JP4254158B2 - Carbon fiber substrate manufacturing method, preform manufacturing method, and composite material manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a carbon fiber base material which can obtain a preform and a composite material with high productivity and has excellent handleability.
[0002]
More specifically, not only can a composite material with good resin impregnation and excellent mechanical properties (especially compressive strength after impact application or wet heat treatment, etc.) be obtained with good productivity, the stiffness of the base material, shape stability, The present invention relates to a carbon fiber base material excellent in handleability such as moldability and tackiness when laminated, a preform obtained by laminating the same, and a method for producing a composite material obtained by impregnating a preform with a matrix resin It is.
[0003]
[Prior art]
Conventionally, composite materials using carbon fibers as reinforcing fibers have been mainly used for aviation, space, and sports applications because they satisfy the required properties such as excellent mechanical properties and light weight. As these typical production methods, an autoclave molding method is known. In such a molding method, a prepreg obtained by impregnating a carbon fiber with a matrix resin in advance is stacked on a molding die on a carbon fiber sheet aligned in one direction, and then heated and pressurized in an autoclave to mold a composite material. The prepreg as the base material used here has an advantage that a highly reliable composite material can be obtained when it is used, but it is too strong and difficult to form, and the production costs high, that is, production. There was a problem with the low nature.
[0004]
  On the other hand, examples of the molding method that is excellent in the productivity of the composite material include injection molding such as a resin transfer molding method (RTM). In such an RTM, a base material made of carbon fiber that is not pre-impregnated with a matrix resin (dry) is placed in a complicated mold, and a liquid (low viscosity) matrix resin is injected into the carbon fiber. Impregnated with matrix resinTeseiShape.
[0005]
However, this injection molding is excellent in the productivity of the composite material, but the base material to be used (for example, dry woven fabric) is easily misaligned (morphological instability), and the base material is too stiff to bend easily. There was a problem regarding the handling properties of the base materials, such as the inability to bond the base materials together (no tackiness). In addition to this, since the matrix resin needs to have a low viscosity, for example, there are problems such as low mechanical properties compared to those having high viscosity used in prepregs, etc. Cannot be fully expressed, causing problems that impair the mechanical properties of the composite material.
[0006]
For example, in US Pat. No. 5,071,711, etc., the thermoplastic fiber-like resin is imparted to the reinforcing fiber fabric to improve the handleability of the dry woven fabric as the base material, and injection molding. Techniques relating to the stabilization of the preform form used in the field have been proposed.
[0007]
James C. Seferis et al. In Journal of Advanced Materials, Volume 32, No. 3, July 2000, P27-34, Composites part A, Volume 32, 2001, P721-729, etc. It has been reported that the mechanical properties (mode I, II interlaminar fracture toughness, etc.) of CFRP obtained by injection molding are improved by applying the blended resin on the fabric.
[0008]
However, in these proposals, the handleability of the substrate is improved, but the mechanical properties are not improved, or the improvement level is insufficient. In other words, for example, the extremely high level of mechanical properties required for aircraft primary structural members cannot be achieved simply by applying a resin to a woven fabric or the like, and the carbon fiber itself does not have the necessary properties. Such a composite material also cannot exhibit necessary mechanical properties (particularly, compressive strength after impact application).
[0009]
Further, in the injection molding described in the above proposal, a bi-directional woven fabric is used because carbon fiber sheets simply arranged in one direction cannot be handled while maintaining fiber orientation in a dry state. However, for example, primary structural members of aircraft have very high mechanical properties (particularly, normal temperature compressive strength after impact application (hereinafter referred to as CAI), high temperature compressive strength after wet heat treatment (hereinafter referred to as CHW)). Required. In bi-directional fabrics, carbon fibers are woven in two directions, so the amount of reinforcing fibers in each direction is essentially halved, and the warp and weft yarns have approximately the same fineness, so the warp and weft yarns are interlaced. In that respect, due to the large bending (crimping) of the carbon fibers, only half the mechanical properties of the prepreg with the carbon fibers arranged in one direction were exhibited.
[0010]
That is, although the characteristics necessary for the carbon fiber to be used and the form of the fabric using the carbon fiber are particularly important factors for developing high mechanical properties, the above-mentioned proposal is not disclosed at all. However, there has been a strong demand for a technique for producing a carbon fiber substrate that satisfies the problems of the present invention.
[0011]
[Problems to be solved by the invention]
In the conventional technique, not only a composite material with good resin impregnation and excellent mechanical properties (particularly CAI, CHW, etc.) cannot be obtained with good productivity, but also the stiffness of the base material, form stability, moldability, A carbon fiber substrate excellent in handling properties such as tackiness has not been obtained. The present invention aims to solve such problems.
[0012]
[Means for Solving the Problems]
  The present invention employs the following means in order to solve such problems. That is, the present inventionUsed as a composite material by impregnating epoxy resin as matrix resin by injection moldingThe method for producing a carbon fiber substrate includes at least the following steps (A) to (C).
(A) Tensile modulus is 210 GPa or moreLess than 600GPa, Fracture strain energy is 40MJ / m³more than80MJ / m ³ Less thanOrOne, reamFabrication process of forming a fabric using the continuous carbon fiber.
(B)Adhesion containing at least one selected from polyethersulfone, polyphenylene ether and polyamide as the main component and epoxy resin as the subcomponentThe resin is applied to the surface of the fabric in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the fabric.Scattered or discontinuous to coverApplication process to apply and bond.
(C)AdhesionThe fabric to which the resin is bondedAdhesiveBelow the melting point of the resin orAdhesiveA cooling step of cooling to a temperature lower than the resin flow start temperature.
[0013]
  MoreAdhesiveresinThermoplastics based on polyamides with higher melting points or flow onset temperaturesWhen using resin, the manufacturing method of the carbon fiber base material of this invention is characterized by including the process of following (E)-(H) at least.
(E) Tensile modulus is 210 GPa or moreLess than 600GPa, Fracture strain energy is 40MJ / m³more than80MJ / m ³ Less thanOrContinuousFabrication process of forming a fabric using the continuous carbon fiber.
(F)AdhesiveThe resin is applied to the surface of the fabric in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the fabric.Scattered or discontinuous to coverApplication process to apply and bond.
(G)AdhesiveTo the fabric to which the resin is bonded,AdhesiveDifferent from resinThermoplastic based on polyamideA re-coating step in which the resin is applied and adhered to the surface of the fabric in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the fabric.
(H)AdhesiveResin andThe thermoplasticThe fabric to which the resin is bondedAdhesiveBelow the melting point of the resin orAdhesionA cooling step of cooling to a temperature lower than the resin flow start temperature.
[0014]
  The preform manufacturing method of the present invention includes at least the following steps (O) to (Q).
(O) A laminating step of laminating at least two carbon fiber substrates.
(P) A carbon fiber base material having two or more layers laminated.AdhesiveMelting point of resin -50 ° C or higher orAdhesiveMolding step in which molding is performed by heating and pressurizing to a temperature at which the resin starts flowing at a temperature of −50 ° C.
(Q) The molded carbon fiber substrateAdhesiveBelow the melting point of the resin orAdhesiveA substrate bonding step in which the carbon fiber substrates are bonded to each other by cooling to a temperature lower than the resin flow start temperature.
[0015]
  Moreover, the manufacturing method of the composite material of this invention is characterized by including the process of the following (R)-(T) at least.
(R) A setting step in which the preform is placed in a mold to form a cavity.
(S) LiquefiedEpoxyResin is injected into the cavity to form a preformThe epoxyResinAs matrix resinImpregnation step for impregnation.
(T)The epoxySolidification process to solidify the resin.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be specifically described with reference to the drawings.
[0017]
  FIG. 1 is a schematic view illustrating one embodiment of the method for producing a carbon fiber substrate of the present invention. Moreover, FIG. 2 is the schematic explaining another one aspect | mode of the manufacturing method of the carbon fiber base material of this invention. The method for producing a carbon fiber substrate of the present invention is a production method including at least the following steps (A) to (C) or a production method including at least the following steps (E) to (H).Such a carbon fiber base material is used because it is impregnated by injection molding with an epoxy resin as a matrix resin to form a composite material.
[0018]
  Fabrication process (A) or (E) (1 in the figure)
  When the fabric to be made is a bi-directional woven fabric, the tensile modulus is 210 GPa or moreLess than 600GPa, Fracture strain energy is 40MJ / m³more than80MJ / m ³ Less thanOrOne, reamThe warp yarn 11 and the weft yarn 12 of the continuous carbon fiber bundle are used. In the case of a unidirectional fabric, the tensile elastic modulus is 210 GPa or more.Less than 600GPa, Fracture strain energy is 40MJ / m³more than80MJ / m ³ Less thanOrOne, reamWeaving using warp yarns 11 of a continuous carbon fiber bundle and auxiliary weft yarns (not shown) such as yarns and processed yarns such as glass fibers and organic fibers, and using weaves 13, 14 and rapier 15 as weaving jigs And form a woven fabric. here, CommunicatingThe continuous carbon fiber bundle means that the carbon fiber bundle is continuous, and includes those in which a single yarn of less than 10% by weight contained in the carbon fiber bundle is cut. Moreover, when manufacturing a carbon fiber base material, what tied and entangled the front-end | tips of a fiber so that carbon fiber can be supplied continuously during the series of manufacture can be included.
[0019]
  The carbon fiber used in the present invention has a tensile modulus of 210 GPa or more.Less than 600GPaIt is. It is preferably more than 250 and less than 600 GPa, more preferably more than 280 and less than 500 GPa, particularly preferably more than 290 and less than 400 GPa. A tensile modulus of less than 210 GPa is not preferable because the mechanical properties of the composite material are not sufficient, and the meaning of using carbon fibers becomes dilute. Here, the tensile modulus refers to a value measured according to JIS R7601, and the unit is GPa.
[0020]
  Further, the carbon fiber used in the present invention has a fracture strain energy of 40 MJ / m.³more than80MJ / m ³ Less thanIt is. More preferably 45MJ / m³Or more, more preferably 53 MJ / m³Above, especially 56MJ / m³The above is preferable. The higher the fracture strain energy, the higherGoodBut 80MJ / m³Generally, it is the following. Fracture strain energy is 40MJ / m³If it is less than the range, the carbon fiber may break when subjected to an impact, and in particular, a composite material having a quasi-isotropic laminated structure of a unidirectional fabric is inferior to CAI, and a composite material having excellent mechanical properties can be obtained. It is not preferable because it cannot be done. That is, only when the carbon fiber has a high fracture strain energy, the carbon fiber is not easily broken when subjected to an impact and can maintain a continuous fiber state, and therefore has excellent mechanical properties (especially CAI). It can be achieved. Such CAI is a mechanical property that is very important when used as a structural member (especially a primary structure) member of a transportation device (especially an aircraft), and the necessity is further increased when the use of a composite material is the above-mentioned use. It can be said that it is expensive. The fracture strain energy (W) is (W) = (σ) 2/2 × (E) when the tensile strength (σ) and tensile elastic modulus (E) measured according to JIS R7601 are used. Refers to the defined value, the unit is MJ / m³(10⁶× J / m³).
[0021]
In the present invention, the cloth to be produced using carbon fibers is not particularly limited, but for example, a two-dimensional unidirectional, bi-directional or more woven fabric, a three-dimensional multi-directional woven fabric, Knitted fabric, multi-axis insertion fabric, carbon fiber sheet aligned in one direction, stabilized with binder, fusible nonwoven fabric, stitch yarn, etc. (unidirectional sheet), unidirectional sheet laminated in two or more directions Multi-axial sheets and the like, which may be joined by stitch yarns, knot yarns or the like, and a plurality of fabrics may be integrated. Especially when used as a structural member (especially primary structure) for transportation equipment (especially aircraft), very high mechanical properties (especially CAI, CHW) are required, but in bi-directional fabrics, carbon fibers are woven in two directions. There are cases where mechanical properties that can withstand the demands are difficult to develop due to the texture, and the crimping of the carbon fiber at the intersection of the warp bundle and the weft bundle becomes large. That is, the fabric used in the present invention is preferably a unidirectional fabric, that is, a unidirectional woven fabric, a unidirectional sheet, or a combination of a plurality of them because the problem can be reliably solved. Furthermore, in consideration of the surface of the matrix resin impregnation, a unidirectional fabric in which a very small crimp is formed between the strands by entanglement of auxiliary weft bundles is particularly preferable. Such a small crimp becomes an impregnation channel for the matrix resin, and has an effect of significantly improving the impregnation property, and can be said to be an optimum fabric in the present invention.
[0022]
Such a unidirectional fabric will be described in more detail. FIG. 6 is a perspective view illustrating one embodiment of the unidirectional fabric preferably used in the present invention. The unidirectional fabric 6A is a plain weave structure in which a warp bundle 11 of carbon fibers arranged in parallel with each other in one direction and an auxiliary weft bundle 12 'orthogonal to the carbon fiber intersect with each other.
[0023]
In the unidirectional woven fabric 6A, the warp yarn bundle 11 preferably has filaments in the range of 5,000 to 50,000 (more preferably 10,000 to 25,000). From another viewpoint, the warp yarn bundle 11 is preferably in the range of 300 to 5000 tex. If it is smaller than this range, there are too many crossing points in the woven fabric, and not only the crimp becomes large but also the number thereof increases, and the mechanical properties may be inferior. On the other hand, if it is larger than this range, there are too few crossing points in the woven fabric and the shape stability may be inferior.
[0024]
In addition, the auxiliary fiber constituting the auxiliary weft bundle 12 'maximizes the characteristics of the carbon fiber of the present invention by reducing the bending (crimp) of the warp bundle 11 at the intersection of the warp bundle 11 and the auxiliary weft bundle 12'. In order to express it to the limit, it is preferably 1/5 or less, more preferably 1/10 or less, of the fineness of the carbon fiber used for the warp bundle 11. The specific fineness varies depending on the types of carbon fibers and auxiliary fibers used and the basis weight of the woven fabric, but for example, 200 g / m using 800 tex carbon fibers.²When the woven fabric is used, the fineness of the auxiliary fibers is preferably 1 to 100 tex, more preferably 10 to 50 tex. The weaving density of the auxiliary weft bundle 12 'is preferably in the range of 0.3 to 6 yarns / cm, more preferably 1 to 4 yarns, in order to stabilize the shape of the fabric and minimize the influence of crimp. / Cm.
[0025]
Any type of auxiliary fiber can be used, but from the standpoint of fabric density stability, those which are difficult to shrink due to heating during molding are preferred. For example, carbon fiber, glass fiber, aramid, polyamide (especially POY : Semi-drawn yarn by high-speed spinning), organic fibers such as PBO, PVA, PE, etc. can be used alone or in combination, and these are secondary processing such as combined yarn processing, twist processing, wool processing, crimp processing, etc. It may have been. Further, the warp bundle 11 and the auxiliary weft bundle 12 'can be used in combination with a component having an adhesive function in order to fix the woven structure.
[0026]
As the component having such an adhesive function, for example, a thermoplastic resin such as nylon or polyester, a thermosetting resin such as epoxy, unsaturated polyester, or phenol can be used. In addition, the form can be combined with a warp bundle or auxiliary weft bundle in any form such as fibrous, particulate, emulsion, or dispersion. Among them, it is preferable to use a fibrous material by twisting or covering with auxiliary fibers and using it as an auxiliary weft bundle because the fixing effect of the woven structure is high.
[0027]
The unidirectional woven fabric preferably used in the present invention includes twill weave and satin weave in addition to the plain weave shown in FIG. 6, but also includes the non-crimp structure shown in FIG. FIG. 7 is a perspective view illustrating another aspect of the unidirectional fabric preferably used in the present invention. In the unidirectional fabric 7A, an auxiliary warp bundle 11 'arranged in parallel to the carbon fiber warp bundle 11 and a group of auxiliary weft bundles 12' orthogonal thereto are crossed with each other to hold the warp bundle 11 integrally. This is a woven fabric having a non-crimp structure. According to such a non-crimp structure, since the crimp can be made smaller than that of the plain weave structure, the characteristics of the carbon fiber of the present invention can be further enhanced. Also, from the aspect of resin impregnation, the impregnation flow path is secured by the presence of auxiliary fibers (particularly auxiliary warp yarns), and very excellent impregnation properties are exhibited.
[0028]
  In the present inventionAdhesiveResin orThe thermoplasticThe resin is applied to the fabric, and the cover factor of the fabric is preferably 90% or more in order to minimize the falling off of the resin. More preferably, it is 95% or more, More preferably, it is 98% or more. With such a cover factor, there is carbon fiber (including auxiliary yarns, stitch yarns, etc.) in the fabric in a unit area of 200 mm × 200 mm when the flattened fabric is viewed from the perpendicular direction.Ru) Percentage of closed part, cover factor (%) = total area of closed part (mm²) / 400. With respect to the closed portion, image processing can be performed based on an image optically captured by a CCD camera, a scanner, or the like, and a total area can be calculated.
[0029]
In order to fabricate a fabric having such a cover factor, carbon fiber is formed by a swinging roller (a nip roller can be used in combination as necessary) or by blowing compressed air before or after forming the fabric. Is preferably opened and widened. It is also possible to fabricate using carbon fibers that have been opened and widened in advance. This method has a carbon fiber basis weight of 300 g / m.²In the following cases, it can be said that this is a particularly effective cloth making method. There is no particular lower limit to the carbon fiber basis weight, but 50 g / m.²This is generally the case.
[0030]
  The fabric used in the present invention will be described later to the preform.EpoxyFrom the point of impregnation of resin, the carbon fiber basis weight is 50 to 600 g / m.²It is preferable to fabricate in this range. More preferably 100 to 350 g / m²More preferably, 150 to 300 g / m²Range.
[0031]
(B) or (F) Application step (2, 2 'in the figure)
The 1st resin 2a is apply | coated to the surface of a cloth in the range of 0.1-20 weight part with respect to 100 weight part of cloths, and it is made to adhere.
  (B) or (F) Application step (2, 2 'in the figure)
  Adhesion containing at least one selected from polyethersulfone, polyphenylene ether and polyamide as the main component and epoxy resin as the subcomponentThe resin 2a is applied and adhered to the surface of the fabric in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the fabric.
[0032]
  AdhesionResin 2a orThermoplastics based on polyamide with a higher melting point or flow starting temperature than the adhesive resin described belowWhen applying the resin 2'a, it is preferable to use a particulate material because not only it is easy to control the amount of resin applied, but also the application device can be simplified. In particular, particulateAdhesiveResin 2a or particulateThe thermoplasticIt is preferable to measure the resin 2'a using the roll 2b and the doctor blade 2c because not only stable measurement is possible but also equipment can be inexpensively installed. Further, it is preferable to use a roll (engraved) with a pattern such as a mesh or a dot because the measurement can be performed more strictly.
[0033]
  Also particulateAdhesiveResin 2a or particulateThe thermoplasticWhen the resin 2'a is naturally dropped and applied to the fabric, it is preferable to pass the vibration net 2d because the resin can be more uniformly dispersed on the fabric.
[0034]
  FIG. 3 is a schematic view illustrating another embodiment of the method for producing a carbon fiber substrate of the present invention. In this aspect, in the coating step 2, the particulate formAdhesiveResin 2a is weighed with a weighing machine 2e, and spray head 2gThroughIt is applied while being uniformly dispersed with a compressed gas 2f (preferably dry compressed gas) by charging it when it is passed or forcibly charging by corona discharge. According to this method, the control of the amount of resin applied can be further facilitated, and the resin can be applied more uniformly. In addition,The thermoplasticAlso when using resin, the method described here is preferably used (not shown in FIG. 3).
[0035]
  ParticulateAdhesiveWhen the resin is used, in order to uniformly disperse the resin on the fabric surface, the average particle diameter is preferably in the range of 1 to 250 μm, more preferably 1 to 150 μm, and further preferably 3 to 100 μm. If the thickness is less than 1 μm, the amount of the carbon fibers constituting the fabric increases and the amount of particles adhered to the surface of the fabric may vary. On the other hand, when the particle diameter exceeds 250 μm, the particle diameter becomes large, and therefore, the number of particles to be bonded decreases with respect to a predetermined particle application amount, and it may be difficult to uniformly disperse the resin.
[0036]
  FIG. 4 is a schematic view illustrating another aspect of the method for producing a carbon fiber substrate of the present invention. In this embodiment,AdhesiveThe resin 2a is applied in a molten state. According to this method,AdhesiveBecause there is no restriction on the form of the resin, as described aboveAdhesiveProcessing to make resin particles can be omitted. In addition,The thermoplasticAlso when using resin, the method described here is preferably used (not shown in FIG. 4).
[0037]
  In the present invention, in addition to the above aspect,AdhesiveResin orThe thermoplasticIt is also possible to apply a resin in which the resin is dispersed or dissolved in water or a solvent. According to such a method, as in the case of using a resin in a molten state, not only the resin form is not limited, but also a heating device for melting is unnecessary, and thus the device can be further simplified. There are advantages. In addition, even when a particulate resin is used, there is an advantage that an effect of preventing scattering of particles can be obtained by applying a dispersion of particles in water or a solvent.
[0038]
  In the present invention,AdhesiveResin 2a,The thermoplasticThe resin 2'a may be applied to one side of the fabric or may be applied to both sides. When applying to one side, the point which can simplify an application | coating process is preferable. Moreover, although it applies to a double-sided application process, it is preferable at the point which does not require separate use of the front and back of a fabric.
[0039]
  In the present invention,AdhesiveResin 2a orThe thermoplasticIn order to adhere the resin 2'a more firmly to the fabric surface, it was appliedAdhesiveResin 2a orThe thermoplasticWhen bonding the resin 2'a,AdhesiveMore than the melting point of the resin orAdhesiveHeat to a temperature above the resin flow start temperature, at leastAdhesiveIt is preferable to bond the resin and the fabric.
[0040]
  here,AdhesiveMore than the melting point of the resin orAdhesiveThe apparatus for heating to a temperature equal to or higher than the flow start temperature of the resin is not particularly limited, but the far infrared heater 22 and / or hot roller (not shown) can easily reach the required temperature corresponding to the change in the cloth making speed. It is preferable because it can be controlled.
[0041]
  1 to 4, the (A) or (E) fabric-making process 1 and the (B) or (F) coating process 2 or the (G) re-coating process 2 'are continuously performed (online). Is done). By such a method, even if the fabric is inferior in form stability,AdhesiveBy using a resin, it becomes possible to stabilize the form, and it is possible to obtain a carbon fiber substrate excellent in handleability while exhibiting high mechanical properties. Hereinafter, a specific example will be given and described in more detail.
[0042]
  Taking a unidirectional woven fabric as an example, the bending (crimping) of carbon fibers caused by the intersection of warp yarns and auxiliary weft yarns adversely affects the mechanical properties. In order to minimize this crimp, for example, when the auxiliary weft yarn of a thin glass fiber yarn of 30 tex or less is used and the auxiliary weft yarn interval is increased to 10 mm or more, it is inferior in shape stability and cannot be handled alone. However, it goes through the coating process 2 continuously from the cloth manufacturing process 1,AdhesiveBy applying and bonding the resin, the shape stability is dramatically improved, and there is an advantage that a carbon fiber base material that can be handled can be obtained.
[0043]
In this case, the processing speed is preferably 0.5 to 5 m / min. More preferably, it is 1-4 m / min. Taking a unidirectional woven fabric as an example, the processing speed in the fabric-making process 1 is generally as low as about 0.3 to 0.4 m / min. However, in the coating process 2, it is possible to process at a faster speed. In order to eliminate this mismatch and improve the processing speed (productivity) as a carbon fiber substrate, use a high-speed loom (for example, a high-speed double rapier loom, a water jet loom, an air jet loom, a needle loom, etc.) It is preferable to set the processing speed to 0.5 m / min or more in the cloth process. On the other hand, if the processing speed exceeds 5 m / min, the fluff from the carbon fiber at the time of fabric production may increase excessively.
[0044]
  Used in the present inventionAdhesiveThe resin is applied and adhered to the surface of the fabric in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the fabric. More preferably, it is 0.1-10 weight part, More preferably, it is 1-9 weight part, Most preferably, it is the range of 3-6 weight part. If the amount is less than 0.1 part by weight, the tackiness (adhesiveness) between the substrates when a carbon fiber substrate is laminated to obtain a preform cannot be sufficiently imparted, and the handleability is poor. This is glued onto the surface of the carbon fiber substrateAdhesiveThis is because tackiness is expressed by the resin. Moreover, when it exceeds 20 parts by weight, not only is it difficult to obtain a composite material excellent in mechanical properties, particularly CHW, but also a matrix resin for a carbon fiber base material or preform when obtaining a composite material, which will be described later.EpoxyOn the contrary, impregnation of the resin may be prevented.
[0045]
  AdhesiveWhen the resin is bonded within the above range, the adjacent carbon fibers are restrained to cause moderate stiffness in the fabric, improving not only the handling property but also preventing the fabric from being misaligned. An effect can also be expressed. Furthermore,AdhesiveSince the resin becomes a crack stopper between the fabrics of the composite material, damage between the fabrics can be suppressed when impacted, and the effect of achieving excellent mechanical properties (especially CAI) (interlayer reinforcement effect) is also exhibited. it can. In addition to the above effects,AdhesiveThe presence of the resin becomes a spacer as described below.Epoxy is a matrix resinThe resin flow path can be secured, especially when it is used for injection molding, not only is impregnation easy, but also the speed of impregnation is increased and composite material productivity is excellent (spacer Effect).
[0046]
  Used in the present inventionAdhesiveThe melting point or flow start temperature of the resin is preferably in the range of 40 to 150 ° C. from the viewpoint of the processing temperature for developing the tack when the carbon fiber base material is laminated. More preferably, it is 50-140 degreeC, More preferably, it is the range of 60-120 degreeC. Here, the melting point refers to the melting temperature of the resin measured using a differential scanning calorimeter (DSC), and the resin showing the melting point by DSC is based on the melting point. For resins that do not exhibit a melting point by DSC, the flow start temperature measured from viscoelasticity measurement (Shimadzu flow tester CFT500D, temperature rising rate 1.5 ° C./min) is used as a reference.
[0047]
  Used in the present inventionAdhesiveResin improves the handling of carbon fiber reinforced substrates and improves the mechanical properties of composite materials obtained using themTherefore, it contains at least one selected from polyether sulfone, polyphenylene ether and polyamide as a main component.
[0050]
  AdhesiveAs a preferred example of maximizing the problems of the present invention as a resin, epoxy is used as a thermosetting resin, and polyether sulfone is used as a thermoplastic resin.phoneUsing at least one selected from polyphenylene ether and polyamide, mixing (preferably compatibilizing) both of them, mixing (preferably compatibilizing) both, and setting the flow start temperature to 180 ° C. or less or glass The transition temperature is 100 ° C. or lower. TakeAdhesionThe resin is described laterNoPoxy resin and curing agent composition (especially liquid)As matrix resinWhen used, it exhibits a remarkably excellent effect.
[0051]
  (I) Pressurization process (2 "in the figure)
  FIG. 5 is a schematic view illustrating another aspect of the method for producing a carbon fiber substrate of the present invention. In this embodiment, the coating was performed after coating step 2.AdhesiveThere is a pressing step 2 ″ of (I) in which the resin 2a and the fabric are pressed by the pressing roll 23.Thermoplastic based on polyamide having higher melting point or flow starting temperature than the adhesive resinWhen using resin, it can also pressurize after a re-application process (not shown).
[0052]
  Such pressurization causes the fabric toAdhesiveResin orThe thermoplasticThe unevenness of the resin can be reduced. When the carbon fiber base material is laminated to obtain a composite material, the unevenness may cause the carbon fiber to be bent by being transferred to the adjacent carbon fiber base material, and may cause a deterioration in compression characteristics such as CHW. From this point of view, on the fabricAdhesiveWith resinThe thermoplasticIt is preferable to apply pressure so that the maximum thickness of the resin portion combined with the resin is 150 μm or less. More preferably, it is 100 micrometers or less, More preferably, it is 60 micrometers or less. From another point of view, the thickness Tr of the carbon fiber substrate isAdhesiveIt is preferable to pressurize in a range not exceeding 150 μm (more preferably 100 μm, still more preferably 60 μm) than the thickness To of the fabric alone to which the resin is not bonded. Such pressurization isAdhesiveResin orThe thermoplasticIn addition to reducing the unevenness of the resin and reducing the thickness of the carbon fiber substrate, an unexpected effect of focusing the bulky carbon fiber bundle and reducing the thickness of the fabric itself is exhibited. With such an effect, it is possible to obtain a composite material that has a higher carbon fiber volume fraction Vf when made into a composite material and is excellent in weight reduction effect.
[0053]
  However, if too much pressure is applied to the fabric surfaceAdhesiveThe resin cannot substantially remain, not only detracting from the effects related to the tackiness of the carbon fiber substrate described above, but also described below.Epoxy is a matrix resinThe impregnation property of the resin may be impaired. From this point of view, it is preferable to pressurize in such a range that Tr does not become smaller than To. In addition, the measurement of the thickness of the cloth alone or the thickness of the carbon fiber base material here is performed according to JIS R7602.
[0054]
Here, the pressure roll 23 may be a heated hot roll, a cold roll that is forcibly cooled, or a roll that is not temperature-controlled. A hot roll is preferable in order to express the effect of pressurization more efficiently. Further, in order to reduce the equipment cost, it is preferable to use a cold roll or a roll that is not temperature-controlled. In these cases, by applying pressure immediately after heating, an effect substantially equivalent to that of a hot roll can be obtained.
[0055]
  From this point of view, the pressure is higher than room temperature, preferablyAdhesiveA melting point of the resin of −50 ° C. or a temperature higher than the flow start temperature −50 ° C., more preferablyAdhesiveIt is preferable to carry out at a temperature equal to or higher than the melting point of the resin or the flow start temperature.
[0056]
  (J) Temporary winding process (1 'in the figure) and (K) Drawing process (1 "in the figure)
  In FIG. 5, after the cloth making process 1, in the temporary winding process 1 'of (J)AdhesiveThe fabric 16 is once wound up before the resin is applied. The fabric 17 once wound up is drawn in the drawing step 1 ″ of (K), and in the coating step 2 as in FIG.AdhesiveResin 2a is applied. That is, the cloth making process 1 and the coating process 2 are performed discontinuously (offline). In such an embodiment, it is not necessary to make the processing speeds of the cloth making process 1 and the coating process 2 capable of processing at a higher speed be the same. That is, there is an advantage that the line speed of the coating process 2 can be increased, and the carbon fiber substrate can be manufactured with higher productivity.
[0057]
  (G) Re-application process (2 'in the figure)
  In the present invention,AdhesiveDifferent from resinThermoplastic based on polyamide having higher melting point or flow starting temperature than the adhesive resinWhen further resin is used, as shown in FIG.AdhesiveTo fabric with resin bonded, The thermoplasticResin 2'a is applied and adhered to the surface of the fabric in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the fabric. TakeThe thermoplasticBy using resin,AdhesiveFunctions that are not present or lacking in the resin (for example, improved mechanical properties) can be imparted.
[0058]
  In particular, from the viewpoint of further improving the mechanical properties, it is used in the present invention.The thermoplasticResinAdhesiveThose having a higher melting point or flow starting temperature than the resin are preferred. SuitableThe thermoplasticThe melting point or flow starting temperature of the resin is 150 ° C. or higher, more preferably 180 ° C. or higher, and still more preferably 210 ° C. or higher. From another point of view,The thermoplasticThe glass transition point of the resin is preferably in the range of 80 to 180 ° C. More preferably, it is 90-160 degreeC, More preferably, it is the range of 100-140 degreeC.
[0059]
  Having the above characteristicsThe thermoplasticBy adhering the resin, the mechanical properties (particularly CAI) of the composite material obtained by laminating the carbon fiber base material can be further enhanced. This is because the resin having a higher melting point or flow start temperature is superior in impact strength and fracture toughness.AdhesiveAn effect far superior to the case of resin alone is exhibited.
[0060]
  TakeThermoplastic based on polyamide having higher melting point or flow starting temperature than the adhesive resinResin isAdhesiveEven if it is bonded to the surface of the fabric together with the resin,The thermoplasticThe resin may be directly bonded to the surface of the fabric.AdhesiveIt is preferably bonded to the surface of the fabric via a resin. By doing this, more reliably,The thermoplasticThe resin can be adhered to the surface of the fabric.The thermoplasticWhen trying to bond the resin directly to the fabric,AdhesiveThe temperature needs to be higher than the temperature at which the resin is bonded.AdhesiveAlong with resin, mainlyAdhesiveAdhesion at a lower temperature is possible by using the adhesive force of the resin, which is preferable from the viewpoint of manufacturing efficiency.
[0061]
  The thermoplasticResin is its main component from the viewpoint of mechanical propertiesIs poLiamideIt is. Polyamide is the main componentAnd the above effects can be easily expressed. In addition,The thermoplasticResinAdhesiveBeing different from a resin means that at least one selected from a resin type, a copolymer composition, a blending composition, an additive composition and the like is different. Therefore, for example, a combination of the same kind of resins having different flow start temperatures can be said to be a preferable combination excellent in compatibility.
[0062]
  (C) or (H) cooling step (3 in the figure)
  AdhesionFor example, cold roller 31 or air coolingAdhesiveBelow the melting point of the resin orAdhesiveThis is a step of cooling to a temperature lower than the resin flow start temperature. With such cooling,AdhesiveThe resin adhesion is completed so that the carbon fiber substrate can be handled stably.
[0063]
  (L) Winding process (4 in the figure) or (M) Cutting process
  Then if necessary,AdhesiveYou may pass through the winding process 4 of (L) which winds up the fabric 41 which resin was adhere | attached,AdhesiveYou may pass through the cutting process (not shown) of (M) which cuts out the fabric 41 to which resin was adhere | attached.
[0064]
  Next, the preferable example of the carbon fiber base material manufactured by the manufacturing method of this invention is shown. FIG. 8 is a plan view of one embodiment of a carbon fiber substrate produced by the method of the present invention. In a bidirectional fabric composed of a warp yarn bundle 11 and a weft yarn bundle 12 made of carbon fiber,AdhesiveResin 2a is applied and bonded to the surface of the fabric.
[0065]
  FIG. 9 is also a plan view of another embodiment of the carbon fiber substrate produced by the method of the present invention. A unidirectional woven fabric composed of a warp bundle 11 made of carbon fibers and an auxiliary weft bundle 12 'made of auxiliary fibers,AdhesiveResin 2a is applied and bonded to the surface of the fabric.
[0066]
  In FIG. 8 or FIG.AdhesiveThe resin 2a may be scattered and bonded to the surface of the fabric as shown in FIG. 8, or may be bonded to cover the surface of the fabric as shown in FIG.AdhesiveThe preferred form differs depending on the type of resin, and it is preferable to select an adhesive form as appropriate depending on the kind.
[0067]
  Manufactured in the present inventionThe carbon fiber substrate is described laterEpoxy is a matrix resinFrom the viewpoint of resin impregnation, the air permeability is 10 to 200 cm.³/ Cm²-Sec range, more preferably 12-120 cm³/ Cm²-Sec, more preferably 15-100 cm³/ Cm²-It is preferable to be in the range of sec. Breathability is 10cm³/ Cm²-Less than sec means inferior resin impregnationTheAlso, breathability is 200cm³/ Cm²・ If it exceeds sec, the impregnation property is excellent, but conversely, the gap between the carbon fibers of the fabric becomes too large, and when it is made into a composite material, the formation of many resin-rich parts deteriorates the mechanical properties, the occurrence of thermal cracks, etc. HappenedTheIn addition, this air permeability refers to the air passage amount measured according to JIS L1096 A method (Fragule type method), and in the present invention, it was measured using AP-360 manufactured by Daiei Scientific Instruments.
[0068]
Next, the preform manufacturing method of the present invention will be described. FIG. 10 is a schematic view illustrating one embodiment of the preform production method of the present invention. The preform of the present invention is produced by a method including at least the following steps (O) to (Q).
[0069]
(O) Lamination process (5 in the figure)
At least two carbon fiber base materials 43 manufactured by the above method are laminated. Here, when the preform is used as a structure (particularly primary structure) member of a transport device (particularly an aircraft), it is preferable to laminate a unidirectional fabric in a pseudo isotropic configuration.
[0070]
(P) Molding process (6 in the figure)
  (P) Molding process (6 in the figure)
  Next, the carbon fiber base material laminated two or more layers,AdhesiveThe melting point of the resin −50 ° C. or higher, or the flow start temperature −50 ° C. or higher, more preferablyAdhesiveHeat to the melting point of the resin or higher than the flow start temperature, pressurize and mold.
[0071]
(Q) Substrate adhesion process (7 in the figure)
  (Q) Substrate adhesion process (7 in the figure)
  Furthermore, the shaped carbon fiber substrateAdhesiveThe carbon fiber base materials are bonded together by cooling to a temperature below the melting point of the resin or below the flow start temperature.
[0072]
  By passing through these steps, not only can the bulk of the laminated carbon fiber base material 43 be reduced, but also they are integrated, so a preform 81 with excellent handling properties can be obtained. In addition, as needed, you may pass through the extraction process 8 which takes out the preform 81 which consists of the adhere | attached carbon fiber base material, and it mentions later without taking out the preform 81 which consists of the adhere | attached carbon fiber base material.Epoxy is a matrix resinYou may pass through the below-mentioned (S) injection | pouring process (not shown) which inject | pours resin. In this case, the preform molds 51 and 52 are used as molds.
[0073]
FIG. 11 is a schematic view illustrating one embodiment of the method for producing a composite material of the present invention. The composite material of the present invention is produced by a method including at least the following steps (R) to (T).
[0074]
(R) Set process (9 in the figure)
The preform 81 manufactured by the above-described method is placed in the molds 91 and 92 to form a cavity.
[0075]
  (S) Injection step (10 in the figure)
  Next, liquefied laterEpoxy is a matrix resinResin 101 is injected into cavity 102 through injection port 93 to form preform 81.EpoxyThe resin 101 is impregnated.
[0076]
  (T) Solidification step (11 in the figure)
  Furthermore,The epoxyThe resin 101 is solidified (cured or polymerized) to obtain the composite material 111 of the present invention. here,The epoxyWhen the resin 101 is solidified, it is preferably heated to increase the solidification efficiency.
[0077]
  If necessary,The epoxyThe resin 101 may be subjected to an extraction process 12 for taking out the composite material 111 solidified, and furtherThe epoxyIn order to ensure the solidification of the resin, an after-curing (complete solidification) step (not shown) in which the composite material 111 is heated and solidified again may be performed.
[0078]
Further, in the above-described setting step 9 of (R), when the molding die includes two including a male die and a female die as shown in FIG. 11, a composite material having excellent dimensional accuracy can be obtained. Further, it is preferable because the molding cost can be reduced as compared with the conventional autoclave molding.
[0079]
FIG. 12 is a schematic view illustrating another aspect of the setting step (R) in the method for producing a composite material of the present invention. As shown in FIG. 12, in the setting step (R), if the mold is made of either a male mold or a female mold (female mold 92 in FIG. 12) and the bag material 95, the cost of the mold is reduced. This is preferable because the molding cost can be further reduced. Examples of the bag material include a film and a flexible rubber material. Since the bag material is usually flexible, a plate (not shown) for imparting rigidity to the surface on the bag material side can be used in combination. The combined use of such plates makes it possible to achieve the same level of dimensional accuracy as when using molds on both sides.
[0080]
  Further, as shown in FIGS. 11 and 12, in the (R) setting process, the inside of the cavity 102 is kept in a vacuum by deaeration from the deaeration port 94 with a vacuum pump or the like.The epoxyWhen resin 101 (not shown) is injected from injection port 93,The epoxyIt is preferable because impregnation with the resin 101 is facilitated, a higher quality composite material can be molded in a short cycle, and the molding cost can be further reduced.
[0081]
  Used in the present inventionEpoxyThe resin is not particularly limited as long as it solves the problems of the present invention.,noteWhen it is used for injection molding, it must be liquid at the injection temperature.. EpoxyAdd an elastomer, rubber component, curing agent, curing accelerator, catalyst, etc. to the resin.UseCan be used.In particularTo achieve the very high mechanical properties (especially CAI, CHW) required by, for example, primary structural components of aircraftAlsoPoxyResin is used.
[0082]
  here, Epoxy resin used as matrix resinHas excellent impregnation properties (low resin viscosity at injection temperature, long gelation time) and excellent mechanical propertiesSelectIt is preferable to use them selectively. of course,AdhesionresinEpoxy used inIn resin, part of itEpoxy resin used as matrix resinThere is no restriction | limiting in using the same component, and it can be said that it is a preferable form from the surface of compatibility of both.
[0083]
  The epoxyIf the preform is impregnated with resin by injection molding,The epoxyIt is preferable that the resin is liquid and has a low viscosity because fast impregnation can be achieved and the molding cycle can be shortened. Specifically, the viscosity is preferably 400 mPa · s or less, more preferably 200 mPa · s or less at the injection temperature. Further, it is preferable that the injection temperature is 100 ° C. or lower because the injection equipment can be simplified.
[0084]
Although it is not specifically limited as a use of the composite material manufactured by the method of the present invention, it has excellent mechanical properties (especially CAI, CHW). When used as a next structural member, exterior member, or interior member, the effect can be maximized.
[0085]
【Example】
Hereinafter, more specific examples will be described.
[0086]
  (referenceExample 1)
  First, a carbon fiber substrate having a length of 30 m and a width of 1 m was produced by the following method.
[0087]
  Mix uniformly the particles (average particle size 16 μm) of epoxy resin (flow start temperature 90 ° C.) containing a curing agent and the particles (average particle size 49 μm) of aromatic polyamide copolymer resin (flow start temperature 220 ° C.). ParticulateAdhesionResin was prepared.
[0088]
Next, the tensile modulus is 294 GPa and the fracture strain energy is 58 MJ / m.^ThreeUnidirectional fabric (plain weave, fabric thickness 0.36mm) with a substantially continuous carbon fiber bundle as a warp and a glass fiber yarn ("ECE" 225 1/0 binder type DP manufactured by Nitto Boseki Co., Ltd.) as an auxiliary weft. , Carbon fiber basis weight 295g / m²A warp yarn density of 2.8 yarns / cm, a weft yarn density of 3 yarns / cm, and a cover factor of 98%).
[0089]
  Subsequent to weaving, the particulate form is continuously woven onto the woven fabric.AdhesiveThe resin was naturally dropped while being measured with a sculpture roll and a doctor blade, and applied while being uniformly dispersed through a vibration net. In addition, the application amount was 4 parts by weight (total 8 parts by weight) with respect to 100 parts by weight of the woven fabric for both the epoxy resin and the aromatic polyamide copolymer resin. Next, the particle-like shape with a far-infrared heaterAdhesiveThe woven fabric coated with the resin was heated to 120 ° C. or higher, and the aromatic polyamide copolymer resin was bonded with an epoxy resin.
[0090]
Then, it cooled to 60 degrees C or less in air | atmosphere, and wound up the carbon fiber base material. In addition, the present Example was continuously performed online from the cloth making process to the cooling process, and the processing speed was 0.3 m / min.
[0091]
The obtained carbon fiber base material had a firmness in the base material and was excellent in shape stability. Moreover, it was excellent also in adhesiveness and shapeability also at the time of the below-mentioned lamination | stacking. Moreover, the carbon fiber base material thickness was 0.44 mm.
[0092]
  (referenceExample 2)
  referenceThe same unidirectional fabric as in Example 1 was similarly woven and wound up. Pull out the unidirectional fabric once wound,referenceSame as example 1AdhesiveResin was applied, bonded, and cooled to wind up the carbon fiber substrate. Ie bookreferenceIn the example, the cloth making process and the coating process were discontinuously performed offline.
[0093]
  Since the warp yarn tension in the fabric making process is once released in the obtained carbon fiber base material,referenceSlightly loosening of the warp yarn was noticeable than that of Example 1, but it was almost the same. In addition, the processing speed of the cloth making process of this example isreferenceAs in Example 1, the processing speed of the coating process can be 2 m / min.referenceThe productivity of the carbon fiber substrate was significantly superior to that of Example 1.
[0094]
  (Example1)
  50 parts by weight of an epoxy resin not containing a curing agent (“Epicoat” 1004AF manufactured by Japan Epoxy Resin Co., Ltd.) and 50 parts by weight of particles (average particle diameter 13 μm) of an aromatic polyamide copolymer resin (glass transition temperature 162 ° C.) Particles having a form in which an aromatic polyamide copolymer resin is coated with an epoxy resin that does not contain a curing agent after being melt-kneaded at 180 ° C. using a kneader and then freeze-pulverized.AdhesionResin was prepared (average particle diameter 38 μm).
[0095]
  referenceThis particulate form on the same unidirectional fabric as in Example 1AdhesiveWhile the resin was charged, 10 parts by weight was applied to 100 parts by weight of the fabric while being uniformly dispersed with compressed gas. Further, while heating the fabric coated with the resin particles to 180 ° C. or higher with a far-infrared heater, the fabric was pressed with a metal roller subjected to a release treatment to adhere the resin particles to the fabric. afterwards,referenceIt cooled similarly to Example 1 and wound up the carbon fiber base material.
[0096]
  The resulting carbon fiber substrate isreferenceAs in Example 1, the handleability was excellent. Also,referenceThe particulate resin was adhered more strongly than in Example 1, and the carbon fiber substrate thickness was small (0.38 mm). Furthermore,referenceThe particulate resin was dispersed more uniformly than in Example 1, and the carbon fiber substrate was superior.
[0097]
  (Example2)
  Biaxial extrusion of 60% by weight of polyethersulfone resin (Sumitomo Chemical Co., Ltd. "Sumika Excel" 5003P finely pulverized product) and 40% by weight of epoxy resin (Nippon Kayaku Co., Ltd. "AK-601") Freeze and pulverize what was melted and kneaded in a machine to make both compatible,AdhesionResin was prepared (average particle diameter 124 μm, glass transition temperature 60 ° C.).
[0098]
  referenceOn the same unidirectional fabric as in Example 1, this particulateAdhesiveResin,referenceIn the same manner as in Example 1, 10 parts by weight was applied to 100 parts by weight of the fabric. Furthermore, while heating to 180-200 ° C. with a far infrared heater, pressurization with a metal nip roller subjected to a release treatment,AdhesiveThe resin was bonded to a unidirectional fabric. afterwards,referenceThe carbon fiber substrate was wound up by cooling in the same manner as in Example 1.
[0099]
  The obtained carbon fiber reinforced substrate isreferenceAs in Example 1, the handleability was excellent. Also,referenceIt is more particulate than Example 1.AdhesiveThe resin was adhered and the carbon fiber substrate thickness was thin (0.37 mm). The air permeability of the carbon fiber substrate is 24 cm.³/ Cm²・ It was sec.
[0100]
  (Example3)
  referenceAnother unidirectional fabric was woven using the same warp yarn as in Example 1 and an auxiliary weft yarn. This fabric has a non-crimp structure, a fabric thickness of 0.24 mm, and a carbon fiber basis weight of 193 g / m.²A woven fabric having a warp density of 1.8 / cm, a weft density of 1 / cm, and a cover factor of 95%. The auxiliary warp yarn was inserted alternately with the warp yarn using the same glass fiber yarn as that of the auxiliary weft yarn (auxiliary warp yarn density 1.8 / cm).
[0101]
  Using such a unidirectional woven fabric, the embodiment was applied to 100 parts by weight of the woven fabric.2The particulate used inAdhesionExample except that 14 parts by weight of resin was applied2In the same manner as above, a carbon fiber reinforced substrate was obtained.
[0102]
  The obtained carbon fiber reinforced substrate isreferenceSimilar to Example 1, it was excellent in handleability. The carbon fiber substrate thickness is 0.25 mm, and the air permeability is 72.0 cm.³/ Cm²・ It was sec.
[0103]
  (Example4)
  referenceExample 1,Example 1~3A preform was produced using the carbon fiber substrate produced in the above. That is, using a carbon fiber base material cut to a length of 340 mm and a width of 340 mm,referenceExample 1,Examples 1 and 2Is a layered structure in which [−45 ° / 0 ° / + 45 ° / 90 °] is repeated twice, Example3Is a three-time repeat, and two sets of each are bonded so that the 90 ° layer is facing each other (bonded to Cilimentley)referenceExample 1,Examples 1 and 2Is a total of 16 layers, Example3Produced a total of 24 layers) by the following method.
[0104]
  The carbon fiber substrate was heated to 120 ° C. using an iron and laminated while adhering the carbon fiber substrates to each other so as to be cut into a predetermined size and to have the above-described laminated structure. After placing the layered product on the surface of the mold and applying vacuum to the cavity sealed with the bag material (polyamide film) and sealant and applying atmospheric pressure,referenceExample 1,Example 1The carbon fiber base material is 120 ° C., Example2,3The substrate was heated to 70 ° C. and held for 1 hour. Thereafter, while maintaining the vacuum state of the cavity, it was cooled to 60 ° C. or lower in the atmosphere and released into the atmosphere to obtain a preform. Such a preform did not fall apart in each layer, had high form stability even during transportation, and was excellent in handleability.
[0105]
  (Example5)
  Example4A composite material was manufactured by the following method using the preform manufactured in (1). First, a preform is placed on the surface of the mold, a polyester fabric that has been subjected to a release treatment as a peel ply, and an aluminum wire mesh as a resin diffusion medium are placed in that order. An inlet and a vacuum suction port were provided and sealed to form a cavity. Then, the inside of the cavity was sucked from the vacuum suction port by a vacuum pump to obtain a vacuum degree of about 0.8 kPa, and the temperature of the mold and the preform was adjusted to 70 ° C.
[0106]
  ThenEpoxyLiquid epoxy resin prepared in a ready-to-inject state after defoaming as a resin (100 parts by weight of the following main liquid plus 32 parts by weight of curing liquid (viscosity by E-type viscometer at 70 ° C .: 250 mPa S) Main liquid: 30 parts by weight of "Araldite" MY-721 manufactured by Vantico, 20 parts by weight of "Epicoat" 825 manufactured by Japan Epoxy Resin, 20 parts by weight of "AK-601" manufactured by Nippon Kayaku Co., Ltd. 30 parts by weight of “Epicron” HP-7200L manufactured by Dainippon Ink & Chemicals, Inc. and 1.4 parts by weight of p-toluenesulfonic acid-n-propyl as a curing accelerator, “Epicure” manufactured by Japan Epoxy Resin Co., Ltd. 18.1 parts by weight of W, 7.2 parts by weight of 3,3′-diaminodiphenylsulfone manufactured by Mitsui Chemical Fine Co., Ltd., “SUMICURE” S manufactured by Sumitomo Chemical Co., Ltd. 7.2 parts by weight) was injected from resin injection port by the atmospheric pressure.The epoxyWhen the resin reached the vacuum suction port, the resin injection port was closed to stop the injection.
[0107]
  After that, the preform was impregnated by holding at 130 ° C. for 2 hours while continuing to reduce pressure from the vacuum suction port with a vacuum pump.The epoxyThe resin was cured.The epoxyAfter confirming that the resin was cured to a demoldable state, each secondary material such as peel ply was removed, and the composite material was taken out of the mold. Furthermore, in order to improve heat resistance, after-curing was performed by holding at 180 ° C. for 2 hours.
[0108]
  When the composite material was inspected, no pinholes or voids were found anywhere, and it was demonstrated that extremely good molding was performed. Further, after applying a 6.67 kJ / m (1500 in · lb / in) falling weight impact to a test piece cut out from the composite material to a length of 152 mm × width of 102 mm using a weight of 5.44 kg (12 lbs). The normal temperature compressive strength (in accordance with CAI, SACMA SRM 2R-94) was measured. As a result, the damage area due to the application of impact could be reduced, and a very high CAI was expressed (referenceExample 1; 228 MPa, Example1248 MPa, Example2246 MPa, Example3278 MPa). The above result is a value obtained by dividing the average value of four samples by Vf and multiplying by 55 (Vf = 55% conversion).
[0109]
  (Example6)
  Example4In the laminated structure of the preform,referenceExample 1,Example 1,2Is [0 °] 4 layers, Example3Is an example using 6 layers laminated5For the composite material molded by the above method, a test piece based on SACMA SRM 1R-94 was immersed in 70 ° C. warm water for 14 days (wet heat treatment), and immediately measured for high temperature (82 ° C.) compressive strength (CHW). However, a decrease in the elastic modulus of the resin due to water absorption can be minimized, and a very high CHW was expressed (referenceExample 1; 1046 MPa, Example1; 1033 MPa, Example2; 981 MPa, Example3960 MPa). The result is a value obtained by dividing the average value of 5 samples by Vf and multiplying by 55 (Vf = 55% conversion).
[0110]
  (Comparative Examples 1-3)
  Except not using particulate resin,referenceCarbon fiber substrate as in Example 1, Example4Preform as in the example5A composite material was manufactured and evaluated in the same manner as described above.
[0111]
The carbon fiber base material of this comparative example that did not use a resin had no stiffness and was inferior in form stability. Moreover, although the obtained preform did not have adhesiveness between carbon fiber base materials and was excellent in formability, the form could not be maintained and the handleability was poor. Moreover, as a mechanical characteristic of the obtained composite material, CAI was 159 MPa, and was significantly inferior to each Example. In addition, CHW was 1049 MPa and was substantially equivalent to each Example.
[0112]
【The invention's effect】
According to the production method of the present invention, not only a composite material with good resin impregnation and excellent mechanical properties (particularly CAI, CHW) can be obtained with good productivity, but also the stiffness, shape stability, and shaping of the substrate. And carbon fiber base material having excellent handling properties such as tackiness when laminated, a preform obtained by laminating the same, and a method for producing a composite material obtained by impregnating the preform with a matrix resin .
[0113]
Such a composite material is particularly suitable for primary structural members of aircraft, including primary structural members, secondary structural members, exterior parts, interior parts or parts thereof in transportation equipment such as aircraft, automobiles, and ships.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic view illustrating one embodiment of a method for producing a carbon fiber substrate of the present invention.
FIG. 2 is a schematic view illustrating another embodiment of the method for producing a carbon fiber substrate of the present invention.
FIG. 3 is a schematic view illustrating another embodiment of the method for producing a carbon fiber substrate of the present invention.
FIG. 4 is a schematic view illustrating another embodiment of the method for producing a carbon fiber substrate of the present invention.
FIG. 5 is a schematic view illustrating another embodiment of the method for producing a carbon fiber substrate of the present invention.
FIG. 6 is a perspective view illustrating one embodiment of a unidirectional fabric preferably used in the present invention.
FIG. 7 is a perspective view illustrating another embodiment of the unidirectional fabric preferably used in the present invention.
FIG. 8 is a plan view of one embodiment of a carbon fiber substrate produced by the method of the present invention.
FIG. 9 is a plan view of one embodiment of a carbon fiber substrate produced by the method of the present invention.
FIG. 10 is a schematic view illustrating one embodiment of the preform manufacturing method of the present invention.
FIG. 11 is a schematic view illustrating one embodiment of a method for producing a composite material of the present invention.
FIG. 12 is a schematic view illustrating another aspect of the (R) setting step in the method for producing a composite material of the present invention.
[Explanation of symbols]
      1: Fabrication process
      11: Warp yarn bundle composed of continuous carbon fibers constituting the fabric
      11 ': an auxiliary warp bundle made of continuous auxiliary fibers constituting the woven fabric
      12: Weft bundle made of continuous carbon fiber constituting the fabric
      12 ': an auxiliary weft bundle made of continuous auxiliary fibers constituting the woven fabric
      13: Samurai
      14: Samurai
      15: Rapier
      16: Fabric
      17: Fabric
      1 ': winding process
      1 ": Draw process
      2: Application process
      21: Hot roller
      22: Far-infrared heater
      2a:Adhesionresin
      2b: Engraving roll
      2c: Doctor blade
      2d: Vibration net
      2e: Weighing machine
      2f: Compressed gas
      2g: Spray head
      2h: Screw
      2i: Gear pump
      2j: Hot melt coater
      2 ': Re-coating process
      2’a:Thermoplasticityresin
      2 ": Pressurization process
      23: Pressure roll
      3: Cooling process
      31: Cold roller
      4: Winding process
      41, 42, 43, 8A, 9A: Carbon fiber substrate
      6A, 7A: Unidirectional fabric
      5: Lamination process
      51: Preform type (male type)
      52: Preform type (female type)
      6: Molding process
      7: Substrate adhesion process
      8: Extraction process
      81: Preform
      9: Set process
      91: Mold (male)
      92: Mold (female)
      93: Injection port
      94: Degassing mouth
      95: Bag material (bag film)
      96: Sealant
    101:matrixresin(Epoxy resin)
    102: cavity
    111: Composite material

Claims (22)

At least look including the following (A) ~ (C) step method of producing a carbon fiber substrate to the epoxy resin characterized in that it is used to be a composite material is impregnated by the injection molding as the matrix resin.
(A) Tensile below modulus above 210 GPa 600 GPa, and fracture strain energy is at 40 MJ / ^{m 3} or more 80 MJ / ^{m 3} or less, or One, manufactured fabric forming a fabric by using a continuous carbonaceous fibers.
(B) A fabric in the range of 0.1 to 20 parts by weight of an adhesive resin containing at least one selected from polyether sulfone, polyphenylene ether and polyamide as a main component and an epoxy resin as an accessory component with respect to 100 parts by weight of the fabric The coating process of applying and bonding in a discontinuous manner so as to be scattered or covered on the surface.
(C) cooling step wherein the fabric adhesive resin is adhered to cool to a temperature below the flow initiation temperature of the melting point or less than the adhesive resin of the adhesive resin. At least viewed including the steps of the following (E) ~ (H), method of producing a carbon fiber base material to the epoxy resin characterized in that it is used to be a composite material is impregnated by the injection molding as the matrix resin.
(E) Tensile below modulus above 210 GPa 600 GPa, and fracture strain energy is at 40 MJ / ^{m 3} or more 80 MJ / ^{m 3} or less, or One, manufactured fabric forming a fabric by using a continuous carbonaceous fibers.
(F) A fabric in which an adhesive resin containing at least one selected from polyether sulfone, polyphenylene ether and polyamide as a main component and an epoxy resin as an accessory component is in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the fabric. The coating process of applying and bonding in a discontinuous manner so as to be scattered or covered on the surface.
(G) said the fabric adhesive resin is adhered, a thermoplastic resin whose main component is polyamide having the adhesive melting point or flow initiation temperature than the resin, 0.1 to 20 parts by weight based on the cloth 100 parts by weight A re-coating step of applying and bonding to the surface of the fabric within the range of
(H) the adhesive resin and the fabric, wherein the thermoplastic resin is adhered, and a cooling step of cooling to a temperature below the flow initiation temperature of the melting point or less than the adhesive resin of the adhesive resin. The method for producing a carbon fiber substrate according to claim 1 or 2, wherein the adhesive resin is 0.1 to 10 parts by weight with respect to 100 parts by weight of the fabric.   The method for producing a carbon fiber substrate according to any one of claims 1 to 3, wherein the fabric to be made is a unidirectional fabric.   The method for producing a carbon fiber substrate according to any one of claims 1 to 4, wherein the fabric to be made is a woven fabric. Carbon fiber warp bundles in which the fabrics to be made are arranged parallel to each other in one direction and auxiliary weft bundles orthogonal thereto are arranged in parallel to each other in a unidirectional woven fabric or carbon fiber warp bundles 6. The auxiliary warp yarn bundle and the auxiliary weft yarn bundle group orthogonal to the auxiliary warp yarn bundle are woven fabrics having a structure in which the warp yarn bundles are held integrally with each other. A method for producing a carbon fiber substrate. After manufacturing fabrics steps (A) or (E), the fabric is subsequently to any one of claims 1 to 6, characterized in that it is subjected to a coating step of continuously respectively (B) or (F) The manufacturing method of the carbon fiber base material of description. The method for producing a carbon fiber substrate according to any one of claims 1 to 7, wherein a particulate resin is used as the adhesive resin or the thermoplastic resin. The method for producing a carbon fiber base material according to claim 8, wherein the adhesive resin or the thermoplastic resin is measured using a roll and a doctor blade, and is applied while being dispersed through a vibration net. . The method for producing a carbon fiber substrate according to claim 8, wherein the adhesive resin or the thermoplastic resin is applied while being charged and dispersed with a compressed gas. The adhesive resin or fabric, wherein the thermoplastic resin is applied and heated above the melting point of the adhesive resin or to a temperature higher than the flow initiation temperature of the adhesive resin, characterized in that adhering at least the adhesive resin and the fabric The manufacturing method of the carbon fiber base material in any one of Claims 1-10. The carbon fiber substrate according to any one of claims 1 to 11, further comprising (I) a pressing step of pressing the fabric coated with the adhesive resin or the thermoplastic resin at a temperature of room temperature or higher. Manufacturing method. The carbon fiber substrate according to claim 11 or 12, wherein the apparatus for heating to a temperature equal to or higher than the melting point of the adhesive resin or equal to or higher than a flow start temperature of the adhesive resin is a far infrared heater and / or a hot roller. Manufacturing method. The method for producing a carbon fiber base material according to any one of claims 1 to 7, wherein the adhesive resin or the thermoplastic resin is applied using a molten material. The method for producing a carbon fiber substrate according to any one of claims 1 to 7, wherein the adhesive resin or the thermoplastic resin is applied by using a resin dispersed or dissolved in water or a solvent.   A fabric having a temporary winding step (J) after winding the fabric after the fabric-making step (A) or (E) and having been wound once before the coating step (B) or (F) The method for producing a carbon fiber substrate according to any one of claims 1 to 5, further comprising a drawing (K) drawing step. The method according to any one of claims 1 to 16, further comprising a winding step (L) of winding the fabric to which the adhesive resin or the thermoplastic resin is bonded after the cooling step of (C) or (H). The manufacturing method of the carbon fiber base material of description. A method for producing a preform, comprising at least the following steps (O) to (Q).
(O) A laminating step of laminating at least two carbon fiber substrates produced by the method according to claim 1.
(P) A molding step in which two or more carbon fiber base materials are heated to a temperature of the melting point of the adhesive resin of −50 ° C. or higher or the flow start temperature of the adhesive resin of −50 ° C. or higher and pressurized to mold.
(Q) A base material bonding step of bonding the carbon fiber base materials by cooling the shaped carbon fiber base material to a temperature below the melting point of the adhesive resin or below the flow start temperature of the adhesive resin. The manufacturing method of the composite material characterized by including the process of at least following (R)-(T).
(R) A setting step of forming a cavity by placing the preform manufactured by the method according to claim 18 in a mold.
(S) An injection step of injecting the liquefied epoxy resin into the cavity and impregnating the preform with the epoxy resin as a matrix resin .
(T) A solidifying step for solidifying the epoxy resin.   20. The method for producing a composite material according to claim 19, wherein, in the setting step (R), the mold includes two molds including at least a male mold and a female mold.   20. The method for producing a composite material according to claim 19, wherein in the setting step (R), the molding die comprises at least one of a male die and a female die and a bag material. In the setting step of (R), the epoxy resin is injected as a matrix resin while maintaining a vacuum in a cavity formed by the molding dies or the molding die and the bag material. A method for producing the composite material according to claim 1.

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