continuously drawing the product and cutting it into a length of 8 m.
  • This unidirectional prepreg was cut with a cutter into a square of 13 cm in the direction of the fiber axis and 13 cm in the direction perpendicular to the fiber axis, and placed between a SUS tool plate and a 13 cm square aluminum pressure plate. After sandwiching and bagging using bag film and sealant, the mixture was heated to 180° C. and cured in an autoclave to obtain a unidirectional prepreg molded product with a width of 13 cm, a length of 13 cm, and a thickness of 1 mm.
  • Example 1 The flame-resistant fiber bundle obtained in Flame-resistant fiber production example 1 was subjected to a twisting treatment to produce a twisted flame-resistant fiber bundle with a twist of 25 turns/m.
  • This twisted flame-resistant fiber bundle was pre-carbonized in a nitrogen atmosphere at a temperature of 300 to 800°C with a drawing ratio of 0.97 to obtain a pre-carbonized fiber bundle.
  • the pre-carbonized fiber bundle was subjected to carbonization treatment in a nitrogen atmosphere at a temperature of 1,000 to 1,800° C. while appropriately adjusting the stretching ratio to obtain a carbon fiber bundle.
  • Table 1 The evaluation results are summarized in Table 1.
  • Example 2 A carbon fiber bundle and a pultrusion molded product were obtained in the same manner as in Example 1, except that the carbonization treatment was performed in a nitrogen atmosphere at a temperature of 1,000 to 2,100°C.
  • the evaluation results of the carbon fibers and pultrusion molded products were as shown in Tables 1 and 2.
  • Example 3 A carbon fiber bundle and a pultrusion molded product were obtained in the same manner as in Example 1, except that the carbonization treatment was performed in a nitrogen atmosphere at a temperature of 1,000 to 1,400°C.
  • the evaluation results of the carbon fibers and pultrusion molded products were as shown in Tables 1 and 2.
  • Example 4 A carbon fiber bundle and a pultruded product were obtained in the same manner as in Example 1, except that the number of twists was 45 turns/m and the volume content of carbon fibers was lowered.
  • the evaluation results of the carbon fibers and pultrusion molded products were as shown in Tables 1 and 2.
  • Example 5 A carbon fiber bundle and a pultrusion molded product were obtained in the same manner as in Example 1, except that the volume content of carbon fibers was lowered. The evaluation results of the carbon fibers and pultrusion molded products were as shown in Tables 1 and 2.
  • Example 6 The flame-resistant fiber bundle obtained in Flame-resistant fiber production example 2 was subjected to a twisting treatment to produce a twisted flame-resistant fiber bundle with a twist of 45 turns/m.
  • This twisted flame-resistant fiber bundle was pre-carbonized in a nitrogen atmosphere at a temperature of 300 to 800°C with a drawing ratio of 0.97 to obtain a pre-carbonized fiber bundle.
  • the pre-carbonized fiber bundle was subjected to carbonization treatment in a nitrogen atmosphere at a temperature of 1,000 to 1,800° C. while appropriately adjusting the stretching ratio to obtain a carbon fiber bundle.
  • Table 1 The evaluation results are summarized in Table 1.
  • Example 7 The flame-resistant fiber bundle obtained in Flame-resistant fiber production example 1 was subjected to a twisting treatment, and a twisted flame-resistant fiber bundle was given a Z twist of 45 turns/m and a twisted flame-resistant fiber bundle was given an S twist of 45 turns/m. Each flame-resistant fiber bundle was produced. Each twisted flame-resistant fiber bundle was pre-carbonized in a nitrogen atmosphere at a temperature of 300 to 800° C. with a drawing ratio of 0.97 to obtain Z-twist and S-twist pre-carbonized fiber bundles, respectively. Next, carbonization treatment was performed on these pre-carbonized fiber bundles in a nitrogen atmosphere at a temperature of 1,000 to 1,800°C while appropriately adjusting the drawing ratio to obtain Z-twist and S-twist carbon fiber bundles. Ta.
  • a pultruded product was obtained according to the pultrusion product manufacturing example.
  • right-handed (Z-twist) carbon fiber bundles 11 and left-handed (S-twist) carbon fiber bundles 12 are alternately rolled in the width direction at a ratio of 7:6. They were arranged in a pultrusion mold 10 so as to be lined up.
  • the evaluation results of Vf, tensile modulus, crack resistance, etc. obtained by analyzing the pultruded products are as shown in Table 2.
  • the properties of the carbon fibers and the elastic modulus and crack resistance of the pultruded product were the same as in Example 4, but the warp of the pultruded product was much smaller than in Example 4, and the pultruded product had high dimensional stability. It was a quality product.
  • Example 8 The flame-resistant fiber bundle obtained in Flame-resistant fiber production example 3 was subjected to a twisting treatment to produce a twisted flame-resistant fiber bundle with a Z twist of 15 turns/m.
  • This twisted flame-resistant fiber bundle was pre-carbonized in a nitrogen atmosphere at a temperature of 300 to 800°C with a drawing ratio of 0.97 to obtain a pre-carbonized fiber bundle.
  • the pre-carbonized fiber bundle was subjected to carbonization treatment in a nitrogen atmosphere at a temperature of 1,000 to 1,800° C. while appropriately adjusting the stretching ratio to obtain a carbon fiber bundle.
  • Table 1 The evaluation results are summarized in Table 1.
  • Example 9 Carbon fiber bundles and pultrusion were produced in the same manner as in Example 1, except that the carbon fiber bundle was untwisted to reduce the residual twist to 5 turns/m, and then a pultruded product was obtained according to the pultrusion product manufacturing example. I got the item.
  • the evaluation results of the carbon fibers and pultrusion molded products were as shown in Tables 1 and 2.
  • Example 10 Carbon fiber bundles and pultrusion were produced in the same manner as in Example 1, except that the carbon fiber bundle was untwisted to reduce the residual twist to 15 turns/m, and then a pultruded product was obtained according to the pultrusion product manufacturing example. I got the item.
  • the evaluation results of carbon fibers and pultrusion molded products are shown in Tables 1 and 2, and it is found that there is a resin-rich part with an area of 3% or more of the cross-sectional area X of the carbon fiber bundle in the cross section of the pultrusion molded product. Although the crack resistance itself was high, the result was inferior to that of Example 1.
  • Example 11 The flame-resistant fiber bundle obtained in Flame-resistant fiber production example 2 was subjected to a twisting treatment to produce a twisted flame-resistant fiber bundle with a twist of 25 turns/m.
  • This twisted flame-resistant fiber bundle was pre-carbonized in a nitrogen atmosphere at a temperature of 300 to 800°C with a drawing ratio of 0.97 to obtain a pre-carbonized fiber bundle.
  • the pre-carbonized fiber bundle was subjected to carbonization treatment in a nitrogen atmosphere at a temperature of 1,000 to 1,800° C. while appropriately adjusting the stretching ratio to obtain a carbon fiber bundle.
  • Table 1 The evaluation results are summarized in Table 1.
  • a unidirectional prepreg molded product was obtained according to an example of manufacturing a unidirectional prepreg molded product.
  • Table 2 shows the evaluation results of the volume content of carbon fiber, tensile modulus of elasticity, and crack resistance along the fiber axis of carbon fiber obtained by analyzing the unidirectional prepreg molded product.
  • Carbon fiber bundles shown in Table 1 were obtained in the same manner as in Example 1 except that the number of twists was 0 turns/m. When the stretching ratio during carbonization treatment was increased in order to increase the tensile modulus of the carbon fiber bundle, a large amount of fuzz was generated. Although an attempt was made to obtain a pultruded product according to the pultruded product manufacturing example, a problem occurred in which fluff accumulated in the nozzle, and the pultruded product could not be obtained.
  • twisted yarn with a large number of twists is untwisted and used to produce a unidirectional composite, and by effectively controlling the fluctuation width of the fiber axis of a single carbon fiber, the fiber axis of the carbon fiber is A unidirectional composite with high resistance to longitudinal cracking can be obtained.
  • a wind turbine blade using such a unidirectional composite for the spar cap can easily avoid damage during post-processing required to accommodate larger sizes.
  • Carbon fiber single fiber 2 Copy paper A: Contact point A
  • B Contact point B
  • Carbon fiber single fiber L Distance between centers of carbon fiber single fibers (when uniformly dispersed)
  • R Average value of the distance between single fibers of carbon fibers included in the unidirectional composite r: Radius of the single carbon fibers 5: Cut surface of the unidirectional composite 6: Single fibers of carbon fibers 7: Resin-rich portion D: Fiber Axial direction E: Crack 8: Evaluation sample 9: Pliers gripping part 10: Pultrusion mold (rectangular hole shape) 11: Right-handed (Z-twist) carbon fiber bundle 12: Left-handed (S-twist) carbon fiber bundle

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JP2023064055A (ja) * 2021-10-25 2023-05-10 東レ株式会社 一方向プリプレグ、炭素繊維強化複合材料、炭素繊維強化複合材料製管状体、およびヨット用マスト
WO2024190111A1 (ja) * 2023-03-13 2024-09-19 東レ株式会社 風車ブレード

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WO2013083451A1 (de) 2011-12-08 2013-06-13 Wobben Properties Gmbh Rotorblatt und verbindungsvorrichtung
JP2014141761A (ja) 2013-01-25 2014-08-07 Toray Ind Inc 炭素繊維束およびその製造方法
JP2018001682A (ja) 2016-07-06 2018-01-11 三菱重工業株式会社 引抜成形材料の製造方法及び引抜成形材料の製造装置
US20190270261A1 (en) 2016-11-17 2019-09-05 Vestas Wind Systems A/S Reinforcing structure for a wind turbine blade
WO2019203088A1 (ja) 2018-04-16 2019-10-24 東レ株式会社 炭素繊維束とその製造方法、プリプレグおよび炭素繊維強化複合材料
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JP2019151956A (ja) * 2018-03-06 2019-09-12 東レ株式会社 炭素繊維束および炭素繊維ならびに炭素繊維束の製造方法

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JP2014141761A (ja) 2013-01-25 2014-08-07 Toray Ind Inc 炭素繊維束およびその製造方法
JP2018001682A (ja) 2016-07-06 2018-01-11 三菱重工業株式会社 引抜成形材料の製造方法及び引抜成形材料の製造装置
US20190270261A1 (en) 2016-11-17 2019-09-05 Vestas Wind Systems A/S Reinforcing structure for a wind turbine blade
WO2019203088A1 (ja) 2018-04-16 2019-10-24 東レ株式会社 炭素繊維束とその製造方法、プリプレグおよび炭素繊維強化複合材料
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WO2024190111A1 (ja) * 2023-03-13 2024-09-19 東レ株式会社 風車ブレード

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