JP3991440B2 - Fiber reinforced plastic and method for molding fiber reinforced plastic - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention comprises carbon fiberFiber reinforced plasticMore specifically, it consists of tow-like thick carbon fiber yarnsOne-wayCarbon fiber weaveThingsThe present invention relates to the fiber reinforced plastic used and its molding method.
[0002]
[Prior art]
Carbon fiber has a low specific gravity, high tensile strength and high tensile modulus, and carbon fiber reinforced plastic (hereinafter referred to as CFRP) solidified with resin is a material with high specific strength and specific elastic modulus. is called.
[0003]
However, the conventional CFRP is made of, for example, thin carbon fiber yarns of 3,000 filaments, and the carbon fiber basis weight is 200 to 400 g / m in which the carbon fiber yarns are arranged in the warp direction and the transverse direction.²A thin bi-directional woven fabric is made by laminating a large number of prepregs impregnated with a resin in advance and then autoclaved to produce molded products. The field was limited to aircraft-related structural materials and premium sports equipment such as premium products, and it was difficult to expand into general industrial fields.
[0004]
A. Thin carbon fiber yarns have low carbon fiber productivity.
[0005]
B. Since the fabric is manufactured with thin yarns, the productivity of the fabric is lowered.
[0006]
C. Since the woven fabric is thin, in order to laminate a predetermined amount of carbon fibers, the number of laminated layers increases, and the labor of lamination increases.
[0007]
D. Since a prepreg process is required, the processing cost of a prepreg is added.
[0008]
E. An autoclave is required and a large capital investment is required.
[0009]
In particular, in order to reduce the cost of large molded products, using conventional carbon fiber woven fabrics, these are laminated in a mold, and a resin transfer molding method in which a room temperature curable resin is injected under pressure, or these are used. A so-called vacuum bag molding method is known in which a film is laminated on a mold and covered with a bag film, the inside of which is evacuated, and a room temperature curable resin is injected. Although this method significantly reduces the cost of CFRP due to the above D and E terms, the A, B and C terms make the CFRP product molded expensive.
[0010]
On the other hand, it is conceivable to use a carbon fiber woven fabric having a large carbon fiber basis weight using conventional carbon fiber yarns, but it has not been practically used due to the following problems.
[0011]
F. A two-way woven fabric in which carbon fibers are arranged in two directions, the warp direction and the weft direction, can be made into a woven fabric having a large carbon fiber basis weight, but the bending (crimp) of the woven yarn is increased by the crossing of the warp and weft. When FRP is used, the strength and modulus of elasticity decrease due to stress concentration.
[0012]
G. Although the woven fabric arranged in one direction does not cause a decrease in strength due to crimping, the carbon fiber yarns are arranged only in one direction, so increasing the carbon fiber basis weight of the fabric increases the fiber density and densely fills the fibers. Therefore, in resin molding methods such as resin transfer molding and vacuum bag molding, the flow of the resin is poor, it takes time to inject the resin, and the impregnation property of the resin into the carbon fiber fabric is deteriorated.
[0013]
[Problems to be solved by the invention]
  The present invention pays attention to such a current situation, and although the fabric has a large carbon fiber basis weight, it is excellent in resin fluidity and impregnation during molding, and excellent in mechanical properties when molded.One-wayCarbon fiber fabricBy usingThe object is to provide an inexpensive fiber-reinforced plastic with excellent mechanical properties. It is another object of the present invention to provide a method for molding a fiber reinforced plastic (hereinafter referred to as FRP) using the above-mentioned woven fabric.
[0014]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention basically has the following configuration.
  That is,The fiber reinforced plastic of the present invention is a fiber reinforced plastic obtained by reinforcing a laminated fiber base material with a resin, and at least one layer of the fiber base material includes:It consists of tow-shaped carbon fiber yarns, and the number of filaments of the carbon fiber yarns is 40,000 to 400,000.Or the yarn fineness is 25,000-350,000 denier, andUnidirectional carbon fiber fabric in which the carbon fiber yarns are arranged in the warp direction, and the auxiliary yarns are arranged in the weft direction, with a gap between the carbon fiber yarnsCharacterized by comprisingIt is.
  The fiber-reinforced plastic molding method of the present invention is a carbon fiber fabric made of tow-shaped carbon fiber yarns, and the number of filaments of the carbon fiber yarns is 40,000 to 400,000. The yarn fineness is 25,000 to 350,000 denier, the carbon fiber yarns are arranged in the warp direction, and the auxiliary yarns are arranged in the weft direction, and a gap is formed between the carbon fiber yarns. A unidirectional carbon fiber woven fabric is laminated on a molding die as a fiber base material and a medium for diffusing the resin in the surface direction is placed thereon, and then the fiber base material and the whole medium are Covering with a bag film, then vacuuming the interior covered with the bag film, diffusing a room temperature curable resin on the surface of the laminated fiber base material, and impregnating the fiber base material with the resin Is.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The carbon fiber yarn used in the present invention is preferably a carbon fiber yarn in which 40,000 to 400,000 multifilaments having a single fiber diameter of 5 to 15 microns converge to form a tow shape. The fineness of the strip is 25,000-350,000 denier.
[0016]
When the number of filaments of the carbon fiber yarn is 40,000 or less and the fineness of the yarn is 25,000 denier or less, the yarn becomes relatively thin, so that the carbon fiber constituting the yarn has a resin impregnation property. Although preferred in terms, the thickness of the yarn is reduced. Therefore, if the basis weight of the carbon fiber fabric is increased, the number of carbon fiber yarns to be used increases and it becomes difficult to provide a gap between the carbon fiber yarns. In molding methods such as resin transfer molding and vacuum bag molding, resin The flow becomes worse. Moreover, the cost reduction of the carbon fiber yarn is not expected. On the other hand, when the number of filaments of the carbon fiber yarn is 400,000 or more and the fineness of the yarn is 350,000 denier or more, the carbon fiber yarn becomes inexpensive and the thickness of the yarn becomes thick. Even if the fabric weight is increased, it is possible to provide a gap between the carbon fiber yarns. However, since the yarns become thicker, the distance to the center of the yarns increases and the resin advances from the periphery of the yarns. Impregnation is incomplete. The number of filaments is 40,000 to 400,000, and the fineness of carbon fiber yarn is 25,000 to 350,000 denier, more preferably, the number of filaments of carbon fiber yarn is 40,000 to 100,000, yarn If the fineness is 30,000 to 70,000 denier, a gap can be provided between the carbon fiber yarns. Therefore, even if the resin flows through resin transfer molding or vacuum bag molding, the entire laminate becomes thicker. The resin can be spread quickly and the impregnation of the resin from the periphery of the yarn can be completed.
[0017]
The gap between the yarns in the carbon fiber fabric of the present invention is preferably 0.2 to 2 mm. When the gap between the yarns is 2 mm or more, the weft thread is thin in the unidirectional woven fabric, so that the draping property of the woven fabric increases, and the woven fabric becomes soft and difficult to handle. In addition, since there are no fibers in the gap, when FRP is used, the surface of the FRP becomes uneven due to shrinkage of the resin during curing. On the other hand, when the gap between the yarns is 0.2 mm or less, the resin flow resistance to the gap between the yarns is increased, and the resin injection rate into the fiber substrate laminate is reduced.
[0018]
When the gap between yarns is 0.2 to 2 mm, when resin is injected into a fiber base material sealed in a mold or bag film, such as resin transfer molding and vacuum bag molding, This gap becomes the resin flow path, and the resin injection time is shortened, leading to an increase in molding efficiency.
[0019]
Such a carbon fiber yarn can be produced by, for example, subjecting a polyacrylonitrile fiber tow to flame resistance and carbonization, and then attaching and sizing a sizing agent. Since tow can be manufactured as a thick yarn, it becomes possible to improve the productivity in the manufacturing process of polyacrylonitrile fiber, flame resistance and carbonized carbon fiber, and to manufacture inexpensive carbon fiber yarn. is there.
[0020]
The carbon fiber of the present invention has a tensile strength according to JIS R7601 of 3 to 4 GPa and a tensile modulus of about 200 to 300 GPa, and 0.5 to 2% by weight in order to improve the weaving operation in the fabric manufacturing process. It is preferable to attach a sizing agent of a degree. In addition, when the carbon fiber yarns constituting the woven fabric are twisted, the converging part of the carbon fiber bundle due to the twisting impedes the resin impregnation, and therefore it is preferable that the carbon fiber yarn is non-twisted.
[0021]
In the present invention, if the carbon fibers composing the yarn are entangled, a gap can be provided between the carbon fibers by the crossing or entanglement of the carbon fibers, so that the carbon fiber yarn and the fabric become bulky, This is preferable because the carbon fiber yarn of the woven fabric can be easily impregnated with the resin. The degree of entanglement of this carbon fiber can be expressed by the hook drop value, and the hook drop value FD₍₁₅₎Is preferably 30 cm or less. Hook drop value FD₍₁₅₎Is 30 cm or more, the degree of entanglement of the fibers is small, and the impregnation of the resin is not improved. In addition, hook drop value FD₍₁₅₎Is 2 cm or less, the entanglement of the carbon fibers becomes large, the carbon fiber yarns and the woven fabric become bulky, the gaps between the carbon fibers are increased, and the resin is easily impregnated, but the bending of the carbon fibers is increased. When this is done, stress concentration occurs and the strength decreases. When the hook drop value is in the range of 2 to 30 cm, more preferably in the range of 2 to 10 cm, an appropriate resin impregnation property is provided, and when the FRP is used, the strength becomes high.
[0022]
However, the hook drop value is only an index for indicating the degree of entanglement, and even if it is difficult or impossible to directly measure the hook drop value, it is measured by other measuring means and the value is appropriately set. It suffices if the value falls within the above-mentioned numerical range when converted into a hook drop value by a method.
[0023]
Hook drop value FD₍₁₅₎Represents the degree of entanglement of the fibers of the carbon fiber yarn constituting the fabric, and can be represented by the free fall distance of the metal hook measured by the measuring device shown in FIGS.
[0024]
If the sizing agent is attached to the carbon fiber yarn, the free fall distance of the metal hook is affected by the amount and state of the sizing agent, so this measurement should be performed after completely removing the sizing agent. Do. For example, the sizing agent can be removed by heat treatment in a nitrogen atmosphere at 700 ° C. for 1 hour.
[0025]
Also, even if carbon fiber yarns are attached or impregnated with prepreg or CFRP resin, the free fall distance of the metal hook is affected or almost impossible to measure, so these resins can be removed completely. Make this measurement. For example, vinyl ester resin can be removed by heat treatment in a nitrogen atmosphere at 700 ° C. for 5 hours.
[0026]
Hook drop value FD of woven carbon fiber yarn₍₁₅₎Extract three woven fabrics with a width of 1,000 mm and a length of 1,000 mm, and from each fabric, loosen the warp yarns from each fabric so that no fluff is generated and no twist is added. Collect 000 mm carbon fiber yarn. A desizing process is performed so that the fiber arrangement state of the loose carbon fiber yarn is not disturbed, and the upper end is fixed to the apparatus by the upper clamp 104. Since the width of the yarn to be fixed, that is, the thickness of the yarn affects the hook drop value, the relationship between the width B (mm) of the yarn to be fixed and the yarn fineness D (denier) should be according to the following formula: The upper clamp 104 was fixed so that the thickness of the yarn was uniform.
[0027]
Thread width B = 4 × 10^-Four× D
Next, in a state where a load of 4 mg / denier is applied to the lower end, the lower clamp 105 is fixed in the vertical direction so that the grip interval is 950 mm so that twist is not applied.
[0028]
Next, a weight (from the upper end of the hook 102) in which a weight 103 is attached to a metal hook 102 (wire diameter: 1 mm, radius: 5 mm) with a cotton thread 106 at the center in the width direction of the carbon fiber yarn 101 with the upper and lower ends fixed. Hook the metal hook 102 with a distance of 30 mm) to the upper end of the weight 103 so that the distance from the lower end of the upper clamp to the upper end of the metal hook 102 is 50 mm. The distance from the position of 50 mm to the upper end of the metal hook 102 at the dropping position) is measured. The weights of the metal hook 102 and the cotton thread 106 are made as light as possible, and the total weight of the metal hook 102, the cotton thread 106 and the weight 103, that is, the weight is 15 g. Hook drop value FD₍₁₅₎Is measured 10 times for one warp of a woven fabric, and is expressed as an average value of n = 30. The metal hook 102 may fall to the position of the lower clamp 105, but the free fall distance at that time is regarded as 900 mm. For this purpose, the metal hook 102 hits the lower clamp 105 but the cotton thread 106 and the weight 103 need not be caught. As shown in FIG. It is necessary to provide a space. The measurement is carried out after the fabric is left for 24 hours in an environment of a temperature of 25 ° C. and a relative humidity of 60%, and then in an environment of a temperature of 25 ° C. and a relative humidity of 60%.
[0029]
The carbon fiber fabric of the present invention has a bulk density of 0.65 g / cm.^ThreeThe following is preferable. Bulk density is 0.65 g / cm^ThreeBelow, the carbon fiber yarns and fabrics become bulky, the gaps between the carbon fibers increase, and the resin is easily impregnated, and resin impregnation is possible not only in resin transfer molding and vacuum bag molding but also in hand layup molding. Become.
[0030]
In the present invention, the bulk density V refers to a value calculated by the following calculation formula.
[0031]
V = w / (t × A)
Where t: fabric thickness (cm)
A: Fabric area (cm²)
w: Carbon fiber weight (g) in the area A of the fabric
In addition, the measuring method of the thickness of a textile fabric used the thickness measuring device of JISR7602 5.6 term according to the dial gauge method. However, the load was 3 kPa, 5 sheets of fabric were overlapped, the value after 20 seconds had elapsed after the load was applied, and the value was divided by the number of fabrics to obtain the thickness per sheet. In order to minimize the influence of the weft yarn as the auxiliary yarn on the thickness of the fabric, the fabrics were overlapped so that the positions of the weft yarns of the fabric to be overlapped were shifted from each other.
[0032]
Specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a unidirectional carbon fiber woven fabric according to an embodiment of the present invention. In the figure, 2 is a carbon fiber yarn, and a large number of carbon fiber yarns are arranged in parallel in the warp direction. This is a so-called unidirectional fabric in which the weft-direction auxiliary yarns 3 are interlaced with carbon fiber yarns.
[0033]
FIG. 2 shows another embodiment of the carbon fiber woven fabric of the present invention, in which the carbon fiber yarns 2 having substantially no bend are aligned in a straight direction parallel to each other and in a sheet shape. The yarn group 2 of the weft auxiliary yarn 3 is located on both sides of the sheet surface of the formed yarn group B, and the weft auxiliary yarn group and the warp direction auxiliary yarn 4 parallel to the carbon fiber yarn group C Is a unidirectional carbon fiber fabric that forms a woven structure and integrally holds the yarn group. Since such a woven fabric does not have bending in the carbon fiber yarns in the warp direction, stress does not concentrate even when molded and CFRP, and the strength becomes high.
[0034]
The auxiliary yarn used in the present invention is not intended to bear a load when it becomes an FRP, but is used for maintaining the shape of the woven fabric. Thin yarns are preferable compared to yarns. In particular, when it is extremely thin compared to 100-500 denier and carbon fiber yarns, and the weft yarn density is about 0.5-8 yarns / cm, the constraint of the carbon fiber yarns by the weft auxiliary yarns is weakened. , Resulting in a bulky fabric. The auxiliary yarn preferably has a dry heat shrinkage at 150 ° C. of 0.1% or less from the viewpoint of dimensional stability of the woven fabric and prevention of shrinkage due to heating during the crushing treatment. Examples of fibers constituting such an auxiliary yarn include carbon fibers, glass fibers, and polyaramid fibers.
[0035]
In the unidirectional woven fabric, the basis weight of the carbon fiber is 400 to 1,500 g / m.²Since the number of laminated layers may be small if it is about, the labor of lamination of the fiber base material at the time of shaping | molding will decrease, and it will lead to labor saving of shaping | molding. Carbon fiber basis weight is 400 to 700 g / m²If it is, the fabric is reasonably soft and the fabric basis weight is relatively light, so it is possible to make the fabric conform to complicated shapes such as corners when laminated, and room temperature curing type with resin viscosity of 2 to 7 poise Resin can be sufficiently impregnated with resin even by impregnation roller application in ordinary hand lay-up molding.
[0036]
In addition, since the carbon fiber yarn of the present invention has a thick carbon fiber yarn, the number of yarns constituting the fabric is reduced. Accordingly, the number of crossing points with the weft yarn is reduced, and the carbon fiber yarn is frayed when cut, resulting in poor workability.
[0037]
Therefore, in the unidirectional carbon fiber fabric of the present invention, as shown in FIGS. 1 and 2, the low melting point polymer 5 extending linearly or in the length direction of the auxiliary yarn in the weft direction is attached, It is preferable that the low melting point polymer is a so-called fine woven fabric in which yarns perpendicular to each other, that is, carbon fiber yarns in the warp direction and auxiliary yarns in the warp direction are bonded at the intersection. 1 and 2 show an example in which the low melting point polymer is attached to the auxiliary yarn in the transverse direction, but it may be attached to the carbon fiber yarn in the warp direction and / or the warp direction auxiliary yarn, Alternatively, it may be attached to the carbon fiber yarn in the warp direction and / or the warp direction auxiliary yarn and the warp direction auxiliary yarn.
[0038]
The abraded fabrics are cut and laminated on the mold in resin transfer molding and vacuum bag molding, etc., but at the time of cutting, fraying of the yarn can be prevented and the workability of molding is greatly improved. To improve.
[0039]
Further, if the adhesion amount of the low melting point polymer is large, it impedes resin impregnation or lowers the mechanical properties of CFRP.²The following is preferred. However, 0.5g / m²If it is less than 0.5, the awakening effect will fade, so 0.5-6 g / m²Is preferred.
[0040]
In the case of unidirectional carbon fiber fabric, if these low-melting polymers are attached to thin auxiliary yarns in large quantities, the auxiliary yarns basically do not carry reinforcement, but the starting point of breakage starts from the auxiliary yarns. In order to prevent this, the adhesion amount of the low melting point polymer is preferably 40% by weight or less of the auxiliary yarn.
[0041]
The low melting point polymer used in the present invention is usually selected from nylon, copolymer nylon, polyester, copolymer polyester, vinylidene chloride, vinyl chloride, and polyurethane. Among them, copolymer nylon is particularly preferably used because it can melt the polymer at a low temperature, has a strong adhesive force, and can achieve the expected effect with a small amount of use.
[0042]
The fiber reinforced plastic of the present invention may be one in which all of the reinforced fiber base material is laminated with a single layer or multiple layers of the carbon fiber fabric of the present invention and impregnated with a resin to be fiber reinforced. At least one layer of the material is the carbon fiber woven fabric of the present invention, which can be combined with a substrate made of other reinforcing fibers such as glass fibers and polyaramid fibers.
[0043]
The resin used for the fiber reinforced plastic of the present invention is, for example, epoxy resin, unsaturated polyester resin, thermosetting resin such as vinyl ester resin or phenol resin, nylon resin, polyester resin, ABS resin, polyethylene resin, polypropylene resin, polychlorinated resin. Thermoplastic resins such as vinyl resin, polyether ether ketone resin and polyphenylene sulfide resin.
[0044]
In the fiber reinforced plastic of the present invention, the fiber base material is composed of thick tow-like yarns and has a high basis weight, but uses a carbon fiber woven fabric with gaps between carbon fiber yarns. The resin has good fluidity and impregnation, and is excellent in mechanical properties and inexpensive.
[0045]
Specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a unidirectional carbon fiber woven fabric according to an embodiment of the present invention. In the figure, 2 is a carbon fiber yarn, and a large number of carbon fiber yarns are arranged in parallel in the warp direction. This is a so-called unidirectional fabric in which the weft-direction auxiliary yarns 3 are interlaced with carbon fiber yarns.
[0046]
FIG. 2 shows another embodiment of the carbon fiber fabric of the present invention, in which carbon fiber yarns 2 having substantially no bend (crimp) in the vertical direction are unidirectionally parallel to each other and in sheet form. Are located on both sides of the sheet surface of the yarn group b, and the weft auxiliary yarn 3 and the weft auxiliary yarn group and the warp direction auxiliary yarn 4 parallel to the carbon fiber yarn group. This is a unidirectional carbon fiber woven fabric in which the yarn group C forms a woven structure and integrally holds the yarn group. Since such a woven fabric does not have a bend (crimp) in the carbon fiber yarn in the warp direction, the stress does not concentrate even if it is molded and CFRP, and the strength becomes high.
[0047]
The auxiliary yarn used in the present invention is not intended to bear a load when it becomes an FRP, but is used for maintaining the shape of the woven fabric. Thin yarns are preferable compared to yarns. In particular, when it is extremely thin compared to 100-500 denier and carbon fiber yarns, and the weft yarn density is about 0.5-8 yarns / cm, the constraint of the carbon fiber yarns by the weft auxiliary yarns is weakened. , Resulting in a bulky fabric. The auxiliary yarn preferably has a dry heat shrinkage at 150 ° C. of 0.1% or less from the viewpoint of dimensional stability of the woven fabric and prevention of shrinkage due to heating during the crushing treatment. Examples of fibers constituting such an auxiliary yarn include carbon fibers, glass fibers, and polyaramid fibers.
[0048]
In the unidirectional woven fabric, the basis weight of the carbon fiber is 400 to 2,000 g / m.²Since the number of laminated layers can be reduced to a small extent, the labor of laminating the fiber base during molding is reduced, and the gap between the threads becomes the resin flow path during molding, reducing the resin injection time. As a result, the molding efficiency is improved.
[0049]
The woven fabric of the present invention can form FRP by a conventionally known method, but in particular, a large molded product can be produced at low cost by the resin transfer molding method or the vacuum bag molding method. Preferably used.
[0050]
  Next, an FRP molding method according to the present invention will be described. FIG. 3 is a cross-sectional view of an embodiment illustrating the FRP molding method of the present invention. In FIG.MoldingOn the mold 6, a predetermined number of carbon fiber fabrics 7 of the present invention are laminated as a fiber base material in a predetermined direction, and a sheet to be removed by peeling after the resin is cured, a so-called peel ply 8 is laminated thereon. Then, a medium 9 for diffusing the resin over the entire surface of the fiber base is placed thereon. Around the fiber base material, a vacuum pump air suction port 10 is attached, and a plurality of porous materials such as woven fabric are laminated and stretched around as an edge breather 11,ThemCover the whole with a bag film 12 and wrap around the bag film with a butyl rubber or silicone rubber sealant 13 to prevent air leakage.MoldingAdhere to the mold. A discharge port 14 for the resin injected from the resin tank is attached to the upper part of the bag film, and is adhered with a sealant 13 so that air does not leak from the attachment portion of the discharge port. The resin tank is filled with a room temperature curable thermosetting resin in the form of a syrup at room temperature with a predetermined amount of curing agent. Next, the inside including the fiber base material covered with the bag film with a vacuum pump is evacuated to a vacuum pressure of about 700 to 760 Torr, and then the valve 15 is released to inject the resin. Since the inside of the bag film is in a vacuum state and the flow direction of the resin is smaller in the surface direction of the medium than in the thickness direction of the fiber substrate, the resin first spreads over the entire surface of the medium, and then the fiber substrate Impregnation in the thickness direction proceeds. In this method, the distance that the resin must flow is the thickness of the fiber base laminate, so that the resin impregnation is completed very quickly. The vacuum pump is preferably operated at least until the impregnation of the resin is completed, and the bag / film is preferably kept in a vacuum state. After completion of resin impregnation, the valve is closed and left at room temperature to cure the resin. After the resin is cured, the peel ply is peeled off to remove the medium, bag and film,MoldingType(Hereafter, it may be simply called a type)The FRP molded product is obtained by removing from the mold.
[0051]
An example of the medium 9 used in the present invention is shown in FIG. 4, and the medium transmits the vacuum pressure in the bag to the fiber base material, and the injected resin passes through the gap between the medium, and the top surface of the fiber base material on the medium side. The resin is distributed throughout. That is, when the resin is injected into the medium located between the bag film and the peel ply, in FIG. 4, the injected resin flows through the gap of the group A bar 16 in contact with the bag film, and the direction of the bar 16 and B Since the resin flows in the direction of the bar 17 through the gap between the bars 17 having a rectangular cross section of the group, the resin diffuses over the entire surface. Further, since the force applied to the bar 16 can be transmitted to the bar 17, the vacuum pressure can be transmitted to the fiber base material. Although the thickness of a bar is not specifically limited, 0.2-2 mm is preferable. The width of the gap is preferably 0.2 to 2 cm. Specific examples of the medium are mesh sheets made of polypropylene, polyethylene, polyester, polyvinyl chloride, metal, etc., for example, mesh resin films, woven fabrics, nets, knitted fabrics, etc. Several of these can be used in layers.
[0052]
Note that the above describes the case where the medium is installed on one surface of the upper surface of the fiber base laminate, but when the fiber base laminate is thick, the medium is installed on the lower and upper surfaces of the fiber base laminate. It is also possible to impregnate the resin from both sides of the material laminate.
[0053]
The molding method described above largely falls within the category of vacuum bag molding method, but differs from the conventional vacuum bag molding method in that the resin is diffused over the entire surface of the fiber base laminate simultaneously with resin injection. It is suitable for use in molding a large FRP molded product.
[0054]
  In addition, on the molding material having a groove to be a resin flow path on the surface, laminated so as to contact the fiber base material,ThemCover the whole with a back film, then vacuum the inside covered with the back film, diffuse the resin from the groove of the molding material in contact with the fiber base material, and room temperature curable thermosetting on the laminated fiber base material The fiber base material and the molding material can also be integrated while impregnating the conductive resin. According to this method, a sandwich structure having FRP as a skin material and a plate-like plate as a core material can be easily formed. According to this method, a fiber reinforced plastic structure integrated with a plate-like plate using FRP as a skin material can be easily formed. FIG. 8 is a cross-sectional view for explaining the FRP molding method of the present invention. In FIG.MoldingOn the mold 6, a required number of blocks 19 in which a predetermined number of blocks of carbon fiber fabric 7 as a fiber base material are wound around a molding material 18 are arranged, and the whole is covered with a bag film 12 so that air does not leak. Seal material 13 around bag / filmMoldingAdhere to the mold 6. An example of the molding material is shown in FIG. 9, and grooves 20 serving as resin flow paths are provided on the upper surface C, the lower surface D, the side surface E, and the front surface F of the molding material.
[0055]
When the inside of the bag film covered with the vacuum port is evacuated by the vacuum pump and the resin is poured from the discharge port, the resin is provided on the upper and lower surfaces and side surfaces of the molding material from the grooves with low flow resistance. After reaching the entire surface, the fiber base material is then impregnated with resin.
[0056]
Next, when the resin is cured at room temperature, the groove of the molding material is filled with the matrix resin, and the groove of the molding material and the matrix resin are bonded together. At the same time, the fiber reinforced plastic and the matrix resin are bonded to each other. The body is obtained.
[0057]
According to the fiber reinforced plastic structure of the present invention, the bonding area between the fiber reinforced plastic and the molding material is not only the surface of the fiber reinforced plastic and the molding material but also the groove of the molding material and the matrix resin. Thus, the integration of the fiber reinforced plastic and the molding material becomes strong.
[0058]
The cross-sectional shape of the groove of the molding material is rectangular, trapezoidal, hemispherical, etc., and the cross-sectional shape and cross-sectional dimension can be appropriately determined depending on the fluidity of the resin and the degree of adhesion between the fiber reinforced plastic and the molding material. In particular, when the trapezoidal shape has a wedge shape with respect to the molding material, the fiber-reinforced plastic and the molding material are more firmly joined.
[0059]
If the molding material used in the present invention is an organic or inorganic foam, it is preferably used because the resulting molded article becomes lighter. However, a resin plate that is not foamed, an inorganic plate, a metal plate, It may be wood or the like. Examples of the organic or inorganic foam include polyurethane, polystyrene, polyethylene, polypropylene, PVC, silicone, isocyanurate, phenol, acrylic resin foam, lightweight cellular concrete, silicate calcium carbonate foam and carbonate carbonate foam.
[0060]
The compression strength of the molding material is 1.0 kgf / cm.²The above is preferable. Compressive strength is 1.0kgf / cm²If it is less than the above, it is not preferable because the vacuum pressure is reduced when vacuum bagging is performed and the molding material is crushed.
[0061]
Although the carbon fiber woven fabric of the present invention has a large fiber basis weight per sheet, there is a gap between the carbon fiber yarns of the woven fabric. Since the resin spreads over the entire surface of the material laminate and the resin impregnation proceeds in the thickness direction of the fiber substrate laminate, not only is the labor of lamination reduced, but the resin is completely impregnated. The injection time is reduced, and workability is improved.
[0062]
In addition, the fiber base material used for this invention does not need to be the carbon fiber fabric of this invention, and what is necessary is just to use at least 1 layer or more. Other fiber substrates may be, for example, ordinary carbon fiber woven fabrics, or other reinforcing fibers such as woven fabrics made of glass fibers or polyaramid fibers, chopped strand mats, and continuous strand mats. The sheets in which these reinforcing fiber yarns are arranged in parallel are laminated at 0 ° (length direction of the fiber base material), 90 ° (width direction of the fiber base material) and ± 45 ° (diagonal direction of the fiber base material), This may be a multi-axis stitched fabric that is stitched with stitch yarns such as glass fibers, polyester fibers, and polyaramid fibers.
[0063]
In particular, when the combination of fiber base materials is the unidirectional carbon fiber woven fabric and the multiaxial stitched fabric of the present invention, the direction in which the FRP structure needs to be reinforced is borne by the unidirectional carbon fiber woven fabric, When the load is applied by a multiaxial stitched fabric, these fiber base materials are straight fibers without bending between carbon fiber yarns for forming the fabric and other reinforcing fiber yarns and without bending. Since it is oriented and the fiber volume content increases, it has excellent mechanical properties when it is made FRP. Further, since the carbon fibers or other reinforcing fibers are not clamped by the crossing of the yarns, the resin can be sufficiently impregnated even in the vacuum bag molding of the present invention, and the impregnation speed can be increased. .
[0064]
The resin used for molding of the present invention is a thermosetting resin such as an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, or a phenol resin, which is a room temperature curable liquid at room temperature. The viscosity of the resin used is preferably a low-viscosity resin from the viewpoint of resin impregnation properties and impregnation speed, and is about 0.5 to 10 poise, more preferably less than 0.5 to 5 poise. Among them, vinyl ester resin can make the resin low viscosity and can increase the resin elongation by 3.5 to 12%, so that it not only has excellent moldability but also has high strength and impact resistance. It is also preferable because it is excellent.
[0065]
The peel ply used in the molding of the present invention is a sheet that is peeled off and removed from the FRP after the resin is cured, but it is necessary to allow the resin to pass through, such as nylon fiber fabric, polyester fiber fabric, glass fiber fabric, etc. It is. In addition, nylon fiber woven fabric and polyester fiber woven fabric are preferably used because they are inexpensive, but in order to prevent the oil agent and sizing agent used in manufacturing these fabrics from being mixed into the FRP resin, scouring is performed, Further, in order to prevent shrinkage due to heat generated by the room temperature curable resin, it is preferable to use a heat-set woven fabric.
[0066]
The edge breather used in the molding of the present invention needs to be able to pass air and resin, and a mat made of nylon fiber fabric, polyester fiber fabric, glass fiber fabric, nylon fiber, or polyester fiber may be used. it can.
[0067]
Further, the bag film used in the molding of the present invention needs to be airtight, and is a nylon film, a polyester film, a PVC film or the like.
[0068]
【Example】
Example 1
A multifilament carbon fiber yarn having a filament number of 70,000 and a fineness of 52,000 denier is used as a warp, an auxiliary yarn made of 608 denier glass fiber is used as a weft, and the warp density is 0.87 / cm. Carbon fiber weight per unit area of 503 g / m in a flat structure in which weft density is 2 / cm and carbon fibers are arranged in one direction²Was prepared. In the squeezing process, the weft of the glass fiber yarn is inserted with the low-melting 50 denier copolymer nylon yarn, and after inserting the weft yarn, the copolymer nylon yarn is attached with a far infrared heater attached on the loom. The method was performed by melting and bonding the carbon fiber yarn and the glass fiber yarn. A tow-shaped yarn was sometimes used as a warp, and a gap between carbon fiber yarns of the obtained woven fabric could be secured, which was 1.2 mm.
[0069]
Next, using the above carbon fiber fabric, molding was performed by the molding method of the present invention described below.
[0070]
Made of two carbon fiber fabrics A of the present invention having a width of 100 cm and a length of 100 cm and glass fibers having a width of 100 cm and a length of 100 cm, the fiber basis weight is 450 g / m²Three chopped strand mats were prepared.
[0071]
First, the carbon fiber woven fabric A of the present invention (hereinafter referred to as carbon fiber woven fabric A is referred to as carbon fiber woven fabric A) as a reinforcing fiber base material on a molding die coated with a release agent.₁It is called. ), And then, three chopped strand mats are laminated one by one so that the end of the mat and the end of the fabric are aligned, and the carbon fiber woven fabric of the present invention (hereinafter referred to as the following) This carbon fiber fabric A is converted to carbon fiber fabric A.₂It is called. ) Was laminated, and a total of five fiber substrates were laminated.
[0072]
A nylon filament woven fabric as a peel ply is placed on a fiber base, and a thickness of 1.0 mm, a mesh opening size of 2.6 × 2.6 mm, and a mesh opening ratio (overall area) as a medium. Two mesh sheets having a mesh opening area ratio of 100 to 62) were placed so as to cover the entire surface of the fiber substrate.
[0073]
A glass fiber fabric as an edge breather was stretched around the laminated fiber base material so as to have the same thickness as that of the base material laminate, and a suction port of a vacuum pump was attached.
[0074]
The whole was covered with a bag film made of nylon film, and the bag film, the mold and the suction port were bonded with a sealing material so that a vacuum state could be maintained.
[0075]
A resin discharge port was provided at the center of the bag film, and the film and the discharge port were bonded together with a sealing material so that a vacuum state could be maintained.
[0076]
    Next, after the inside of the bag film covered with a vacuum pump was evacuated to 755 Torr, the valve was opened and a room temperature curable vinyl ester resin having a resin viscosity of 3 poise was injected. The resin immediately diffused over the entire surface of the laminated base material in the resin diffusion medium. Next, the resin flows from the carbon fiber fabric A1 and through the gap between the carbon fiber yarns of the carbon fiber fabric A1 to the chopped strand mat layer in the thickness direction of the laminated substrate, and the resin is impregnated between the fibers. The time required for impregnating the laminated base material with the resin was 16 minutes.
  After curing the resinFiber reinforced plastic obtained by demolding from moldWhen the plate was cut and the cross section was observed, the resin was completely impregnated because it was impregnated with the resin in a vacuum state.
[0077]
(Comparative Example 1)
For comparison, a multifilament carbon fiber yarn having a filament number of 12,000 and a fineness of 7,200 denier is used as a warp yarn, an auxiliary yarn made of 608 denier glass fiber is wefted, and the warp yarn density is 6.20. Carbon fiber weight per unit area of 496 g / m in a plain structure in which carbon fibers are arranged in one direction with a weft / cm, weft density of 2 / cm²A carbon fiber fabric B was prepared. There was almost no gap between the carbon fiber yarns of the obtained woven fabric, and it was 0 mm.
[0078]
Only the carbon fiber woven fabric is changed from the woven fabric A to the woven fabric B, and the others are the same as the embodiment (the woven fabric B₁Is textile A₁In addition, weaving B₂Is textile A₂(Corresponding to each). The fabric B in the upper part of the laminated base material, although the resin is immediately diffused to the entire surface of the laminated base material in the resin diffusion medium.₂In addition, since the fabric has a large carbon fiber basis weight and almost no gap between the carbon fiber yarns, the resin does not flow easily into the chopped strand mat layer, and the fabric B is laminated at the bottom.₁The resin did not flow sufficiently until, and gelation of the resin started 50 minutes after the start of resin injection, and the molding failed.
[0079]
【The invention's effect】
  As explained above, the present inventionUnidirectionality used inThe carbon fiber woven fabric is composed of tow-like thick carbon fiber yarns, and there is a gap between the carbon fiber yarns of the woven fabric, although the fiber basis weight per sheet is large. According to the above, since the resin spreads over the entire surface of the fiber base laminate where the resin easily flows and the resin impregnation proceeds in the thickness direction of the fiber base laminate, not only the labor of the lamination is reduced, Impregnation is performed completely, and the resin injection time is reduced, so that workability is improved.
[0080]
Further, the fiber reinforced plastic of the present invention is composed of a tow-like thick carbon fiber yarn, but since it is easily impregnated with a resin, it is inexpensive and has excellent mechanical properties, so that FRP can be obtained.
[0081]
  In addition, according to the FRP molding method of the present invention, a bulky carbon fiber woven fabric is used, and in vacuum bag molding, the resin is diffused over the entire surface, or the resin is provided by grooves provided in the molding material. Since it is diffused over the entire surface, the resin impregnation property is good and the resin impregnation time can be reduced, so that an FRP molded product can be manufactured at a low cost.
[Brief description of the drawings]
FIG. 1 shows a unidirectional carbon fiber fabric according to an embodiment of the present invention.
FIG. 2 shows an example embodiment of a unidirectional reinforcing fabric of the present invention having warp direction assist yarns.
FIG. 3 is a cross-sectional view of one embodiment illustrating a method for molding FRP of the present invention.
FIG. 4 is a perspective view of a resin diffusion medium.
FIG. 5 is a perspective view of a hook drop value measuring apparatus.
FIG. 6 is an enlarged partial front view of a hook drop value measuring apparatus.
FIG. 7 is a partial perspective view of a hook drop value measuring apparatus.
FIG. 8 is a cross-sectional view of another embodiment for explaining the FRP molding method of the present invention.
FIG. 9 is a schematic perspective view illustrating a molding material.
[Explanation of symbols]
  1: Cross section of carbon fiber yarn
  2: Carbon fiber yarn
  3: Auxiliary thread
  4: Warp direction auxiliary thread
  5: Awakening agent
  6:MoldingType
  7: Carbon fiber fabric
  8: Peel ply
  9: Medium
10: Suction port
11: Edge breather
12: Bag film
13: Sealing material
14: Discharge port
15: Valve
16: Group A bar
17: Group B bars
18: Molding material
19: Block in which carbon fiber fabric is wrapped around the molding material
20: Groove
101: Carbon fiber yarn
102: Metal hook
103: Weight
104: Upper clamp
105: Lower clamp
106: Cotton yarn

Claims (11)

A fiber reinforced plastic obtained by reinforcing a laminated fiber base material with a resin, wherein at least one layer of the fiber base material comprises a tow-like carbon fiber yarn, and the number of filaments of the carbon fiber yarn is 40. , 000～400,000 present der Luke, or a thread strip fineness of 25,000～350,000 deniers, and, arranged in the direction vertical is the carbon fiber yarns and auxiliary yarns A fiber-reinforced plastic, characterized in that it is composed of a unidirectional carbon fiber fabric that is arranged in the transverse direction and has a gap between the carbon fiber yarns . In the unidirectional carbon fiber fabric, fiber reinforced plastic according to claim 1, basis weight of said carbon fibers are characterized by a 450~1,500g / m ^2. In the unidirectional carbon fiber woven fabric, filaments number of the carbon fiber thread is 40,000-100,000 present, a yarn fineness of 30,000 to 70,000 deniers, the basis weight of the carbon fiber 400~700g The fiber reinforced plastic according to claim 1 , wherein the fiber reinforced plastic is / m ² . In the unidirectional carbon fiber woven fabric, the carbon fiber yarns constitute a yarn group without substantially bending, and the weft direction auxiliary yarn group intersecting the carbon fiber yarn group on both sides of the yarn group. And the weft direction auxiliary yarn group and the warp direction auxiliary yarn group parallel to the carbon fiber yarn group form a woven structure to hold the carbon fiber yarn group together. The fiber-reinforced plastic according to any one of claims 1 to 3 . The fiber-reinforced plastic according to any one of claims 1 to 4 , wherein in the unidirectional carbon fiber fabric, a gap between the carbon fiber yarns is 0.2 to 2 mm . In the unidirectional carbon fiber fabric, carbon and carbon fiber yarns and / or vertical direction auxiliary yarns, lateral auxiliary yarns of claims 1 to 5, characterized in that they are bonded together at their intersections The fiber reinforced plastic in any one . Consists in claim 1 to molding material and fiber-reinforced plastic other than the fiber-reinforced plastic according to any one of 6, and the molding material is integrated with the matrix resin forming the fiber reinforced plastic and fiber reinforced plastic, and fiber A fiber reinforced plastic structure, wherein the matrix resin is also filled in a groove provided in a molding material on the reinforced plastic side. It is a carbon fiber woven fabric made of tow-like carbon fiber yarns, and the number of filaments of the carbon fiber yarns is 40,000 to 400,000, or the yarn fineness is 25,000 to 350,000 denier. A unidirectional carbon fiber fabric in which the carbon fiber yarns are arranged in the warp direction and the auxiliary yarns are arranged in the weft direction, and there is a gap between the carbon fiber yarns. After laminating at least one layer on a mold and placing a medium for diffusing the resin in the surface direction on it, the entire fiber substrate and medium were covered with a bag film, and then covered with a bag film. A method for molding a fiber reinforced plastic, characterized in that the inside is evacuated, a room temperature curable resin is diffused on the surface of the laminated fiber base material, and the fiber base material is impregnated with the resin. It is a carbon fiber woven fabric made of tow-like carbon fiber yarns, and the number of filaments of the carbon fiber yarns is 40,000 to 400,000, or the yarn fineness is 25,000 to 350,000 denier. A unidirectional carbon fiber fabric in which the carbon fiber yarns are arranged in the warp direction and the auxiliary yarns are arranged in the weft direction, and there is a gap between the carbon fiber yarns. And then laminating at least one layer of the fiber base material on a mold on which a medium for diffusing in the plane direction is placed, and further placing the medium thereon, the fiber base material and the entire medium are then used as a bag film. Then, the interior covered with the bag film is evacuated, the room temperature curable resin is diffused on the surface of the laminated fiber base material, and the fiber base material is impregnated with the resin. Plastic molding method. It is a carbon fiber woven fabric made of tow-like carbon fiber yarns, and the number of filaments of the carbon fiber yarns is 40,000 to 400,000, or the yarn fineness is 25,000 to 350,000 denier. A unidirectional carbon fiber fabric in which the carbon fiber yarns are arranged in the warp direction and the auxiliary yarns are arranged in the weft direction, and there is a gap between the carbon fiber yarns. And at least one layer of the fiber base material is laminated so as to be in contact with the groove on the molding material having a groove serving as a resin flow path on the surface, and the whole of the fiber base material, the molding material and the medium are further laminated. Covered with back film, then vacuumed inside, covered with back film, diffused resin from groove of molding material in contact with fiber base material, room temperature curable thermosetting resin on laminated fiber base material Fiber substrate and molding material while impregnating Method for producing a fiber-reinforced plastic, characterized in that to conjugated. The method for producing a fiber-reinforced plastic according to claim 10 , wherein the molding material is a foam.

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