JP2003136550A - Method for manufacturing carbon fiber base material, method for manufacturing preform, and method for manufacturing composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain with good productivity a composite material with good impregnation with a resin and excellent mechanical characteristics and more practically, to provide a method for manufacturing a carbon fiber base material with excellent handling properties and mechanical characteristics, a preform made by laminating it and a composite material made by impregnating the preform with a matrix resin. SOLUTION: The method for manufacturing the carbon fiber base material comprises at least the following processes (A)-(C). A fabric manufacturing process (A) in which a fabric is formed by using a carbon fiber with a tensile elasticity of at least 210 GPa and a breaking strain energy of at least 40 MJ/m<3> and being substantially continuous. A coating process (B) in which the surface of the fabric is continuously coated and stuck with the first resin in a range of 0.1-10 pts.wt. to the fabric of 100 pts.wt. A cooling process (C) in which the fabric stuck with the first resin is cooled to a lower temperature than the melting point of the first resin or the flow starting temperature of the first resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field 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.

More specifically, it has good resin impregnation and mechanical properties (especially compressive strength after impact or wet heat treatment).
A carbon fiber base material that not only yields excellent composite materials with good productivity but also has excellent handleability such as stiffness, morphological stability, moldability, and tackiness when laminating, and laminating it. And a composite material obtained by impregnating the preform with a matrix resin.

[0003]

2. Description of the Related Art Conventionally, composite materials containing carbon fibers as reinforcing fibers have been mainly used for aviation, space and sports applications because they satisfy excellent mechanical properties and required properties such as weight reduction. An autoclave molding method is known as a typical manufacturing method for these. In such a molding method, a prepreg obtained by impregnating carbon fibers with a matrix resin in advance in a carbon fiber sheet aligned in one direction is stacked in a molding die and heated and pressed by an autoclave to mold a composite material. The prepreg as the base material used here has the advantage that a highly reliable composite material can be obtained by using it, but it is too rigid and difficult to shape, and it costs a lot to manufacture, that is, production. There was a problem that it was low in sex.

On the other hand, as a molding method which is excellent in the productivity of the composite material, there is an injection molding method such as a resin transfer molding molding method (RTM). In such RTM, a base material made of (dry) carbon fiber not pre-impregnated with the matrix resin is placed in a complicated molding die, and a liquid (low viscosity) matrix resin is injected into Then, the matrix resin is impregnated with the resin and molded.

However, although this injection molding is excellent in the productivity of the composite material, it is used as a base material (for example, dry woven fabric).
Is easily misaligned (morphological instability), the base material is too rigid to bend easily, and the base materials cannot be adhered to each other when stacked (no tackiness). . In addition to this, since the matrix resin needs to have a low viscosity, there are problems such as lower mechanical properties than those having a high viscosity used in prepregs. Was not sufficiently expressed, causing a problem of impairing the mechanical properties of the composite material.

To solve the above problem, for example, US Pat.
No. 71,711, etc., proposes a technique for imparting a thermoplastic-like resin to a reinforced fiber cloth, improving the handleability of a dry woven fabric as a base material, and stabilizing the preform shape used for injection molding. Has been done.

James C. Seferis et al., Journal of A
dvanced Materials, Volume32, No.3, July 2000, P27-34,
Composites part A, Volume32, 2001, P721-729, etc., and mechanical properties of CFRP obtained by injection molding (Mode I, II by applying resin mixed with epoxy resin and elastomer particles or polyamide 6 onto a woven fabric. Interlaminar fracture toughness) has been reported.

However, in these proposals, the handling property of the substrate is improved, but the mechanical properties are not improved.
Or the improvement level was insufficient. In other words, for example, the extremely high level mechanical properties required for primary structural members of aircraft cannot be achieved simply by applying a resin to a woven fabric or the like, and when the carbon fiber itself used does not have the required properties, However, such a composite material also cannot exhibit the required mechanical properties (particularly the compressive strength after impact is applied).

In addition, in the injection molding described in the above proposal, since the carbon fiber sheet simply arranged in one direction cannot be handled while maintaining the fiber orientation in a dry state, a bidirectional woven fabric is used. . However, for example, in a primary structural member of an aircraft, very high mechanical properties (in particular, cold compressive strength after impact (hereinafter referred to as CAI), high temperature compressive strength after wet heat treatment (hereinafter referred to as CHW)) Required. In a bidirectional woven fabric, since carbon fibers are woven in two directions, the amount of reinforcing fibers in each direction is essentially halved.Because the warp and weft yarns have almost the same fineness, the warp and weft yarns are interwoven. At this point, due to the large bending (crimp) of the carbon fibers, only half the mechanical properties of the prepreg in which the carbon fibers were arranged in one direction were exhibited.

That is, although the properties required for the carbon fiber to be used and the morphology of the fabric using the carbon fiber are particularly important factors for exhibiting high mechanical properties, the description relating thereto is completely disclosed in the above proposal. However, the technology for producing a carbon fiber base material that satisfies the problems of the present invention has been eagerly desired.

[0011]

According to the prior art, not only is it difficult to obtain a composite material having good resin impregnation and excellent mechanical properties (especially CAI, CHW, etc.) with high productivity, but also the elasticity of the base material. However, a carbon fiber substrate excellent in handleability such as morphological stability, moldability and tackiness has not been obtained. The present invention aims to solve such problems.

[0012]

The present invention employs the following means in order to solve the above problems. That is, the method for producing a carbon fiber base material of the present invention is characterized by including at least the following steps (A) to (C). (A) A cloth-making process in which a tensile elastic modulus is 210 GPa or more, a breaking strain energy is 40 MJ / m ³ or more, and a cloth is formed using substantially continuous carbon fibers. (B) The first resin is added in an amount of 0.1 to 100 parts by weight of the cloth.
A coating step of coating and adhering to the surface of the fabric in the range of 20 parts by weight. (C) A cooling step in which the cloth to which the first resin is bonded is cooled to a temperature lower than the melting point of the first resin or lower than the flow starting temperature of the first resin.

Further, when the second resin is used, the method for producing the carbon fiber base material of the present invention is at least the following (E) to (H).
It is characterized by including the step of. (E) A fabric-making step of forming a fabric by using carbon fibers having a tensile elastic modulus of 210 GPa or more and a breaking strain energy of 40 MJ / m ³ or more and being substantially continuous. (F) The first resin is added in an amount of 0.1 with respect to 100 parts by weight of the cloth.
A coating step of coating and adhering to the surface of the fabric in the range of ˜20 parts by weight. (G) A second resin different from the first resin is added to the cloth to which the first resin is adhered in an amount of 0.1 to 100 parts by weight of the cloth.
A re-applying step of applying and adhering to the surface of the fabric in the range of 20 parts by weight. (H) A cloth to which the first resin and the second resin are adhered,
A cooling step of cooling to a temperature below the melting point of the first resin or below the flow starting temperature of the first resin.

The preform manufacturing method of the present invention is characterized by including at least the following steps (O) to (Q). (O) A laminating step of laminating at least two layers of the carbon fiber base material. (P) The melting point of the first resin of the carbon fiber base material having two or more layers laminated is -50 ° C or higher or the flow starting temperature of the first resin is -50
A shaping step of heating and pressurizing to a temperature of ℃ or more and shaping. (Q) A base material adhering step of adhering the carbon fiber base materials to each other by cooling the shaped carbon fiber base material to a temperature below the melting point of the first resin or below the flow starting temperature of the first resin.

The method for producing a composite material of the present invention is characterized by including at least the following steps (R) to (T). (R) A setting step of arranging the preform in a molding die to form a cavity. (S) A step of injecting the liquefied third resin into the cavity to impregnate the preform with the third resin. (T) A solidification step of solidifying the third resin.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described with reference to the drawings.

FIG. 1 is a schematic view illustrating one embodiment of the method for producing a carbon fiber base material of the present invention. Further, FIG. 2 is a schematic view illustrating another aspect of the method for producing a carbon fiber base material of the present invention. The method for producing a carbon fiber substrate of the present invention comprises at least the following steps (A) to (C), or
It is a manufacturing method including at least the following steps (E) to (H).

Fabrication step (A) or (E) (1 in the figure) When the fabric to be fabricated is a bidirectional fabric, the tensile elastic modulus is 21.
Warp yarn 11 having a carbon fiber bundle of 0 GPa or more, a breaking strain energy of 40 MJ / m ³ or more, and a substantially continuous carbon fiber bundle.
In the case of a unidirectional woven fabric, the tensile elastic modulus is 210 GPa or more and the breaking strain energy is 40.
As a weaving jig, a warp yarn 11 having a carbon fiber bundle of MJ / m ³ or more and substantially continuous, and an auxiliary weft yarn (not shown) such as a yarn of glass fiber or organic fiber or a processed yarn are used. Weaving using heddle 13, reed 14, rapier 15,
Form a fabric. Here, the substantially continuous carbon fiber bundle means that the carbon fiber bundle is continuous, and also includes a carbon fiber bundle in which a single yarn of less than 10 wt% is cut. Also, when manufacturing a carbon fiber substrate,
Carbon fibers may be bundled or entangled with each other so that carbon fibers can be continuously supplied during the series of production.

The carbon fiber used in the present invention has a tensile elastic modulus of 210 GPa or more. Preferably more than 250 6
Less than 00 GPa, more preferably more than 280 and 500 G
It is preferably less than Pa, particularly more than 290 and less than 400 GPa. When the tensile elastic modulus is less than 210 GPa, the mechanical properties of the composite material are not sufficient, and the meaning of using carbon fiber becomes unsatisfactory, which is not preferable. Here, the tensile elastic modulus refers to a value measured according to JIS R7601, and the unit is GPa.

The carbon fiber used in the present invention has a breaking strain energy of 40 MJ / m ³ or more. More preferably 45 MJ / m ³ or more, still more preferably 53 MJ / m
^It is preferably ³ or more, especially 56 MJ / m ³ or more. The higher the breaking strain energy, the better,
Although there is no upper limit, it is generally 80 MJ / m ³ or less. When the breaking strain energy is less than 40 MJ / m ³ , the carbon fiber may be broken when an impact is applied, and in particular, the composite material having a pseudo isotropic laminated structure of unidirectional fabric is inferior in CAI and has mechanical properties. It is not preferable because a composite material having excellent heat resistance cannot be obtained. In other words, only when the carbon fiber has high breaking strain energy,
The carbon fibers have excellent mechanical properties (especially CA
I) can be achieved. Note that such CAI is a mechanical property that is very important when used as a structural (particularly primary structure) member of transportation equipment (particularly aircraft), and is more necessary when the use of the composite material is the aforementioned use. Can be said to be expensive. The breaking strain energy (W) is JIS
The measured tensile strength in compliance with R7601 (sigma), when the tensile modulus (E), (W) = (σ) 2/2 ×
Refers to the value defined in (E), the unit is MJ / m ³ (10 ⁶
× J / m ³ ).

In the present invention, the cloth made by using carbon fibers is not particularly limited, but for example, a two-dimensional unidirectional fabric, a bidirectional fabric, or a fabric having more than one directional fabric, a three-dimensional multi-directional fabric. Woven fabrics, knitted fabrics, multiaxially inserted fabrics, unidirectionally aligned carbon fiber sheets that are morphologically stabilized with a binder, fusible non-woven fabric, stitch threads, etc. (unidirectional sheet), unidirectional sheet Examples include multiaxial sheets laminated in more than one direction, which may be joined by stitch threads, knot threads, or the like to integrate a plurality of cloths. Particularly when used as structural (particularly primary structure) members of transportation equipment (particularly aircraft), very high mechanical properties (particularly CAI, CHW) are required, but in bidirectional fabrics, carbon fibers are woven in two directions. Due to the texture and the increase in the crimp of the carbon fiber at the intersection of the warp yarn bundle and the weft yarn bundle, the mechanical properties that can withstand the demand may not be easily expressed. That is, in terms of reliably eliminating such a problem, the cloth used in the present invention is a unidirectional cloth,
That is, a unidirectional woven fabric, a unidirectional sheet, or a combination of a plurality thereof is preferable. Further, in consideration of the surface impregnated with the matrix resin, the unidirectional woven fabric in which extremely small crimps are formed between the strands by the entanglement of the auxiliary weft yarn bundle is particularly preferable. Such a small crimp serves as an impregnation channel for the matrix resin and has an effect of remarkably improving impregnation property, and can be said to be an optimum cloth in the present invention.

The unidirectional woven 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. Unidirectional fabric 6A
Is a warp yarn bundle 11 of carbon fibers arranged parallel to each other in one direction, and an auxiliary weft yarn bundle 12 'orthogonal to the bundle, forming a plain weave design.

In the unidirectional woven fabric 6A, the warp yarn bundle 11 is 5,000 to 50,000 yarns (more preferably 10,000 to 5,000 yarns).
Those having filaments in the range of 25,000) are preferable. From another viewpoint, the warp yarn bundle 11 is 300 to 500.
Those in the range of 0 tex are preferable. If it is smaller than this range, the number of cross points in the woven fabric is too large, and not only the number of crimps becomes large but also the number thereof becomes large, which may result in poor mechanical properties. On the other hand, when it is larger than this range, the number of crossing points in the woven fabric is too small and the morphological stability may be poor.

The auxiliary fibers forming the auxiliary weft yarn bundle 12 'are made of the carbon fiber of the present invention by reducing the bending (crimp) of the warp yarn bundle 11 at the intersection of the warp yarn bundle 11 and the auxiliary weft yarn bundle 12'. In order to maximize the characteristics, the fineness of the carbon fibers used in the warp yarn bundle 11 is preferably ⅕ or less, more preferably 1/10 or less. The specific fineness varies depending on the types of carbon fibers and auxiliary fibers used and the fabric weight.
In the case of making a woven fabric of 200 g / m ² by using x, the preferable fineness of the auxiliary fiber is in the range of 1 to 100 tex, more preferably 10 to 50 tex. The woven density of the auxiliary weft yarn 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 morphology of the fabric and minimize the influence of crimp. Within the range of / cm.

Although any type of auxiliary fiber can be used, it is preferable that the auxiliary fiber does not easily shrink due to the stability of the cloth density due to heating during molding, for example, carbon fiber, glass fiber, aramid, polyamide. (Particularly POY: semi-drawn yarn by high-speed spinning), organic fibers such as PBO, PVA, PE and the like can be used alone or in combination,
These may be those that have been subjected to secondary processing such as yarn processing, twist processing, wool processing, and crimping processing. Further, the warp yarn bundle 11 and the auxiliary weft yarn bundle 12 'can be used in combination with a component having an adhesive function in order to fix the woven structure.

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. Further, the form thereof can be combined with the warp yarn bundle and the auxiliary weft yarn bundle in any form such as fibrous form, particle form, emulsion form, dispersion form and the like. Among them, it is preferable to use a fibrous material as an auxiliary weft bundle by twisting or covering with auxiliary fibers and using the bundle as an auxiliary weft.

The unidirectional fabric preferably used in the present invention includes a twill weave design and a satin weave design in addition to the plain weave design 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 woven fabric 7A, an auxiliary warp yarn bundle 11 'arranged in parallel with the carbon fiber warp yarn bundle 11 and an auxiliary weft yarn bundle 12' group orthogonal to the auxiliary warp yarn bundle 11 'are crossed with each other and the warp yarn bundle 11 is integrally held. It is a woven fabric with a different structure (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 viewpoint of resin impregnation, the impregnation channel is secured by the presence of auxiliary fibers (particularly auxiliary warp yarns), and extremely excellent impregnability is exhibited.

In the present invention, the first resin or the second resin is applied to the cloth, but the cover factor of the cloth is preferably 90% or more in order to minimize the detachment thereof. It is more preferably 95% or more, still more preferably 98% or more. What is such a cover factor?
200 mm when viewed from the direction perpendicular to the flat fabric
× Percentage of the closed part where carbon fibers (including auxiliary yarns and stitch yarns, etc.) in the fabric per unit area of 200 mm exist (not covered), cover factor (%) = total area of closed part (mm ² ) / 400. With respect to the closed portion, image processing is performed based on an image optically captured by a CCD camera, a scanner or the like, and the total area can be calculated.

In order to fabricate a cloth having such a cover factor, before or after forming the cloth, a rocking roller (a nip roller may be used together if necessary) or compressed air is blown. It is preferable to open and widen the carbon fiber. It is also possible to fabricate using carbon fibers that have been opened and widened in advance. It can be said that such a method is a particularly effective cloth making method when the carbon fiber areal weight is 300 g / m ² or less. The carbon fiber areal weight has no particular lower limit, but is generally 50 g / m ² or more.

The cloth used in the present invention preferably has a carbon fiber areal weight of 50 to 600 g / m ² in terms of impregnation of a preform with a third resin described later. More preferably 100~350g / m ^2, more preferably in the range of 150 to 300 g / m ^2.

(B) or (F) coating step (2 in the figure,
2 ′) 0.1 to 2 of the first resin 2a with respect to 100 parts by weight of the cloth
The surface of the fabric is coated and adhered in the range of 0 part by weight.

When the first resin 2a or the second resin 2'a is applied in the form of particles, not only the control of the applied amount of the resin is easy, but also the applying device can be simplified. Therefore, it is preferable. In particular, when the first resin 2a in particle form or the second resin 2'a in particle form is measured using the roll 2b and the doctor blade 2c, not only stable measurement is possible but also inexpensive. It is preferable because it can be installed in the equipment. Further, it is preferable to use a roll (engraved) on which a pattern such as a mesh or a dot is applied as the roll, because the weighing can be performed more strictly.

Further, when the particulate first resin 2a or the particulate second resin 2'a is naturally dropped and applied to the cloth, when the vibrating net 2d is passed, the resin is more evenly distributed on the cloth. It is preferable because various dispersions are possible.

FIG. 3 is a schematic view for explaining another embodiment of the method for producing a carbon fiber base material of the present invention. In this aspect, in the coating step 2, the particulate first resin 2a
Is weighed by a weighing machine 2e and charged by passing the spray head 2g through them, or forcibly charged by corona discharge, and uniformly dispersed by a compressed gas 2f (preferably dry compressed gas). Applying while doing. According to this method, it becomes easier to control the coating amount of the resin and it becomes possible to coat the resin more uniformly. The method described here is also preferably used when the second resin is used (not shown in FIG. 3).

When the particulate first resin is used, in order to uniformly disperse the resin on the surface of the cloth, the average particle diameter is in the range of 1 to 250 μm, more preferably 1 to 150 μm.
m, more preferably 3 to 100 μm. If the particle size is less than 1 μm, a large amount of particles enter between the carbon fibers constituting the cloth, and the amount of particles adhered to the surface of the cloth may vary. On the other hand, if it exceeds 250 μm, the particle diameter becomes large, so that the number of particles to be adhered becomes small with respect to a predetermined amount of particle dispersion, and it may be difficult to uniformly disperse the resin.

FIG. 4 is a schematic view for explaining another embodiment of the method for producing a carbon fiber base material of the present invention. In this aspect, the first resin 2a is applied in a molten state. According to this method, since the form of the first resin is not limited, it is possible to omit the process of forming the first resin into particles as described above. The method described here is also preferably used when the second resin is used (not shown in FIG. 4).

In the present invention, in addition to the above embodiment, the first resin or the second resin dispersed or dissolved in water or a solvent may be used for coating. According to such a method, similarly to the case of using a resin in a molten state, not only is there no restriction on the resin form, but also a heating device for melting is unnecessary, so that the device can be further simplified. There are advantages. Further, even in the case of using the particulate resin, there is an advantage that the dispersion of the particles can be prevented by applying a dispersion of the particles in water or a solvent.

In the present invention, the first resin 2a and the second resin 2'a may be applied to one side of the cloth,
It may be coated on both sides. When coating on one side, it is preferable that the coating process can be simplified. Further, when coating on both sides, although the coating process is large, it is preferable in that it is not necessary to properly use the front and back of the cloth.

In the present invention, in order to firmly adhere the first resin 2a or the second resin 2'a to the fabric surface, the applied first resin 2a or the second resin 2 '
At the time of adhering a, it is preferable to heat at least the melting point of the first resin or the flow starting temperature of the first resin to adhere at least the first resin and the cloth.

Here, the melting point of the first resin or higher or the first
The device for heating the resin to a temperature above the flow start temperature of the resin is not particularly limited, but if it is a far-infrared heater 22 and / or a hot roller (not shown), the temperature required to easily respond to changes in the cloth-making speed is required. It is preferable because it can be controlled to.

It should be noted that, in FIGS. 1 to 4, a cloth making process 1 of (A) or (E) and a coating process 2 or (G) of (B) or (F).
Re-applying step 2 ′ is continuously (online) performed. By such a method, even if the fabric is inferior in morphological stability, it is possible to stabilize morphology by using the first resin, and a carbon fiber substrate which exhibits high mechanical properties and is excellent in handleability. The material can be obtained. Hereinafter, a specific example will be described in more detail.

Taking a unidirectional woven fabric as an example, the bending (crimp) of the carbon fiber caused by the intersection of the warp yarn and the auxiliary weft yarn adversely affects the mechanical properties. In order to minimize this crimp, for example, if the auxiliary weft interval is expanded to 10 mm or more and a thin glass fiber yarn auxiliary weft of 30 tex or less is used, the shape stability is poor and it cannot be handled by itself. However, it is possible to obtain a handleable carbon fiber base material by dramatically improving the morphological stability by applying and adhering the first resin through the cloth making step 1 and the applying step 2 continuously. There are advantages.

In this case, the processing speed is preferably 0.5 to 5 m / min. More preferably, it is 1 to 4 m / min. Taking a unidirectional woven fabric as an example, the processing speed in the fabric making step 1 is generally as low as about 0.3 to 0.4 m / min. However, the coating process 2 can be processed 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, high-speed double rapier loom, water jet loom, air jet loom, needle loom, etc.)
It is preferable that the processing speed is 0.5 m / min or more in the cloth making process. On the other hand, if the processing speed exceeds 5 m / min, the fluff from the carbon fibers during the fabric making may increase excessively.

The first resin used in the present invention is the cloth 10
It is applied and adhered to the surface of the fabric in the range of 0.1 to 20 parts by weight with respect to 0 parts by weight. More preferably 0.1-10
The amount is in the range of preferably 1 to 9 parts by weight, more preferably 3 to 6 parts by weight. If it is less than 0.1 part by weight, tackiness (adhesiveness) between the base materials when laminating the carbon fiber base materials to obtain a preform cannot be sufficiently imparted, and the handleability thereof is poor. This is because the tackiness is exhibited by the first resin adhered on the surface of the carbon fiber base material.
Further, when it exceeds 20 parts by weight, not only is it difficult to obtain a composite material having excellent mechanical properties, especially CHW, but also a third resin described below which is a matrix resin for a carbon fiber base material or a preform when the composite material is obtained. On the contrary, the impregnation may be hindered.

When the first resin is adhered within the above range, the carbon fibers adjacent to each other are restrained, so that the cloth is appropriately stiff, which not only improves the handleability but also improves the handling property.
A morphological stabilizing effect such as prevention of misalignment of the cloth can be exhibited. Further, since the first resin serves as a crack stopper between the cloths of the composite material, it is possible to suppress damage between the cloths when an impact is applied and to achieve excellent mechanical properties (particularly CAI) (interlayer strengthening). The effect) can also be expressed.
In addition to the above effects, the presence of the first resin serves as a spacer to secure a flow path for a third resin, which will be described later. Particularly, when the first resin is subjected to injection molding, impregnation is facilitated. Not only that, but also the impregnation speed is increased and the productivity of the composite material is also excellent, which is an unexpected effect (spacer effect).

The melting point or flow initiation temperature of the first resin used in the present invention is in the range of 40 to 150 ° C. from the viewpoint of processing temperature for developing tack when laminating carbon fiber base materials. preferable. The range is more preferably 50 to 140 ° C, and further preferably 60 to 120 ° C. Here, the melting point refers to a melting temperature of a resin measured using a differential scanning calorimeter (DSC), and a resin having a melting point in DSC is based on the melting point. For resins that do not show melting points in DSC, viscoelasticity measurements (Shimadzu flow tester CF
T500D, temperature rising rate of 1.5 ° C./min) is used as a reference for the flow start temperature.

The first resin used in the present invention is not particularly limited as long as it is a resin that improves the handleability of the carbon fiber reinforced substrate and improves the mechanical properties of the composite material obtained by using the same. As the curable resin and / or the thermoplastic resin, those having excellent compatibility and adhesiveness with the third resin used as a matrix resin described later can be appropriately selected and used. In addition, when a plurality of resins are combined and used in the form of particles as the first resin, a mixture of a plurality of resins in advance or a compatibilization thereof may be used in the form of particles. The resins may be mixed and used.

Examples of the thermosetting resin include epoxy, phenol (resole type), polybenzimidazole, benzoxazine, cyanate ester, unsaturated polyester, vinyl ester, urea, melamine, bismaleimide, polyimide, polyamideimide and polyurethane. Etc., and copolymers and modified products thereof and resins obtained by blending two or more kinds thereof can be used. Furthermore, an elastomer, a rubber component, a curing agent, a curing accelerator, a resin to which a catalyst or the like is added can be used.

Examples of the thermoplastic resin include polyester, polyolefin, styrene resin, polyoxymethylene, polyamide, polyurethane, polyurea, polydicyclopentadiene, polycarbonate, polymethylmethacrylate, polyvinyl chloride, polyphenylene sulfide, polyphenylene ether, and polyphenylene ether. Ether imide, polysulfone, polyarylate, polyethersulfone, polyetherethersulfone, polyketone, polyetherketone, polyetheretherketone, polyetherketone, polyarylate, polyethernitrile, phenol (novolak type, etc.), phenoxy resin, poly Fluorine-based resin such as tetrafluoroethylene,
Further, a thermoplastic elastomer, a resin for RIM (for example, polyamide 6, polyamide 12, polyurethane, polyurea,
Polydicyclopentadiene-containing catalysts), cyclic oligomers (polycarbonate, polybutylene terephthalate-containing catalysts, etc.), their copolymers, modified products, and blended resins of two or more kinds. Etc. can be used. Further, a resin obtained by adding an elastomer or a rubber component to these resins may also be used.

As a preferred example for maximizing the object of the present invention as the first resin, epoxy is used as the thermosetting resin and at least one selected from polyether sulfone, polyphenylene ether and polyamide as the thermoplastic resin. The seeds may be used and mixed (preferably compatibilized) with each other so that the flow starting temperature is 180 ° C. or lower or the glass transition temperature is 100 ° C. or lower. Such a first resin exhibits a remarkably excellent effect when a composition (particularly a liquid material) of an epoxy resin and a curing agent is used as a third resin described later.

(I) Pressurizing step (2 "in the figure) Fig. 5 is a schematic view for explaining another embodiment of the method for producing a carbon fiber substrate of the present invention. In this embodiment, the coating step 2 After that, there is a pressing step 2 ″ of (I) in which the applied first resin 2a and the cloth are pressed by the pressing roll 23. When using the second resin, it is also possible to apply pressure after the reapplication process (not shown).

By such pressurization, the unevenness of the first resin or the second resin on the cloth can be reduced. Such unevenness is obtained when a carbon fiber base material is laminated to obtain a composite material.
Transfer to adjacent carbon fiber base material to bend the carbon fiber,
In particular, it may be a cause of impairing compression characteristics such as CHW. From this point of view, it is preferable to apply pressure so that the maximum thickness of the combined resin portion of the first resin and the second resin on the cloth is 150 μm or less. More preferably 100
It is less than or equal to μm, and more preferably less than or equal to 60 μm. From another viewpoint, a range in which the thickness Tr of the carbon fiber base material does not exceed 150 μm (more preferably 100 μm, further preferably 60 μm) than the thickness To of the cloth alone to which the first resin is not adhered It is preferable to pressurize. Such pressurization not only reduces the unevenness of the first resin or the second resin and reduces the thickness of the carbon fiber base material, but also focuses the bulky carbon fiber bundle and reduces the thickness of the fabric itself. It produces unexpected effects. Due to this effect,
When the carbon fiber volume ratio Vf of the composite material is made higher,
It is possible to obtain a composite material that is excellent in weight reduction effect.

However, if the pressure is excessively applied, the first resin cannot substantially remain on the surface of the fabric, and not only the above-mentioned effect relating to the tackiness of the carbon fiber base material is impaired, but also the third resin described below is used. The impregnating property may be impaired. From this viewpoint, Tr
It is preferable to pressurize within a range that does not become smaller than To. The thickness of the cloth alone and the thickness of the carbon fiber base material used herein are those measured according to JIS R7602.

Here, the pressure roll 23 may be a hot roll that is heated, a cold roll that is forcibly cooled, or a roll that is not temperature-controlled. A hot roll is preferable in order to more efficiently develop the effect of pressurization. Further, in order to reduce the equipment cost, it is preferable to use a cold roll or a roll whose temperature is not adjusted. In these cases, by applying pressure immediately after heating, it is possible to obtain an effect substantially equivalent to that of the hot roll.

From this point of view, pressurization is performed at a temperature above room temperature,
It is preferable that the temperature is higher than the melting point of the first resin −50 ° C. or the flow starting temperature −50 ° C., and more preferably the melting point or flow starting temperature of the first resin or higher.

(J) Temporary winding step (1 'in the figure) and (K) Drawing step (1 "in the figure) In FIG. 5, after the fabric making step 1, the temporary winding step 1'of (J)
The cloth 16 is once wound before applying the first resin. The once-wound fabric 17 is drawn out in the drawing step 1 ″ of (K), and the first resin 2a is applied in the applying step 2 as in FIG. 1. That is, the cloth making step 1 and the applying step The step 2 is performed discontinuously (off-line) In such an embodiment, it is necessary to make the processing speed of the cloth making step 1 and that of the coating step 2 which can be processed at a faster speed the same. That is, there is an advantage that the line speed of the coating step 2 can be increased and the carbon fiber base material can be manufactured with higher productivity.

(G) Re-applying step (2 'in the figure) In the present invention, when a second resin different from the first resin is further used, a cloth to which the first resin is bonded as shown in FIG. Then, the second resin 2'a different from the first resin is applied to the surface of the cloth in an amount of 0.1 to 20 parts by weight with respect to 100 parts by weight of the cloth, and is adhered thereto. By using such a second resin, it is possible to impart a function (for example, improvement in mechanical properties) that the first resin does not have or lacks.

From the viewpoint of further improving the mechanical properties, the second resin used in the present invention preferably has a higher melting point or flow starting temperature than the first resin. A suitable second resin has a melting point or flow initiation temperature of 1
The temperature is 50 ° C. or higher, more preferably 180 ° C. or higher, and further preferably 210 ° C. or higher. From another viewpoint, the glass transition point of the second resin is preferably in the range of 80 to 180 ° C. The range is more preferably 90 to 160 ° C, and further preferably 100 to 140 ° C.

By adhering the second resin having the above-mentioned properties, the mechanical properties (particularly CAI) of the composite material obtained by laminating the carbon fiber base materials can be further enhanced. This is because a resin having a higher melting point or a higher flow starting temperature is more excellent in impact strength and fracture toughness, and thus a markedly superior effect is exhibited as compared with the case where only the first resin is used.

The second resin may be adhered to the surface of the cloth together with the first resin, or the second resin may be directly adhered to the surface of the cloth. Further, it is preferable that the first resin is bonded to the surface of the cloth through the first resin. By doing so, the second resin can be more reliably adhered to the surface of the cloth. If you try to bond the second resin directly to the fabric,
It is necessary to make the temperature higher than the temperature at which the resin of (1) is bonded, but by bonding together with the first resin mainly by using the adhesive force of the first resin, bonding at a lower temperature becomes possible. Therefore, it is preferable in terms of manufacturing efficiency.

From the viewpoint of mechanical properties, the second resin is preferably a thermoplastic resin as the main component, and the resins mentioned above as examples of the first resin can be used. Among them, at least one selected from polyamide, polyimide, polyetherimide, polysulfone, polyethersulfone, polyphenylene ether, polyetheretherketone and polyetherketone is preferable because the above effects can be easily exhibited. In addition, that the second resin is different from the first resin means that at least one selected from a resin type, a copolymerization composition, a compounding composition, an additive composition and the like is different. Therefore, for example, a combination of the same kind of resin but different flow starting temperature can be said to be a preferable combination having excellent compatibility.

Cooling step (C) or (H) (3 in the figure) A cloth to which the first resin is adhered is applied, for example, to a cold roller 3
1 or a step of cooling to a temperature below the melting point of the first resin or below the flow starting temperature of the first resin by air cooling. By such cooling, the adhesion of the first resin is completed, and the carbon fiber base material can be handled in a stable state.

(L) Winding step (4 in the figure) or (M) Cutting step After that, if necessary, the cloth 41 to which the first resin is adhered
The winding step 4 of winding (L) may be performed, or the cutting step (M) of cutting out the fabric 41 to which the first resin is adhered (not shown) may be performed.

Next, preferred examples of the carbon fiber base material produced by the production method of the present invention will be shown. FIG. 8 is a plan view of an embodiment of the carbon fiber substrate manufactured by the method of the present invention. The first resin 2a is applied to the surface of the woven fabric and adhered to the bidirectional woven fabric composed of the warp yarn bundle 11 and the weft yarn bundle 12 made of carbon fibers.

FIG. 9 is also a plan view of another embodiment of the carbon fiber base material manufactured by the method of the present invention. A unidirectional woven fabric composed of a warp yarn bundle 11 made of carbon fibers and an auxiliary weft yarn bundle 12 'made of auxiliary fibers, and a first resin 2
a is applied and adhered to the surface of the fabric.

In FIG. 8 or 9, the first resin 2a
May be scattered and adhered to the surface of the fabric as shown in FIG. 8, or may be adhered so as to cover the surface of the fabric as shown in FIG. The preferred form differs depending on the type of the first resin, and it is preferable to select an appropriate adhesion form depending on the type.

The carbon fiber base material has an air permeability of 10 to 200 cm ³ / in view of the third resin impregnating property described later.
cm ² · sec range, more preferably 12 to 120 c
m ³ / cm ² · sec, more preferably 15 to 100 cm
^It is preferably in the range of ³ / cm ² · sec. If the air permeability is less than 10 cm ³ / cm ² · sec, it means that the impregnation property of the resin is poor, which is not preferable. Further, when the air permeability exceeds 200 cm ³ / cm ² · sec, the impregnation property is excellent, but conversely, the gap between the carbon fibers of the cloth becomes too large, and when a composite material is formed, a large amount of resin-rich portion is formed. It is not preferable because mechanical properties are deteriorated and thermal cracks occur. In addition, such breathability is JIS
This refers to the amount of air passing measured according to the L1096 A method (flajour method), and in the present invention, it was measured using AP-360 manufactured by Daiei Kagaku Seiki Seisakusho.

Next, a method for producing the preform of the present invention will be described. FIG. 10 is a schematic view for explaining one aspect of the preform manufacturing method of the present invention. The preform of the present invention is manufactured by a method including at least the following steps (O) to (Q).

(O) Laminating step (5 in the figure) At least two carbon fiber base materials 43 produced by the above method are used.
Stack more than one layer. Here, when the preform is used as a structural (particularly primary structure) member for transportation equipment (particularly aircraft), it is preferable to laminate unidirectional cloth in a pseudo isotropic structure.

(P) Molding step (6 in the figure) Next, the carbon fiber base material in which two or more layers are laminated is subjected to a melting point of the first resin of −50 ° C. or higher or a flow starting temperature of −50 ° C. or higher. Preferably, it is heated to a temperature above the melting point of the first resin or above the flow starting temperature and pressurized to shape.

(Q) Base material adhering step (7 in the figure) Further, the shaped carbon fiber base materials are cooled to a temperature lower than the melting point of the first resin or lower than the flow starting temperature to bond the carbon fiber base materials to each other. To do.

By passing through these steps, not only the volume of the laminated carbon fiber base material 43 can be reduced, but also they are integrated, so that the preform 81 excellent in handleability can be obtained. . In addition, if necessary, a preform 8 made of a bonded carbon fiber base material.
1 may be taken out, or an injection step (S) described later (not shown) in which a third resin described below is directly injected without taking out the preform 81 made of the bonded carbon fiber base material ) May be passed. In this case, the preform molds 51 and 52 are used as molding dies.

FIG. 11 is a schematic view for explaining one embodiment of the method for manufacturing the composite material of the present invention. The composite material of the present invention is manufactured by a method including at least the following steps (R) to (T).

(R) Setting step (9 in the figure) The preform 81 manufactured by the above-mentioned method is used for the molding die 91,
Place at 92 to form a cavity.

(S) Injection step (10 in the figure) Next, a liquefied third resin 101, which will be described later, is injected into the cavity 102 through the injection port 93, and the third resin 101 is applied to the preform 81. Impregnate.

(T) Solidifying step (11 in the figure) Further, the third resin 101 is solidified (cured or polymerized) to obtain the composite material 111 of the present invention. Here, the third resin 1
When 01 is solidified, it is preferable to heat it in order to increase the solidification efficiency.

If necessary, the extraction step 12 for taking out the composite material 111 in which the third resin 101 is solidified may be carried out, and in order to further ensure the solidification of the third resin, the composite material 111 An after-curing (complete solidification) step (not shown) in which 111 is heated again to be solidified may be performed.

Further, in the above-mentioned (R) setting step 9, if the forming mold is composed of two molds including a male mold and a female mold 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.

FIG. 12 is a schematic view for explaining another aspect of the (R) setting step in the method for producing a composite material according to the present invention. As shown in FIG. 12, in the (R) setting step, the mold is either a male mold or a female mold (see FIG.
Among them, the use of the female mold 92) and the bag material 95 is preferable because the molding die cost can be reduced and the molding cost can be further reduced. As such a bag material,
For example, a film, a flexible rubber material, or the like can be used. Since the bag material is usually flexible, a plate (not shown) or the like for imparting rigidity to the surface on the bag material side can be used together. By using such plates together,
It is possible to achieve the same level of dimensional accuracy as when a mold is used on both sides.

Further, as shown in FIGS. 11 and 12,
In the (R) setting step, when the third resin 101 (not shown) is injected from the injection port 93 while maintaining the inside of the cavity 102 in a vacuum state by degassing with a vacuum pump or the like, the preform 81 It is preferable that the third resin 101 be easily impregnated into the resin, a higher quality composite material can be molded in a short cycle, and the molding cost can be further reduced.

The third resin used in the present invention is not particularly limited as long as it can solve the problems of the present invention, but is preferably a thermosetting resin in view of its moldability and mechanical properties. Those listed in the example of the first resin of are preferably used. However, the point different from the first resin is that when it is used for injection molding, it must be liquid at the injection temperature. It is preferable to use at least one selected from the group consisting of epoxy, phenol, vinyl ester, unsaturated polyester, cyanate ester and benzoxazine as the thermosetting resin having such properties because the object of the present invention can be easily achieved. A resin obtained by further adding an elastomer, a rubber component, a curing agent, a curing accelerator, a catalyst or the like to these resins can also be preferably used. Among them, epoxy or bismaleimide is preferable, and epoxy is particularly preferable, in order to achieve extremely high mechanical properties (particularly CAI, CHW) required for primary structural members of aircraft.

Here, since the roles of the third resin and the first resin and the second resin are different,
It is preferable to select in consideration of that point. That is, the third resin has excellent impregnation property (the resin viscosity is low at the injection temperature,
The gelling time is long) and the mechanical properties are excellent, and the first resin and the second resin which improve the handleability of the fabric and impart high mechanical properties are selected and used. It is preferable. Of course, in the first resin, the second resin, and the third resin, there is no limitation in using the same component as a part thereof, and it can be said that it is a preferable form from the viewpoint of compatibility between the two.

When the preform is impregnated with the third resin by injection molding, it is preferable that the third resin is in a liquid state and has a low viscosity because rapid impregnation can be achieved and the molding cycle can be shortened. Specifically, 40 at the injection temperature
The viscosity is preferably 0 mPa · s or less, more preferably 200 mPa · s or less. The injection temperature is 10
It is preferable that the temperature is 0 ° C. or lower because the injection equipment can be simplified.

Although the use of the composite material produced by the method of the present invention is not particularly limited, it has excellent mechanical properties (especially CA).
I, CHW), especially aircraft, automobiles,
Primary structural members, secondary structural members in ship transportation equipment,
When used as an exterior member or an interior member, the effect can be maximized.

[0085]

EXAMPLE A more specific example will be described below.

Example 1 First, a carbon fiber base material having a length of 30 m and a width of 1 m was manufactured by the following method.

Particles of epoxy resin containing a curing agent (flow starting temperature 90 ° C.) (average particle diameter 16 μm) and particles of aromatic polyamide copolymer resin (flow starting temperature 220 ° C.) (average particle diameter 49 μm) were made uniform. Mixed with the particulate first
Of resin was prepared.

Next, a substantially continuous carbon fiber bundle having a tensile elastic modulus of 294 GPa and a breaking strain energy of 58 MJ / m ³ was used as a warp, and a glass fiber yarn (Nitto Boseki Co., Ltd.) was used.
"ECE" 225 1/0 binder type DP)
As an auxiliary weft, a unidirectional fabric (plain weave, fabric thickness 0.
36 mm, carbon fiber basis weight 295 g / m ² , warp yarn density 2.8 yarns / cm, weft yarn density 3 yarns / cm, cover factor 98%) were woven.

Subsequent to the weaving, the above-mentioned particulate first resin was naturally dropped while being measured by an engraving roll and a doctor blade onto a continuously woven fabric, and was applied while being uniformly dispersed through a vibrating net. did. Incidentally, the coating amount of both the epoxy resin and the aromatic polyamide copolymer resin,
4 parts by weight (total 8 parts by weight) was added to 100 parts by weight of the woven fabric. Next, the fabric coated with the first particulate resin was heated to 120 ° C. or higher with a far infrared heater, and the aromatic polyamide copolymer resin was bonded with an epoxy resin.

Then, the carbon fiber base material was wound up by cooling to 60 ° C. or lower in the atmosphere. In this example, the process from the cloth making process to the cooling process was continuously performed online, and the processing speed was 0.3 m / min.

The obtained carbon fiber base material had a firm base material and was excellent in morphological stability. Further, it was also excellent in adhesiveness and shapeability even when laminating as described later. The carbon fiber substrate thickness was 0.44 mm.

Example 2 The same unidirectional fabric as in Example 1 was woven and wound in the same manner. The once-wound unidirectional woven fabric was drawn out, and the first resin was applied, adhered, and cooled in the same manner as in Example 1 to wind the carbon fiber base material. That is, in this example, the cloth making process and the coating process were discontinuously performed off-line.

Since the warp tension of the obtained carbon fiber base material was once released during the cloth making process, the looseness of the warp yarn (bubbling) was more noticeable than that of Example 1, but almost the same. It was a thing. Further, while the processing speed of the cloth making process of this example was the same as that of Example 1, the processing speed of the coating process could be 2 m / min, and the productivity of the carbon fiber base material was significantly superior to that of Example 1. .

Example 3 Particles (average particle diameter) of 50 parts by weight of an epoxy resin containing no curing agent (“Epicoat” 1004AF manufactured by Japan Epoxy Resin Co., Ltd.) and an aromatic polyamide copolymer resin (glass transition temperature 162 ° C.) Thirteen
Particles having a form in which 50 parts by weight of 100 μm) are melt-kneaded at 180 ° C. using a kneader and then frozen and pulverized to coat the aromatic polyamide copolymer resin with an epoxy resin containing no curing agent. A first resin having a shape of a circle was prepared (average particle diameter: 38 μm).

On the same unidirectional woven fabric as in Example 1, 10 parts by weight of 100 parts by weight of the woven fabric was applied while the first resin in particulate form was charged and uniformly dispersed with compressed gas. . Further, while the fabric coated with the resin particles was heated to 180 ° C. or higher with a far infrared heater, it was pressed by a metal roller subjected to a mold release treatment to bond the resin particles to the fabric. Then, it cooled similarly to Example 1, and wound up the carbon fiber base material.

The obtained carbon fiber base material was excellent in handleability as in Example 1. Further, the particulate resin was adhered more firmly than in Example 1, and the thickness of the carbon fiber substrate was smaller (0.38 mm). Furthermore, the resin particles were dispersed more uniformly than in Example 1, and the carbon fiber substrate was more excellent.

(Example 4) Polyether sulfone resin ("Sumika Excel" 5003P manufactured by Sumitomo Chemical Co., Ltd.)
Finely pulverized product) and epoxy resin (“KA-601” manufactured by Nippon Kayaku Co., Ltd.) 40% by weight are melt-kneaded in a twin-screw extruder to compatibilize the two and freeze-pulverized. Then, a particulate first resin was prepared (average particle diameter 12
4 μm, glass transition temperature 60 ° C.).

The same unidirectional woven fabric as in Example 1 was coated with this particulate first resin in the same manner as in Example 1 to produce woven fabric 10.
10 parts by weight was applied to 0 parts by weight. Further, while being heated to 180 to 200 ° C. with a far infrared heater, pressure is applied by a metal nip roller that has been subjected to a mold release treatment, and the particulate first
Resin was adhered to the unidirectional fabric. Then, it cooled similarly to Example 1, and wound up the carbon fiber base material.

The obtained carbon fiber reinforced substrate was excellent in handleability as in Example 1. Further, the particulate resin was more firmly bonded than in Example 1, and the thickness of the carbon fiber substrate was thin (0.37 mm). The air permeability of the carbon fiber base material was 24 cm ³ / cm ² · sec.

Example 5 Another unidirectional woven fabric was woven using the same warp yarn and auxiliary weft yarn as in Example 1. This fabric has a non-crimp structure and a fabric thickness of 0.24 mm,
Carbon fiber basis weight 193 g / m ² , warp yarn density 1.8 yarns / c
It is a woven fabric having m, a weft density of 1 yarn / cm, and a cover factor of 95%. As the auxiliary warp yarn, the same glass fiber yarn as that of the auxiliary weft yarn was used, and the auxiliary warp yarn was inserted alternately with the warp yarn (auxiliary warp yarn density 1.8 yarns / cm).

A carbon fiber reinforced substrate was prepared in the same manner as in Example 4 except that 100 parts by weight of the unidirectional woven fabric was coated with 14 parts by weight of the particulate first resin used in Example 4. Got

The carbon fiber reinforced substrate thus obtained was excellent in handleability as in Example 1. The carbon fiber base material has a thickness of 0.25 mm and air permeability of 72.0 cm ^3.
/ Cm ² · sec.

Example 6 A preform was produced using the carbon fiber base material produced in Examples 1, 3 to 5. That is, using a carbon fiber base material cut into a length of 340 mm and a width of 340 mm, Examples 1, 3, and 4 have a laminated structure [-4.
5 ° / 0 ° / + 45 ° / 90 °] twice, and Example 5 was repeated three times, and two pairs of each were used so that 90 ° layers face each other. A preform which was laminated (laminated in a series) (total of 16 layers in Examples 1, 3 and 4 and total of 24 layers in Example 5) was produced by the following method.

The carbon fiber base materials were laminated with the carbon fiber base materials being adhered to each other by the resin of particles by heating the carbon fiber base materials with an iron to 120 ° C. so that the carbon fiber base materials were cut into a predetermined size to have the above-mentioned laminated structure. After placing such a laminate on the surface of the molding die and applying a vacuum to the cavity sealed with the bag material (polyamide film) and the sealant to apply atmospheric pressure, the carbon fiber base materials of Examples 1 and 3 are 120 C., the substrates of Examples 4 and 5 were heated to 70.degree. C. and held for 1 hour. Then, while maintaining the vacuum state of the cavity, 60 in the atmosphere.
It was cooled to below ℃ and exposed to the atmosphere to obtain a preform. In such a preform, the layers were not disjointed, the morphological stability was high even during transportation, and the handleability was excellent.

(Example 7) Using the preform produced in Example 6, a composite material was produced by the following method. First,
A preform is placed on the surface of the molding die, a polyester fabric subjected to a release treatment as a peel ply, and an aluminum wire mesh as a resin diffusion medium are placed in that order, and they are used as a resin injection port with a bag material and a sealant. A vacuum suction port was provided and sealed to form a cavity. Then, the inside of the cavity was sucked from the vacuum suction port with a vacuum pump to a vacuum degree of about 0.8 kPa, and the temperature of the mold and preform was adjusted to 70 ° C.

After that, a liquid epoxy resin that had been defoamed in advance and was prepared as a third resin as a third resin (100 parts by weight of the following main liquid and 32 parts by weight of a hardening liquid (70 ° C.) was added. Viscosity by E-type viscometer at 250 m
Pa · 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 Resins, 20 parts by weight of "AK-601" manufactured by Nippon Kayaku Co., Ltd., Dainippon Ink and Chemicals 30 parts by weight of "Epiclon" HP-7200L manufactured by Kogyo Co., Ltd.,
And p-toluenesulfonic acid-n as a curing accelerator
-Propyl 1.4 parts by weight, curing liquid; 18.1 parts by weight of "Epicure" W manufactured by Japan Epoxy Resins Co., Ltd., 7.2 parts by weight of 3,3'-diaminodiphenyl sulfone manufactured by Mitsui Chemicals Fine Co., Ltd., Sumitomo Chemical Co., Ltd. "Sumicure" S (7.2 parts by weight) was injected from the resin injection port by atmospheric pressure. When the third resin reached the vacuum suction port, the resin injection port was closed and the injection was stopped.

After that, the third resin impregnated in the preform was cured by keeping the pressure at 130 ° C. for 2 hours while continuing to reduce the pressure from the vacuum suction port with a vacuum pump. After confirming that the third resin had cured to a demoldable state, each auxiliary material such as peel ply was removed, and the composite material was taken out from the molding die. Furthermore, in order to improve heat resistance, 180
After-curing was performed by holding at 2 ° C. for 2 hours.

When the composite material was inspected, pinholes and voids were not found anywhere, demonstrating that extremely good molding was performed. In addition, a test piece cut out from such a composite material to a length of 152 mm and a width of 102 mm was measured with a weight of 5.44 kg (12 lbs) and 6.67 kJ.
/ M (1500 in · lb / in) falling weight impact, then room temperature compressive strength (CAI, SACMA SRM 2R
-94) was measured, and it was possible to suppress the damaged area due to impact application to a small extent, and a very high CAI was expressed (Example 1; 228 MPa, Example 3; 248).
MPa, Example 4; 246 MPa, Example 5; 278M
Pa). The above result is a value obtained by dividing the average value of 4 samples by Vf and multiplying by 55 (Vf = 55% conversion).

(Embodiment 8) In Embodiment 6, as a laminated structure of preforms, Embodiments 1, 3 and 4 were laminated with 4 layers of [0 °], and Embodiment 5 was laminated with 6 layers. Example 7
SACMA SR for composite materials molded by
A test piece conforming to M1R-94 was placed in warm water at 70 ° C
Immersion for 4 days (wet heat treatment) and immediately measuring the compressive strength (CHW) at high temperature (82 ° C.) showed that the elastic modulus decrease of the resin due to water absorption could be suppressed to a minimum, and a very high CHW was developed (Examples). 1; 1046 MPa, Example 3; 103
3 MPa, Example 4; 981 MPa, Example 5; 960
Was MPa). The above results are obtained by dividing the average value of 5 samples by Vf and multiplying by 55 (Vf = 55% conversion).
Is.

(Comparative Examples 1 to 3) A carbon fiber substrate was prepared in the same manner as in Example 1, a preform was prepared in the same manner as in Example 6, and a composite material was prepared in the same manner as in Example 7, except that no particulate resin was used. Was manufactured and evaluated.

The carbon fiber base material of this comparative example, in which no resin was used, had no stiffness and was inferior in morphological stability.
Further, although the obtained preform had no adhesiveness between the carbon fiber base materials and was excellent in shapeability, it could not maintain its shape and was inferior in handleability. The mechanical properties of the obtained composite material are CAI of 159 MPa.
It was significantly inferior to the examples. The CHW was 1049 MPa, which was almost the same as that of each example.

[0112]

EFFECTS OF THE INVENTION According to the production method of the present invention, not only can a composite material having good resin impregnation and excellent mechanical properties (in particular, CAI and CHW) be obtained with high productivity,
A carbon fiber base material having excellent handleability such as shape stability, moldability, and tackiness when laminated, a preform laminated with the same, and a composite material obtained by impregnating the preform with a matrix resin. Can be provided.

Such composite materials are used for aircraft, automobiles,
It is particularly suitable for primary structural members of aircraft such as primary structural members, secondary structural members, exterior parts, interior parts or their parts in transportation equipment such as ships.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating one embodiment of a method for producing a carbon fiber base material of the present invention.

FIG. 2 is a schematic view illustrating another aspect of the method for producing a carbon fiber base material of the present invention.

FIG. 3 is a schematic view illustrating another aspect of the method for producing a carbon fiber base material of the present invention.

FIG. 4 is a schematic view illustrating another aspect of the method for producing a carbon fiber base material of the present invention.

FIG. 5 is a schematic view illustrating another aspect of the method for producing a carbon fiber base material of the present invention.

FIG. 6 is a perspective view illustrating an embodiment of the unidirectional fabric preferably used in the present invention.

FIG. 7 is a perspective view illustrating another aspect of the unidirectional woven fabric preferably used in the present invention.

FIG. 8 is a plan view of one embodiment of a carbon fiber substrate manufactured by the method of the present invention.

FIG. 9 is a plan view of an embodiment of a carbon fiber substrate manufactured by the method of the present invention.

FIG. 10 is a schematic view illustrating one embodiment of a method for manufacturing a preform of the present invention.

FIG. 11 is a schematic view illustrating one embodiment of a method for producing a composite material according to the present invention.

FIG. 12 (R) in the method for producing a composite material of the present invention
It is the schematic explaining another one aspect of a setting process.

[Explanation of symbols]

1: Fabrication step 11: Warp yarn bundle 11 'made of continuous carbon fibers constituting a woven fabric 11': Auxiliary warp yarn bundle made of continuous auxiliary fibers constituting a woven fabric 12: Weft yarn bundle 12 made of continuous carbon fibers constituting a woven fabric ': Auxiliary weft yarn bundle 13 consisting of continuous auxiliary fibers constituting a woven fabric 13: Heald 14: Reed 15: Rapier 16: Fabric 17: Fabric 1': Winding step 1 ": Drawing step 2: Application step 21: Hot roller 22 : Far infrared heater 2a: First resin 2b: Engraving roll 2c: Doctor blade 2d: Vibrating net 2e: Measuring machine 2f: Compressed gas 2g: Spray head 2h: Screw 2i: Gear pump 2j: Hot melt coater 2 ': Re Coating process 2'a: Second resin 2 ": Pressing process 23: Pressing roll 3: Cooling process 31: Cold roller 4: Winding process 41, 42, 43, 8 , 9A: Carbon fiber base material 6A, 7A: Unidirectional woven fabric 5: Laminating step 51: Preform type (male type) 52: Preform type (female type) 6: Molding step 7: Base material adhering step 8: Extraction step 81: Preform 9: Setting step 91: Mold (male) 92: Mold (female) 93: Inlet 94: Degas 95: Bag material (bag film) 96: Sealant 101: Third Resin 102: cavity 111: composite material

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 101: 00 C08L 101: 00 F term (reference) 4F072 AB09 AB10 AB28 AC06 AC08 AC10 AC12 AC13 AC14 AD08 AD11 AD13 AD23 AD38 AD43 AG02 AG03 AG16 AH02 AH04 AK02 AK06 AL02 AL04 4F204 AD02 AD16 AG01 AG03 AK04 AK07 AR06 AR08 EA03 EB01 EB02 EB11 EB22 EF01 EF05 EF23 EK07 EK09 EK15 EK15 EK24 4L048 AA03 CAA01 BA01 BA01 DAA06

Claims (22)

[Claims] 1. A method for producing a carbon fiber base material, which comprises at least the following steps (A) to (C): (A) A cloth-making process in which a tensile elastic modulus is 210 GPa or more, a breaking strain energy is 40 MJ / m ³ or more, and a cloth is formed using substantially continuous carbon fibers. (B) The first resin is added in an amount of 0.1 to 100 parts by weight of the cloth.
A coating step of coating and adhering to the surface of the fabric in the range of ˜20 parts by weight. (C) A cooling step in which the cloth to which the first resin is bonded is cooled to a temperature lower than the melting point of the first resin or lower than the flow starting temperature of the first resin. 2. A method for producing a carbon fiber base material, which comprises at least the following steps (E) to (H): (E) A fabric-making step of forming a fabric by using carbon fibers having a tensile elastic modulus of 210 GPa or more, a breaking strain energy of 40 MJ / m ³ or more, and substantially continuous. (F) The first resin is added in an amount of 0.1 with respect to 100 parts by weight of the cloth.
A coating step of coating and adhering to the surface of the fabric in the range of ˜20 parts by weight. (G) A second resin different from the first resin is added to the cloth to which the first resin is adhered in an amount of 0.1 to 100 parts by weight of the cloth.
A re-applying step in which 20 parts by weight is applied to the surface of the fabric and adhered thereto. (H) A cloth to which the first resin and the second resin are adhered,
A cooling step of cooling to a temperature below the melting point of the first resin or below the flow starting temperature of the first resin. 3. The method for producing a carbon fiber base material according to claim 1, wherein the first resin is 0.1 to 10 parts by weight with respect to 100 parts by weight of the cloth. 4. The method for producing a carbon fiber base material according to claim 1, wherein the cloth to be made is a unidirectional cloth. 5. The method for producing a carbon fiber base material according to claim 1, wherein the cloth to be made is a woven fabric. 6. The method according to claim 1, wherein after the fabric-making step of (A) or (E), the fabric is continuously subjected to the coating step of (B) or (F), respectively. 6. The method for producing a carbon fiber base material according to any one of 5 above. 7. The method for producing a carbon fiber base material according to claim 6, wherein the processing speed is 0.5 to 5 m / min. 8. The method for producing a carbon fiber base material according to claim 1, wherein a particulate resin is used as the first resin or the second resin. 9. The carbon according to claim 8, wherein the first resin or the second resin is weighed using a roll and a doctor blade, and is applied while being dispersed through a vibration net. A method for manufacturing a fiber base material. 10. The method for producing a carbon fiber base material according to claim 8, wherein the first resin or the second resin is applied while being charged and dispersed with a compressed gas. 11. A fabric coated with the first resin or the second resin is heated to a temperature not lower than the melting point of the first resin or not lower than the flow starting temperature of the first resin to obtain at least the first resin. And a cloth are adhered to each other.
11. The method for producing a carbon fiber base material according to any one of 10. 12. The method according to claim 1, further comprising (I) a pressurizing step of pressurizing the cloth coated with the first resin or the second resin at a temperature of room temperature or higher. A method for producing the carbon fiber base material described. 13. A far infrared heater and / or a hot roller is used as a device for heating to a temperature not lower than the melting point of the first resin or not lower than the flow starting temperature of the first resin. The method for producing a carbon fiber substrate according to. 14. The first resin or the second resin,
The method for producing a carbon fiber base material according to any one of claims 1 to 7, wherein the molten material is applied. 15. The first resin or the second resin,
The method for producing a carbon fiber base material according to any one of claims 1 to 7, wherein the dispersion or dissolution in water or a solvent is applied. 16. A method comprising: (J) a temporary winding step of winding the cloth after the cloth-making step of (A) or (E); and (B)
Alternatively, the method for producing a carbon fiber base material according to any one of claims 1 to 5, further comprising a (K) withdrawing step of withdrawing the once wound cloth before the (F) applying step. 17. The method according to claim 1, further comprising a winding step (L) of winding the cloth to which the first resin or the second resin is adhered, after the cooling step of (C) or (H).
17. The method for producing a carbon fiber base material according to any one of to 16. 18. A method of manufacturing a preform, comprising at least the following steps (O) to (Q). (O) A laminating step of laminating at least two layers of the carbon fiber base material produced by the method according to any one of claims 1 to 17. (P) The melting point of the first resin of the carbon fiber base material having two or more layers laminated is -50 ° C or higher or the flow starting temperature of the first resin is -50
A shaping step of heating to a temperature of ℃ or more and applying pressure to shape. (Q) A base material adhering step of adhering the carbon fiber base materials to each other by cooling the shaped carbon fiber base material to a temperature below the melting point of the first resin or below the flow starting temperature of the first resin. 19. A method for producing a composite material, comprising at least the following steps (R) to (T). (R) A setting step in which a preform manufactured by the method according to claim 18 is placed in a molding die to form a cavity. (S) A step of injecting the liquefied third resin into the cavity to impregnate the preform with the third resin. (T) A solidification step of solidifying the third resin. 20. The method for producing a composite material according to claim 19, wherein in the (R) setting step, the molding dies consist of two molds including at least a male mold and a female mold. 21. 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. 22. In the setting step of (R), the third resin is injected while maintaining a vacuum in a cavity formed between the molds or between the mold and the bag material. 22. The method for manufacturing the composite material according to any one of 21.