WO2019220846A1 - Method for manufacturing sheet molding compound, carbon fiber bundle, and use for carbon fiber bundle - Google Patents

Method for manufacturing sheet molding compound, carbon fiber bundle, and use for carbon fiber bundle Download PDF

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Publication number
WO2019220846A1
WO2019220846A1 PCT/JP2019/016440 JP2019016440W WO2019220846A1 WO 2019220846 A1 WO2019220846 A1 WO 2019220846A1 JP 2019016440 W JP2019016440 W JP 2019016440W WO 2019220846 A1 WO2019220846 A1 WO 2019220846A1
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carbon fiber
fiber bundle
component
procedure
test
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PCT/JP2019/016440
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French (fr)
Japanese (ja)
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洋之 中尾
征司 土屋
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三菱ケミカル株式会社
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Priority to JP2019525913A priority Critical patent/JPWO2019220846A1/en
Publication of WO2019220846A1 publication Critical patent/WO2019220846A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B15/00—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00
    • B29B15/08—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00 of reinforcements or fillers

Definitions

  • the present invention relates to a method for producing a sheet molding compound, a carbon fiber bundle useful for producing a sheet molding compound, and the use of the carbon fiber bundle for producing a sheet molding compound.
  • a sheet molding compound (hereinafter also referred to as “SMC”) is a compound in which a matrix resin composition containing a thermosetting resin and the like and a cut chopped reinforcing fiber bundle are blended.
  • SMC is heated and pressed in the mold, the matrix resin composition and the reinforcing fiber bundle flow together to fill the cavity of the mold. Therefore, SMC is an intermediate material that is advantageous for obtaining molded products of various shapes such as molded products with partially different thickness, molded products having ribs, bosses, etc. Widely used in other general industrial applications.
  • carbon fibers have the highest specific strength and specific elastic modulus, and the weight of the member can be greatly reduced. Therefore, the practical use is progressing in the above-mentioned fields, and the reinforcing fibers used for SMC are also conventional. Replacement of glass fiber with carbon fiber is progressing.
  • the SMC is cut smaller than the shape of the molded body before pressing and placed on the mold, and molding is performed while flowing into the shape of the molded body by pressing.
  • the mechanical strength properties of the molded body are likely to deteriorate and vary.
  • Patent Document 1 discloses a method in which a carbon fiber bundle (strand) is opened and then cut to obtain a thin chopped carbon fiber bundle, which is then impregnated with a thermosetting resin to form SMC.
  • Patent Document 2 discloses an SMC in which the thickness of a fiber bundle is controlled to a specific thickness or less.
  • the chopped carbon fiber bundle is deformed at the time of pressure molding, and mechanical strength such as tensile strength, tensile elastic modulus, bending strength, and bending elastic modulus is sufficiently high. It may be difficult to obtain a molded body (fiber reinforced composite material produced using SMC).
  • An object of the present invention is to provide an SMC manufacturing method and a carbon fiber bundle capable of manufacturing an SMC from which a molded article having high mechanical strength such as tensile strength, tensile elastic modulus, bending strength and bending elastic modulus can be obtained. .
  • the present invention has the following configuration.
  • a method for producing a sheet molding compound comprising impregnating a matrix resin composition into a plurality of chopped carbon fiber bundles obtained by cutting long carbon fiber bundles, The fiber length of the chopped carbon fiber bundle is 1 to 60 mm, A method for producing a sheet molding compound, wherein the bulk density of the carbon fiber bundle calculated by the following method (I) is 60 to 400 g / L. (Method (I)) (Procedure I-1) 100 g of a chopped carbon fiber bundle for testing obtained by cutting a carbon fiber bundle with a rotary cutter so that the fiber length is 25 mm is filled in a 2 L measuring cylinder (cylindrical shape having a diameter of 88 mm and a height of 485 mm).
  • the test carbon fiber bundle is placed on the horizontal plane of a measuring table having a horizontal plane and a slope having an inclination angle of 45 degrees inclined downward from one end of the horizontal plane.
  • the first end of the carbon fiber bundle in the length direction is aligned with the boundary line A between the inclined surface and the horizontal plane, a pressing plate is placed on the test carbon fiber bundle, and the end of the pressing plate is Align with boundary A.
  • the pressing plate is moved to the slope side in the horizontal direction at 2 cm / second, and the pressing plate is moved when the first end portion of the test carbon fiber bundle comes into contact with the slope. Stop.
  • the movement distance x (mm) of the pressing plate in the procedure II-3 is measured.
  • the content of the chopped carbon fiber bundle is 40 to 70% by mass with respect to the mass of the sheet molding compound, and the basis weight of the carbon fiber substrate made of the chopped carbon fiber bundle is 500 to 2500 mg / m 2.
  • the matrix resin composition is Component (A): a component comprising a compound having one or more ethylenically unsaturated groups in the molecule, Component (B): diisocyanate compound, The method for producing a sheet molding compound according to any one of [1] to [6], comprising: component (C): a polymerization inhibitor; and component (D): a polymerization initiator.
  • component (A) includes at least one selected from the group consisting of the following component (A-1) and the following component (A-2).
  • component (A-1) an unsaturated polyester resin having one or more ethylenically unsaturated groups and one or more hydroxyl groups in one molecule.
  • Component (A-2) An epoxy (meth) acrylate resin having one or more ethylenically unsaturated groups and one or more hydroxyl groups in the molecule.
  • component (C) is a polymerization inhibitor having no hydroxyl group in the molecule and reacts with an active radical species that causes radical polymerization at a temperature of 100 ° C.
  • Manufacturing method of sheet molding compound [12]
  • the bulk density calculated by the following method (I) is 60 to 400 g / L, and the average width W (mm) and the average thickness H (mm) satisfy the following formulas (1) and (2). Carbon fiber bundle.
  • the test carbon fiber bundle is placed on the horizontal plane of a measuring table having a horizontal plane and a slope having an inclination angle of 45 degrees inclined downward from one end of the horizontal plane.
  • the first end of the carbon fiber bundle in the length direction is aligned with the boundary line A between the inclined surface and the horizontal plane, a pressing plate is placed on the test carbon fiber bundle, and the end of the pressing plate is Align with boundary A.
  • the pressing plate is moved to the slope side in the horizontal direction at 2 cm / second, and the pressing plate is moved when the first end portion of the test carbon fiber bundle comes into contact with the slope. Stop.
  • the movement distance x (mm) of the pressing plate in the procedure II-3 is measured.
  • an SMC from which a molded body having high mechanical strength such as tensile strength, tensile elastic modulus, bending strength, bending elastic modulus and the like can be obtained.
  • FIG. 5 is a schematic diagram for explaining procedures II-1 and II-2 in measuring a cantilever value by a method (II).
  • FIG. 6 is a schematic diagram for explaining procedures II-3 and II-4 in measurement of a cantilever value by a method (II). It is a schematic diagram explaining the procedure II-5 in the measurement of the cantilever value by the method (II). It is a schematic diagram explaining the procedure II-5 in the measurement of the cantilever value by the method (II).
  • the SMC manufacturing method of the present invention includes impregnating a matrix resin composition into a plurality of chopped carbon fiber bundles obtained by cutting long carbon fiber bundles.
  • the chopped carbon fiber bundle has a fiber length of 1 to 60 mm, and the bulk density calculated by the method (I) described later is 60 to 60 mm as a long carbon fiber bundle to be cut.
  • a carbon fiber bundle that is 400 g / L is used.
  • the long carbon fiber bundle to be cut preferably has a cantilever value calculated by the method (II) described later of 100 mm or more.
  • Carbon fiber bundle Examples of the carbon fiber constituting the carbon fiber bundle include polyacrylonitrile (PAN) -based carbon fiber, rayon-based carbon fiber, and pitch-based carbon fiber.
  • PAN polyacrylonitrile
  • the number of filaments in the carbon fiber bundle is usually about 1000 to 60000.
  • a long carbon fiber bundle cut to obtain a plurality of chopped carbon fiber bundles has a bulk density of 60 to 400 g / L calculated by the method (I) described later.
  • the bulk density calculated by the method (I) is a value that artificially represents the bulk density of a carbon fiber substrate made of a chopped carbon fiber bundle for producing SMC.
  • the bulk density of the long carbon fiber bundles cut to obtain a plurality of chopped carbon fiber bundles measured by the method (I) is 60 to 400 g / L, preferably 70 to 350 g / L, 80 Is more preferably from 320 to 320 g / L, further preferably from 100 to 280 g / L, particularly preferably from 130 to 250 g / L. If the bulk density of the carbon fiber bundles measured by the method (I) is within the above range, the chopped carbon fiber bundles are strongly entangled in the SMC, so that a high-strength molded product can be obtained.
  • the bulk density varies depending on the cantilever value of the carbon fiber bundle
  • the value of the bulk density of the carbon fiber bundle within the above range, it becomes possible to achieve both the rigidity of the chopped carbon fiber bundle and the resin impregnation property.
  • the mechanical strength characteristics can be improved.
  • the bulk density of the carbon fiber bundle measured by the method (I) is 60 g / L or more, since the resin impregnation property during SMC production is excellent, the mechanical properties of the molded body are improved.
  • the bulk density of the carbon fiber bundle measured by the method (I) is preferably 70 g / L or more, more preferably 80 g / L or more, still more preferably 100 g / L or more, and particularly preferably 130 g / L. L or more.
  • the bulk density of the carbon fiber bundle measured by the method (I) is 400 g / L or less, the chopped carbon fiber bundles are strongly entangled with each other in the SMC, so that a high-strength molded product can be obtained.
  • the bulk density of the carbon fiber bundle measured by the method (I) is preferably 350 g / L or less, more preferably 320 g / L or less, further preferably 280 g / L or less, particularly preferably 250 g / L. L or less.
  • the long carbon fiber bundle cut to obtain a plurality of chopped carbon fiber bundles further has a cantilever value calculated by the method (II) described later of 100 mm or more.
  • Test carbon fiber bundle 100 having a length of 40 cm is cut out from the carbon fiber bundle.
  • a test is carried out on a horizontal plane 12 of a measuring table 10 having a horizontal plane 12 and an inclined plane 14 inclined downward from one end of the horizontal plane 12 and having an inclination angle of 45 degrees.
  • the carbon fiber bundle 100 for use is mounted.
  • the first end portion 102 in the length direction of the test carbon fiber bundle 100 is aligned with the boundary line A between the slope 14 and the horizontal plane 12.
  • the pressing plate 200 is placed on the test carbon fiber bundle 100 and the end 202 of the pressing plate 200 is aligned with the boundary line A.
  • the size of the pressing plate 200 may be any size as long as it does not hinder measurement, and can be, for example, a plate having a length of 1000 mm ⁇ width of 200 mm ⁇ thickness of 5 mm.
  • the weight of the pressing plate 200 may be a weight that does not hinder measurement, and can be set to, for example, 1000 g.
  • the cantilever value of the long carbon fiber bundle cut to obtain a plurality of chopped carbon fiber bundles measured by the method (II) is preferably 100 mm or more, more preferably 120 mm or more and 300 mm or less, and 130 mm or more and 200 m or less. Is more preferable, and 140 mm or more and 190 mm or less are particularly preferable.
  • the cantilever value of the carbon fiber bundle measured by the method (II) is 100 mm or more, the carbon fiber bundle becomes a rigid strand, and the thickness of the carbon fiber bundle does not change suddenly when impregnated with the matrix resin composition after cutting. . That is, the chopped carbon fiber bundle is disturbed during SMC production, and the width and thickness of the carbon fiber bundle can be prevented from changing suddenly due to folding or bending. Moreover, it can suppress that the thickness of a chopped carbon fiber bundle changes rapidly at the time of shaping
  • the cantilever value of the carbon fiber bundle measured by the method (II) is more preferably 120 mm or more, further preferably 130 mm or more, and particularly preferably 140 mm or more.
  • the cantilever value of the carbon fiber bundle measured by the method (II) is 300 mm or less, since the resin impregnation property at the time of SMC production is excellent, the mechanical properties of the molded body tend to be improved, which is more preferable.
  • the cantilever value of the carbon fiber bundle measured by the method (II) is more preferably 200 mm or less, and particularly preferably 190 mm or less.
  • the cantilever value of the carbon fiber bundle can be adjusted by the composition and amount of the sizing agent that adheres to the carbon fiber bundle.
  • the cantilever value of the carbon fiber bundle in the present invention is the carbon to which the sizing agent is attached. It is a measured value about a fiber bundle.
  • a carbon fiber bundle to which a sizing agent is attached may be used as a long carbon fiber bundle cut to obtain a plurality of chopped carbon fiber bundles.
  • the sizing agent attached to the carbon fiber bundle is not particularly limited, and a sizing agent usually used for the carbon fiber bundle can be used.
  • the method for adhering the sizing agent to the carbon fiber bundle is not particularly limited, and examples thereof include a method of applying a sizing agent solution in which the sizing agent is dispersed or dissolved in water or an organic solvent to the carbon fiber bundle and drying it. Examples of the method for applying the sizing solution to the carbon fiber bundle include a roller dipping method and a roller contact method.
  • the adhesion amount of the sizing agent in the carbon fiber bundle is preferably 0.1 to 3.0% by mass, and more preferably 0.5 to 2.0% by mass with respect to the total mass of the carbon fiber bundle and the sizing agent. If the adhesion amount of the sizing agent in the carbon fiber bundle is equal to or more than the lower limit value, good convergence is easily secured when the carbon fiber bundle is cut. If the adhesion amount of the sizing agent in the carbon fiber bundle is equal to or less than the upper limit value, the chopped carbon fiber bundle is easily dispersed uniformly in the SMC.
  • the amount of the sizing agent attached to the carbon fiber bundle can be adjusted by the concentration of the sizing agent liquid and the amount of squeezing.
  • the bulk density calculated by the method (I) is 60 to 400 g / L, and preferably the long cantilever value calculated by the method (II) is 100 mm or more.
  • Impregnating a matrix resin composition into a plurality of chopped carbon fiber bundles obtained by cutting the carbon fiber bundle (hereinafter also referred to as “impregnation step”).
  • a cutting process and a thickening process may be included other than said impregnation process, for example.
  • Cutting step In order to obtain a plurality of chopped carbon fiber bundles prior to the impregnation step, the bulk density calculated by the method (I) is 60 to 400 g / L, preferably further calculated by the method (II). A long carbon fiber bundle having a cantilever value of 100 mm or more is cut.
  • Impregnation step In order to obtain the SMC precursor, a matrix resin composition is impregnated into a carbon fiber substrate made of a plurality of chopped carbon fiber bundles obtained in the cutting step. Thickening step: After the impregnation step, the matrix resin composition in the SMC precursor is thickened to obtain SMC.
  • a method for cutting a long carbon fiber bundle to obtain a plurality of chopped carbon fiber bundles is not particularly limited, but a rotary cutter method is preferred from the viewpoint of mass productivity.
  • a rotary cutter method is preferred from the viewpoint of mass productivity.
  • the carbon fiber bundle is preferably thinner.
  • the fiber length of the chopped carbon fiber bundle obtained in the cutting step is 1 to 60 mm, and preferably 1 to 25 mm. If the fiber length of the chopped carbon fiber bundle is not less than the lower limit, a molded article having high mechanical strength can be easily obtained. If the fiber length of the chopped carbon fiber bundle is equal to or less than the upper limit, good fluidity can be easily obtained when press molding SMC.
  • mm) preferably satisfies the following formulas (1) and (2). 0.05 ⁇ H ⁇ 0.2 (1) 10 ⁇ W / H ⁇ 40 (2)
  • average width W (mm) and average thickness H (mm) are the average values of the width and thickness measured about 300 chopped carbon fiber bundles.
  • the average thickness H of the chopped carbon fiber bundle is preferably 0.05 mm or more and 0.2 mm or less, more preferably 0.07 mm or more and 0.15 mm or less, and further preferably 0.08 mm or more and 0.13 mm or less.
  • the average thickness H of the chopped carbon fiber bundle is more preferably 0.07 mm or more, and further preferably 0.08 mm or more.
  • the average thickness H of the chopped carbon fiber bundle is 0.2 mm or less, a molded article having high mechanical strength is easily obtained.
  • the average thickness H of the chopped carbon fiber bundle is more preferably 0.15 mm or less, and still more preferably 0.13 mm or less.
  • W / H is preferably 10 or more and 40 or less, and more preferably 15 or more and 30 or less. If W / H is the said range, a molded object with high mechanical strength will be easy to be obtained.
  • the average width W of the chopped carbon fiber bundle is preferably 2.5 mm or less, more preferably 2.0 mm or less, further preferably 1.8 mm or less, and particularly preferably 1.5 mm or less.
  • the lower limit value of the average width W of the chopped carbon fiber bundle is substantially about 0.5 mm.
  • the average width W and average thickness H of the chopped carbon fiber bundle can be adjusted by the width and thickness of the long carbon fiber bundle that is cut to obtain a plurality of chopped carbon fiber bundles immediately before cutting.
  • the width and thickness of a long carbon fiber bundle that is cut to obtain a carbon fiber bundle is adjusted immediately before cutting in the cutting process by, for example, opening with air or vibration, or splitting with multiple blades. May be.
  • the method of impregnating the matrix resin composition into the carbon fiber substrate composed of a plurality of chopped carbon fiber bundles obtained in the cutting step is not particularly limited, but examples thereof include the following methods. It is done. A matrix resin composition is applied to each of the two carrier films to form a matrix resin composition layer. In order to form a carbon fiber substrate composed of chopped carbon fiber bundles on the matrix resin composition layer of one carrier film, the chopped carbon fiber bundles are spread on the matrix resin composition layer so that the fiber directions are random. .
  • the other carrier film is laminated so that the matrix resin composition layer side faces the carbon fiber base material side, and is pressed from above and below, and between the carbon fiber bundles of the carbon fiber base material and in the carbon fiber bundle Impregnated with a matrix resin composition.
  • the carrier film is not particularly limited, and for example, a polypropylene film can be used.
  • the coating amount of the matrix resin composition and the application amount of the chopped carbon fiber bundle can be appropriately set according to the content of the carbon fiber bundle in the obtained SMC precursor.
  • the content of the chopped carbon fiber bundle in the SMC precursor is preferably 40 to 70% by mass and more preferably 45 to 60% by mass with respect to the total mass of the SMC precursor.
  • the content of the chopped carbon fiber bundle in the SMC precursor is equal to or higher than the lower limit value, the reinforcing effect by the chopped carbon fiber bundle is sufficiently exhibited, and a molded body with higher mechanical strength is easily obtained. If the content of the chopped carbon fiber bundle in the SMC precursor is less than or equal to the above upper limit value, the fluidity during SMC molding is more excellent.
  • the basis weight of the carbon fiber substrate formed of the chopped carbon fiber bundle formed on the matrix resin composition layer of one carrier film can be set to, for example, 500 to 2500 mg / m 2 .
  • matrix resin compositions include thermosetting resins such as epoxy resins, phenol resins, unsaturated polyester resins, vinyl ester resins, phenoxy resins, alkyd resins, urethane resins, urea resins, melamine resins, maleimide resins, and cyanate resins.
  • Thermoplastic resins such as polyolefin resins, polyamide resins, polyester resins, polyphenylene sulfide resins, polyether ketone resins, polyether sulfone resins, aromatic polyamide resins can be used, and are not particularly limited. However, the thing containing the below-mentioned component (A), component (B), and component (C) is mentioned, for example.
  • the matrix resin composition contains the component (A), the component (B), and the component (C)
  • the impregnation property of the matrix resin composition into the carbon fiber bundle during SMC production is excellent. Therefore, it is easy to obtain a molded body having higher mechanical strength.
  • the fluidity of the SMC during storage and transportation is prevented from being lowered over time, and the flow stability is excellent. Therefore, SMC can be molded well even after long-term storage.
  • the matrix resin composition further includes a component (D) in addition to the component (A), the component (B), and the component (C).
  • the matrix resin composition may further contain other components other than the component (A), the component (B), the component (C), and the component (D) as long as they do not impair the effects of the present invention. Good.
  • Component (A) is a component composed of a compound having one or more ethylenically unsaturated groups in one molecule.
  • the component (A) is preferably a component composed of a compound having one or more ethylenically unsaturated groups and one or more hydroxyl groups in one molecule.
  • the component (A) preferably contains at least one selected from the group consisting of the following component (A-1) and the following component (A-2).
  • Component (A-1) an unsaturated polyester resin having one or more ethylenically unsaturated groups and one or more hydroxyl groups in the molecule.
  • Component (A-2) An epoxy (meth) acrylate resin having one or more ethylenically unsaturated groups and one or more hydroxyl groups in one molecule.
  • a matrix resin composition has thermosetting because a matrix resin composition contains the component (A) which has an ethylenically unsaturated group.
  • the component (A) contains at least one selected from the group consisting of unsaturated polyester resins and epoxy (meth) acrylate resins, the polymerizability at the time of curing of the matrix resin composition is more excellent. Since the unsaturated polyester resin or the epoxy (meth) acrylate resin has a hydroxyl group, the matrix resin composition can be thickened in combination with the component (B).
  • the compound constituting the component (A) may be one kind or two or more kinds.
  • the compound constituting Component (A) is one kind, the compound is at least one selected from the group consisting of Component (A-1) and Component (A-2).
  • all of these compounds may be at least one selected from the group consisting of component (A-1) and component (A-2).
  • a part of the compound is at least one selected from the group consisting of the component (A-1) and the component (A-2), and the remainder is other compounds (for example, a polymerizable vinyl monomer described later).
  • component (A) contains other compounds, the other compounds may be compounds having one or more hydroxyl groups in one molecule, or may be compounds having no hydroxyl groups, There may be.
  • Component (A-1) can be appropriately selected from known unsaturated polyester resins.
  • the number of ethylenically unsaturated groups in the molecule of component (A-1) may be one or more. If the number of ethylenically unsaturated groups is not more than the above upper limit, the polymerizability at the time of curing of the matrix resin composition is more excellent.
  • Component (A-1) preferably has 1 to 2.5 hydroxyl groups in one molecule.
  • the number of hydroxyl groups is at least the lower limit, the thickening property of the matrix resin composition is more excellent when combined with the component (B). If the number of hydroxyl groups is less than or equal to the above upper limit, the fluidity of the matrix resin composition is more excellent when combined with the component (B).
  • Component (A-1) is typically an unsaturated polyester resin ( ⁇ , ⁇ -olefinic unsaturated dicarboxylic acid synthesized by condensation of an ⁇ , ⁇ -olefinic unsaturated dicarboxylic acid and a divalent glycol. And a polycondensate of divalent glycol).
  • dicarboxylic acids other than ⁇ , ⁇ -olefinic unsaturated dicarboxylic acids saturated dicarboxylic acids, aromatic dicarboxylic acids, etc.
  • dicyclopentadiene that reacts with dicarboxylic acids
  • Alcohols other than divalent glycol monovalent alcohol (monool), trivalent alcohol (triol), etc.
  • divalent glycol monovalent alcohol (monool), trivalent alcohol (triol), etc.
  • Examples of the ⁇ , ⁇ -olefin unsaturated dicarboxylic acid include maleic acid, fumaric acid, itaconic acid, citraconic acid, and anhydrides of these dicarboxylic acids. Of these, fumaric acid is preferred.
  • Examples of the divalent glycol include alkanediol, oxaalkanediol, and an alkylene oxide adduct of bisphenol A.
  • Examples of the alkylene oxide include ethylene oxide and propylene oxide.
  • alkanediol examples include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1, Examples include 6-hexanediol and cyclohexanediol.
  • oxaalkanediol include dioxyethylene glycol, dipropylene glycol, and triethylene glycol.
  • neopentyl glycol and dipropylene glycol are preferable as the divalent glycol.
  • Examples of monovalent or trivalent alcohol that can be used in combination with glycol include octyl alcohol, oleyl alcohol, trimethylolpropane, and the like.
  • Component (A-2) can be appropriately selected from known epoxy (meth) acrylate resins.
  • the number of ethylenically unsaturated groups contained in one molecule of component (A-2) is preferably 1 to 2. If the number of ethylenically unsaturated groups is not more than the above upper limit, the polymerizability at the time of curing of the matrix resin composition is more excellent.
  • Component (A-2) preferably has 1 to 2.5 hydroxyl groups in one molecule.
  • the number of hydroxyl groups is at least the lower limit, the thickening property of the matrix resin composition is more excellent when combined with the component (B). If the number of hydroxyl groups is less than or equal to the above upper limit, the fluidity of the matrix resin composition is more excellent when combined with the component (B).
  • Component (A-2) is typically an unsaturated acid epoxy ester obtained from the reaction of an epoxy resin component and an unsaturated monobasic acid component.
  • the epoxy resin component is a compound having at least two epoxy groups in one molecule, for example, a diglycidyl ether type epoxy resin having a bisphenol compound represented by bisphenol A, bisphenol F, or brominated bisphenol A as a main skeleton.
  • the unsaturated monobasic acid component is a monobasic acid having an ethylenically unsaturated group, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, and sorbic acid. These unsaturated monobasic acid components may be used individually by 1 type, and may use multiple types together. Among the above, acrylic acid is preferable as the unsaturated monobasic acid component.
  • Component (A-1) and Component (A-2) may be used alone or in combination of two or more.
  • Component (A) may further contain a compound other than component (A-1) and component (A-2).
  • the other compound is not particularly limited as long as it is a compound having an ethylenically unsaturated group.
  • an unsaturated polyester resin other than a polymerizable vinyl monomer and component (A-1) for example, having a hydroxyl group.
  • Non-unsaturated polyester resin), epoxy (meth) acrylate resins other than component (A-2) for example, epoxy (meth) acrylate resins having no hydroxyl group
  • the polymerizable vinyl monomer is a monomer having an ethylenically unsaturated group.
  • the polymerizable vinyl monomer functions as a reactive diluent.
  • examples of the polymerizable vinyl monomer include a polymerizable vinyl monomer having no hydroxyl group such as styrene and vinyl chloride; a polymerizable vinyl monomer having a hydroxyl group such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate. Examples include a polymer. These polymerizable vinyl monomers may be used individually by 1 type, and may use multiple types together.
  • Examples of unsaturated polyester resins other than component (A-1) and epoxy (meth) acrylate resins other than component (A-2) include unsaturated polyester resins and epoxy (meth) acrylate resins commonly used as SMC materials. It can be selected appropriately.
  • the total content of component (A-1) and component (A-2) in component (A) is preferably 90% by mass or more, more preferably 95% by mass or more based on the total mass of component (A). Preferably, 100 mass% is most preferable. That is, the component (A) is most preferably composed of only one or both of the component (A-1) and the component (A-2).
  • Component (B) is a diisocyanate compound. Component (B) acts as a thickener in the matrix resin composition. When the component (A) has a hydroxyl group, the hydroxyl group of the component (A) reacts with the isocyanate group of the component (B) to produce an ethylenically unsaturated group-containing prepolymer. Cause it to occur.
  • component (B) examples include a diisocyanate compound (B-1) and a diisocyanate prepolymer (B-2) represented by the formula: OCN—R 1 —NCO (where R 1 is a hydrocarbon group). And modified products thereof.
  • diisocyanate compound (B-1) examples include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and the like.
  • Examples of the diisocyanate prepolymer (B-2) include a diisocyanate prepolymer having an isocyanate group at both ends obtained by a reaction between a polyether polyol or polyester polyol having a hydroxyl group and a diisocyanate compound (B-1). .
  • Component (C) is a polymerization inhibitor.
  • Component (C) preferably has no hydroxyl group and can react with an active radical species to generate an inactive radical species or a stable compound.
  • the component (C) is a polymerization inhibitor having no hydroxyl group in the molecule, and reacts with an active radical species that causes radical polymerization at a temperature of 100 ° C. or higher and does not cause radical polymerization. It preferably has an effect of forming an inert radical or a stable compound.
  • the action of reacting with an active radical species that causes radical polymerization to form an inert radical or a stable compound that does not cause radical polymerization is, in short, an action of capturing active radical species, a so-called polymerization inhibiting action.
  • the component (C) is preferably a polymerization inhibitor that exhibits a polymerization inhibiting action at a temperature of 100 ° C. or higher.
  • the matrix resin composition contains the component (C)
  • active radical species for example, radicals generated from the component (D) described later
  • active radical species generated in a trace amount during the thickening step described later are captured by the component (C).
  • the progress of reaction polymerization of component (A), crosslinking reaction, etc.
  • active radical species due to active radical species is suppressed. For this reason, the fall of the fluidity
  • the temperature at which component (C) exhibits a polymerization inhibiting action is preferably 100 to 140 ° C.
  • the temperature at which the polymerization inhibitor such as component (C) exhibits a polymerization inhibiting action can be confirmed by differential scanning calorimetry (DSC).
  • Component (C) preferably has no hydroxyl group in the molecule.
  • the polymerization inhibitors exhibiting the polymerization inhibiting action as described above there are compounds having a hydroxyl group such as hydroquinone.
  • the polymerization inhibitor and the isocyanate group of the component (B) react.
  • the isocyanate group which originally reacted with the component (A) and expected to act as a thickener is lost, so that the thickening effect is inhibited.
  • the radical scavenging action as a polymerization inhibitor does not act sufficiently due to this reaction, the radical scavenging action near the molding temperature of SMC (120 to 160 ° C.) does not work sufficiently, and the fluidity during molding is low. Damaged. Since component (C) does not have a hydroxyl group, the thickening effect is not inhibited, and the fluidity during molding is not impaired.
  • the component (C) is not particularly limited as long as it satisfies the above conditions, and can be appropriately selected from various compounds generally known as polymerization inhibitors.
  • Preferred examples of component (C) include p-benzoquinone, naphthoquinone, phenanthraquinone, p-xyloquinone, p-toluquinone, 2,6-dichloroquinone, 2,5-diphenyl-p-benzoquinone, 2,5-diacetoxy And quinones such as -p-benzoquinone and 2,5-dicaproxy-p-benzoquinone.
  • These quinones have a very strong trapping action of radicals generated from the component (D) described later, particularly radicals generated from organic peroxides, and remarkably suppress a decrease in fluidity during molding. The property is particularly excellent.
  • These quinones may be used individually by 1 type, and may use multiple types together. Among these, as the component (C), p-benzoquinone is preferable.
  • Examples of the hydroxyl group-containing compound exhibiting the above-described polymerization inhibiting action at a temperature of 100 ° C. or higher include catechols such as catechol and t-butylcatechol, hydroquinone, pt-butylcatechol, 2,5-t- And hydroquinones such as butyl hydroquinone and mono-t-butyl hydroquinone. These compounds, like quinones, have a very strong radical scavenging action. However, since it has a hydroxyl group, there are concerns that the thickening effect is inhibited and the radical scavenging action does not sufficiently work.
  • Component (D) is a polymerization initiator. There is no restriction
  • component (D) examples include 1,1-di (t-butylperoxy) cyclohexane, t-butylperoxyisopropyl carbonate, t-amyl peroxyisopropyl carbonate, methyl ethyl ketone peroxide, t-butyl peroxybenzoate, Organic peroxides such as benzoyl peroxide, dicumyl peroxide, cumene hydroperoxide and the like can be mentioned. These organic peroxides may be used individually by 1 type, and may use multiple types together.
  • components other than component (A), component (B), component (C), and component (D) that can be included in the matrix resin composition include inorganic fillers, internal mold release agents, stabilizers, Examples thereof include additives such as pigments and colorants.
  • the type of the inorganic filler is not particularly limited, and examples thereof include calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, silica, fused silica, barium sulfate, titanium oxide, magnesium oxide, calcium oxide, and oxidation.
  • Known materials such as aluminum, calcium phosphate, talc, mica, clay, and glass powder can be used. These inorganic fillers may be used individually by 1 type, and may use multiple types together.
  • the type of the internal mold release agent is not particularly limited, and known materials such as phosphate ester derivatives, fatty acid metal salts such as zinc stearate, and surfactants such as sodium dialkylsulfosuccinate can be used. . These internal mold release agents may be used individually by 1 type, and may use multiple types together.
  • the content of the component (A) in the matrix resin composition is preferably 50 to 95% by mass and more preferably 60 to 85% by mass with respect to the total mass of the matrix resin composition. If content of the component (A) in a matrix resin composition is more than the said lower limit, the mechanical characteristics of the molded object obtained will be more excellent. When the content of the component (A) in the matrix resin composition is not more than the above upper limit value, the impregnation property of the matrix resin composition into the carbon fiber bundle at the time of SMC production is more excellent.
  • the content of component (B) in the matrix resin composition is preferably such that the number of isocyanate groups in component (B) relative to one hydroxyl group in component (A) is 0.1 or more and 1.0 or less. If the number of isocyanate groups in component (B) relative to one hydroxyl group in component (A) is 0.1 or more, the matrix resin composition can be sufficiently thickened. If the number of isocyanate groups in component (B) relative to one hydroxyl group in component (A) is 1.0 or less, excess isocyanate groups react with moisture and foam, and after molding, bubbles are formed (that is, (Fiber-reinforced composite material) can be prevented from remaining inside.
  • the number of the isocyanate groups of the component (B) with respect to one hydroxyl group which a component (A) has are more preferable.
  • the content of the component (B) in the matrix resin composition is preferably 5 to 25% by mass and more preferably 15 to 25% by mass with respect to the total mass of the matrix resin composition.
  • the content of the component (C) in the matrix resin composition is preferably 0.001 to 0.1 parts by mass and more preferably 0.03 to 0.05 parts by mass with respect to 100 parts by mass of the component (A). If content of the component (C) in a matrix resin composition is more than the said lower limit, SMC will show sufficient fluidity at the time of heat press molding. In addition, the fluidity is less likely to deteriorate over time. If content of the component (C) in a matrix resin composition is below the said upper limit, a sufficiently quick hardening rate will be obtained at the time of heat-press molding, and it will be excellent in quick curability. Further, the cured product is sufficiently cross-linked, and excellent surface direction quality can be obtained.
  • the content of the component (D) in the matrix resin composition is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass with respect to 100 parts by mass of the component (A). If content of the component (D) in a matrix resin composition is more than the said lower limit, a sufficiently quick hardening rate will be obtained at the time of heat-press molding, and it will be excellent in quick curability. If content of the component (D) in a matrix resin composition is below the said upper limit, SMC will show sufficient fluidity
  • the matrix resin composition may further contain, as another component, a compound having a hydroxyl group that exhibits the above-described polymerization inhibiting action at a temperature of 100 ° C. or higher.
  • this compound having a hydroxyl group may cause problems such as inhibiting the thickening effect and insufficient radical scavenging action. Therefore, in the matrix resin composition, the content of the compound having a hydroxyl group that exhibits the above-described polymerization inhibition action at a temperature of 100 ° C. or higher is preferably as low as possible. For example, 0.01 mass with respect to 100 mass parts of the component (A) Part or less is preferable, and it is particularly preferable not to include it.
  • the viscosity of the SMC precursor after initial thickening at 25 ° C. is preferably 10 to 500 Pa ⁇ s, and more preferably 20 to 300 Pa ⁇ s.
  • “initial thickening” means the viscosity when the SMC precursor is held at 25 ° C. for 60 minutes. If the viscosity of the SMC precursor after initial thickening at 25 ° C. is not more than the above upper limit, the impregnation property of the matrix resin composition into the carbon fiber bundle is more excellent. If the viscosity of the SMC precursor after initial thickening at 25 ° C. is equal to or higher than the lower limit value, the SMC has sufficient shape retention and handling properties are more excellent.
  • the matrix resin composition can be prepared by mixing the component (A), the component (B), and the component (C), and the component (D) and other components used as necessary.
  • a mixing method it is only necessary to uniformly disperse or dissolve each component, and a conventionally used general method can be used.
  • the components constituting the matrix resin composition may be prepared by mixing at the same time, or if necessary, components other than component (B) may be mixed in advance, and the resulting mixture and component (B) May be mixed immediately before the impregnation step.
  • a mixer such as a three-roll mill, a planetary mixer, a kneader, a universal stirrer, a homogenizer, or a homodispenser can be used, but is not limited thereto.
  • the method of thickening the matrix resin composition in the SMC precursor is not particularly limited.
  • the SMC precursor can be thickened by reacting the component (A) and the component (B) in the matrix resin composition impregnated in the fiber base material.
  • substantially isothermal means that the fluctuation of the holding temperature is ⁇ 5 ° C. or less.
  • the holding temperature and time can be appropriately set according to the type and amount of component (A) and component (B).
  • the holding temperature is about 10 to 50 ° C.
  • the holding time is about several days to several tens of days (for example, 7 to 50 days).
  • the SMC obtained by the production method described above includes a plurality of chopped carbon fiber bundles and a thickened material of the matrix resin composition.
  • a thickened material of the matrix resin composition As described above, when the hydroxyl group of component (A) in the matrix resin composition reacts with the isocyanate group of component (B), an ethylenically unsaturated group-containing prepolymer is produced, and the matrix resin composition is thickened. To do. Therefore, the thickened material of the matrix resin composition contains an ethylenically unsaturated group-containing prepolymer. On the other hand, the matrix resin composition before thickening does not substantially contain an ethylenically unsaturated group-containing prepolymer.
  • the preferable range of the content of the carbon fiber bundle with respect to the total mass of the SMC is the same as the preferable range of the content of the carbon fiber bundle with respect to the total mass of the SMC precursor.
  • the basis weight of the carbon fiber bundle in SMC can be set to, for example, 500 to 2500 mg / m 2 .
  • a molded body that is a fiber-reinforced composite material is obtained.
  • the molded product obtained using the SMC produced by the production method of the present invention may be obtained by using only the SMC produced by the production method of the present invention, and produced by the production method of the present invention. It may be obtained by combining the manufactured SMC and another member.
  • the molding conditions for molding the SMC are not particularly limited, and examples include conditions of heating and pressurizing for 2 minutes under conditions of a mold temperature of 140 ° C. and a pressure of 8 MPa. It does not specifically limit as a molded object, For example, the molded object which has a partially different thickness, a rib, the boss
  • the usage of the molded body is not particularly limited, and examples thereof include an automobile outer plate, an interior material, and a structural material.
  • the bulk density calculated by the method (I) is 60 to 400 g / L, and preferably the cantilever value calculated by the method (II) is 100 mm or more.
  • a plurality of chopped carbon fiber bundles obtained by cutting the length carbon fiber bundle is impregnated with the matrix resin composition to produce SMC.
  • the thickness of the chopped carbon fiber bundle is less likely to change suddenly during SMC manufacturing or molding.
  • the chopped carbon fiber bundles are rigid, and the chopped carbon fiber bundles easily form a three-dimensional network. Therefore, it is possible to produce an SMC from which a molded body having high mechanical strength such as tensile strength, tensile elastic modulus, bending strength and bending elastic modulus can be obtained.
  • the bulk density calculated by the method (I) is 60 to 400 g / L, and the average width W (mm) and the average thickness H (mm) are the above formulas (1) and (2).
  • a long carbon fiber bundle satisfying the above can be used. Since such a long carbon fiber bundle is excellent in cutting stability, the shape stability of the chopped carbon fiber bundle obtained when used in the cutting process tends to be good. Further, by using a long carbon fiber bundle whose cantilever value calculated by the method (II) is 100 mm or more, the mechanical properties of the molded product can be further enhanced.
  • the manufacturing method of SMC of this invention is not limited to the said method, The addition of a structure, omission, substitution, and other changes are possible within the range which does not deviate from the meaning of this invention.
  • Carbon fiber bundle (I) Carbon fiber bundle having 15,000 filaments (manufactured by Mitsubishi Chemical Corporation, TR50S 15L).
  • Component (A) A mixture of an epoxy (meth) acrylate resin and an unsaturated polyester resin (manufactured by Nippon Iupika Co., Ltd., product name: Neopol (registered trademark) 8113).
  • Component (B) > Component (B1): Modified diphenylmethane diisocyanate (Mitsui Chemicals, product name: Cosmonate (registered trademark) LL).
  • Component (D1) 75% by mass solution of 1,1-di (t-butylperoxy) cyclohexane (manufactured by NOF Corporation, product name: Perhexa (registered trademark) C-75 (EB)).
  • Component (D2) 74% by mass solution of t-butylperoxyisopropyl carbonate (manufactured by Kayaku Akzo Co., Ltd., product name: Kayacarbon (registered trademark) BIC-75).
  • Component (E1) Internal mold release agent (phosphate ester derivative composition) (manufactured by Accel Plastic Research Laboratory, product name: MOLD WIZ INT-EQ-6).
  • the bulk density of the carbon fiber bundle was measured by the following procedures I-1 and I-2.
  • (Procedure I-1) 100 g of a cut piece obtained by cutting a carbon fiber bundle with a rotary cutter so that the fiber length was 25 mm was filled in a 2 L graduated cylinder ( ⁇ 88 mm, columnar height 485 mm).
  • (Procedure I-2) Apply a load of 500 g uniformly from the top of the cut piece in the graduated cylinder, measure the total volume (L) of the filled cut piece when there is no change in volume, The bulk density was calculated by dividing the mass (100 g) by the total volume (L) of the cut piece.
  • the cantilever value of the carbon fiber bundle was measured by the following procedures II-1 to II-6.
  • (Procedure II-1) A test carbon fiber bundle having a length of 40 cm was cut out from the carbon fiber bundle.
  • (Procedure II-2) A test carbon fiber bundle is placed on a horizontal plane of a measuring table having a horizontal plane and a slope with an inclination angle of 45 degrees inclined downward from one end of the horizontal plane. The first end portion in the length direction was aligned with the boundary line A between the slope and the horizontal plane.
  • a pressing plate was placed on the test carbon fiber bundle, and the end of the pressing plate was aligned with the boundary line A.
  • the obtained SMC was charged into a molding die at a charge rate (ratio of SMC area to mold area) of 65%, and cured by heating and pressing for 2 minutes under the conditions of a mold temperature of 140 ° C. and a pressure of 8 MPa, A flat carbon fiber reinforced plastic (CFRP) molded body (molded plate) having a thickness of 2 mm and a 300 mm square was obtained.
  • CFRP flat carbon fiber reinforced plastic
  • tensile test pieces having a length of 250 mm and a width of 25 mm were cut out for those that could be molded without problems.
  • a strain gauge KFGS-20-120-C1-11L1M2R manufactured by Kyowa Denki Co., Ltd. was applied to the test piece, and a tensile strength / elastic modulus test was performed using a 100 kN Instron universal tester at a gauge length of 150 mm and a crosshead speed of 2.0 mm / min The tensile strength and the tensile modulus were measured.
  • the tensile strength is preferably 250 MPa or more when the carbon fiber content (carbon fiber content) is 60% by mass.
  • the tensile modulus is preferably 35 GPa or more.
  • a bending test piece having a length of 60 mm and a width of 25 mm was cut out of the obtained molded plate that could be molded without any problem.
  • the bending strength is preferably 400 MPa or more when the carbon fiber content (carbon fiber content) is 60% by mass.
  • the flexural modulus is preferably 30 GPa or more.
  • a sizing treatment carbon fiber bundle was produced by applying a sizing agent to the carbon fiber bundle (I) according to the following procedure.
  • An immersion tank having an immersion roller therein was filled with an aqueous dispersion of a sizing agent, and the carbon fiber bundle (I) was immersed in the aqueous dispersion.
  • a sizing-treated carbon fiber bundle was obtained by drying with hot air.
  • the obtained sizing-treated carbon fiber bundle was wound up on a bobbin.
  • the cantilever value of the obtained sizing-treated carbon fiber bundle was 152 mm.
  • ⁇ Preparation of matrix resin composition 100 parts by weight of component (A1), 0.5 parts by weight of component (D1), 0.5 parts by weight of component (D2), 0.35 parts by weight of component (E1), 22.0 of component (B1) Mass parts and 0.04 parts by mass of the component (C1) were sufficiently mixed and stirred using a universal stirrer to obtain a matrix resin composition.
  • the obtained matrix resin composition was applied onto a polyethylene film (carrier film) using a doctor blade so as to have a thickness of 1.0 mm, and a chopped carbon fiber bundle having a fiber length of 25 mm was coated thereon with carbon fiber. The bundle was spread so that the basis weight of the bundle was substantially uniform and the direction of the carbon fiber bundle was random.
  • the same matrix resin composition is applied on another polyethylene carrier film so as to have a thickness of 1.0 mm, and is laminated on the dispersed carbon fiber bundle so that the matrix resin composition side faces each other. Got the body. The laminate was pressed between rolls to impregnate the carbon fiber bundle with the matrix resin composition to obtain an SMC precursor.
  • the obtained SMC precursor was allowed to stand at room temperature (23 ° C.) for 168 hours (7 days). As a result, the matrix resin composition in the SMC precursor was sufficiently thickened to obtain SMC.
  • the content rate (carbon fiber content) of the carbon fiber with respect to the total mass of the obtained SMC was 50% by mass.
  • the basis weight of the carbon fiber in SMC was 2000 mg / m 2 .
  • Example 1 (Examples 2 to 7, Comparative Examples 1 to 3) Example 1 except that the cantilever value, bulk density, fiber length, average thickness H, average width W, and carbon fiber content of the sizing-treated carbon fiber bundle were changed as shown in Table 1. Thus, SMC was manufactured.
  • Table 1 shows the manufacturing conditions and evaluation results for each example.
  • Examples 1 to 3 and Examples 5 to 7 were excellent in the impregnation properties of the matrix resin composition into the carbon fiber bundle during SMC production.
  • the molded bodies obtained using the SMCs of Examples 1 to 3 and Examples 5 to 7 had higher mechanical strength than Comparative Examples 1 to 3.
  • Example 4 the impregnation property of the matrix resin composition into the carbon fiber bundle at the time of SMC production was slightly inferior, but showed higher mechanical strength than Comparative Examples 1 to 3. Moreover, in any Example, the form of the chopped carbon fiber bundle obtained at the time of SMC production was stable, and troubles due to cutting or winding of the carbon fiber bundle did not occur in the cutting step.

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Abstract

Provided are a carbon fiber bundle and a method for manufacturing a sheet molding compound, whereby a sheet molding compound can be manufactured from which a molded article having high tensile strength or tensile elasticity, and mechanical strength such as bending strength, bending elasticity, and the like is obtained. This method for manufacturing a sheet molding compound includes impregnating, with a matrix resin composition, a plurality of chopped carbon fiber bundles obtained by cutting a long carbon fiber bundle, the fiber length of the chopped carbon fiber bundles being 1-60 mm, and the bulk density of the carbon fiber bundles calculated by a specific method (I) is 60-400 g/L.

Description

シートモールディングコンパウンドの製造方法、炭素繊維束、及び炭素繊維束の使用Manufacturing method of sheet molding compound, carbon fiber bundle, and use of carbon fiber bundle
　本発明は、シートモールディングコンパウンドの製造方法、シートモールディングコンパウンドの製造に有用な炭素繊維束、及びシートモールディングコンパウンドを製造するための炭素繊維束の使用に関する。
　本願は、２０１８年５月１４日に日本出願された特願２０１８－０９２９７３号に基づき優先権を主張し、その内容をここに援用する。
　本願は、２０１８年１０月３０日に日本出願された特願２０１８－２０４３３５号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a method for producing a sheet molding compound, a carbon fiber bundle useful for producing a sheet molding compound, and the use of the carbon fiber bundle for producing a sheet molding compound.
This application claims priority based on Japanese Patent Application No. 2018-092973 filed in Japan on May 14, 2018, the contents of which are incorporated herein by reference.
This application claims priority based on Japanese Patent Application No. 2018-204335 for which it applied in Japan on October 30, 2018, and uses the content here.
　シートモールディングコンパウンド（以下、「ＳＭＣ」とも記す。）は、熱硬化性樹脂等を含むマトリックス樹脂組成物と、裁断したチョップド強化繊維束とを配合したコンパウンドである。
　ＳＭＣを金型内で加熱加圧成形すると、マトリックス樹脂組成物と強化繊維束とが一体として流動し、金型のキャビティを充填する。そのため、ＳＭＣは、部分的に肉厚の異なる成形品、リブ、ボスを有する成形品等、各種形状の成形品を得るのに有利な中間材であり、自動車の外板、内装材及び構造材料、その他一般産業用途等で広く用いられる。 A sheet molding compound (hereinafter also referred to as “SMC”) is a compound in which a matrix resin composition containing a thermosetting resin and the like and a cut chopped reinforcing fiber bundle are blended.
When SMC is heated and pressed in the mold, the matrix resin composition and the reinforcing fiber bundle flow together to fill the cavity of the mold. Therefore, SMC is an intermediate material that is advantageous for obtaining molded products of various shapes such as molded products with partially different thickness, molded products having ribs, bosses, etc. Widely used in other general industrial applications.
　強化繊維のなかでも、炭素繊維は、比強度、比弾性率が最も高く、部材を大幅に軽量化できることから、上述した分野で実用化が進んでおり、ＳＭＣに使用される強化繊維も従来のガラス繊維から炭素繊維への置き換えが進んでいる。 Among the reinforcing fibers, carbon fibers have the highest specific strength and specific elastic modulus, and the weight of the member can be greatly reduced. Therefore, the practical use is progressing in the above-mentioned fields, and the reinforcing fibers used for SMC are also conventional. Replacement of glass fiber with carbon fiber is progressing.
　多くの場合、ＳＭＣは加圧前に成形体の形状より小さく切断して成形型上に配置し、加圧により成形体の形状へと流動させつつ成形を行う。ＳＭＣのシート化工程において、チョップド強化繊維束の分布ムラや配向ムラが発生すると、成形体の機械的強度物性の低下やバラツキが生じやすい。 In many cases, the SMC is cut smaller than the shape of the molded body before pressing and placed on the mold, and molding is performed while flowing into the shape of the molded body by pressing. In the SMC sheeting process, if uneven distribution or uneven alignment of the chopped reinforcing fiber bundle occurs, the mechanical strength properties of the molded body are likely to deteriorate and vary.
　機械的強度の高い成形体が得られるＳＭＣの製造方法としては、チョップド強化繊維束を薄くする方法がある。
　特許文献１には、炭素繊維束（ストランド）を開繊させた後に裁断し、厚みの薄いチョップド炭素繊維束を得た後、熱硬化性樹脂を含浸させてＳＭＣとする方法が開示されている。
　特許文献２には、繊維束の厚みを特定の厚み以下に制御したＳＭＣが開示されている。 As a method for producing SMC that can obtain a molded article having high mechanical strength, there is a method of thinning a chopped reinforcing fiber bundle.
Patent Document 1 discloses a method in which a carbon fiber bundle (strand) is opened and then cut to obtain a thin chopped carbon fiber bundle, which is then impregnated with a thermosetting resin to form SMC. .
Patent Document 2 discloses an SMC in which the thickness of a fiber bundle is controlled to a specific thickness or less.
日本国特開２００８－２５４１９１号公報Japanese Unexamined Patent Publication No. 2008-254191 国際公開第２０１７／１５９２６４号International Publication No. 2017/159264
　しかし、特許文献１又は２に開示されたＳＭＣは、加圧成形時にチョップド炭素繊維束が変形してしまい、引張強度や引張弾性率、曲げ強度や曲げ弾性率等の機械的強度が充分に高い成形体（ＳＭＣを用いて作製される繊維強化複合材料）が得られにくいことがある。 However, in the SMC disclosed in Patent Document 1 or 2, the chopped carbon fiber bundle is deformed at the time of pressure molding, and mechanical strength such as tensile strength, tensile elastic modulus, bending strength, and bending elastic modulus is sufficiently high. It may be difficult to obtain a molded body (fiber reinforced composite material produced using SMC).
　本発明は、引張強度や引張弾性率、曲げ強度や曲げ弾性率等の機械的強度が高い成形体が得られるＳＭＣを製造できる、ＳＭＣの製造方法及び炭素繊維束を提供することを目的とする。 An object of the present invention is to provide an SMC manufacturing method and a carbon fiber bundle capable of manufacturing an SMC from which a molded article having high mechanical strength such as tensile strength, tensile elastic modulus, bending strength and bending elastic modulus can be obtained. .
　本発明は、以下の構成を有する。 The present invention has the following configuration.
［１］長尺の炭素繊維束が裁断された複数のチョップド炭素繊維束にマトリックス樹脂組成物を含浸させることを含むシートモールディングコンパウンドの製造方法であって、
　前記チョップド炭素繊維束の繊維長が１～６０ｍｍであり、
　下記方法（Ｉ）で算出される前記炭素繊維束の嵩密度が６０～４００ｇ／Ｌである、シートモールディングコンパウンドの製造方法。
（方法（Ｉ））
　（手順Ｉ－１）炭素繊維束を繊維長が２５ｍｍとなるようにロータリーカッターで裁断した試験用チョップド炭素繊維束１００ｇを２Ｌのメスシリンダー（Φ８８ｍｍ、高さ４８５ｍｍの円柱状）に充填する。
　（手順Ｉ－２）メスシリンダー内の前記試験用チョップド炭素繊維束の上部から均一に５００ｇの荷重をかけ、体積に変化が無くなったときの充填された前記試験用チョップド炭素繊維束の総体積（Ｌ）を測定し、前記試験用チョップド炭素繊維束の総質量（１００ｇ）を前記試験用チョップド炭素繊維束の総体積（Ｌ）で除して嵩密度を算出する。
［２］下記方法（ＩＩ）で算出される前記炭素繊維束のカンチレバー値が１００ｍｍ以上である、［１］に記載のシートモールディングコンパウンドの製造方法。
（方法（ＩＩ））
　（手順ＩＩ－１）炭素繊維束から長さ４０ｃｍの試験用炭素繊維束を切り出す。
　（手順ＩＩ－２）水平面と、前記水平面の一端から下方に向かって傾斜する、傾斜角度が４５度の斜面とを有する測定台の、前記水平面上に前記試験用炭素繊維束を載せ、前記試験用炭素繊維束の長さ方向の第１の端部を前記斜面と前記水平面との境界線Ａに合わせ、前記試験用炭素繊維束の上に押さえ板を載せ、前記押さえ板の端部を前記境界線Ａに合わせる。
　（手順ＩＩ－３）前記押さえ板を前記斜面側に水平方向に２ｃｍ／秒で移動させ、前記試験用炭素繊維束の前記第１の端部が前記斜面と接触した時点で前記押さえ板の移動を停止させる。
　（手順ＩＩ－４）前記手順ＩＩ－３における前記押さえ板の移動距離ｘ（ｍｍ）を測定する。
　（手順ＩＩ－５）前記試験用炭素繊維束を裏返し、さらに長さ方向に反転させて長さ方向の第２の端部を前記境界線Ａに合わせ、前記手順ＩＩ－２～ＩＩ－４と同じ手順で前記押さえ板の移動距離ｙ（ｍｍ）を測定する。
　（手順ＩＩ－６）炭素繊維束のカンチレバー値として、移動距離ｘと移動距離ｙとの平均値を算出する。
［３］前記チョップド炭素繊維束の平均幅Ｗ（ｍｍ）及び平均厚みＨ（ｍｍ）が下記式（１）及び式（２）を満たす、［１］又は［２］に記載のシートモールディングコンパウンドの製造方法。
　０．０５≦Ｈ≦０．２　・・・（１）
　１０≦Ｗ／Ｈ≦４０　・・・（２）
［４］前記チョップド炭素繊維束の平均幅Ｗ（ｍｍ）が０．５～２．５ｍｍである、［３］に記載のシートモールディングコンパウンドの製造方法。
［５］前記炭素繊維束にサイジング剤が付着しており、前記炭素繊維束における前記サイジング剤の付着量が、前記炭素繊維束及び前記サイジング剤の合計質量に対して、０．１～３．０質量％である、［１］～［４］のいずれかに記載のシートモールディングコンパウンドの製造方法。
［６］前記シートモールディングコンパウンドの質量に対して、前記チョップド炭素繊維束の含有量が４０～７０質量％であり、前記チョップド炭素繊維束からなる炭素繊維基材の目付けが５００～２５００ｍｇ／ｍ２である、［１］～［５］のいずれかに記載のシートモールディングコンパウンドの製造方法。
［７］前記マトリックス樹脂組成物が、
　　成分（Ａ）：１分子中にエチレン性不飽和基を１個以上有する化合物からなる成分、
　　成分（Ｂ）：ジイソシアネート化合物、
　　成分（Ｃ）：重合禁止剤、及び
　　成分（Ｄ）：重合開始剤
を含む、［１］～［６］のいずれかに記載のシートモールディングコンパウンドの製造方法。
［８］前記成分（Ａ）が、下記成分（Ａ－１）及び下記成分（Ａ－２）からなる群から選ばれる少なくとも一種を含む、［７］に記載のシートモールディングコンパウンドの製造方法。
　成分（Ａ－１）：１分子中に１個以上のエチレン性不飽和基及び１個以上の水酸基を有する、不飽和ポリエステル樹脂。
　成分（Ａ－２）：１分子中に１個以上のエチレン性不飽和基及び１個以上の水酸基を有する、エポキシ（メタ）アクリレート樹脂。
［９］前記成分（Ｃ）が、分子中に水酸基を有さない重合禁止剤であり、かつ１００℃以上の温度において、ラジカル重合を引き起こす活性なラジカル種と反応し、ラジカル重合を引き起こさない不活性なラジカル種又は安定な化合物にする作用を有する、［７］又は［８］に記載のシートモールディングコンパウンドの製造方法。
［１０］前記成分（Ｃ）がｐ－ベンゾキノンである、［９］に記載のシートモールディングコンパウンドの製造方法。
［１１］前記成分（Ｃ）の含有量が、前記成分（Ａ）の１００質量部に対し、０．００１～０．１質量部である、［７］～［１０］のいずれかに記載のシートモールディングコンパウンドの製造方法。
［１２］下記方法（Ｉ）で算出される嵩密度が６０～４００ｇ／Ｌであり、平均幅Ｗ（ｍｍ）及び平均厚みＨ（ｍｍ）が下記式（１）及び式（２）を満たす、炭素繊維束。
　０．０５≦Ｈ≦０．２　・・・（１）
　１０≦Ｗ／Ｈ≦４０　・・・（２）
（方法（Ｉ））
　（手順Ｉ－１）炭素繊維束を繊維長が２５ｍｍとなるようにロータリーカッターで裁断した試験用チョップド炭素繊維束１００ｇを２Ｌのメスシリンダー（Φ８８ｍｍ、高さ４８５ｍｍの円柱状）に充填する。
　（手順Ｉ－２）メスシリンダー内の前記試験用チョップド炭素繊維束の上部から均一に５００ｇの荷重をかけ、体積に変化が無くなったときの充填された前記試験用チョップド炭素繊維束の総体積（Ｌ）を測定し、前記試験用チョップド炭素繊維束の総質量（１００ｇ）を前記試験用チョップド炭素繊維束の総体積（Ｌ）で除して嵩密度を算出する。
［１３］下記方法（ＩＩ）で算出されるカンチレバー値が１００ｍｍ以上である、［１２］に記載の炭素繊維束。
（方法（ＩＩ））
　（手順ＩＩ－１）炭素繊維束から長さ４０ｃｍの試験用炭素繊維束を切り出す。
　（手順ＩＩ－２）水平面と、前記水平面の一端から下方に向かって傾斜する、傾斜角度が４５度の斜面とを有する測定台の、前記水平面上に前記試験用炭素繊維束を載せ、前記試験用炭素繊維束の長さ方向の第１の端部を前記斜面と前記水平面との境界線Ａに合わせ、前記試験用炭素繊維束の上に押さえ板を載せ、前記押さえ板の端部を前記境界線Ａに合わせる。
　（手順ＩＩ－３）前記押さえ板を前記斜面側に水平方向に２ｃｍ／秒で移動させ、前記試験用炭素繊維束の前記第１の端部が前記斜面と接触した時点で前記押さえ板の移動を停止させる。
　（手順ＩＩ－４）前記手順ＩＩ－３における前記押さえ板の移動距離ｘ（ｍｍ）を測定する。
　（手順ＩＩ－５）前記試験用炭素繊維束を裏返し、さらに長さ方向に反転させて長さ方向の第２の端部を前記境界線Ａに合わせ、前記手順ＩＩ－２～ＩＩ－４と同じ手順で前記押さえ板の移動距離ｙ（ｍｍ）を測定する。
　（手順ＩＩ－６）炭素繊維束のカンチレバー値として、移動距離ｘと移動距離ｙとの平均値を算出する。
［１４］シートモールディングコンパウンドを製造するための、［１２］又は［１３］に記載の炭素繊維束の使用。 [1] A method for producing a sheet molding compound comprising impregnating a matrix resin composition into a plurality of chopped carbon fiber bundles obtained by cutting long carbon fiber bundles,
The fiber length of the chopped carbon fiber bundle is 1 to 60 mm,
A method for producing a sheet molding compound, wherein the bulk density of the carbon fiber bundle calculated by the following method (I) is 60 to 400 g / L.
(Method (I))
(Procedure I-1) 100 g of a chopped carbon fiber bundle for testing obtained by cutting a carbon fiber bundle with a rotary cutter so that the fiber length is 25 mm is filled in a 2 L measuring cylinder (cylindrical shape having a diameter of 88 mm and a height of 485 mm).
(Procedure I-2) The total volume of the chopped carbon fiber bundle filled when the test chopped carbon fiber bundle in the graduated cylinder was uniformly loaded with a load of 500 g and no change in volume occurred ( L) is measured, and the total mass (100 g) of the test chopped carbon fiber bundle is divided by the total volume (L) of the test chopped carbon fiber bundle to calculate the bulk density.
[2] The method for producing a sheet molding compound according to [1], wherein a cantilever value of the carbon fiber bundle calculated by the following method (II) is 100 mm or more.
(Method (II))
(Procedure II-1) A test carbon fiber bundle having a length of 40 cm is cut out from the carbon fiber bundle.
(Procedure II-2) The test carbon fiber bundle is placed on the horizontal plane of a measuring table having a horizontal plane and a slope having an inclination angle of 45 degrees inclined downward from one end of the horizontal plane. The first end of the carbon fiber bundle in the length direction is aligned with the boundary line A between the inclined surface and the horizontal plane, a pressing plate is placed on the test carbon fiber bundle, and the end of the pressing plate is Align with boundary A.
(Procedure II-3) The pressing plate is moved to the slope side in the horizontal direction at 2 cm / second, and the pressing plate is moved when the first end portion of the test carbon fiber bundle comes into contact with the slope. Stop.
(Procedure II-4) The movement distance x (mm) of the pressing plate in the procedure II-3 is measured.
(Procedure II-5) The test carbon fiber bundle is turned upside down and further inverted in the length direction so that the second end in the length direction is aligned with the boundary A, and the procedures II-2 to II-4 are performed. The moving distance y (mm) of the pressing plate is measured by the same procedure.
(Procedure II-6) The average value of the movement distance x and the movement distance y is calculated as the cantilever value of the carbon fiber bundle.
[3] The sheet molding compound according to [1] or [2], wherein an average width W (mm) and an average thickness H (mm) of the chopped carbon fiber bundle satisfy the following formulas (1) and (2): Production method.
0.05 ≦ H ≦ 0.2 (1)
10 ≦ W / H ≦ 40 (2)
[4] The method for producing a sheet molding compound according to [3], wherein an average width W (mm) of the chopped carbon fiber bundle is 0.5 to 2.5 mm.
[5] A sizing agent is attached to the carbon fiber bundle, and an amount of the sizing agent attached to the carbon fiber bundle is 0.1 to 3.% relative to a total mass of the carbon fiber bundle and the sizing agent. The method for producing a sheet molding compound according to any one of [1] to [4], which is 0% by mass.
[6] The content of the chopped carbon fiber bundle is 40 to 70% by mass with respect to the mass of the sheet molding compound, and the basis weight of the carbon fiber substrate made of the chopped carbon fiber bundle is 500 to 2500 mg / m 2. The method for producing a sheet molding compound according to any one of [1] to [5].
[7] The matrix resin composition is
Component (A): a component comprising a compound having one or more ethylenically unsaturated groups in the molecule,
Component (B): diisocyanate compound,
The method for producing a sheet molding compound according to any one of [1] to [6], comprising: component (C): a polymerization inhibitor; and component (D): a polymerization initiator.
[8] The method for producing a sheet molding compound according to [7], wherein the component (A) includes at least one selected from the group consisting of the following component (A-1) and the following component (A-2).
Component (A-1): an unsaturated polyester resin having one or more ethylenically unsaturated groups and one or more hydroxyl groups in one molecule.
Component (A-2): An epoxy (meth) acrylate resin having one or more ethylenically unsaturated groups and one or more hydroxyl groups in the molecule.
[9] The component (C) is a polymerization inhibitor having no hydroxyl group in the molecule and reacts with an active radical species that causes radical polymerization at a temperature of 100 ° C. or higher, and does not cause radical polymerization. The method for producing a sheet molding compound according to [7] or [8], which has an action of forming an active radical species or a stable compound.
[10] The method for producing a sheet molding compound according to [9], wherein the component (C) is p-benzoquinone.
[11] The content according to any one of [7] to [10], wherein the content of the component (C) is 0.001 to 0.1 parts by mass with respect to 100 parts by mass of the component (A). Manufacturing method of sheet molding compound.
[12] The bulk density calculated by the following method (I) is 60 to 400 g / L, and the average width W (mm) and the average thickness H (mm) satisfy the following formulas (1) and (2). Carbon fiber bundle.
0.05 ≦ H ≦ 0.2 (1)
10 ≦ W / H ≦ 40 (2)
(Method (I))
(Procedure I-1) 100 g of a chopped carbon fiber bundle for testing obtained by cutting a carbon fiber bundle with a rotary cutter so that the fiber length is 25 mm is filled in a 2 L measuring cylinder (cylindrical shape having a diameter of 88 mm and a height of 485 mm).
(Procedure I-2) The total volume of the chopped carbon fiber bundle filled when the test chopped carbon fiber bundle in the graduated cylinder was uniformly loaded with a load of 500 g and no change in volume occurred ( L) is measured, and the total mass (100 g) of the test chopped carbon fiber bundle is divided by the total volume (L) of the test chopped carbon fiber bundle to calculate the bulk density.
[13] The carbon fiber bundle according to [12], wherein the cantilever value calculated by the following method (II) is 100 mm or more.
(Method (II))
(Procedure II-1) A test carbon fiber bundle having a length of 40 cm is cut out from the carbon fiber bundle.
(Procedure II-2) The test carbon fiber bundle is placed on the horizontal plane of a measuring table having a horizontal plane and a slope having an inclination angle of 45 degrees inclined downward from one end of the horizontal plane. The first end of the carbon fiber bundle in the length direction is aligned with the boundary line A between the inclined surface and the horizontal plane, a pressing plate is placed on the test carbon fiber bundle, and the end of the pressing plate is Align with boundary A.
(Procedure II-3) The pressing plate is moved to the slope side in the horizontal direction at 2 cm / second, and the pressing plate is moved when the first end portion of the test carbon fiber bundle comes into contact with the slope. Stop.
(Procedure II-4) The movement distance x (mm) of the pressing plate in the procedure II-3 is measured.
(Procedure II-5) The test carbon fiber bundle is turned upside down and further inverted in the length direction so that the second end in the length direction is aligned with the boundary A, and the procedures II-2 to II-4 are performed. The moving distance y (mm) of the pressing plate is measured by the same procedure.
(Procedure II-6) The average value of the movement distance x and the movement distance y is calculated as the cantilever value of the carbon fiber bundle.
[14] Use of the carbon fiber bundle according to [12] or [13] for producing a sheet molding compound.
　本発明によれば、引張強度や引張弾性率、曲げ強度や曲げ弾性率等の機械的強度が高い成形体が得られるＳＭＣを製造できる。 According to the present invention, it is possible to produce an SMC from which a molded body having high mechanical strength such as tensile strength, tensile elastic modulus, bending strength, bending elastic modulus and the like can be obtained.
方法（ＩＩ）によるカンチレバー値の測定における手順ＩＩ－１、ＩＩ－２について説明する模式図である。FIG. 5 is a schematic diagram for explaining procedures II-1 and II-2 in measuring a cantilever value by a method (II). 方法（ＩＩ）によるカンチレバー値の測定における手順ＩＩ－３、ＩＩ－４について説明する模式図である。FIG. 6 is a schematic diagram for explaining procedures II-3 and II-4 in measurement of a cantilever value by a method (II). 方法（ＩＩ）によるカンチレバー値の測定における手順ＩＩ－５について説明する模式図である。It is a schematic diagram explaining the procedure II-5 in the measurement of the cantilever value by the method (II). 方法（ＩＩ）によるカンチレバー値の測定における手順ＩＩ－５について説明する模式図である。It is a schematic diagram explaining the procedure II-5 in the measurement of the cantilever value by the method (II).
　本発明のＳＭＣの製造方法は、長尺の炭素繊維束が裁断された複数のチョップド炭素繊維束にマトリックス樹脂組成物を含浸させることを含む。
　本発明のＳＭＣの製造方法においては、チョップド炭素繊維束の繊維長が１～６０ｍｍであり、裁断される長尺の炭素繊維束として、後述の方法（Ｉ）で算出される嵩密度が６０～４００ｇ／Ｌである炭素繊維束を用いる。また、裁断される長尺の炭素繊維束は、後述の方法（ＩＩ）で算出されるカンチレバー値が１００ｍｍ以上であることが好ましい。 The SMC manufacturing method of the present invention includes impregnating a matrix resin composition into a plurality of chopped carbon fiber bundles obtained by cutting long carbon fiber bundles.
In the SMC manufacturing method of the present invention, the chopped carbon fiber bundle has a fiber length of 1 to 60 mm, and the bulk density calculated by the method (I) described later is 60 to 60 mm as a long carbon fiber bundle to be cut. A carbon fiber bundle that is 400 g / L is used. The long carbon fiber bundle to be cut preferably has a cantilever value calculated by the method (II) described later of 100 mm or more.
（炭素繊維束）
　炭素繊維束を構成する炭素繊維としては、例えばポリアクリロニトリル（ＰＡＮ）系炭素繊維、レーヨン系炭素繊維、ピッチ系炭素繊維等が挙げられる。
　炭素繊維束のフィラメント数は、通常１０００～６００００本程度である。 (Carbon fiber bundle)
Examples of the carbon fiber constituting the carbon fiber bundle include polyacrylonitrile (PAN) -based carbon fiber, rayon-based carbon fiber, and pitch-based carbon fiber.
The number of filaments in the carbon fiber bundle is usually about 1000 to 60000.
　複数のチョップド炭素繊維束を得るために裁断される長尺の炭素繊維束は、後述の方法（Ｉ）で算出される嵩密度が６０～４００ｇ／Ｌである。 A long carbon fiber bundle cut to obtain a plurality of chopped carbon fiber bundles has a bulk density of 60 to 400 g / L calculated by the method (I) described later.
　以下、炭素繊維束の嵩密度を算出するための方法（Ｉ）について説明する。 Hereinafter, the method (I) for calculating the bulk density of the carbon fiber bundle will be described.
　（手順Ｉ－１）裁断される長尺の炭素繊維束を繊維長が２５ｍｍとなるようにロータリーカッターで裁断した試験用チョップド炭素繊維束１００ｇを２Ｌのメスシリンダー（Φ８８ｍｍ、高さ４８５ｍｍの円柱状）に充填する。 (Procedure I-1) A chopped carbon fiber bundle for testing 100 g obtained by cutting a long carbon fiber bundle to be cut with a rotary cutter so that the fiber length is 25 mm is used as a 2 L graduated cylinder (Φ88 mm, height 485 mm columnar) ).
　（手順Ｉ－２）メスシリンダー内の試験用チョップド炭素繊維束の上部から均一に５００ｇの荷重をかけ、体積に変化が無くなったときの充填された試験用チョップド炭素繊維束の総体積Ｖ（Ｌ）を測定し、試験用チョップド炭素繊維束の総質量Ｍ（ｇ：Ｍ＝１００ｇ）を総体積Ｖ（Ｌ）で除して嵩密度（ｇ／Ｌ）を算出する。 (Procedure I-2) When a load of 500 g is uniformly applied from above the test chopped carbon fiber bundle in the graduated cylinder, the total volume V (L ) And the total mass M (g: M = 100 g) of the test chopped carbon fiber bundle is divided by the total volume V (L) to calculate the bulk density (g / L).
　方法（Ｉ）で算出される嵩密度は、ＳＭＣを製造するためのチョップド炭素繊維束からなる炭素繊維基材の嵩密度を擬似的に表した値である。 The bulk density calculated by the method (I) is a value that artificially represents the bulk density of a carbon fiber substrate made of a chopped carbon fiber bundle for producing SMC.
　方法（Ｉ）で測定される、複数のチョップド炭素繊維束を得るために裁断される長尺の炭素繊維束の嵩密度は、６０～４００ｇ／Ｌであり、７０～３５０ｇ／Ｌが好ましく、８０～３２０ｇ／Ｌがより好ましく、１００～２８０ｇ／Ｌがさらに好ましく、１３０～２５０ｇ／Ｌが特に好ましい。
　方法（Ｉ）で測定される炭素繊維束の嵩密度が前記範囲内であれば、ＳＭＣ中でチョップド炭素繊維束同士が強固に絡み合うため、高強度の成形体を得ることができる。 The bulk density of the long carbon fiber bundles cut to obtain a plurality of chopped carbon fiber bundles measured by the method (I) is 60 to 400 g / L, preferably 70 to 350 g / L, 80 Is more preferably from 320 to 320 g / L, further preferably from 100 to 280 g / L, particularly preferably from 130 to 250 g / L.
If the bulk density of the carbon fiber bundles measured by the method (I) is within the above range, the chopped carbon fiber bundles are strongly entangled in the SMC, so that a high-strength molded product can be obtained.
　嵩密度は炭素繊維束のカンチレバー値によっても変動するが、炭素繊維束の嵩密度の値を前記範囲とすることで、チョップド炭素繊維束の剛直さと樹脂含浸性を両立することが可能となり、機械的強度特性の向上が可能となる。 Although the bulk density varies depending on the cantilever value of the carbon fiber bundle, by making the value of the bulk density of the carbon fiber bundle within the above range, it becomes possible to achieve both the rigidity of the chopped carbon fiber bundle and the resin impregnation property. The mechanical strength characteristics can be improved.
　方法（Ｉ）で測定される炭素繊維束の嵩密度が６０ｇ／Ｌ以上であれば、ＳＭＣ製造時の樹脂含浸性に優れるため、成形体の機械的特性が向上する。方法（Ｉ）で測定される炭素繊維束の嵩密度は、好ましくは７０ｇ／Ｌ以上であり、より好ましくは８０ｇ／Ｌ以上であり、さらに好ましくは１００ｇ／Ｌ以上であり、特に好ましくは１３０ｇ／Ｌ以上である。 If the bulk density of the carbon fiber bundle measured by the method (I) is 60 g / L or more, since the resin impregnation property during SMC production is excellent, the mechanical properties of the molded body are improved. The bulk density of the carbon fiber bundle measured by the method (I) is preferably 70 g / L or more, more preferably 80 g / L or more, still more preferably 100 g / L or more, and particularly preferably 130 g / L. L or more.
　また、方法（Ｉ）で測定される炭素繊維束の嵩密度が４００ｇ／Ｌ以下であれば、ＳＭＣ中でチョップド炭素繊維束同士が強固に絡み合うため、高強度の成形体を得ることができる。方法（Ｉ）で測定される炭素繊維束の嵩密度は、好ましくは３５０ｇ／Ｌ以下であり、より好ましくは３２０ｇ／Ｌ以下であり、さらに好ましくは２８０ｇ／Ｌ以下であり、特に好ましくは２５０ｇ／Ｌ以下である。 Further, when the bulk density of the carbon fiber bundle measured by the method (I) is 400 g / L or less, the chopped carbon fiber bundles are strongly entangled with each other in the SMC, so that a high-strength molded product can be obtained. The bulk density of the carbon fiber bundle measured by the method (I) is preferably 350 g / L or less, more preferably 320 g / L or less, further preferably 280 g / L or less, particularly preferably 250 g / L. L or less.
　複数のチョップド炭素繊維束を得るために裁断される長尺の炭素繊維束は、さらに後述の方法（ＩＩ）で算出されるカンチレバー値が１００ｍｍ以上であることが好ましい。 It is preferable that the long carbon fiber bundle cut to obtain a plurality of chopped carbon fiber bundles further has a cantilever value calculated by the method (II) described later of 100 mm or more.
　以下、炭素繊維束のカンチレバー値を算出するための方法（ＩＩ）について、図１～４に基づいて説明する。 Hereinafter, the method (II) for calculating the cantilever value of the carbon fiber bundle will be described with reference to FIGS.
　（手順ＩＩ－１）炭素繊維束から長さ４０ｃｍの試験用炭素繊維束１００を切り出す。 (Procedure II-1) A test carbon fiber bundle 100 having a length of 40 cm is cut out from the carbon fiber bundle.
　（手順ＩＩ－２）図１に示すように、水平面１２と、水平面１２の一端から下方に向かって傾斜する、傾斜角度が４５度の斜面１４とを有する測定台１０の、水平面１２上に試験用炭素繊維束１００を載せる。このとき、試験用炭素繊維束１００の長さ方向の第１の端部１０２を斜面１４と水平面１２との境界線Ａに合わせる。試験用炭素繊維束１００の上に押さえ板２００を載せ、押さえ板２００の端部２０２を境界線Ａに合わせる。 (Procedure II-2) As shown in FIG. 1, a test is carried out on a horizontal plane 12 of a measuring table 10 having a horizontal plane 12 and an inclined plane 14 inclined downward from one end of the horizontal plane 12 and having an inclination angle of 45 degrees. The carbon fiber bundle 100 for use is mounted. At this time, the first end portion 102 in the length direction of the test carbon fiber bundle 100 is aligned with the boundary line A between the slope 14 and the horizontal plane 12. The pressing plate 200 is placed on the test carbon fiber bundle 100 and the end 202 of the pressing plate 200 is aligned with the boundary line A.
　（手順ＩＩ－３）図２に示すように、押さえ板２００を斜面１４側に水平方向に２ｃｍ／秒で移動させ、試験用炭素繊維束１００の第１の端部１０２が斜面１４と接触した時点で押さえ板２００の移動を停止させる。 (Procedure II-3) As shown in FIG. 2, the holding plate 200 was moved to the inclined surface 14 side in the horizontal direction at 2 cm / second, and the first end 102 of the test carbon fiber bundle 100 was in contact with the inclined surface 14. At that time, the movement of the pressing plate 200 is stopped.
　（手順ＩＩ－４）手順ＩＩ－３における押さえ板２００の移動距離ｘ（ｍｍ）を測定する。 (Procedure II-4) The moving distance x (mm) of the pressing plate 200 in Procedure II-3 is measured.
　（手順ＩＩ－５）図３に示すように、試験用炭素繊維束１００を裏返し、さらに長さ方向に反転させて長さ方向の第２の端部１０４を境界線Ａに合わせる。図４に示すように、手順ＩＩ－２～ＩＩ－４と同じ手順で、試験用炭素繊維束１００の第２の端部１０４が斜面１４と接触した時点で押さえ板２００の移動を停止させ、押さえ板２００の移動距離ｙ（ｍｍ）を測定する。 (Procedure II-5) As shown in FIG. 3, the test carbon fiber bundle 100 is turned upside down and further inverted in the length direction so that the second end portion 104 in the length direction is aligned with the boundary line A. As shown in FIG. 4, the movement of the pressing plate 200 is stopped when the second end 104 of the test carbon fiber bundle 100 comes into contact with the inclined surface 14 in the same procedure as the procedures II-2 to II-4. The moving distance y (mm) of the pressing plate 200 is measured.
　（手順ＩＩ－６）炭素繊維束のカンチレバー値として、移動距離ｘと移動距離ｙとの平均値を算出する。 (Procedure II-6) The average value of the movement distance x and the movement distance y is calculated as the cantilever value of the carbon fiber bundle.
　押さえ板２００の大きさは、測定に支障がない大きさであればよく、例えば、縦１０００ｍｍ×横２００ｍｍ×厚み５ｍｍの板とすることができる。
　押さえ板２００の重さは、測定に支障がない重さであればよく、例えば、１０００ｇとすることができる。 The size of the pressing plate 200 may be any size as long as it does not hinder measurement, and can be, for example, a plate having a length of 1000 mm × width of 200 mm × thickness of 5 mm.
The weight of the pressing plate 200 may be a weight that does not hinder measurement, and can be set to, for example, 1000 g.
　方法（ＩＩ）で測定される、複数のチョップド炭素繊維束を得るために裁断される長尺の炭素繊維束のカンチレバー値は、１００ｍｍ以上が好ましく、１２０ｍｍ以上３００ｍｍ以下がより好ましく、１３０ｍｍ以上２００ｍ以下がさらに好ましく、１４０ｍｍ以上１９０ｍｍ以下が特に好ましい。 The cantilever value of the long carbon fiber bundle cut to obtain a plurality of chopped carbon fiber bundles measured by the method (II) is preferably 100 mm or more, more preferably 120 mm or more and 300 mm or less, and 130 mm or more and 200 m or less. Is more preferable, and 140 mm or more and 190 mm or less are particularly preferable.
　方法（ＩＩ）で測定される炭素繊維束のカンチレバー値が１００ｍｍ以上であれば、炭素繊維束が剛直なストランドとなり、裁断後のマトリックス樹脂組成物の含浸時に炭素繊維束の厚みが急激に変化しない。すなわち、ＳＭＣ製造時にチョップド炭素繊維束の形態が乱れ、折り畳まりや曲がりによって炭素繊維束の幅や厚みが急激に変化することを抑制できる。また、成形時にチョップド炭素繊維束の厚みが急激に変化することも抑制できる。そのため、成形時にチョップド炭素繊維束同士が３次元的ネットワークを形成しやすく、成形体の曲げ強度や曲げ弾性率といった機械的強度特性が高くなる。方法（ＩＩ）で測定される炭素繊維束のカンチレバー値は、より好ましくは１２０ｍｍ以上であり、さらに好ましくは１３０ｍｍ以上であり、特に好ましくは１４０ｍｍ以上である。 If the cantilever value of the carbon fiber bundle measured by the method (II) is 100 mm or more, the carbon fiber bundle becomes a rigid strand, and the thickness of the carbon fiber bundle does not change suddenly when impregnated with the matrix resin composition after cutting. . That is, the chopped carbon fiber bundle is disturbed during SMC production, and the width and thickness of the carbon fiber bundle can be prevented from changing suddenly due to folding or bending. Moreover, it can suppress that the thickness of a chopped carbon fiber bundle changes rapidly at the time of shaping | molding. Therefore, the chopped carbon fiber bundles easily form a three-dimensional network at the time of molding, and mechanical strength characteristics such as bending strength and bending elastic modulus of the molded body are increased. The cantilever value of the carbon fiber bundle measured by the method (II) is more preferably 120 mm or more, further preferably 130 mm or more, and particularly preferably 140 mm or more.
　また、方法（ＩＩ）で測定される炭素繊維束のカンチレバー値が３００ｍｍ以下であれば、ＳＭＣ製造時の樹脂含浸性に優れるため、成形体の機械的特性が向上する傾向にあり、より好ましい。方法（ＩＩ）で測定される炭素繊維束のカンチレバー値は、さらに好ましくは２００ｍｍ以下であり、特に好ましくは１９０ｍｍ以下である。 Further, if the cantilever value of the carbon fiber bundle measured by the method (II) is 300 mm or less, since the resin impregnation property at the time of SMC production is excellent, the mechanical properties of the molded body tend to be improved, which is more preferable. The cantilever value of the carbon fiber bundle measured by the method (II) is more preferably 200 mm or less, and particularly preferably 190 mm or less.
　炭素繊維束のカンチレバー値は、炭素繊維束に付着するサイジング剤の組成や付着量等により調節できる。複数のチョップド炭素繊維束を得るために裁断される長尺の炭素繊維束として、サイジング剤が付着した炭素繊維束を用いる場合、本発明における炭素繊維束のカンチレバー値は、サイジング剤が付着した炭素繊維束についての測定値である。
　複数のチョップド炭素繊維束を得るために裁断される長尺の炭素繊維束として、サイジング剤が付着した炭素繊維束を用いてもよい。 The cantilever value of the carbon fiber bundle can be adjusted by the composition and amount of the sizing agent that adheres to the carbon fiber bundle. When a carbon fiber bundle to which a sizing agent is attached is used as a long carbon fiber bundle that is cut to obtain a plurality of chopped carbon fiber bundles, the cantilever value of the carbon fiber bundle in the present invention is the carbon to which the sizing agent is attached. It is a measured value about a fiber bundle.
As a long carbon fiber bundle cut to obtain a plurality of chopped carbon fiber bundles, a carbon fiber bundle to which a sizing agent is attached may be used.
　炭素繊維束にサイジング剤が付着している場合、炭素繊維束に付着するサイジング剤としては、特に限定されず、炭素繊維束に通常用いられるサイジング剤を用いることができる。
　炭素繊維束へのサイジング剤の付着方法としては、特に限定されず、例えば、水又は有機溶剤にサイジング剤を分散又は溶解させたサイジング剤液を、炭素繊維束に塗布して乾燥する方法が挙げられ、サイジング剤液の炭素繊維束への塗布方法としては、ローラー浸漬法、ローラー接触法等が挙げられる。 When the sizing agent is attached to the carbon fiber bundle, the sizing agent attached to the carbon fiber bundle is not particularly limited, and a sizing agent usually used for the carbon fiber bundle can be used.
The method for adhering the sizing agent to the carbon fiber bundle is not particularly limited, and examples thereof include a method of applying a sizing agent solution in which the sizing agent is dispersed or dissolved in water or an organic solvent to the carbon fiber bundle and drying it. Examples of the method for applying the sizing solution to the carbon fiber bundle include a roller dipping method and a roller contact method.
　炭素繊維束におけるサイジング剤の付着量は、炭素繊維束及びサイジング剤の合計質量に対して、０．１～３．０質量％が好ましく、０．５～２．０質量％がより好ましい。
　炭素繊維束におけるサイジング剤の付着量が前記下限値以上であれば、炭素繊維束を裁断する際に良好な収束性が確保されやすい。炭素繊維束におけるサイジング剤の付着量が前記上限値以下であれば、チョップド炭素繊維束がＳＭＣ中に均一に分散しやすい。 The adhesion amount of the sizing agent in the carbon fiber bundle is preferably 0.1 to 3.0% by mass, and more preferably 0.5 to 2.0% by mass with respect to the total mass of the carbon fiber bundle and the sizing agent.
If the adhesion amount of the sizing agent in the carbon fiber bundle is equal to or more than the lower limit value, good convergence is easily secured when the carbon fiber bundle is cut. If the adhesion amount of the sizing agent in the carbon fiber bundle is equal to or less than the upper limit value, the chopped carbon fiber bundle is easily dispersed uniformly in the SMC.
　炭素繊維束におけるサイジング剤の付着量は、サイジング剤液の濃度や絞り量により調節することができる。 The amount of the sizing agent attached to the carbon fiber bundle can be adjusted by the concentration of the sizing agent liquid and the amount of squeezing.
　本発明のＳＭＣの製造方法においては、方法（Ｉ）で算出される嵩密度が６０～４００ｇ／Ｌであり、好ましくは、さらに方法（ＩＩ）で算出されるカンチレバー値が１００ｍｍ以上である長尺の炭素繊維束が裁断された複数のチョップド炭素繊維束にマトリックス樹脂組成物を含浸させること（以下、「含浸工程」とも記す。）を含む。本発明のＳＭＣの製造方法においては、例えば、上記の含浸工程のほか、裁断工程や増粘工程を含んでもよい。 In the method for producing SMC of the present invention, the bulk density calculated by the method (I) is 60 to 400 g / L, and preferably the long cantilever value calculated by the method (II) is 100 mm or more. Impregnating a matrix resin composition into a plurality of chopped carbon fiber bundles obtained by cutting the carbon fiber bundle (hereinafter also referred to as “impregnation step”). In the manufacturing method of SMC of this invention, a cutting process and a thickening process may be included other than said impregnation process, for example.
　裁断工程：含浸工程に先立ち、複数のチョップド炭素繊維束を得るために、方法（Ｉ）で算出される嵩密度が６０～４００ｇ／Ｌであり、好ましくは、さらに方法（ＩＩ）で算出されるカンチレバー値が１００ｍｍ以上である長尺の炭素繊維束を裁断する。
　含浸工程：ＳＭＣ前駆体を得るために、裁断工程で得られた複数のチョップド炭素繊維束からなる炭素繊維基材にマトリックス樹脂組成物を含浸する。
　増粘工程：含浸工程のあと、ＳＭＣを得るために、ＳＭＣ前駆体中のマトリックス樹脂組成物を増粘させる。 Cutting step: In order to obtain a plurality of chopped carbon fiber bundles prior to the impregnation step, the bulk density calculated by the method (I) is 60 to 400 g / L, preferably further calculated by the method (II). A long carbon fiber bundle having a cantilever value of 100 mm or more is cut.
Impregnation step: In order to obtain the SMC precursor, a matrix resin composition is impregnated into a carbon fiber substrate made of a plurality of chopped carbon fiber bundles obtained in the cutting step.
Thickening step: After the impregnation step, the matrix resin composition in the SMC precursor is thickened to obtain SMC.
（裁断工程）
　複数のチョップド炭素繊維束を得るために、長尺の炭素繊維束を裁断する方式としては、特に限定されないが、大量生産性の点から、ロータリーカッター方式が好ましい。
　ロータリーカッターによる裁断では、炭素繊維束の厚みが充分に薄ければ、切り損じが生じたり、ロータにトウが巻き付いて操作不能になったり、チョップド炭素繊維束の形態に不具合が生じたりすることを抑制しやすい。そのため、ロータリーカッターにより裁断する場合、炭素繊維束の厚みは薄いほうが好ましい。 (Cutting process)
A method for cutting a long carbon fiber bundle to obtain a plurality of chopped carbon fiber bundles is not particularly limited, but a rotary cutter method is preferred from the viewpoint of mass productivity.
When cutting with a rotary cutter, if the thickness of the carbon fiber bundle is sufficiently thin, cutting may occur, the tow may wrap around the rotor, making it impossible to operate, or the shape of the chopped carbon fiber bundle may be defective. Easy to suppress. Therefore, when cutting with a rotary cutter, the carbon fiber bundle is preferably thinner.
　裁断工程で得られるチョップド炭素繊維束の繊維長は、１～６０ｍｍであり、１～２５ｍｍが好ましい。
　チョップド炭素繊維束の繊維長が前記下限値以上であれば、機械的強度が高い成形体が得られやすい。
　チョップド炭素繊維束の繊維長が前記上限値以下であれば、ＳＭＣをプレス成形する際に良好な流動性が得られやすい。 The fiber length of the chopped carbon fiber bundle obtained in the cutting step is 1 to 60 mm, and preferably 1 to 25 mm.
If the fiber length of the chopped carbon fiber bundle is not less than the lower limit, a molded article having high mechanical strength can be easily obtained.
If the fiber length of the chopped carbon fiber bundle is equal to or less than the upper limit, good fluidity can be easily obtained when press molding SMC.
　複数のチョップド炭素繊維束を得るために裁断される裁断直前の長尺の炭素繊維束、及び長尺の炭素繊維束が裁断されたチョップド炭素繊維束の平均幅Ｗ（ｍｍ）及び平均厚みＨ（ｍｍ）は、下記式（１）及び式（２）を満たすことが好ましい。
　０．０５≦Ｈ≦０．２　・・・（１）
　１０≦Ｗ／Ｈ≦４０　・・・（２）
　なお、平均幅Ｗ（ｍｍ）及び平均厚みＨ（ｍｍ）は、３００個のチョップド炭素繊維束について測定した幅及び厚みの平均値である。 An average width W (mm) and an average thickness H of a long carbon fiber bundle immediately before cutting, and a chopped carbon fiber bundle from which the long carbon fiber bundle is cut to obtain a plurality of chopped carbon fiber bundles. mm) preferably satisfies the following formulas (1) and (2).
0.05 ≦ H ≦ 0.2 (1)
10 ≦ W / H ≦ 40 (2)
In addition, average width W (mm) and average thickness H (mm) are the average values of the width and thickness measured about 300 chopped carbon fiber bundles.
　チョップド炭素繊維束の平均厚みＨは、０．０５ｍｍ以上０．２ｍｍ以下が好ましく、０．０７ｍｍ以上０．１５ｍｍ以下がより好ましく、０．０８ｍｍ以上０．１３ｍｍ以下がさらに好ましい。
　チョップド炭素繊維束の平均厚みＨが０．０５ｍｍ以上であれば、チョップド繊維束の取り扱いが容易であり、さらに、炭素繊維基材にマトリックス樹脂組成物を含浸させることが容易になる。チョップド炭素繊維束の平均厚みＨは、より好ましくは０．０７ｍｍ以上であり、さらに好ましくは０．０８ｍｍ以上である。
　チョップド炭素繊維束の平均厚みＨが０．２ｍｍ以下であれば、機械的強度が高い成形体が得られやすい。チョップド炭素繊維束の平均厚みＨは、より好ましくは０．１５ｍｍ以下であり、さらに好ましくは０．１３ｍｍ以下である。 The average thickness H of the chopped carbon fiber bundle is preferably 0.05 mm or more and 0.2 mm or less, more preferably 0.07 mm or more and 0.15 mm or less, and further preferably 0.08 mm or more and 0.13 mm or less.
When the average thickness H of the chopped carbon fiber bundle is 0.05 mm or more, handling of the chopped fiber bundle is easy, and furthermore, it becomes easy to impregnate the carbon fiber substrate with the matrix resin composition. The average thickness H of the chopped carbon fiber bundle is more preferably 0.07 mm or more, and further preferably 0.08 mm or more.
When the average thickness H of the chopped carbon fiber bundle is 0.2 mm or less, a molded article having high mechanical strength is easily obtained. The average thickness H of the chopped carbon fiber bundle is more preferably 0.15 mm or less, and still more preferably 0.13 mm or less.
　Ｗ／Ｈは、１０以上４０以下が好ましく、１５以上３０以下がより好ましい。
　Ｗ／Ｈが前記範囲であれば、機械的強度が高い成形体が得られやすい。 W / H is preferably 10 or more and 40 or less, and more preferably 15 or more and 30 or less.
If W / H is the said range, a molded object with high mechanical strength will be easy to be obtained.
　チョップド炭素繊維束の平均幅Ｗは、２．５ｍｍ以下が好ましく、２．０ｍｍ以下がより好ましく、１．８ｍｍ以下がさらに好ましく、１．５ｍｍ以下が特に好ましい。
　チョップド炭素繊維束の平均幅Ｗが２．５ｍｍ以下であれば、ＳＭＣ中でチョップド炭素繊維束同士が強固に絡み合い、機械的強度が高い成形体が得られやすい。
　チョップド炭素繊維束の平均幅Ｗの下限値は、実質的には０．５ｍｍ程度である。 The average width W of the chopped carbon fiber bundle is preferably 2.5 mm or less, more preferably 2.0 mm or less, further preferably 1.8 mm or less, and particularly preferably 1.5 mm or less.
When the average width W of the chopped carbon fiber bundle is 2.5 mm or less, the chopped carbon fiber bundles are entangled firmly in the SMC, and a molded article having high mechanical strength is easily obtained.
The lower limit value of the average width W of the chopped carbon fiber bundle is substantially about 0.5 mm.
　チョップド炭素繊維束の平均幅Ｗ及び平均厚みＨは、裁断直前の複数のチョップド炭素繊維束を得るために裁断される長尺の炭素繊維束の幅と厚みにより調整でき、裁断直前の複数のチョップド炭素繊維束を得るために裁断される長尺の炭素繊維束の幅と厚みは、裁断工程における裁断直前に、例えばエアーや振動による開繊や、複数の刃物による分繊を行うことにより調節してもよい。 The average width W and average thickness H of the chopped carbon fiber bundle can be adjusted by the width and thickness of the long carbon fiber bundle that is cut to obtain a plurality of chopped carbon fiber bundles immediately before cutting. The width and thickness of a long carbon fiber bundle that is cut to obtain a carbon fiber bundle is adjusted immediately before cutting in the cutting process by, for example, opening with air or vibration, or splitting with multiple blades. May be.
（含浸工程）
　ＳＭＣ前駆体を得るために、裁断工程で得られた複数のチョップド炭素繊維束からなる炭素繊維基材にマトリックス樹脂組成物を含浸する方法としては、特に限定されないが、例えば、以下の方法が挙げられる。
　２枚のキャリアフィルムのそれぞれにマトリックス樹脂組成物を塗工し、マトリックス樹脂組成物層を形成する。一方のキャリアフィルムのマトリックス樹脂組成物層上にチョップド炭素繊維束からなる炭素繊維基材を形成するために、マトリックス樹脂組成物層上にチョップド炭素繊維束を繊維方向がランダムになるように散布する。炭素繊維基材上に、他方のキャリアフィルムをマトリックス樹脂組成物層側が炭素繊維基材側に向くように重ね、上下方向から圧着し、炭素繊維基材の炭素繊維束間及び炭素繊維束内にマトリックス樹脂組成物を含浸させる。 (Impregnation process)
In order to obtain the SMC precursor, the method of impregnating the matrix resin composition into the carbon fiber substrate composed of a plurality of chopped carbon fiber bundles obtained in the cutting step is not particularly limited, but examples thereof include the following methods. It is done.
A matrix resin composition is applied to each of the two carrier films to form a matrix resin composition layer. In order to form a carbon fiber substrate composed of chopped carbon fiber bundles on the matrix resin composition layer of one carrier film, the chopped carbon fiber bundles are spread on the matrix resin composition layer so that the fiber directions are random. . On the carbon fiber base material, the other carrier film is laminated so that the matrix resin composition layer side faces the carbon fiber base material side, and is pressed from above and below, and between the carbon fiber bundles of the carbon fiber base material and in the carbon fiber bundle Impregnated with a matrix resin composition.
　キャリアフィルムとしては、特に限定されず、例えばポリプロピレン製のフィルムを用いることができる。 The carrier film is not particularly limited, and for example, a polypropylene film can be used.
　マトリックス樹脂組成物の塗工量及びチョップド炭素繊維束の散布量は、得られるＳＭＣ前駆体中の炭素繊維束の含有量に応じて適宜設定できる。
　ＳＭＣ前駆体におけるチョップド炭素繊維束の含有量は、ＳＭＣ前駆体の総質量に対し、４０～７０質量％が好ましく、４５～６０質量％がより好ましい。
　ＳＭＣ前駆体におけるチョップド炭素繊維束の含有量が前記下限値以上であれば、チョップド炭素繊維束による補強効果が充分に発揮され、機械的強度がより高い成形体が得られやすい。
　ＳＭＣ前駆体におけるチョップド炭素繊維束の含有量が前記上限値以下であれば、ＳＭＣの成形時の流動性がより優れる。 The coating amount of the matrix resin composition and the application amount of the chopped carbon fiber bundle can be appropriately set according to the content of the carbon fiber bundle in the obtained SMC precursor.
The content of the chopped carbon fiber bundle in the SMC precursor is preferably 40 to 70% by mass and more preferably 45 to 60% by mass with respect to the total mass of the SMC precursor.
When the content of the chopped carbon fiber bundle in the SMC precursor is equal to or higher than the lower limit value, the reinforcing effect by the chopped carbon fiber bundle is sufficiently exhibited, and a molded body with higher mechanical strength is easily obtained.
If the content of the chopped carbon fiber bundle in the SMC precursor is less than or equal to the above upper limit value, the fluidity during SMC molding is more excellent.
　一方のキャリアフィルムのマトリックス樹脂組成物層上に形成された、チョップド炭素繊維束からなる炭素繊維基材の目付けは、例えば５００～２５００ｍｇ／ｍ２とすることができる。 The basis weight of the carbon fiber substrate formed of the chopped carbon fiber bundle formed on the matrix resin composition layer of one carrier film can be set to, for example, 500 to 2500 mg / m 2 .
　（マトリックス樹脂組成物）
　マトリックス樹脂組成物としては、エポキシ樹脂、フェノール樹脂、不飽和ポリエステル樹脂、ビニルエステル樹脂、フェノキシ樹脂、アルキド樹脂、ウレタン樹脂、尿素性樹脂、メラミン樹脂、マレイミド樹脂、シアネート樹脂等の熱硬化性樹脂や、ポリオレフィン系樹脂、ポリアミド系樹脂、ポリエステル系樹脂、ポリフェニレンサルファイド樹脂、ポリエーテルケトン樹脂、ポリエーテルスルフォン樹脂、芳香族ポリアミド樹脂等の熱可塑性樹脂を使用することができ、特に限定されるものではないが、例えば、後述の成分（Ａ）、成分（Ｂ）、及び成分（Ｃ）を含むものが挙げられる。
　マトリックス樹脂組成物が成分（Ａ）、成分（Ｂ）、及び成分（Ｃ）を含むことで、ＳＭＣ製造時におけるマトリックス樹脂組成物の炭素繊維束への含浸性が優れる。そのため、機械的強度がより高い成形体が得られやすい。さらに、ＳＭＣの保管時、輸送時等における経時的な成形時の流動性の低下が抑制され、流動安定性に優れる。そのため、長期の保管後においてもＳＭＣを良好に成形できる。また、欠損、変形、フクレ等の不具合が少なく精度、外観等に優れた成形体が得られやすい。 (Matrix resin composition)
Examples of matrix resin compositions include thermosetting resins such as epoxy resins, phenol resins, unsaturated polyester resins, vinyl ester resins, phenoxy resins, alkyd resins, urethane resins, urea resins, melamine resins, maleimide resins, and cyanate resins. , Thermoplastic resins such as polyolefin resins, polyamide resins, polyester resins, polyphenylene sulfide resins, polyether ketone resins, polyether sulfone resins, aromatic polyamide resins can be used, and are not particularly limited. However, the thing containing the below-mentioned component (A), component (B), and component (C) is mentioned, for example.
When the matrix resin composition contains the component (A), the component (B), and the component (C), the impregnation property of the matrix resin composition into the carbon fiber bundle during SMC production is excellent. Therefore, it is easy to obtain a molded body having higher mechanical strength. In addition, the fluidity of the SMC during storage and transportation is prevented from being lowered over time, and the flow stability is excellent. Therefore, SMC can be molded well even after long-term storage. In addition, it is easy to obtain a molded body with few defects such as chipping, deformation and blistering and excellent in accuracy and appearance.
　マトリックス樹脂組成物は、成分（Ａ）、成分（Ｂ）、及び成分（Ｃ）に加えて、成分（Ｄ）をさらに含むことが好ましい。
　マトリックス樹脂組成物は、必要に応じて、本発明の効果を損なわない範囲で、成分（Ａ）、成分（Ｂ）、成分（Ｃ）、及び成分（Ｄ）以外の他の成分をさらに含んでもよい。 It is preferable that the matrix resin composition further includes a component (D) in addition to the component (A), the component (B), and the component (C).
The matrix resin composition may further contain other components other than the component (A), the component (B), the component (C), and the component (D) as long as they do not impair the effects of the present invention. Good.
　（成分（Ａ））
　成分（Ａ）は、１分子中にエチレン性不飽和基を１個以上有する化合物からなる成分である。成分（Ａ）は、１分子中にエチレン性不飽和基を１個以上有し、かつ水酸基を１個以上有する化合物からなる成分であることが好ましい。 (Ingredient (A))
Component (A) is a component composed of a compound having one or more ethylenically unsaturated groups in one molecule. The component (A) is preferably a component composed of a compound having one or more ethylenically unsaturated groups and one or more hydroxyl groups in one molecule.
　成分（Ａ）は、下記成分（Ａ－１）及び下記成分（Ａ－２）からなる群から選ばれる少なくとも一種を含むことが好ましい。
・成分（Ａ－１）：１分子中に１個以上のエチレン性不飽和基及び１個以上の水酸基を有する、不飽和ポリエステル樹脂。
・成分（Ａ－２）：１分子中に、１個以上のエチレン性不飽和基及び１個以上の水酸基を有する、エポキシ（メタ）アクリレート樹脂。 The component (A) preferably contains at least one selected from the group consisting of the following component (A-1) and the following component (A-2).
Component (A-1): an unsaturated polyester resin having one or more ethylenically unsaturated groups and one or more hydroxyl groups in the molecule.
Component (A-2): An epoxy (meth) acrylate resin having one or more ethylenically unsaturated groups and one or more hydroxyl groups in one molecule.
　マトリックス樹脂組成物がエチレン性不飽和基を有する成分（Ａ）を含むことで、マトリックス樹脂組成物が熱硬化性を有する。
　成分（Ａ）が不飽和ポリエステル樹脂及びエポキシ（メタ）アクリレート樹脂からなる群から選ばれる少なくとも一種を含む場合、マトリックス樹脂組成物の硬化時の重合性がより優れる。
　不飽和ポリエステル樹脂又はエポキシ（メタ）アクリレート樹脂が水酸基を有することで、成分（Ｂ）との組み合わせにより、マトリックス樹脂組成物を増粘させることができる。 A matrix resin composition has thermosetting because a matrix resin composition contains the component (A) which has an ethylenically unsaturated group.
When the component (A) contains at least one selected from the group consisting of unsaturated polyester resins and epoxy (meth) acrylate resins, the polymerizability at the time of curing of the matrix resin composition is more excellent.
Since the unsaturated polyester resin or the epoxy (meth) acrylate resin has a hydroxyl group, the matrix resin composition can be thickened in combination with the component (B).
　成分（Ａ）を構成する化合物は、一種でもよく二種以上でもよい。
　成分（Ａ）を構成する化合物が一種である場合、その化合物は、成分（Ａ－１）及び成分（Ａ－２）からなる群から選ばれる少なくとも一種である。
　成分（Ａ）を構成する化合物が二種以上である場合、それらの化合物の全てが成分（Ａ－１）及び成分（Ａ－２）からなる群から選ばれる少なくとも一種であってもよく、それらの化合物の一部が成分（Ａ－１）及び成分（Ａ－２）からなる群から選ばれる少なくとも一種であり、残部がそれら以外の他の化合物（例えば後述する重合性ビニル単量体）であってもよい。
　成分（Ａ）が他の化合物を含む場合、他の化合物は、１分子中に水酸基を１個以上有する化合物であってもよく、水酸基を有さない化合物であってもよく、それらの両方であってもよい。 The compound constituting the component (A) may be one kind or two or more kinds.
When the compound constituting Component (A) is one kind, the compound is at least one selected from the group consisting of Component (A-1) and Component (A-2).
When there are two or more compounds constituting component (A), all of these compounds may be at least one selected from the group consisting of component (A-1) and component (A-2). A part of the compound is at least one selected from the group consisting of the component (A-1) and the component (A-2), and the remainder is other compounds (for example, a polymerizable vinyl monomer described later). There may be.
When component (A) contains other compounds, the other compounds may be compounds having one or more hydroxyl groups in one molecule, or may be compounds having no hydroxyl groups, There may be.
　成分（Ａ－１）としては、公知の不飽和ポリエステル樹脂から適宜選択することができる。 Component (A-1) can be appropriately selected from known unsaturated polyester resins.
　成分（Ａ－１）が１分子中に有するエチレン性不飽和基の数は、１個以上であればよい。
　エチレン性不飽和基の数が前記上限値以下であれば、マトリックス樹脂組成物の硬化時の重合性がより優れる。 The number of ethylenically unsaturated groups in the molecule of component (A-1) may be one or more.
If the number of ethylenically unsaturated groups is not more than the above upper limit, the polymerizability at the time of curing of the matrix resin composition is more excellent.
　成分（Ａ－１）が１分子中に有する水酸基の数は、１～２．５個が好ましい。
　水酸基の数が前記下限値以上であれば、成分（Ｂ）との組み合わせ時、マトリックス樹脂組成物の持つ増粘性がより優れる。
　水酸基の数が前記上限値以下であれば、成分（Ｂ）との組み合わせ時、マトリックス樹脂組成物の流動性がより優れる。 Component (A-1) preferably has 1 to 2.5 hydroxyl groups in one molecule.
When the number of hydroxyl groups is at least the lower limit, the thickening property of the matrix resin composition is more excellent when combined with the component (B).
If the number of hydroxyl groups is less than or equal to the above upper limit, the fluidity of the matrix resin composition is more excellent when combined with the component (B).
　成分（Ａ－１）は、典型的には、α，β－オレフィン系不飽和ジカルボン酸と２価のグリコールとの縮合で合成された不飽和ポリエステル樹脂（α，β－オレフィン系不飽和ジカルボン酸と２価のグリコールとの重縮合体）である。
　不飽和ポリエステル樹脂の合成においては、これら２成分のほかに、α，β－オレフィン系不飽和ジカルボン酸以外のジカルボン酸（飽和ジカルボン酸、芳香族ジカルボン酸等）、ジカルボン酸と反応するジシクロペンタジエン、２価のグリコール以外のアルコール（１価のアルコール（モノオール）、３価のアルコール（トリオール）等）等を併用することができる。 Component (A-1) is typically an unsaturated polyester resin (α, β-olefinic unsaturated dicarboxylic acid synthesized by condensation of an α, β-olefinic unsaturated dicarboxylic acid and a divalent glycol. And a polycondensate of divalent glycol).
In the synthesis of unsaturated polyester resins, in addition to these two components, dicarboxylic acids other than α, β-olefinic unsaturated dicarboxylic acids (saturated dicarboxylic acids, aromatic dicarboxylic acids, etc.), dicyclopentadiene that reacts with dicarboxylic acids Alcohols other than divalent glycol (monovalent alcohol (monool), trivalent alcohol (triol), etc.) and the like can be used in combination.
　α，β－オレフィン系不飽和ジカルボン酸としては、例えばマレイン酸、フマル酸、イタコン酸、シトラコン酸、及びこれらジカルボン酸の無水物等が挙げられる。中でもフマル酸が好ましい。 Examples of the α, β-olefin unsaturated dicarboxylic acid include maleic acid, fumaric acid, itaconic acid, citraconic acid, and anhydrides of these dicarboxylic acids. Of these, fumaric acid is preferred.
　α，β－オレフィン系不飽和ジカルボン酸と併用可能な他のジカルボン酸としては、例えばアジピン酸、セバシン酸、コハク酸、グルコン酸、フタル酸無水物、ｏ－フタル酸、イソフタル酸、テレフタル酸、テトラヒドロフタル酸、テトラクロロフタル酸等が挙げられる。中でもイソフタル酸が好ましい。 Other dicarboxylic acids that can be used in combination with the α, β-olefinic unsaturated dicarboxylic acid include, for example, adipic acid, sebacic acid, succinic acid, gluconic acid, phthalic anhydride, o-phthalic acid, isophthalic acid, terephthalic acid, Examples include tetrahydrophthalic acid and tetrachlorophthalic acid. Of these, isophthalic acid is preferred.
　２価のグリコールとしては、例えばアルカンジオール、オキサアルカンジオール、ビスフェノールＡのアルキレンオキサイド付加物等が挙げられる。アルキレンオキサイドとしては、エチレンオキシド、プロピレンオキシド等が挙げられる。 Examples of the divalent glycol include alkanediol, oxaalkanediol, and an alkylene oxide adduct of bisphenol A. Examples of the alkylene oxide include ethylene oxide and propylene oxide.
　アルカンジオールとしては、例えばエチレングリコール、１，２－プロピレングリコール、１，３－プロピレングリコール、１，３－ブタンジオール、１，４－ブタンジオール、ネオペンチルグリコール、１，５－ペンタンジオール、１，６－ヘキサンジオール、シクロヘキサンジオール等が挙げられる。
　オキサアルカンジオールとしては、例えばジオキシエチレングリコール、ジプロピレングリコール、トリエチレングリコール等が挙げられる。 Examples of the alkanediol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1, Examples include 6-hexanediol and cyclohexanediol.
Examples of the oxaalkanediol include dioxyethylene glycol, dipropylene glycol, and triethylene glycol.
　上記の中でも、２価のグリコールとしては、ネオペンチルグリコール及びジプロピレングリコールが好ましい。 Among these, neopentyl glycol and dipropylene glycol are preferable as the divalent glycol.
　グリコールと併用可能な１価あるいは３価のアルコールとしては、例えばオクチルアルコール、オレイルアルコール、トリメチロールプロパン等が挙げられる。 Examples of monovalent or trivalent alcohol that can be used in combination with glycol include octyl alcohol, oleyl alcohol, trimethylolpropane, and the like.
　成分（Ａ－２）としては、公知のエポキシ（メタ）アクリレート樹脂から適宜選択することができる。 Component (A-2) can be appropriately selected from known epoxy (meth) acrylate resins.
　成分（Ａ－２）が１分子中に有するエチレン性不飽和基の数は、１～２個が好ましい。
　エチレン性不飽和基の数が前記上限値以下であれば、マトリックス樹脂組成物の硬化時の重合性がより優れる。 The number of ethylenically unsaturated groups contained in one molecule of component (A-2) is preferably 1 to 2.
If the number of ethylenically unsaturated groups is not more than the above upper limit, the polymerizability at the time of curing of the matrix resin composition is more excellent.
　成分（Ａ－２）が１分子中に有する水酸基の数は、１～２．５個が好ましい。
　水酸基の数が前記下限値以上であれば、成分（Ｂ）との組み合わせ時、マトリックス樹脂組成物の持つ増粘性がより優れる。
　水酸基の数が前記上限値以下であれば、成分（Ｂ）との組み合わせ時、マトリックス樹脂組成物の流動性がより優れる。 Component (A-2) preferably has 1 to 2.5 hydroxyl groups in one molecule.
When the number of hydroxyl groups is at least the lower limit, the thickening property of the matrix resin composition is more excellent when combined with the component (B).
If the number of hydroxyl groups is less than or equal to the above upper limit, the fluidity of the matrix resin composition is more excellent when combined with the component (B).
　成分（Ａ－２）は、典型的には、エポキシ樹脂成分と不飽和一塩基酸成分との反応から得られる不飽和酸エポキシエステルである。
　エポキシ樹脂成分は、１分子中に少なくとも２個のエポキシ基を有する化合物であり、例えば、ビスフェノールＡ、ビスフェノールＦ、ブロム化ビスフェノールＡに代表されるビスフェノール化合物を主骨格としたジグリシジルエーテル型エポキシ樹脂；フェノールノボラック、クレゾールノボラック、ブロム化フェノールノボラックに代表される多核フェノール化合物を主骨格としたポリグリシジルエーテル型エポキシ樹脂；ダイマー酸、トリメリット酸に代表される有機多塩基酸を主骨格とするポリグリシジルエステル型エポキシ樹脂；ビスフェノールＡのエチレンオキサイドもしくはプロピレンオキサイド付加物、グリコール、及び水添ビスフェノールＡ等のジオール化合物を主骨格としたグリシジルエーテル型エポキシ樹脂等が挙げられる。
　これらのエポキシ樹脂は一種を単独で使用してもよく複数種を併用してもよい。
　上記の中でも、エポキシ樹脂成分としては、ビスフェノールＡを主骨格としたジグリシジルエーテル型エポキシ樹脂が好ましい。 Component (A-2) is typically an unsaturated acid epoxy ester obtained from the reaction of an epoxy resin component and an unsaturated monobasic acid component.
The epoxy resin component is a compound having at least two epoxy groups in one molecule, for example, a diglycidyl ether type epoxy resin having a bisphenol compound represented by bisphenol A, bisphenol F, or brominated bisphenol A as a main skeleton. ; Polyglycidyl ether type epoxy resin mainly composed of polynuclear phenolic compounds represented by phenol novolac, cresol novolac, brominated phenol novolac; Poly polybasic acid composed mainly of organic polybasic acid represented by dimer acid and trimellitic acid Glycidyl ester type epoxy resin; glycidyl ether type epoxy resin having diol compound such as ethylene oxide or propylene oxide adduct of bisphenol A, glycol and hydrogenated bisphenol A as the main skeleton It is.
These epoxy resins may be used individually by 1 type, and may use multiple types together.
Among these, as the epoxy resin component, a diglycidyl ether type epoxy resin having bisphenol A as a main skeleton is preferable.
　不飽和一塩基酸成分は、エチレン性不飽和基を有する一塩基酸であり、例えばアクリル酸、メタクリル酸、クロトン酸、ソルビン酸等が挙げられる。
　これらの不飽和一塩基酸成分は一種を単独で使用してもよく複数種を併用してもよい。
　上記の中でも、不飽和一塩基酸成分としては、アクリル酸が好ましい。 The unsaturated monobasic acid component is a monobasic acid having an ethylenically unsaturated group, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, and sorbic acid.
These unsaturated monobasic acid components may be used individually by 1 type, and may use multiple types together.
Among the above, acrylic acid is preferable as the unsaturated monobasic acid component.
　成分（Ａ－１）、成分（Ａ－２）はそれぞれ一種を単独で使用してもよく、複数種を併用してもよい。 Component (A-1) and Component (A-2) may be used alone or in combination of two or more.
　成分（Ａ）は、成分（Ａ－１）及び成分（Ａ－２）以外の他の化合物をさらに含んでもよい。
　他の化合物としては、エチレン性不飽和基を有する化合物であれば特に制限はなく、例えば、重合性ビニル単量体、成分（Ａ－１）以外の不飽和ポリエステル樹脂（例えば、水酸基を有さない不飽和ポリエステル樹脂）、成分（Ａ－２）以外のエポキシ（メタ）アクリレート樹脂（例えば、水酸基を有さないエポキシ（メタ）アクリレート樹脂）等が挙げられる。 Component (A) may further contain a compound other than component (A-1) and component (A-2).
The other compound is not particularly limited as long as it is a compound having an ethylenically unsaturated group. For example, an unsaturated polyester resin other than a polymerizable vinyl monomer and component (A-1) (for example, having a hydroxyl group). Non-unsaturated polyester resin), epoxy (meth) acrylate resins other than component (A-2) (for example, epoxy (meth) acrylate resins having no hydroxyl group), and the like.
　重合性ビニル単量体は、エチレン性不飽和基を有する単量体である。重合性ビニル単量体は反応性希釈剤として機能する。
　重合性ビニル単量体としては、例えばスチレン、塩化ビニル等の水酸基を有さない重合性ビニル単量体；ヒドロキシエチル（メタ）アクリレートやヒドロキシプロピル（メタ）アクリレート等の水酸基を有する重合性ビニル単量体等が挙げられる。
　これらの重合性ビニル単量体は一種を単独で使用してもよく複数種を併用してもよい。 The polymerizable vinyl monomer is a monomer having an ethylenically unsaturated group. The polymerizable vinyl monomer functions as a reactive diluent.
Examples of the polymerizable vinyl monomer include a polymerizable vinyl monomer having no hydroxyl group such as styrene and vinyl chloride; a polymerizable vinyl monomer having a hydroxyl group such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate. Examples include a polymer.
These polymerizable vinyl monomers may be used individually by 1 type, and may use multiple types together.
　成分（Ａ－１）以外の不飽和ポリエステル樹脂や成分（Ａ－２）以外のエポキシ（メタ）アクリレート樹脂としては、ＳＭＣ材料として通常用いられている不飽和ポリエステル樹脂及びエポキシ（メタ）アクリレート樹脂から適宜選択することができる。 Examples of unsaturated polyester resins other than component (A-1) and epoxy (meth) acrylate resins other than component (A-2) include unsaturated polyester resins and epoxy (meth) acrylate resins commonly used as SMC materials. It can be selected appropriately.
　成分（Ａ）中の成分（Ａ－１）と成分（Ａ－２）との合計の含有量は、成分（Ａ）の総質量に対し、９０質量％以上が好ましく、９５質量％以上がより好ましく、１００質量％が最も好ましい。すなわち、成分（Ａ）が、成分（Ａ－１）及び成分（Ａ－２）の一方又は両方のみからなることが最も好ましい。 The total content of component (A-1) and component (A-2) in component (A) is preferably 90% by mass or more, more preferably 95% by mass or more based on the total mass of component (A). Preferably, 100 mass% is most preferable. That is, the component (A) is most preferably composed of only one or both of the component (A-1) and the component (A-2).
　（成分（Ｂ））
　成分（Ｂ）は、ジイソシアネート化合物である。
　成分（Ｂ）は、マトリックス樹脂組成物において増粘剤として作用する。成分（Ａ）が水酸基を有する場合、成分（Ａ）が有する水酸基と成分（Ｂ）が有するイソシアネート基とが反応することにより、エチレン性不飽和基含有プレポリマーが生じ、ＳＭＣに適度な粘度を生じさせる。 (Ingredient (B))
Component (B) is a diisocyanate compound.
Component (B) acts as a thickener in the matrix resin composition. When the component (A) has a hydroxyl group, the hydroxyl group of the component (A) reacts with the isocyanate group of the component (B) to produce an ethylenically unsaturated group-containing prepolymer. Cause it to occur.
　成分（Ｂ）としては、例えば、式：ＯＣＮ－Ｒ１－ＮＣＯ（ただし、Ｒ１は炭化水素基である。）で表されるジイソシアネート化合物（Ｂ－１）、ジイソシアネートプレポリマー（Ｂ－２）、それらの変性物等が挙げられる。 Examples of the component (B) include a diisocyanate compound (B-1) and a diisocyanate prepolymer (B-2) represented by the formula: OCN—R 1 —NCO (where R 1 is a hydrocarbon group). And modified products thereof.
　ジイソシアネート化合物（Ｂ－１）としては、例えば２，４－トルエンジイソシアネート、２，６－トルエンジイソシアネート、４，４’－ジフェニルメタンジイソシアネート、イソホロンジイソシアネート、ヘキサメチレンジイソシアネート等が挙げられる。 Examples of the diisocyanate compound (B-1) include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and the like.
　ジイソシアネートプレポリマー（Ｂ－２）としては、例えば、水酸基を有するポリエーテルポリオール又はポリエステルポリオールとジイソシアネート化合物（Ｂ－１）との反応により得られる、両末端にイソシアネート基を有するジイソシアネートプレポリマーが挙げられる。 Examples of the diisocyanate prepolymer (B-2) include a diisocyanate prepolymer having an isocyanate group at both ends obtained by a reaction between a polyether polyol or polyester polyol having a hydroxyl group and a diisocyanate compound (B-1). .
　（成分（Ｃ））
　成分（Ｃ）は、重合禁止剤である。
　成分（Ｃ）は、水酸基を有さず、かつ活性なラジカル種と反応し、不活性なラジカル種又は安定な化合物を生成しうる化合物であることが好ましい。具体的には、成分（Ｃ）は、分子中に水酸基を有さない重合禁止剤であり、かつ１００℃以上の温度において、ラジカル重合を引き起こす活性なラジカル種と反応し、ラジカル重合を引き起こさない不活性なラジカル又は安定な化合物にする作用を有することが好ましい。 (Ingredient (C))
Component (C) is a polymerization inhibitor.
Component (C) preferably has no hydroxyl group and can react with an active radical species to generate an inactive radical species or a stable compound. Specifically, the component (C) is a polymerization inhibitor having no hydroxyl group in the molecule, and reacts with an active radical species that causes radical polymerization at a temperature of 100 ° C. or higher and does not cause radical polymerization. It preferably has an effect of forming an inert radical or a stable compound.
　「ラジカル重合を引き起こす活性なラジカル種と反応し、ラジカル重合を引き起こさない不活性なラジカル又は安定な化合物にする作用」とは、要するに、活性なラジカル種を捕捉する作用、いわゆる重合禁止作用である。つまり、成分（Ｃ）は、１００℃以上の温度において重合禁止作用を示す重合禁止剤であることが好ましい。 “The action of reacting with an active radical species that causes radical polymerization to form an inert radical or a stable compound that does not cause radical polymerization” is, in short, an action of capturing active radical species, a so-called polymerization inhibiting action. . That is, the component (C) is preferably a polymerization inhibitor that exhibits a polymerization inhibiting action at a temperature of 100 ° C. or higher.
　マトリックス樹脂組成物が成分（Ｃ）を含むことで、後述する増粘工程の際に微量に生じる活性なラジカル種（例えば、後述する成分（Ｄ）から生じるラジカル）が成分（Ｃ）によって捕捉され、活性なラジカル種による反応（成分（Ａ）の重合、架橋反応等）の進行が抑制される。このため、ＳＭＣの成形時（硬化反応時）の流動性の低下を抑制できる。 When the matrix resin composition contains the component (C), active radical species (for example, radicals generated from the component (D) described later) generated in a trace amount during the thickening step described later are captured by the component (C). , The progress of reaction (polymerization of component (A), crosslinking reaction, etc.) due to active radical species is suppressed. For this reason, the fall of the fluidity | liquidity at the time of shaping | molding of SMC (at the time of hardening reaction) can be suppressed.
　成分（Ｃ）が重合禁止作用を示す温度は、１００～１４０℃が好ましい。
　成分（Ｃ）等の重合禁止剤が重合禁止作用を示す温度は、示差走査熱量測定（ＤＳＣ）により確認できる。 The temperature at which component (C) exhibits a polymerization inhibiting action is preferably 100 to 140 ° C.
The temperature at which the polymerization inhibitor such as component (C) exhibits a polymerization inhibiting action can be confirmed by differential scanning calorimetry (DSC).
　成分（Ｃ）は、分子中に水酸基を有さないことが好ましい。
　前記のような重合禁止作用を示す重合禁止剤の中には、例えばハイドロキノンのような水酸基を有する化合物が存在する。重合禁止剤が水酸基を有すると、重合禁止剤と成分（Ｂ）が有するイソシアネート基とが反応する。その結果、本来、成分（Ａ）と反応して増粘剤としての作用を期待していたイソシアネート基が失われてしまうため、増粘効果が阻害される。また、この反応により、重合禁止剤としてのラジカル捕捉作用が充分に作用せず、ＳＭＣの成形温度付近（１２０～１６０℃）でのラジカルの補捉作用が充分働かず、成形時の流動性が損なわれる。
　成分（Ｃ）が水酸基を有さないことで、増粘効果が阻害されず、また成形時の流動性が損なわれない。 Component (C) preferably has no hydroxyl group in the molecule.
Among the polymerization inhibitors exhibiting the polymerization inhibiting action as described above, there are compounds having a hydroxyl group such as hydroquinone. When the polymerization inhibitor has a hydroxyl group, the polymerization inhibitor and the isocyanate group of the component (B) react. As a result, the isocyanate group which originally reacted with the component (A) and expected to act as a thickener is lost, so that the thickening effect is inhibited. In addition, the radical scavenging action as a polymerization inhibitor does not act sufficiently due to this reaction, the radical scavenging action near the molding temperature of SMC (120 to 160 ° C.) does not work sufficiently, and the fluidity during molding is low. Damaged.
Since component (C) does not have a hydroxyl group, the thickening effect is not inhibited, and the fluidity during molding is not impaired.
　成分（Ｃ）としては、上記条件を満たすものであればよく、一般に重合禁止剤として知られている各種の化合物の中から、適宜選択することができる。
　成分（Ｃ）の好ましい例として、ｐ－ベンゾキノン、ナフトキノン、フェナンスラキノン、ｐ－キシロキノン、ｐ－トルキノン、２，６－ジクロロキノン、２，５－ジフェニル－ｐ－ベンゾキノン、２，５－ジアセトキシ－ｐ－ベンゾキノン、２，５－ジカプロキシ－ｐ－ベンゾキノン等のキノン類が挙げられる。これらキノン類は、後述する成分（Ｄ）から生じるラジカル、特に有機過酸化物から生じるラジカルの補捉作用が非常に強く、成形時の流動性の低下を顕著に抑制するため、ＳＭＣの保存安定性が特に優れる。
　これらのキノン類は一種を単独で使用してもよく、複数種を併用してもよい。
　上記の中でも、成分（Ｃ）としては、ｐ－ベンゾキノンが好ましい。 The component (C) is not particularly limited as long as it satisfies the above conditions, and can be appropriately selected from various compounds generally known as polymerization inhibitors.
Preferred examples of component (C) include p-benzoquinone, naphthoquinone, phenanthraquinone, p-xyloquinone, p-toluquinone, 2,6-dichloroquinone, 2,5-diphenyl-p-benzoquinone, 2,5-diacetoxy And quinones such as -p-benzoquinone and 2,5-dicaproxy-p-benzoquinone. These quinones have a very strong trapping action of radicals generated from the component (D) described later, particularly radicals generated from organic peroxides, and remarkably suppress a decrease in fluidity during molding. The property is particularly excellent.
These quinones may be used individually by 1 type, and may use multiple types together.
Among these, as the component (C), p-benzoquinone is preferable.
　なお、１００℃以上の温度において前記の重合禁止作用を示す、水酸基を有する化合物としては、例えばカテコール、ｔ－ブチルカテコール等のカテコール類、ハイドロキノン、ｐ－ｔ－ブチルカテコール、２，５－ｔ－ブチルハイドロキノン、モノ－ｔ－ブチルハイドロキノン等のハイドロキノン類が挙げられる。
　これらの化合物は、キノン類と同様に、ラジカルの補捉作用が非常に強い。しかし、水酸基を有するため、増粘効果を阻害する、ラジカル捕捉作用が充分に作用しない等の懸念が生じうる。 Examples of the hydroxyl group-containing compound exhibiting the above-described polymerization inhibiting action at a temperature of 100 ° C. or higher include catechols such as catechol and t-butylcatechol, hydroquinone, pt-butylcatechol, 2,5-t- And hydroquinones such as butyl hydroquinone and mono-t-butyl hydroquinone.
These compounds, like quinones, have a very strong radical scavenging action. However, since it has a hydroxyl group, there are concerns that the thickening effect is inhibited and the radical scavenging action does not sufficiently work.
　（成分（Ｄ））
　成分（Ｄ）は、重合開始剤である。
　成分（Ｄ）に特に制限はなく、通常のエポキシ（メタ）アクリレート樹脂や不飽和ポリエステル樹脂の硬化の際に使用される重合開始剤から選択することができる。 (Component (D))
Component (D) is a polymerization initiator.
There is no restriction | limiting in particular in a component (D), It can select from the polymerization initiator used in the case of hardening of a normal epoxy (meth) acrylate resin or unsaturated polyester resin.
　成分（Ｄ）としては、例えば１，１－ジ（ｔ－ブチルパーオキシ）シクロヘキサン、ｔ－ブチルパーオキシイソプロピルカーボネート、ｔ－アミルパーオキイシイソプロピルカーボネート、メチルエチルケトンパーオキサイド、ｔ－ブチルパーオキシベンゾエート、ベンゾイルパーオキサイド、ジクミルパーオキサイド、クメンハイドロパーオキサイド等の有機過酸化物が挙げられる。
　これらの有機過酸化物は一種を単独で使用してもよく、複数種を併用してもよい。 Examples of the component (D) include 1,1-di (t-butylperoxy) cyclohexane, t-butylperoxyisopropyl carbonate, t-amyl peroxyisopropyl carbonate, methyl ethyl ketone peroxide, t-butyl peroxybenzoate, Organic peroxides such as benzoyl peroxide, dicumyl peroxide, cumene hydroperoxide and the like can be mentioned.
These organic peroxides may be used individually by 1 type, and may use multiple types together.
　（他の成分）
　マトリックス樹脂組成物に含まれうる、成分（Ａ）、成分（Ｂ）、成分（Ｃ）、及び成分（Ｄ）以外の他の成分としては、例えば無機充填剤、内部離型剤、安定剤、顔料、着色料等の添加物が挙げられる。 (Other ingredients)
Examples of components other than component (A), component (B), component (C), and component (D) that can be included in the matrix resin composition include inorganic fillers, internal mold release agents, stabilizers, Examples thereof include additives such as pigments and colorants.
　無機充填剤の種類は、特に制限はなく、例えば、炭酸カルシウム、炭酸マグネシウム、水酸化アルミニウム、水酸化マグネシウム、水酸化カルシウム、シリカ、溶融シリカ、硫酸バリウム、酸化チタン、酸化マグネシウム、酸化カルシウム、酸化アルミニウム、リン酸カルシウム、タルク、マイカ、クレー、ガラスパウダー等の公知の材料を使用することができる。
　これらの無機充填剤は一種を単独で使用してもよく複数種を併用してもよい。 The type of the inorganic filler is not particularly limited, and examples thereof include calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, silica, fused silica, barium sulfate, titanium oxide, magnesium oxide, calcium oxide, and oxidation. Known materials such as aluminum, calcium phosphate, talc, mica, clay, and glass powder can be used.
These inorganic fillers may be used individually by 1 type, and may use multiple types together.
　内部離型剤の種類には、特に制限はなく、例えばリン酸エステル系誘導体、ステアリン酸亜鉛等の脂肪酸金属塩、ジアルキルスルホコハク酸ナトリウム等の界面活性剤等の公知の材料を使用することができる。
　これらの内部離型剤は一種を単独で使用してもよく複数種を併用してもよい。 The type of the internal mold release agent is not particularly limited, and known materials such as phosphate ester derivatives, fatty acid metal salts such as zinc stearate, and surfactants such as sodium dialkylsulfosuccinate can be used. .
These internal mold release agents may be used individually by 1 type, and may use multiple types together.
　（各成分の割合）
　マトリックス樹脂組成物における成分（Ａ）の含有量は、マトリックス樹脂組成物の総質量に対し、５０～９５質量％が好ましく、６０～８５質量％がより好ましい。
　マトリックス樹脂組成物における成分（Ａ）の含有量が前記下限値以上であれば、得られる成形体の機械的特性がより優れる。
　マトリックス樹脂組成物における成分（Ａ）の含有量が前記上限値以下であれば、ＳＭＣ製造時におけるマトリックス樹脂組成物の炭素繊維束への含浸性がより優れる。 (Ratio of each component)
The content of the component (A) in the matrix resin composition is preferably 50 to 95% by mass and more preferably 60 to 85% by mass with respect to the total mass of the matrix resin composition.
If content of the component (A) in a matrix resin composition is more than the said lower limit, the mechanical characteristics of the molded object obtained will be more excellent.
When the content of the component (A) in the matrix resin composition is not more than the above upper limit value, the impregnation property of the matrix resin composition into the carbon fiber bundle at the time of SMC production is more excellent.
　マトリックス樹脂組成物における成分（Ｂ）の含有量は、成分（Ａ）が有する水酸基１個に対する成分（Ｂ）のイソシアネート基の数が０．１個以上１．０個以下となる量が好ましい。
　成分（Ａ）が有する水酸基１個に対する成分（Ｂ）のイソシアネート基の数が０．１個以上であれば、マトリックス樹脂組成物を充分に増粘させることができる。
　成分（Ａ）が有する水酸基１個に対する成分（Ｂ）のイソシアネート基の数が１．０個以下であれば、余分なイソシアネート基が水分と反応して発泡し、成形後に気泡が成形物（すなわち繊維強化複合材料）内部に残ることを抑制できる。 The content of component (B) in the matrix resin composition is preferably such that the number of isocyanate groups in component (B) relative to one hydroxyl group in component (A) is 0.1 or more and 1.0 or less.
If the number of isocyanate groups in component (B) relative to one hydroxyl group in component (A) is 0.1 or more, the matrix resin composition can be sufficiently thickened.
If the number of isocyanate groups in component (B) relative to one hydroxyl group in component (A) is 1.0 or less, excess isocyanate groups react with moisture and foam, and after molding, bubbles are formed (that is, (Fiber-reinforced composite material) can be prevented from remaining inside.
　成分（Ａ）が有する水酸基１個に対する成分（Ｂ）のイソシアネート基の数は、０．３個以上０．８個以下がより好ましい。
　マトリックス樹脂組成物における成分（Ｂ）の含有量は、マトリックス樹脂組成物の総質量に対し、５～２５質量％が好ましく、１５～２５質量％がより好ましい。 As for the number of the isocyanate groups of the component (B) with respect to one hydroxyl group which a component (A) has, 0.3 or more and 0.8 or less are more preferable.
The content of the component (B) in the matrix resin composition is preferably 5 to 25% by mass and more preferably 15 to 25% by mass with respect to the total mass of the matrix resin composition.
　マトリックス樹脂組成物における成分（Ｃ）の含有量は、成分（Ａ）の１００質量部に対し、０．００１～０．１質量部が好ましく、０．０３～０．０５質量部がより好ましい。
　マトリックス樹脂組成物における成分（Ｃ）の含有量が前記下限値以上であれば、加熱加圧成形時にＳＭＣが充分な流動性を示す。また、その流動性の経時的な低下が生じにくい。
　マトリックス樹脂組成物における成分（Ｃ）の含有量が前記上限値以下であれば、加熱加圧成形時に充分に速い硬化速度が得られ、速硬化性に優れる。また、硬化物が充分に架橋し、優れた面方向品質性が得られる。 The content of the component (C) in the matrix resin composition is preferably 0.001 to 0.1 parts by mass and more preferably 0.03 to 0.05 parts by mass with respect to 100 parts by mass of the component (A).
If content of the component (C) in a matrix resin composition is more than the said lower limit, SMC will show sufficient fluidity at the time of heat press molding. In addition, the fluidity is less likely to deteriorate over time.
If content of the component (C) in a matrix resin composition is below the said upper limit, a sufficiently quick hardening rate will be obtained at the time of heat-press molding, and it will be excellent in quick curability. Further, the cured product is sufficiently cross-linked, and excellent surface direction quality can be obtained.
　マトリックス樹脂組成物における成分（Ｄ）の含有量は、成分（Ａ）の１００質量部に対し、０．１～５質量部が好ましく、０．５～３質量部がより好ましい。
　マトリックス樹脂組成物における成分（Ｄ）の含有量が前記下限値以上であれば、加熱加圧成形時に充分に速い硬化速度が得られ、速硬化性に優れる。
　マトリックス樹脂組成物における成分（Ｄ）の含有量が前記上限値以下であれば、加熱加圧成形時にＳＭＣが充分な流動性を示す。 The content of the component (D) in the matrix resin composition is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass with respect to 100 parts by mass of the component (A).
If content of the component (D) in a matrix resin composition is more than the said lower limit, a sufficiently quick hardening rate will be obtained at the time of heat-press molding, and it will be excellent in quick curability.
If content of the component (D) in a matrix resin composition is below the said upper limit, SMC will show sufficient fluidity | liquidity at the time of heat press molding.
　マトリックス樹脂組成物は、他の成分として、１００℃以上の温度において前記の重合禁止作用を示す、水酸基を有する化合物をさらに含んでもよい。しかし、水酸基を有するこの化合物は、増粘効果を阻害する、ラジカル捕捉作用が充分に作用しない等の懸念が生じうる。そのため、マトリックス樹脂組成物において、１００℃以上の温度において前記の重合禁止作用を示す、水酸基を有する化合物の含有量は少ないほど好ましく、例えば成分（Ａ）の１００質量部に対し、０．０１質量部以下が好ましく、含まないことが特に好ましい。 The matrix resin composition may further contain, as another component, a compound having a hydroxyl group that exhibits the above-described polymerization inhibiting action at a temperature of 100 ° C. or higher. However, this compound having a hydroxyl group may cause problems such as inhibiting the thickening effect and insufficient radical scavenging action. Therefore, in the matrix resin composition, the content of the compound having a hydroxyl group that exhibits the above-described polymerization inhibition action at a temperature of 100 ° C. or higher is preferably as low as possible. For example, 0.01 mass with respect to 100 mass parts of the component (A) Part or less is preferable, and it is particularly preferable not to include it.
　ＳＭＣ前駆体の２５℃における初期増粘後の粘度は、１０～５００Ｐａ・ｓが好ましく、２０～３００Ｐａ・ｓがより好ましい。ここで「初期増粘」とは、ＳＭＣ前駆体を２５℃で６０分保持した時点での粘度を意味する。
　ＳＭＣ前駆体の２５℃における初期増粘後の粘度が前記上限値以下であれば、マトリックス樹脂組成物の炭素繊維束への含浸性がより優れる。
　ＳＭＣ前駆体の２５℃における初期増粘後の粘度が前記下限値以上であれば、ＳＭＣが充分な形態保持性を有し、取り扱い性がより優れる。 The viscosity of the SMC precursor after initial thickening at 25 ° C. is preferably 10 to 500 Pa · s, and more preferably 20 to 300 Pa · s. Here, “initial thickening” means the viscosity when the SMC precursor is held at 25 ° C. for 60 minutes.
If the viscosity of the SMC precursor after initial thickening at 25 ° C. is not more than the above upper limit, the impregnation property of the matrix resin composition into the carbon fiber bundle is more excellent.
If the viscosity of the SMC precursor after initial thickening at 25 ° C. is equal to or higher than the lower limit value, the SMC has sufficient shape retention and handling properties are more excellent.
　マトリックス樹脂組成物は、成分（Ａ）、成分（Ｂ）、及び成分（Ｃ）、ならびに必要に応じて使用する成分（Ｄ）及び他の成分を混合することにより調製できる。
　混合方法としては、各成分を均一に分散又は溶解できればよく、従来から用いられる一般的な方法を用いることができる。例えば、マトリックス樹脂組成物を構成する各成分を同時に混合して調製してもよく、あるいは、必要に応じて予め成分（Ｂ）以外の成分を混合し、得られた混合物と成分（Ｂ）とを、含浸工程の直前に混合してもよい。 The matrix resin composition can be prepared by mixing the component (A), the component (B), and the component (C), and the component (D) and other components used as necessary.
As a mixing method, it is only necessary to uniformly disperse or dissolve each component, and a conventionally used general method can be used. For example, the components constituting the matrix resin composition may be prepared by mixing at the same time, or if necessary, components other than component (B) may be mixed in advance, and the resulting mixture and component (B) May be mixed immediately before the impregnation step.
　混合操作には、三本ロールミル、プラネタリミキサー、ニーダー、万能撹拌機、ホモジナイザー、ホモディスペンサー等の混合機を用いることができるが、これらに限定されるものではない。 For the mixing operation, a mixer such as a three-roll mill, a planetary mixer, a kneader, a universal stirrer, a homogenizer, or a homodispenser can be used, but is not limited thereto.
（増粘工程）
　ＳＭＣを得るために、ＳＭＣ前駆体中のマトリックス樹脂組成物を増粘させる方法としては、特に限定されないが、例えば、含浸工程で得られたＳＭＣ前駆体を、ほぼ等温で保持することにより、炭素繊維基材に含浸されたマトリックス樹脂組成物中の成分（Ａ）と成分（Ｂ）とを反応させてＳＭＣ前駆体を増粘させることができる。
　ここで、「ほぼ等温」とは、保持温度の振れが±５℃以下であることを意味する。 (Thickening process)
In order to obtain SMC, the method of thickening the matrix resin composition in the SMC precursor is not particularly limited. For example, by maintaining the SMC precursor obtained in the impregnation step substantially isothermally, The SMC precursor can be thickened by reacting the component (A) and the component (B) in the matrix resin composition impregnated in the fiber base material.
Here, “substantially isothermal” means that the fluctuation of the holding temperature is ± 5 ° C. or less.
　保持温度及び時間は、成分（Ａ）及び成分（Ｂ）の種類や量に応じて適宜設定できる。通常は、保持温度が１０～５０℃程度、保持時間が数日～数十日間（例えば７～５０日間）程度とされる。 The holding temperature and time can be appropriately set according to the type and amount of component (A) and component (B). Usually, the holding temperature is about 10 to 50 ° C., and the holding time is about several days to several tens of days (for example, 7 to 50 days).
　前述した製造方法で得られるＳＭＣは、複数のチョップド炭素繊維束と、マトリックス樹脂組成物の増粘物とを含む。前述のように、マトリックス樹脂組成物中の成分（Ａ）が有する水酸基と成分（Ｂ）が有するイソシアネート基とが反応すると、エチレン性不飽和基含有プレポリマーが生じ、マトリックス樹脂組成物が増粘する。したがって、マトリックス樹脂組成物の増粘物は、エチレン性不飽和基含有プレポリマーを含む。一方、増粘前のマトリックス樹脂組成物は、エチレン性不飽和基含有プレポリマーを実質的に含まない。 The SMC obtained by the production method described above includes a plurality of chopped carbon fiber bundles and a thickened material of the matrix resin composition. As described above, when the hydroxyl group of component (A) in the matrix resin composition reacts with the isocyanate group of component (B), an ethylenically unsaturated group-containing prepolymer is produced, and the matrix resin composition is thickened. To do. Therefore, the thickened material of the matrix resin composition contains an ethylenically unsaturated group-containing prepolymer. On the other hand, the matrix resin composition before thickening does not substantially contain an ethylenically unsaturated group-containing prepolymer.
　ＳＭＣの総質量に対する炭素繊維束の含有量の好ましい範囲は、前述のＳＭＣ前駆体の総質量に対する炭素繊維束の含有量の好ましい範囲と同様である。
　ＳＭＣにおける炭素繊維束の目付けは、例えば５００～２５００ｍｇ／ｍ２とすることができる。 The preferable range of the content of the carbon fiber bundle with respect to the total mass of the SMC is the same as the preferable range of the content of the carbon fiber bundle with respect to the total mass of the SMC precursor.
The basis weight of the carbon fiber bundle in SMC can be set to, for example, 500 to 2500 mg / m 2 .
　本発明の製造方法で製造されたＳＭＣを加熱加圧成形することで、繊維強化複合材料である成形体が得られる。
　本発明の製造方法で製造されたＳＭＣを用いて得られる成形体は、本発明の製造方法で製造されたＳＭＣのみを用いて得られたものであってもよく、本発明の製造方法で製造されたＳＭＣと他の部材とを組み合わせて得られたものであってもよい。 By molding the SMC produced by the production method of the present invention under heat and pressure, a molded body that is a fiber-reinforced composite material is obtained.
The molded product obtained using the SMC produced by the production method of the present invention may be obtained by using only the SMC produced by the production method of the present invention, and produced by the production method of the present invention. It may be obtained by combining the manufactured SMC and another member.
　ＳＭＣを成形する際の成形条件は、特に限定されず、例えば金型温度１４０℃、圧力８ＭＰａの条件で２分間加熱加圧する条件が挙げられる。
　成形体としては、特に限定されず、例えば部分的に肉厚の異なる成形体、リブ、ボスを有する成形体等であってよい。
　成形体の用途としては、特に限定されず、例えば自動車の外板、内装材及び構造材料等が挙げられる。 The molding conditions for molding the SMC are not particularly limited, and examples include conditions of heating and pressurizing for 2 minutes under conditions of a mold temperature of 140 ° C. and a pressure of 8 MPa.
It does not specifically limit as a molded object, For example, the molded object which has a partially different thickness, a rib, the boss | hub, etc. may be sufficient.
The usage of the molded body is not particularly limited, and examples thereof include an automobile outer plate, an interior material, and a structural material.
　以上説明したように、本発明においては、方法（Ｉ）で算出される嵩密度が６０～４００ｇ／Ｌであり、好ましくは、さらに方法（ＩＩ）で算出されるカンチレバー値が１００ｍｍ以上である長尺の炭素繊維束が裁断された複数のチョップド炭素繊維束にマトリックス樹脂組成物を含浸させてＳＭＣを製造する。
　このような長尺の炭素繊維束を用いることで、ＳＭＣの製造時や成形時にチョップド炭素繊維束の厚みが急激に変化しにくくなる。また、チョップド炭素繊維束が剛直であり、チョップド炭素繊維束同士が３次元的ネットワークを形成しやすくなる。そのため、引張強度や引張弾性率、曲げ強度や曲げ弾性率等の機械的強度が高い成形体が得られるＳＭＣを製造できる。 As described above, in the present invention, the bulk density calculated by the method (I) is 60 to 400 g / L, and preferably the cantilever value calculated by the method (II) is 100 mm or more. A plurality of chopped carbon fiber bundles obtained by cutting the length carbon fiber bundle is impregnated with the matrix resin composition to produce SMC.
By using such a long carbon fiber bundle, the thickness of the chopped carbon fiber bundle is less likely to change suddenly during SMC manufacturing or molding. Further, the chopped carbon fiber bundles are rigid, and the chopped carbon fiber bundles easily form a three-dimensional network. Therefore, it is possible to produce an SMC from which a molded body having high mechanical strength such as tensile strength, tensile elastic modulus, bending strength and bending elastic modulus can be obtained.
　本発明においては、方法（Ｉ）で算出される嵩密度が６０～４００ｇ／Ｌであるとともに、平均幅Ｗ（ｍｍ）及び平均厚みＨ（ｍｍ）が上述の式（１）及び式（２）を満たす長尺の炭素繊維束を用いることができる。
　このような長尺の炭素繊維束は、裁断安定性に優れるため、裁断工程に用いると得られるチョップド炭素繊維束の形態安定性が良好となる傾向にある。
　また、さらに方法（ＩＩ）で算出されるカンチレバー値が１００ｍｍ以上である長尺の炭素繊維束を使用することにより、成形品の機械的特性をさらに高めることができる。
　なお、本発明のＳＭＣの製造方法は、前記方法には限定されず、本発明の趣旨を逸脱しない範囲内で、構成の付加、省略、置換、及びその他の変更が可能である。 In the present invention, the bulk density calculated by the method (I) is 60 to 400 g / L, and the average width W (mm) and the average thickness H (mm) are the above formulas (1) and (2). A long carbon fiber bundle satisfying the above can be used.
Since such a long carbon fiber bundle is excellent in cutting stability, the shape stability of the chopped carbon fiber bundle obtained when used in the cutting process tends to be good.
Further, by using a long carbon fiber bundle whose cantilever value calculated by the method (II) is 100 mm or more, the mechanical properties of the molded product can be further enhanced.
In addition, the manufacturing method of SMC of this invention is not limited to the said method, The addition of a structure, omission, substitution, and other changes are possible within the range which does not deviate from the meaning of this invention.
　以下、実施例によって本発明を具体的に説明するが、本発明は以下の記載によっては限定されない。 Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by the following description.
（使用材料）
　使用した材料を以下に示す。 (Materials used)
The materials used are shown below.
　炭素繊維束（Ｉ）：フィラメント数が１５０００本の炭素繊維束（三菱ケミカル株式会社製、ＴＲ５０Ｓ　１５Ｌ）。 Carbon fiber bundle (I): Carbon fiber bundle having 15,000 filaments (manufactured by Mitsubishi Chemical Corporation, TR50S 15L).
＜成分（Ａ）＞
　成分（Ａ１）：エポキシ（メタ）アクリレート樹脂と不飽和ポリエステル樹脂との混合物（日本ユピカ株式会社製、製品名：ネオポール（登録商標）８１１３）。 <Component (A)>
Component (A1): A mixture of an epoxy (meth) acrylate resin and an unsaturated polyester resin (manufactured by Nippon Iupika Co., Ltd., product name: Neopol (registered trademark) 8113).
＜成分（Ｂ）＞
　成分（Ｂ１）：変性ジフェニルメタンジイソシアネート（三井化学株式会社製、製品名：コスモネート（登録商標）ＬＬ）。 <Component (B)>
Component (B1): Modified diphenylmethane diisocyanate (Mitsui Chemicals, product name: Cosmonate (registered trademark) LL).
＜成分（Ｃ）＞
　成分（Ｃ１）：１，４－ベンゾキノン（精工化学株式会社製）。１００℃以上の温度において重合禁止作用を有する。 <Ingredient (C)>
Component (C1): 1,4-benzoquinone (manufactured by Seiko Chemical Co., Ltd.). Has a polymerization inhibiting action at temperatures of 100 ° C. or higher
＜成分（Ｄ）＞
　成分（Ｄ１）：１，１－ジ（ｔ－ブチルパーオキシ）シクロヘキサンの７５質量％溶液（日油株式会社製、製品名：パーヘキサ（登録商標）Ｃ－７５（ＥＢ））。
　成分（Ｄ２）：ｔ－ブチルパーオキシイソプロピルカーボネートの７４質量％溶液（化薬アクゾ株式会社製、製品名：カヤカルボン（登録商標）ＢＩＣ－７５）。 <Component (D)>
Component (D1): 75% by mass solution of 1,1-di (t-butylperoxy) cyclohexane (manufactured by NOF Corporation, product name: Perhexa (registered trademark) C-75 (EB)).
Component (D2): 74% by mass solution of t-butylperoxyisopropyl carbonate (manufactured by Kayaku Akzo Co., Ltd., product name: Kayacarbon (registered trademark) BIC-75).
＜他の成分＞
　成分（Ｅ１）：内部離型剤（リン酸エステル系誘導体組成物）（アクセルプラスチックリサーチラボラトリー社製、製品名：ＭＯＬＤ　ＷＩＺ　ＩＮＴ－ＥＱ－６）。 <Other ingredients>
Component (E1): Internal mold release agent (phosphate ester derivative composition) (manufactured by Accel Plastic Research Laboratory, product name: MOLD WIZ INT-EQ-6).
（炭素繊維束の嵩密度の測定）
　炭素繊維束の嵩密度の測定は、以下の手順Ｉ－１～Ｉ－２により行った。
　（手順Ｉ－１）炭素繊維束を繊維長が２５ｍｍとなるようにロータリーカッターで裁断した切断片１００ｇを２Ｌのメスシリンダー（Φ８８ｍｍ、高さ４８５ｍｍの円柱状）に充填した。
　（手順Ｉ－２）メスシリンダー内の切断片の上部から均一に５００ｇの荷重をかけ、体積に変化が無くなったときの充填された切断片の総体積（Ｌ）を測定し、切断片の総質量（１００ｇ）を切断片の総体積（Ｌ）で除して嵩密度を算出した。 (Measurement of bulk density of carbon fiber bundle)
The bulk density of the carbon fiber bundle was measured by the following procedures I-1 and I-2.
(Procedure I-1) 100 g of a cut piece obtained by cutting a carbon fiber bundle with a rotary cutter so that the fiber length was 25 mm was filled in a 2 L graduated cylinder (Φ88 mm, columnar height 485 mm).
(Procedure I-2) Apply a load of 500 g uniformly from the top of the cut piece in the graduated cylinder, measure the total volume (L) of the filled cut piece when there is no change in volume, The bulk density was calculated by dividing the mass (100 g) by the total volume (L) of the cut piece.
（炭素繊維束のカンチレバー値の測定）
　炭素繊維束のカンチレバー値の測定は、以下の手順ＩＩ－１～ＩＩ－６により行った。
　（手順ＩＩ－１）炭素繊維束から長さ４０ｃｍの試験用炭素繊維束を切り出した。
　（手順ＩＩ－２）水平面と、水平面の一端から下方に向かって傾斜する、傾斜角度が４５度の斜面とを有する測定台の、水平面上に試験用炭素繊維束を載せ、試験用炭素繊維束の長さ方向の第１の端部を斜面と水平面との境界線Ａに合わせた。試験用炭素繊維束の上に押さえ板を載せ、押さえ板の端部を境界線Ａに合わせた。
　（手順ＩＩ－３）押さえ板を斜面側に水平方向に２ｃｍ／秒で移動させ、試験用炭素繊維束の第１の端部が斜面と接触した時点で押さえ板の移動を停止させた。
　（手順ＩＩ－４）手順ＩＩ－３における押さえ板の移動距離ｘ（ｍｍ）を測定した。
　（手順ＩＩ－５）試験用炭素繊維束を裏返し、さらに長さ方向に反転させて長さ方向の第２の端部を境界線Ａに合わせ、手順ＩＩ－２～ＩＩ－４と同じ手順で押さえ板の移動距離ｙ（ｍｍ）を測定した。
　（手順ＩＩ－６）炭素繊維束のカンチレバー値として、移動距離ｘと移動距離ｙとの平均値を算出した。 (Measurement of cantilever value of carbon fiber bundle)
The cantilever value of the carbon fiber bundle was measured by the following procedures II-1 to II-6.
(Procedure II-1) A test carbon fiber bundle having a length of 40 cm was cut out from the carbon fiber bundle.
(Procedure II-2) A test carbon fiber bundle is placed on a horizontal plane of a measuring table having a horizontal plane and a slope with an inclination angle of 45 degrees inclined downward from one end of the horizontal plane. The first end portion in the length direction was aligned with the boundary line A between the slope and the horizontal plane. A pressing plate was placed on the test carbon fiber bundle, and the end of the pressing plate was aligned with the boundary line A.
(Procedure II-3) The holding plate was moved horizontally at 2 cm / sec to the slope side, and the movement of the holding plate was stopped when the first end of the test carbon fiber bundle contacted the slope.
(Procedure II-4) The movement distance x (mm) of the pressing plate in Procedure II-3 was measured.
(Procedure II-5) Turn over the test carbon fiber bundle, turn it over in the length direction, and align the second end in the length direction with the boundary line A, and follow the same procedure as in Procedures II-2 to II-4. The movement distance y (mm) of the pressing plate was measured.
(Procedure II-6) The average value of the movement distance x and the movement distance y was calculated as the cantilever value of the carbon fiber bundle.
（ＳＭＣの樹脂含浸性の評価）
　ＳＭＣ前駆体を得た際に、樹脂含浸性を目視と触感で確認し、以下の評価基準で評価した。
　Ａ：マトリックス樹脂組成物が、チョップド炭素繊維束に充分に含浸している。
　Ｂ：マトリックス樹脂組成物が、チョップド炭素繊維束に含浸していない部分が若干確認される。
　Ｃ：マトリックス樹脂組成物が、チョップド炭素繊維束に含浸していない部分が数多く確認される。 (Evaluation of resin impregnation of SMC)
When the SMC precursor was obtained, the resin impregnation property was confirmed visually and tactilely and evaluated according to the following evaluation criteria.
A: The matrix resin composition sufficiently impregnates the chopped carbon fiber bundle.
B: The part which the matrix resin composition is not impregnating the chopped carbon fiber bundle is confirmed a little.
C: Many portions where the matrix resin composition is not impregnated in the chopped carbon fiber bundle are confirmed.
（成形体の機械的強度の評価）
　得られたＳＭＣを、成形用金型にチャージ率（金型面積に対するＳＭＣの面積の割合）６５％でチャージし、金型温度１４０℃、圧力８ＭＰａの条件で２分間加熱加圧して硬化させ、厚さ２ｍｍ、３００ｍｍ角の平板状の炭素繊維強化プラスチック（ＣＦＲＰ）成形体（成形板）を得た。 (Evaluation of mechanical strength of molded body)
The obtained SMC was charged into a molding die at a charge rate (ratio of SMC area to mold area) of 65%, and cured by heating and pressing for 2 minutes under the conditions of a mold temperature of 140 ° C. and a pressure of 8 MPa, A flat carbon fiber reinforced plastic (CFRP) molded body (molded plate) having a thickness of 2 mm and a 300 mm square was obtained.
　得られた成形板のうち、問題なく成形できたものについて、長さ２５０ｍｍ、幅２５ｍｍの引張試験片を切り出した。共和電業製ひずみゲージＫＦＧＳ－２０－１２０－Ｃ１－１１Ｌ１Ｍ２Ｒを試験片に貼り、１００ｋＮインストロン万能試験機を用い、ゲージ長１５０ｍｍ、クロスヘッド速度２．０ｍｍ／分で引張強度・弾性率試験を実施し、引張強度及び引張弾性率を測定した。
　測定した試験片の数はｎ＝６とし、平均値をそれぞれ成形板の引張強度、引張弾性率とした。引張強度や引張弾性率が高いほど、機械的強度に優れる。
　引張強度としては、炭素繊維の含有率（炭素繊維含有量）が６０質量％のときは、２５０ＭＰａ以上が好ましい。引張弾性率としては、３５ＧＰａ以上が好ましい。 Among the obtained molded plates, tensile test pieces having a length of 250 mm and a width of 25 mm were cut out for those that could be molded without problems. A strain gauge KFGS-20-120-C1-11L1M2R manufactured by Kyowa Denki Co., Ltd. was applied to the test piece, and a tensile strength / elastic modulus test was performed using a 100 kN Instron universal tester at a gauge length of 150 mm and a crosshead speed of 2.0 mm / min The tensile strength and the tensile modulus were measured.
The number of test pieces measured was n = 6, and the average values were the tensile strength and tensile modulus of the molded plate, respectively. The higher the tensile strength and tensile modulus, the better the mechanical strength.
The tensile strength is preferably 250 MPa or more when the carbon fiber content (carbon fiber content) is 60% by mass. The tensile modulus is preferably 35 GPa or more.
　また、得られた成形板のうち、成形が問題なくできたものについて、長さ６０ｍｍ、幅２５ｍｍの曲げ試験片を切り出した。５ｋＮインストロン万能試験機を用い、Ｌ／Ｄ＝１６、クロスヘッド速度１．４ｍｍ／分で３点曲げ強度・曲げ弾性率試験を実施し、曲げ強度及び曲げ弾性率を測定した。
　測定した試験片の数はｎ＝６とし、平均値をそれぞれ成形板の曲げ強度、曲げ弾性率とした。曲げ強度や曲げ弾性率が高いほど、機械的強度に優れる。
　曲げ強度としては、炭素繊維の含有率（炭素繊維含有量）が６０質量％の時は、４００ＭＰａ以上が好ましい。曲げ弾性率としては、３０ＧＰａ以上が好ましい。 In addition, a bending test piece having a length of 60 mm and a width of 25 mm was cut out of the obtained molded plate that could be molded without any problem. Using a 5 kN Instron universal testing machine, a three-point bending strength / flexural modulus test was conducted at L / D = 16 and a crosshead speed of 1.4 mm / min, and the bending strength and the flexural modulus were measured.
The number of test pieces measured was n = 6, and the average values were the bending strength and bending elastic modulus of the molded plate, respectively. The higher the flexural strength and flexural modulus, the better the mechanical strength.
The bending strength is preferably 400 MPa or more when the carbon fiber content (carbon fiber content) is 60% by mass. The flexural modulus is preferably 30 GPa or more.
（実施例１）
　＜サイジング処理炭素繊維束の製造＞
　炭素繊維束（Ｉ）に対し、以下の手順でサイジング剤を付与してサイジング処理炭素繊維束を製造した。
　内部に浸漬ローラーを有する浸漬槽内に、サイジング剤の水分散液を満たし、該水分散液中に炭素繊維束（Ｉ）を浸漬した。その後、熱風乾燥することによってサイジング処理炭素繊維束を得た。得られたサイジング処理炭素繊維束はボビンに巻き取った。
　得られたサイジング処理炭素繊維束のカンチレバー値は、１５２ｍｍであった。 (Example 1)
<Manufacture of sizing-treated carbon fiber bundles>
A sizing treatment carbon fiber bundle was produced by applying a sizing agent to the carbon fiber bundle (I) according to the following procedure.
An immersion tank having an immersion roller therein was filled with an aqueous dispersion of a sizing agent, and the carbon fiber bundle (I) was immersed in the aqueous dispersion. Then, a sizing-treated carbon fiber bundle was obtained by drying with hot air. The obtained sizing-treated carbon fiber bundle was wound up on a bobbin.
The cantilever value of the obtained sizing-treated carbon fiber bundle was 152 mm.
　＜チョップド炭素繊維束の製造＞
　得られたサイジング処理炭素繊維束に対し、チョップド炭素繊維束の平均厚みＨが１００μｍ、平均幅Ｗが１．５ｍｍとなるように、振動による開繊及び複数の刃物による分繊を行った後、ロータリーカッターで裁断し、繊維長２５ｍｍのチョップド炭素繊維束を得た。得られたチョップド炭素繊維束の形態は安定しており、この裁断に際して、炭素繊維束の切り損じや巻き付きによるトラブルは生じなかった。このチョップド炭素繊維束の嵩密度は、１３３ｇ／Ｌであった。 <Manufacture of chopped carbon fiber bundle>
For the obtained sizing-treated carbon fiber bundle, after performing fiber opening and splitting with a plurality of blades so that the average thickness H of the chopped carbon fiber bundle is 100 μm and the average width W is 1.5 mm, Cut with a rotary cutter to obtain a chopped carbon fiber bundle having a fiber length of 25 mm. The shape of the obtained chopped carbon fiber bundle was stable, and troubles due to cutting or winding of the carbon fiber bundle did not occur during this cutting. The bulk density of the chopped carbon fiber bundle was 133 g / L.
　＜マトリックス樹脂組成物の調製＞
　成分（Ａ１）の１００質量部、成分（Ｄ１）の０．５質量部、成分（Ｄ２）の０．５質量部、成分（Ｅ１）の０．３５質量部、成分（Ｂ１）の２２．０質量部、成分（Ｃ１）の０．０４質量部を、万能撹拌機を用いて充分に混合撹拌し、マトリックス樹脂組成物を得た。 <Preparation of matrix resin composition>
100 parts by weight of component (A1), 0.5 parts by weight of component (D1), 0.5 parts by weight of component (D2), 0.35 parts by weight of component (E1), 22.0 of component (B1) Mass parts and 0.04 parts by mass of the component (C1) were sufficiently mixed and stirred using a universal stirrer to obtain a matrix resin composition.
　＜ＳＭＣの製造＞
　得られたマトリックス樹脂組成物を、ドクターブレードを用いてポリエチレン製フィルム（キャリアフィルム）上に厚さ１．０ｍｍになるように塗布し、その上に繊維長２５ｍｍのチョップド炭素繊維束を、炭素繊維束の目付が略均一になるように、かつ炭素繊維束の方向がランダムになるように散布した。別のポリエチレン製のキャリアフィルム上に、同じマトリックス樹脂組成物を厚さ１．０ｍｍになるように塗布し、前記の散布した炭素繊維束上に、マトリックス樹脂組成物側が対向するように重ね、積層体を得た。この積層体を、ロールの間に通して押圧して、マトリックス樹脂組成物を炭素繊維束に含浸させてＳＭＣ前駆体を得た。
　得られたＳＭＣ前駆体を室温（２３℃）にて１６８時間（７日間）静置した。これにより、ＳＭＣ前駆体中のマトリックス樹脂組成物を充分に増粘させてＳＭＣを得た。得られたＳＭＣの総質量に対する炭素繊維の含有率（炭素繊維含有量）は５０質量％であった。また、ＳＭＣにおける炭素繊維の目付けは２０００ｍｇ／ｍ２であった。 <Manufacturing SMC>
The obtained matrix resin composition was applied onto a polyethylene film (carrier film) using a doctor blade so as to have a thickness of 1.0 mm, and a chopped carbon fiber bundle having a fiber length of 25 mm was coated thereon with carbon fiber. The bundle was spread so that the basis weight of the bundle was substantially uniform and the direction of the carbon fiber bundle was random. The same matrix resin composition is applied on another polyethylene carrier film so as to have a thickness of 1.0 mm, and is laminated on the dispersed carbon fiber bundle so that the matrix resin composition side faces each other. Got the body. The laminate was pressed between rolls to impregnate the carbon fiber bundle with the matrix resin composition to obtain an SMC precursor.
The obtained SMC precursor was allowed to stand at room temperature (23 ° C.) for 168 hours (7 days). As a result, the matrix resin composition in the SMC precursor was sufficiently thickened to obtain SMC. The content rate (carbon fiber content) of the carbon fiber with respect to the total mass of the obtained SMC was 50% by mass. Moreover, the basis weight of the carbon fiber in SMC was 2000 mg / m 2 .
（実施例２～７、比較例１～３）
　サイジング処理炭素繊維束のカンチレバー値、嵩密度、チョップド炭素繊維束の繊維長、平均厚みＨ、平均幅Ｗ、及び炭素繊維含有量を表１に示すように変更した以外は、実施例１と同様にしてＳＭＣを製造した。 (Examples 2 to 7, Comparative Examples 1 to 3)
Example 1 except that the cantilever value, bulk density, fiber length, average thickness H, average width W, and carbon fiber content of the sizing-treated carbon fiber bundle were changed as shown in Table 1. Thus, SMC was manufactured.
　各例の製造条件及び評価結果を表１に示す。 Table 1 shows the manufacturing conditions and evaluation results for each example.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、実施例１～３及び実施例５～７では、ＳＭＣ製造時におけるマトリックス樹脂組成物の炭素繊維束への含浸性に優れていた。また、実施例１～３及び実施例５～７のＳＭＣを用いて得た成形体は、比較例１～３に比べて機械的強度が高かった。 As shown in Table 1, Examples 1 to 3 and Examples 5 to 7 were excellent in the impregnation properties of the matrix resin composition into the carbon fiber bundle during SMC production. In addition, the molded bodies obtained using the SMCs of Examples 1 to 3 and Examples 5 to 7 had higher mechanical strength than Comparative Examples 1 to 3.
　実施例４では、ＳＭＣ製造時におけるマトリックス樹脂組成物の炭素繊維束への含浸性はやや劣っていたが、比較例１～３に比べて高い機械的強度を示した。
　また、いずれの実施例においても、ＳＭＣ製造時に得られたチョップド炭素繊維束の形態は安定しており、前記裁断工程において、炭素繊維束の切り損じや巻き付きによるトラブルは生じなかった。 In Example 4, the impregnation property of the matrix resin composition into the carbon fiber bundle at the time of SMC production was slightly inferior, but showed higher mechanical strength than Comparative Examples 1 to 3.
Moreover, in any Example, the form of the chopped carbon fiber bundle obtained at the time of SMC production was stable, and troubles due to cutting or winding of the carbon fiber bundle did not occur in the cutting step.
　１０　測定台
　１２　水平面
　１４　斜面
　１００　試験用炭素繊維束
　１０２　第１の端部
　１０４　第２の端部
　２００　押さえ板
　２０２　端部
　Ａ　境界線 DESCRIPTION OF SYMBOLS 10 Measurement stand 12 Horizontal surface 14 Slope 100 Carbon fiber bundle for a test 102 1st edge part 104 2nd edge part 200 Holding plate 202 End part A Boundary line

Claims (14)

  1. 　長尺の炭素繊維束が裁断された複数のチョップド炭素繊維束にマトリックス樹脂組成物を含浸させることを含むシートモールディングコンパウンドの製造方法であって、
    　前記チョップド炭素繊維束の繊維長が１～６０ｍｍであり、
    　下記方法（Ｉ）で算出される前記炭素繊維束の嵩密度が６０～４００ｇ／Ｌである、シートモールディングコンパウンドの製造方法。
    （方法（Ｉ））
    　（手順Ｉ－１）炭素繊維束を繊維長が２５ｍｍとなるようにロータリーカッターで裁断した試験用チョップド炭素繊維束１００ｇを２Ｌのメスシリンダー（Φ８８ｍｍ、高さ４８５ｍｍの円柱状）に充填する。
    　（手順Ｉ－２）メスシリンダー内の前記試験用チョップド炭素繊維束の上部から均一に５００ｇの荷重をかけ、体積に変化が無くなったときの充填された前記試験用チョップド炭素繊維束の総体積（Ｌ）を測定し、前記試験用チョップド炭素繊維束の総質量（１００ｇ）を前記試験用チョップド炭素繊維束の総体積（Ｌ）で除して嵩密度を算出する。     A method for producing a sheet molding compound comprising impregnating a matrix resin composition into a plurality of chopped carbon fiber bundles obtained by cutting long carbon fiber bundles,
    The fiber length of the chopped carbon fiber bundle is 1 to 60 mm,
    A method for producing a sheet molding compound, wherein the bulk density of the carbon fiber bundle calculated by the following method (I) is 60 to 400 g / L.
    (Method (I))
    (Procedure I-1) 100 g of a chopped carbon fiber bundle for testing obtained by cutting a carbon fiber bundle with a rotary cutter so that the fiber length is 25 mm is filled in a 2 L measuring cylinder (cylindrical shape having a diameter of 88 mm and a height of 485 mm).
    (Procedure I-2) The total volume of the chopped carbon fiber bundle filled when the test chopped carbon fiber bundle in the graduated cylinder was uniformly loaded with a load of 500 g and no change in volume occurred ( L) is measured, and the total mass (100 g) of the test chopped carbon fiber bundle is divided by the total volume (L) of the test chopped carbon fiber bundle to calculate the bulk density.
  2. 　下記方法（ＩＩ）で算出される前記炭素繊維束のカンチレバー値が１００ｍｍ以上である、請求項１に記載のシートモールディングコンパウンドの製造方法。
    （方法（ＩＩ））
    　（手順ＩＩ－１）炭素繊維束から長さ４０ｃｍの試験用炭素繊維束を切り出す。
    　（手順ＩＩ－２）水平面と、前記水平面の一端から下方に向かって傾斜する、傾斜角度が４５度の斜面とを有する測定台の、前記水平面上に前記試験用炭素繊維束を載せ、前記試験用炭素繊維束の長さ方向の第１の端部を前記斜面と前記水平面との境界線Ａに合わせ、前記試験用炭素繊維束の上に押さえ板を載せ、前記押さえ板の端部を前記境界線Ａに合わせる。
    　（手順ＩＩ－３）前記押さえ板を前記斜面側に水平方向に２ｃｍ／秒で移動させ、前記試験用炭素繊維束の前記第１の端部が前記斜面と接触した時点で前記押さえ板の移動を停止させる。
    　（手順ＩＩ－４）前記手順ＩＩ－３における前記押さえ板の移動距離ｘ（ｍｍ）を測定する。
    　（手順ＩＩ－５）前記試験用炭素繊維束を裏返し、さらに長さ方向に反転させて長さ方向の第２の端部を前記境界線Ａに合わせ、前記手順ＩＩ－２～ＩＩ－４と同じ手順で前記押さえ板の移動距離ｙ（ｍｍ）を測定する。
    　（手順ＩＩ－６）炭素繊維束のカンチレバー値として、移動距離ｘと移動距離ｙとの平均値を算出する。     The manufacturing method of the sheet molding compound of Claim 1 whose cantilever value of the said carbon fiber bundle calculated by the following method (II) is 100 mm or more.
    (Method (II))
    (Procedure II-1) A test carbon fiber bundle having a length of 40 cm is cut out from the carbon fiber bundle.
    (Procedure II-2) The test carbon fiber bundle is placed on the horizontal plane of a measuring table having a horizontal plane and a slope having an inclination angle of 45 degrees inclined downward from one end of the horizontal plane. The first end of the carbon fiber bundle in the length direction is aligned with the boundary line A between the inclined surface and the horizontal plane, a pressing plate is placed on the test carbon fiber bundle, and the end of the pressing plate is Align with boundary A.
    (Procedure II-3) The pressing plate is moved to the slope side in the horizontal direction at 2 cm / second, and the pressing plate is moved when the first end portion of the test carbon fiber bundle comes into contact with the slope. Stop.
    (Procedure II-4) The movement distance x (mm) of the pressing plate in the procedure II-3 is measured.
    (Procedure II-5) The test carbon fiber bundle is turned upside down and further inverted in the length direction so that the second end in the length direction is aligned with the boundary A, and the procedures II-2 to II-4 are performed. The moving distance y (mm) of the pressing plate is measured by the same procedure.
    (Procedure II-6) The average value of the movement distance x and the movement distance y is calculated as the cantilever value of the carbon fiber bundle.
  3. 　前記チョップド炭素繊維束の平均幅Ｗ（ｍｍ）及び平均厚みＨ（ｍｍ）が下記式（１）及び式（２）を満たす、請求項１又は２に記載のシートモールディングコンパウンドの製造方法。
    　０．０５≦Ｈ≦０．２　・・・（１）
    　１０≦Ｗ／Ｈ≦４０　・・・（２）     The manufacturing method of the sheet molding compound of Claim 1 or 2 with which average width W (mm) and average thickness H (mm) of the said chopped carbon fiber bundle satisfy | fill following formula (1) and Formula (2).
    0.05 ≦ H ≦ 0.2 (1)
    10 ≦ W / H ≦ 40 (2)
  4. 　前記チョップド炭素繊維束の平均幅Ｗ（ｍｍ）が０．５～２．５ｍｍである、請求項３に記載のシートモールディングコンパウンドの製造方法。 The method for producing a sheet molding compound according to claim 3, wherein an average width W (mm) of the chopped carbon fiber bundle is 0.5 to 2.5 mm.
  5. 　前記炭素繊維束にサイジング剤が付着しており、前記炭素繊維束における前記サイジング剤の付着量が、前記炭素繊維束及び前記サイジング剤の合計質量に対して、０．１～３．０質量％である、請求項１～４のいずれか一項に記載のシートモールディングコンパウンドの製造方法。 A sizing agent is attached to the carbon fiber bundle, and an amount of the sizing agent attached to the carbon fiber bundle is 0.1 to 3.0% by mass with respect to a total mass of the carbon fiber bundle and the sizing agent. The method for producing a sheet molding compound according to any one of claims 1 to 4, wherein:
  6. 　前記シートモールディングコンパウンドの質量に対して、前記チョップド炭素繊維束の含有量が４０～７０質量％であり、前記チョップド炭素繊維束からなる炭素繊維基材の目付けが５００～２５００ｍｇ／ｍ２である、請求項１～５のいずれか一項に記載のシートモールディングコンパウンドの製造方法。 The content of the chopped carbon fiber bundle is 40 to 70% by mass with respect to the mass of the sheet molding compound, and the basis weight of the carbon fiber substrate made of the chopped carbon fiber bundle is 500 to 2500 mg / m 2 . The method for producing a sheet molding compound according to any one of claims 1 to 5.
  7. 　前記マトリックス樹脂組成物が、
    　　成分（Ａ）：１分子中にエチレン性不飽和基を１個以上有する化合物からなる成分、
    　　成分（Ｂ）：ジイソシアネート化合物、
    　　成分（Ｃ）：重合禁止剤、及び
    　　成分（Ｄ）：重合開始剤
    を含む、請求項１～６のいずれか一項に記載のシートモールディングコンパウンドの製造方法。     The matrix resin composition is
    Component (A): a component comprising a compound having one or more ethylenically unsaturated groups in the molecule,
    Component (B): diisocyanate compound,
    The method for producing a sheet molding compound according to any one of claims 1 to 6, comprising: component (C): a polymerization inhibitor; and component (D): a polymerization initiator.
  8. 　前記成分（Ａ）が、下記成分（Ａ－１）及び下記成分（Ａ－２）からなる群から選ばれる少なくとも一種を含む、請求項７に記載のシートモールディングコンパウンドの製造方法。
    　成分（Ａ－１）：１分子中に１個以上のエチレン性不飽和基及び１個以上の水酸基を有する、不飽和ポリエステル樹脂。
    　成分（Ａ－２）：１分子中に１個以上のエチレン性不飽和基及び１個以上の水酸基を有する、エポキシ（メタ）アクリレート樹脂。     The method for producing a sheet molding compound according to claim 7, wherein the component (A) includes at least one selected from the group consisting of the following component (A-1) and the following component (A-2).
    Component (A-1): an unsaturated polyester resin having one or more ethylenically unsaturated groups and one or more hydroxyl groups in one molecule.
    Component (A-2): An epoxy (meth) acrylate resin having one or more ethylenically unsaturated groups and one or more hydroxyl groups in the molecule.
  9. 　前記成分（Ｃ）が、分子中に水酸基を有さない重合禁止剤であり、かつ１００℃以上の温度において、ラジカル重合を引き起こす活性なラジカル種と反応し、ラジカル重合を引き起こさない不活性なラジカル種又は安定な化合物にする作用を有する、請求項７又は８に記載のシートモールディングコンパウンドの製造方法。 The component (C) is a polymerization inhibitor having no hydroxyl group in the molecule, and reacts with an active radical species that causes radical polymerization at a temperature of 100 ° C. or higher, and thus an inert radical that does not cause radical polymerization. The manufacturing method of the sheet molding compound of Claim 7 or 8 which has the effect | action which makes it a seed | species or a stable compound.
  10. 　前記成分（Ｃ）がｐ－ベンゾキノンである、請求項９に記載のシートモールディングコンパウンドの製造方法。 The method for producing a sheet molding compound according to claim 9, wherein the component (C) is p-benzoquinone.
  11. 　前記成分（Ｃ）の含有量が、前記成分（Ａ）の１００質量部に対し、０．００１～０．１質量部である、請求項７～１０のいずれか一項に記載のシートモールディングコンパウンドの製造方法。 The sheet molding compound according to any one of claims 7 to 10, wherein the content of the component (C) is 0.001 to 0.1 parts by mass with respect to 100 parts by mass of the component (A). Manufacturing method.
  12. 　下記方法（Ｉ）で算出される嵩密度が６０～４００ｇ／Ｌであり、平均幅Ｗ（ｍｍ）及び平均厚みＨ（ｍｍ）が下記式（１）及び式（２）を満たす、炭素繊維束。
    　０．０５≦Ｈ≦０．２　・・・（１）
    　１０≦Ｗ／Ｈ≦４０　・・・（２）
    （方法（Ｉ））
    　（手順Ｉ－１）炭素繊維束を繊維長が２５ｍｍとなるようにロータリーカッターで裁断した試験用チョップド炭素繊維束１００ｇを２Ｌのメスシリンダー（Φ８８ｍｍ、高さ４８５ｍｍの円柱状）に充填する。
    　（手順Ｉ－２）メスシリンダー内の前記試験用チョップド炭素繊維束の上部から均一に５００ｇの荷重をかけ、体積に変化が無くなったときの充填された前記試験用チョップド炭素繊維束の総体積（Ｌ）を測定し、前記試験用チョップド炭素繊維束の総質量（１００ｇ）を前記試験用チョップド炭素繊維束の総体積（Ｌ）で除して嵩密度を算出する。     A carbon fiber bundle having a bulk density calculated by the following method (I) of 60 to 400 g / L, an average width W (mm) and an average thickness H (mm) satisfying the following formulas (1) and (2): .
    0.05 ≦ H ≦ 0.2 (1)
    10 ≦ W / H ≦ 40 (2)
    (Method (I))
    (Procedure I-1) 100 g of a chopped carbon fiber bundle for testing obtained by cutting a carbon fiber bundle with a rotary cutter so that the fiber length is 25 mm is filled in a 2 L measuring cylinder (cylindrical shape having a diameter of 88 mm and a height of 485 mm).
    (Procedure I-2) The total volume of the chopped carbon fiber bundle filled when the test chopped carbon fiber bundle in the graduated cylinder was uniformly loaded with a load of 500 g and no change in volume occurred ( L) is measured, and the total mass (100 g) of the test chopped carbon fiber bundle is divided by the total volume (L) of the test chopped carbon fiber bundle to calculate the bulk density.
  13. 　下記方法（ＩＩ）で算出されるカンチレバー値が１００ｍｍ以上である、請求項１２に記載の炭素繊維束。
    （方法（ＩＩ））
    　（手順ＩＩ－１）炭素繊維束から長さ４０ｃｍの試験用炭素繊維束を切り出す。
    　（手順ＩＩ－２）水平面と、前記水平面の一端から下方に向かって傾斜する、傾斜角度が４５度の斜面とを有する測定台の、前記水平面上に前記試験用炭素繊維束を載せ、前記試験用炭素繊維束の長さ方向の第１の端部を前記斜面と前記水平面との境界線Ａに合わせ、前記試験用炭素繊維束の上に押さえ板を載せ、前記押さえ板の端部を前記境界線Ａに合わせる。
    　（手順ＩＩ－３）前記押さえ板を前記斜面側に水平方向に２ｃｍ／秒で移動させ、前記試験用炭素繊維束の前記第１の端部が前記斜面と接触した時点で前記押さえ板の移動を停止させる。
    　（手順ＩＩ－４）前記手順ＩＩ－３における前記押さえ板の移動距離ｘ（ｍｍ）を測定する。
    　（手順ＩＩ－５）前記試験用炭素繊維束を裏返し、さらに長さ方向に反転させて長さ方向の第２の端部を前記境界線Ａに合わせ、前記手順ＩＩ－２～ＩＩ－４と同じ手順で前記押さえ板の移動距離ｙ（ｍｍ）を測定する。
    　（手順ＩＩ－６）炭素繊維束のカンチレバー値として、移動距離ｘと移動距離ｙとの平均値を算出する。     The carbon fiber bundle according to claim 12, wherein the cantilever value calculated by the following method (II) is 100 mm or more.
    (Method (II))
    (Procedure II-1) A test carbon fiber bundle having a length of 40 cm is cut out from the carbon fiber bundle.
    (Procedure II-2) The test carbon fiber bundle is placed on the horizontal plane of a measuring table having a horizontal plane and a slope having an inclination angle of 45 degrees inclined downward from one end of the horizontal plane. The first end of the carbon fiber bundle in the length direction is aligned with the boundary line A between the inclined surface and the horizontal plane, a pressing plate is placed on the test carbon fiber bundle, and the end of the pressing plate is Align with boundary A.
    (Procedure II-3) The pressing plate is moved to the slope side in the horizontal direction at 2 cm / second, and the pressing plate is moved when the first end portion of the test carbon fiber bundle comes into contact with the slope. Stop.
    (Procedure II-4) The movement distance x (mm) of the pressing plate in the procedure II-3 is measured.
    (Procedure II-5) The test carbon fiber bundle is turned upside down and further inverted in the length direction so that the second end in the length direction is aligned with the boundary A, and the procedures II-2 to II-4 are performed. The moving distance y (mm) of the pressing plate is measured by the same procedure.
    (Procedure II-6) The average value of the movement distance x and the movement distance y is calculated as the cantilever value of the carbon fiber bundle.
  14. 　シートモールディングコンパウンドを製造するための、請求項１２又は１３に記載の炭素繊維束の使用。 Use of the carbon fiber bundle according to claim 12 or 13 for producing a sheet molding compound.
PCT/JP2019/016440 2018-05-14 2019-04-17 Method for manufacturing sheet molding compound, carbon fiber bundle, and use for carbon fiber bundle WO2019220846A1 (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114761191A (en) * 2019-11-25 2022-07-15 Dic株式会社 Sheet molding compound and method for producing molded article
JP7458191B2 (en) 2020-01-23 2024-03-29 ジャパンコンポジット株式会社 Molding materials and molded products

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02175729A (en) * 1987-12-19 1990-07-09 Toyota Motor Corp Fiber-reinforced resin composition
WO2014081002A1 (en) * 2012-11-26 2014-05-30 三菱レイヨン株式会社 Chopped carbon fiber bundles and method for producing chopped carbon fiber bundles
WO2016039326A1 (en) * 2014-09-12 2016-03-17 三菱レイヨン株式会社 Molding material, sheet molding compound, and fiber-reinforced composite material obtained using same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02175729A (en) * 1987-12-19 1990-07-09 Toyota Motor Corp Fiber-reinforced resin composition
WO2014081002A1 (en) * 2012-11-26 2014-05-30 三菱レイヨン株式会社 Chopped carbon fiber bundles and method for producing chopped carbon fiber bundles
WO2016039326A1 (en) * 2014-09-12 2016-03-17 三菱レイヨン株式会社 Molding material, sheet molding compound, and fiber-reinforced composite material obtained using same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114761191A (en) * 2019-11-25 2022-07-15 Dic株式会社 Sheet molding compound and method for producing molded article
JP7458191B2 (en) 2020-01-23 2024-03-29 ジャパンコンポジット株式会社 Molding materials and molded products

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