JP2022068616A - Reinforced fiber base material for resin injection molding, reinforced fiber laminate for resin injection molding and fiber reinforced resin - Google Patents

Abstract

To provide a reinforced fiber base material and a reinforced fiber laminate with excellent handling properties (especially, form stability) as well as high productivity of a fiber reinforced resin with good matrix resin impregnation and excellent mechanical properties such as impact resistance and mechanical properties at high temperature.SOLUTION: A reinforced fiber base material for resin injection molding comprises a resin material, which is a semi-aromatic polyamide containing a terephthalic acid component, disposed on at least one side surface of a reinforced fiber assembly selected from [1]: a reinforced fiber yarn, [2]: a group of reinforced fiber yarn consisting of parallel strands of reinforced fiber yarn, and [3]: a reinforced fiber fabric comprising [1] or [2].SELECTED DRAWING: Figure 1

Description

The present invention relates to a reinforcing fiber base material, a reinforcing fiber laminate, and a fiber reinforced resin composed thereof.

Fiber reinforced plastic (FRP), which is made by impregnating reinforced fibers with a matrix resin, has been mainly used for aerospace, space, and sports applications because it satisfies the required characteristics such as excellent mechanical properties and weight reduction. An autoclave molding method is known as a typical production method for these. In such a molding method, a prepreg in which a group of reinforced fiber bundles is impregnated with a matrix resin in advance is laminated on a molding die and heated and pressed by an autoclave to form an FRP. The use of prepreg has the advantage of obtaining extremely reliable FRP, but has the problem of high manufacturing cost.

On the other hand, examples of the molding method having excellent FRP productivity include resin injection molding such as a resin transfer molding method (RTM). The RTM molding method is performed by laminating a reinforcing fiber base material composed of a group of dry reinforcing fiber bundles not pre-impregnated with a matrix resin on a molding die and injecting a liquid and low-viscosity matrix resin. This is a molding method for molding FRP by impregnating and solidifying a matrix resin.

The resin injection molding method is excellent in the productivity of FRP, but since the matrix resin needs to have a low viscosity, it has sufficient mechanical properties as compared with the FRP molded from the high viscosity matrix resin used for the prepreg. In some cases, it could not be demonstrated.

As a solution to the above, as disclosed in Patent Document 1 and Patent Document 2, for example, an intermediate layer in which a unidirectional layer of carbon fiber having a specified basis weight and a thermoplastic fiber web (nonwoven fabric) having a specified thickness are combined. Materials have been proposed. However, although it is disclosed that certain thermoplastic properties can be exhibited when these thermoplastic fiber webs are used, some thermoplastic fiber webs have low heat resistance, so that the high temperature mechanical properties of FRP are exhibited. Was not fully expressed in some cases.

Special Table 2012-506499 Gazette Japanese Patent Publication No. 2008-517812

The present invention solves the problems of the prior art. Specifically, the present invention produces a fiber-reinforced resin having good impregnation property of a matrix resin and excellent mechanical properties such as impact resistance and high temperature mechanical properties. It is intended to provide a reinforcing fiber base material and a reinforcing fiber laminate which are not only well obtained but also excellent in handleability (particularly, morphological stability). Further, the present invention is intended to provide a fiber reinforced resin obtained from such a reinforced fiber base material and a reinforced fiber laminate.

The present invention employs the following means in order to solve such a problem. That is,
(1) [1]: Reinforcing fiber thread, [2]: Reinforcing fiber thread group formed by arranging reinforcing fiber threads in parallel, [3]: Reinforcing fiber composed of [1] or [2] It is a reinforcing fiber base material in which a resin material is arranged on at least one side surface of a reinforcing fiber aggregate selected from any of fabrics, and the resin material is a semi-aromatic polyamide containing a terephthalic acid component. A characteristic reinforcing fiber base material for resin injection molding.
(2) The reinforcing fiber base material for resin injection molding according to (1), wherein the resin material has a porous shape.
(3) The reinforcing fiber base material for resin injection molding according to (1) or (2), which has the resin material in the range of 1 to 20% by weight with respect to the reinforcing fiber base material.
(4) The reinforcing fiber for resin injection molding according to any one of (1) to (3), wherein the reinforcing fiber thread group is in the form of a sheet in which a plurality of reinforcing fiber threads are arranged in parallel. Base material.
(5) The reinforcement for resin injection molding according to any one of (1) to (3), wherein the reinforcing fiber yarn group is in the form of a sheet arranged in parallel by an automated fiber placement device. Fiber substrate.
(6) Reinforcing fiber threads having a fineness extending in a direction intersecting with a group of reinforcing fiber threads in which the reinforcing fiber aggregates are aligned in parallel in one direction and a reinforcing fiber thread. The reinforcing fiber base material for resin injection molding according to any one of (1) to (3), which is a unidirectional fabric composed of an auxiliary fiber thread group having a fineness of 1/5 or less of the above.
(7) The reinforcing fiber aggregate is a bidirectional woven fabric composed of the reinforcing fiber thread group arranged in one direction and the reinforcing fiber thread group arranged in one direction in different directions. The reinforcing fiber base material for resin injection molding according to any one of (1) to (3).
(8) At least two or more layers of the reinforcing fiber yarn group arranged in one direction and the reinforcing fiber yarn group arranged in a different direction are cross-laminated, and the fineness of the reinforcing fiber cloth is increased. The reinforcing fiber base material for resin injection molding according to any one of (1) to (3), which is a stitch fabric sutured and integrated by a group of auxiliary fiber threads which is 1/5 or less of the reinforcing fiber threads.
(9) A reinforcing fiber laminate for resin injection molding containing the reinforcing fiber base material for resin injection molding according to any one of (1) to (8) as the reinforcing fiber.
(10) The reinforcing fiber laminate for resin injection molding according to (9), which is integrated by heat fusion or stitching.
(11) Fiber reinforcement containing the reinforcing fiber base material for resin injection molding according to any one of (1) to (8) or the reinforcing fiber laminate for resin injection molding according to (9) or (10) as the reinforcing fiber. resin.
Is.

According to the present invention, as described in detail below, a reinforced fiber base material and a reinforced fiber laminate having not only excellent morphological stability but also excellent resin impregnation property during RTM molding can be obtained, and post-molding resistance It is possible to obtain FRP having excellent impact resistance and heat resistance.

It is a schematic sectional drawing explaining one aspect of the reinforcing fiber base material in this invention. It is a schematic side view which shows one aspect of the manufacturing apparatus of the reinforcing fiber base material in this invention. It is a schematic perspective view which shows one aspect of the reinforcing fiber thread group in this invention. It is a schematic perspective view which shows one aspect of the unidirectional woven fabric as a reinforcing fiber aggregate in this invention. It is a schematic perspective view which shows one aspect of the bidirectional woven fabric as a reinforcing fiber aggregate in this invention. It is a schematic perspective view which shows one aspect of the stitch cloth as a reinforcing fiber aggregate in this invention.

Hereinafter, examples of embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view illustrating an aspect of the reinforcing fiber base material 11 in the present invention. The reinforcing fiber base material 11 shown in this figure is one in which the resin material 13 is arranged on one side of the reinforcing fiber aggregate 12 and then bonded and integrated.

The reinforcing fiber base material 11 is a reinforcing fiber aggregate 12 selected from any of a reinforcing fiber thread, a reinforcing fiber thread group, or a reinforcing fiber cloth composed of a reinforcing fiber thread or a reinforcing fiber thread group. It is important to have the resin material 13 on at least one side surface. By allowing the resin material 13 to be present on at least one side surface, morphological stability such as the width and fiber orientation of the reinforcing fiber base material 11 can be improved, or a sheet-shaped reinforcing fiber group composed of a group of reinforcing fiber threads can be improved. It is possible to improve the handleability of the material 11 when it is transported.

Further, it is possible to impart adhesiveness between the reinforcing fiber aggregates 12 when obtaining a laminated body (preform) in which the reinforcing fiber base material 11 or the reinforcing fiber aggregate 12 described later is laminated, or the preform is appropriate. It is possible to improve the handleability of the preform, such as being able to impart rigidity and imparting a morphological stabilizing effect such as preventing misalignment of the reinforcing fibers in the preform.

In particular, the resin material 13 can secure a space for flowing and diffusing the matrix resin described later between the layers of the reinforcing fiber aggregate 12 (giving the plastic deformability between the layers of the reinforcing fiber aggregate 12 by the matrix resin). Further, when the resin material 13 acts as a stopper for cracks generated between the layers of the reinforcing fiber aggregate 12, it is possible to suppress damage between the layers of the reinforcing fiber aggregate 12 when an impact is received, and particularly excellent mechanical properties. (Especially, the compression strength after impact: CAI) can be achieved. In addition, the resin material 13 serves as a spacer to secure a flow path of the matrix resin between the layers of the reinforcing fiber aggregate 12, which not only facilitates impregnation of the matrix resin when subjected to resin injection molding. The impregnation rate is also increased, and the effect of being more excellent in the productivity of FRP is also exhibited.

The resin material 13 may be adhered to the reinforcing fiber aggregate 12 and may be present at least on one side surface of the reinforcing fiber aggregate 12, and may be present inside the reinforcing fiber aggregate 12 (penetrates into the reinforcing fiber thread). May be. It is preferable that 50% by weight or more, more preferably 70% by weight or more thereof is unevenly distributed on the surface of the reinforcing fiber aggregate 12 for the above-mentioned reason. Further, a binder component may be contained for the purpose of adhering the resin material 13 and the reinforcing fiber bundle 12, and for example, a thermoplastic resin having a lower softening point (melting point or glass transition temperature Tg) than the resin material 13 or a thermosetting resin. It is also possible to use.

Further, the form of the resin material 13 is preferably porous. In the present invention, the porous shape means a shape having holes in the thickness direction on the plane, and in the case of such a shape, the matrix resin and the air flow path are formed in the thickness direction of the reinforcing fiber base material 11. Not only can it be secured, but because there is a connection in the plane direction, the width stability is improved when the reinforcing fiber threads are used, and the sheet-shaped reinforcing fiber base material 11 made of the reinforcing fiber threads is handled during transportation. It is possible to improve the properties and the morphological stability of the base material when the reinforcing fiber yarn group or the cloth is used. Examples of the porous resin material 13 include a non-woven fabric, a mat, a net, a mesh, a woven fabric, a knitted fabric, a short fiber group, a perforated film, and a porous film. Among them, the non-woven fabric, the mat or the mesh is preferable because it can be obtained at a low price and the matrix resin and the air flow path are formed in the plane direction, so that the above effect is highly exhibited. When the resin material 13 is a non-woven fabric, the morphology of the constituent fibers includes long fibers and short fibers, which are produced by methods such as melt blow, spunbond, airlaid, carding, and papermaking, but are not particularly limited. Further, as a sub-component, a binder component for binding the fibers to each other may be contained. The fiber diameter of the constituent fibers is preferably 1 μm or more and less than 100 μm, more preferably 5 μm or more and less than 80 μm, and further preferably 10 μm or more and less than 60 μm. If the fiber diameter is less than 1 μm, the surface area of the resin material becomes large, which may hinder the flow of the resin in the resin impregnation step described later, which is not preferable. Further, when the fiber diameter is 100 μm or more, the thickness between the layers of the reinforcing fiber base material when FRP is used becomes large, and the fiber volume content (Vf) decreases, which is not preferable.

The resin material 13 used in the present invention is preferably 1 to 20% by weight of the reinforcing fiber base material 11. It is preferably 2 to 18% by weight, more preferably 3 to 16% by weight. By arranging the resin material 13 in the above range, the morphological stability of the reinforcing fiber base material 11 is brought about, and it becomes possible to obtain the reinforcing fiber base material 11 having excellent handleability. If it is less than 1% by weight, not only the handleability of the reinforcing fiber base material 11 is lowered, but also the effect of improving the mechanical properties (particularly CAI) is reduced, which is not preferable. On the other hand, if it exceeds 20% by weight, the volume content of the reinforced fiber when it is made into FRP may become too low, and the heat resistance, chemical resistance and compressive strength of FRP may decrease, which is not preferable.

It is important that the resin material 13 is a semi-aromatic polyamide containing a terephthalic acid component, which has many advantages such as heat resistance, high rigidity, chemical resistance, and low water absorption. Examples of the semi-aromatic polyamide containing terephthalic acid include polyamide 6T, polyamide 9T, polyamide 10T, polyamide 6T / 6, polyamide 6T / 12, polyamide 6T / 66, polyamide 6T / 6I, and polyamide 66 / 6T / 6I. Of these, those having a long methylene chain portion such as polyamide 9T and polyamide 10T are preferable from the viewpoint of water absorption and impact resistance. Such a resin material 13 can form a layer having high toughness between FRP layers, and can not only enhance mechanical properties (particularly CAI and ILSS [interlayer shear strength]), but also improve chemical resistance and water absorption resistance. It is possible to obtain a fiber-reinforced composite material which is excellent, especially excellent in compression characteristics at high temperature and water absorption.

Examples of the semi-aromatic polyamide containing no terephthalic acid component include semi-aromatic polyamides containing an isophthalic acid component. However, since most of these are amorphous polymers, the semi-aromatic polyamide containing a terephthalic acid component can be used. In comparison, chemical resistance and water absorption resistance may be inferior.

Further, if the resin material 13 has a low affinity for the matrix resin of FRP, peeling may occur at the interface between the resin material 13 and the matrix resin, and the effect of improving the mechanical properties may not be satisfactorily obtained. Therefore, the absolute value of the solubility parameter difference between the resin material 13 and the matrix resin is preferably 5 or less, preferably 3 or less. The solubility parameter of the resin material 13 is obtained by the following equation (1). The method is described in "Osamu Fukumoto (1988)" Polyamide Resin Handbook "Nikkan Kogyo Shimbun."

here,
M: Molecular weight ρ: Density ΔH: Interaction between amide groups T: Temperature.

The solubility parameter of the matrix resin is determined by the value of the repeating unit of the polymer at a temperature of 25 ° C. determined by the Fedors method. The method is described in F.I. Fedors, Polym. Eng. Sci. , 14 (2), 147 (1974).

The reinforcing fiber yarn in the present invention is a multifilament yarn, which is a glass fiber yarn, an organic (aramid, PBO, PVA, PE, etc.) fiber yarn, a carbon fiber (PAN-based, pitch-based, etc.) yarn, and the like. Since carbon fiber has excellent specific strength and specific elastic modulus and hardly absorbs water, it is preferably used as a reinforcing fiber for aircraft structural materials and automobiles.

The reinforcing fiber yarn used in the present invention is preferably 3,000 to 50,000 filaments, and particularly preferably 12,000 to 24,000 filaments from the viewpoint of handleability. The form of the reinforcing fiber yarn is not particularly limited, but it is preferably a non-twisted yarn having excellent stability in the width and thickness of the yarn, and more preferably an open fiber yarn having an excellent fiber orientation.

Here, the reinforcing fiber base material in the present invention is [1]: reinforcing fiber threads, [2]: a group of reinforcing fiber threads in which reinforcing fiber threads are arranged in parallel, or [3] reinforcing fiber threads or. It is important that it consists of a reinforcing fiber aggregate selected from any of the reinforcing fiber fabrics composed of the reinforcing fiber yarn group.

First, [1]: The reinforcing fiber base material 21 made of the reinforcing fiber threads is produced, for example, by using the apparatus illustrated in FIG. 2. Specifically, the reinforcing fiber thread 22 drawn out from the bobbin 20 is opened by the fiber opening unit 201, adjusted to a desired width by the width regulating roller 202, and then slit into a desired width in advance (preferably a resin material 23). Is created by superimposing a porous resin material), heating it with a heater 203, and crimping it with a press roll 204. The fiber opening unit 201 is composed of a vibrating roller or the like, and includes a mechanism for applying vibration in the vertical direction or the horizontal direction perpendicular to the traveling direction of the reinforcing fiber thread 22. Further, the fiber opening unit 201 may be provided with a heater (not shown) for softening the sizing agent adhering to the surface of the reinforcing fiber thread 22. At this time, assuming that the thread width of the reinforcing fiber thread 22 drawn from the bobbin 20 is w0, the width of the reinforcing fiber thread 22 after opening is widened to w1 (w0 <w1), and then by the width regulating roller 202. The width is adjusted to w2 (w1> w2). It is preferable to adjust w2 according to the basis weight required for the reinforcing fiber base material 21. Further, in order to improve the width accuracy of the reinforcing fiber base material 21, it is preferable that the press roll 204 has a grooved structure.

The reinforcing fiber base material 21 produced by such an apparatus has good stability in width and basis weight, and is also excellent in fiber orientation, so that it can contribute to improvement of mechanical properties (particularly compressive strength) of FRP. Further, it is preferable to arrange the resin material 23 on both sides of the reinforcing fiber thread group because the morphological stability of the reinforcing fiber base material 21 is further improved.

Next, [2]: The reinforcing fiber base material 21 composed of the reinforcing fiber yarn group has a plurality of bobbins in the apparatus exemplified in FIG. 2, for example, in the same manner as the method for producing the reinforcing fiber base material consisting of the reinforcing fiber yarn 22. It is created by multiplying by 20 and pulling out a plurality of reinforcing fiber threads 22 while aligning them in parallel. Here, "aligning in parallel" means aligning the adjacent reinforcing fiber threads 22 so that they do not substantially intersect or intersect with each other, and preferably, the two adjacent reinforcing fiber threads are aligned by 100 mm. When approximated to a straight line within the range of length, the angles formed by the approximated straight line are aligned so as to be 5 ° or less, more preferably 2 ° or less. Here, approximating the reinforcing fiber thread 22 to a straight line means forming a straight line by connecting the starting point and the ending point of 100 mm. Further, the adjacent reinforcing fiber threads 22 may be spaced apart from each other at a certain interval according to the required basis weight of the reinforcing fiber base material 21, or may be overlapped with each other. When separated by a certain interval, the interval is preferably 200% or less of the width of the reinforcing fiber threads 22, and when overlapping, 100% of the width of the reinforcing fiber threads 22 may be overlapped. It is preferable that the reinforcing fiber yarn group pulled out while being drawn in parallel in this way passes through the fiber opening unit to uniformly distribute the basis weight in the width direction. Further, the reinforcing fiber base material 21 made from the reinforcing fiber thread group can be slit to an arbitrary width if necessary.

[3] The reinforcing fiber fabric composed of the reinforcing fiber threads or the reinforcing fiber threads group will be described later.

Further, as the reinforcing fiber base material 21 using the reinforcing fiber thread 22 and the reinforcing fiber thread group, an automated fiber placement (AFP) or an automated tape layup (ATL) device is preferably used. Such a device is used for the purpose of reducing the disposal rate of the reinforcing fiber base material 21 and automating the laminating process, but since the width and fiber orientation after placement are strictly required, the morphological stability of the reinforcing fiber base material 21 is important. Become. Here, since the porous resin material 23 used in the present invention has a porous shape, it is excellent in width stability and morphological stability due to the connection in the plane direction, and therefore can be suitably used for AFP and ATL.

Further, as another aspect of the reinforcing fiber yarn group in the present invention, there is also a sheet-like one arranged in parallel by AFP or ATL. FIG. 3 shows one aspect of the reinforcing fiber yarn group used in the present invention, in which the reinforcing fiber yarn 32 is supplied by the AFP head 300 and is aligned and arranged in parallel. A reinforcing fiber base material can be obtained by arranging a porous resin material (not shown) so as to be superposed on the reinforcing fiber thread group 31 and heat-adhering it with a far-infrared heater or the like. Since the sheet-shaped reinforcing fiber thread group 31 aligned and arranged by AFP or ATL is not restricted in the direction intersecting the fiber direction, there is a problem that the form of the reinforcing fiber thread group 31 collapses during transportation. By arranging and adhering the porous resin material to the problem, a binding force in the direction intersecting the fiber direction is generated, and the problem of transportation can be solved. Further, when the reinforcing fiber threads 32 are aligned and arranged by AFP or ATL, the distance between the reinforcing fiber threads 32 is preferably 0.5 to 2 mm. If the interval is less than 0.5 mm, the resin impregnation property at the time of RTM molding may not be sufficient. If the interval exceeds 2 mm, when a plurality of reinforcing fiber base materials are laminated, the upper reinforcing fibers fall between the lower reinforcing fiber threads 32, causing undulations in the thickness direction and mechanical properties (particularly compression). Strength) may decrease.

Next, as the reinforcing fiber cloth composed of [3] reinforcing fiber threads or a group of reinforcing fiber threads, woven fabrics (unidirectional, bidirectional, multiaxial), knitted fabrics, braids, and unidirectionally aligned. Examples thereof include a woven sheet (one-way sheet) and a multi-axis sheet in which two or more layers of unidirectional sheets are stacked. Such a reinforcing fiber aggregate may be a combination of a plurality of such reinforcing fiber aggregates by various joining means such as stitch yarn, knotting yarn, sackcloth, and resin such as a binder. In particular, when used as a structural (particularly primary structure) member of a transport device (particularly an aircraft), a unidirectional sheet, a unidirectional woven fabric, or a multiaxial sheet (particularly stitch-joined) is preferable.

FIG. 4 is a schematic perspective view showing one aspect of the unidirectional woven fabric 41 as the reinforcing fiber cloth used in the present invention. Reinforcing fiber threads 42 and warp auxiliary threads 43 are arranged in the length direction of the unidirectional woven fabric 41, that is, in the warp direction, and weft auxiliary threads 44 thinner than the reinforcing fiber threads 42 are arranged in the weft direction to assist the warp. It is a unidirectional woven fabric in which the yarn 43 and the weft auxiliary yarn 44 are interlaced and have the weaving structure shown in FIG. The auxiliary yarn 43 preferably has low shrinkage, and examples thereof include glass fiber yarn, aramid fiber yarn, carbon fiber yarn, and the like, and the fineness (weight per unit length) of the auxiliary yarn is reinforced fiber. It is preferably 1/5 or less of the thread. If it exceeds 1/5, the auxiliary yarn becomes thicker, so that the auxiliary yarn crimps the reinforcing fiber threads, resulting in a slight decrease in the strength of the reinforcing fiber when FRP is used. On the other hand, from the viewpoint of morphological stability and production stability of the reinforcing fiber aggregate, the fineness of the auxiliary yarn is preferably 0.05% or more of that of the reinforcing fiber yarn. When the fineness is in the above range, the decrease in strength is minimized, and the gaps between the reinforcing fiber threads 42 formed by the warp auxiliary yarns during molding serve as resin flow paths, and the impregnation of the matrix resin can be promoted, which is preferable.

FIG. 5 is a schematic perspective view showing one aspect of the bidirectional woven fabric 51 as the reinforcing fiber cloth used in the present invention. The reinforcing fiber threads 52 are arranged in the length direction of the bidirectional woven fabric 51, that is, in the warp direction, the reinforcing fiber threads 53 are arranged in the weft direction, and the warp threads 52 and the weft threads 53 are interlaced, and the weave shown in FIG. It is a bidirectional woven fabric with a texture.

FIG. 6 is a schematic perspective view showing one aspect of the stitch fabric 61 as the reinforcing fiber fabric used in the present invention. From the lower surface of the stitch fabric 61, a large number of reinforcing fiber threads are first arranged in parallel in the diagonal direction with respect to the length direction a to form a + α ° layer 62, and then a large number of reinforcing fibers are reinforced in the width direction of the reinforced fabric. The fiber threads are arranged in parallel to form the 90 ° layer 63, and then a large number of reinforcing fiber threads are arranged in parallel in the diagonal direction to form the −α ° layer 64, and then in the length direction of the reinforcing cloth. A large number of reinforcing fiber threads are arranged in parallel to form a 0 ° layer 65, and four layers having different arrangement directions are laminated, and these four layers are stitched and integrated with the stitch thread 66. There is. Examples of the sewing structure formed by the stitch thread 66 in integrating the stitches include single ring stitching and 1/1 tricot knitting. The material of the stitch thread can be selected from polyester resin, polyamide resin, polyethylene resin, vinyl alcohol resin, polyphenylene sulfide resin, polyaramid resin, and compositions thereof. Of these, polyester resin and polyamide resin are preferable. From the viewpoint of the shapeability of the fabric, it is preferable to use a processed yarn of spandex (polyurethane elastic fiber), polyamide resin or polyester resin. The fineness of the stitch thread is preferably 1/5 or less of that of the reinforcing fiber thread in order to suppress the crimp of the reinforcing fiber thread. Further, from the viewpoint of morphological stability and production stability of the reinforcing fiber aggregate, it is preferably 10 dtex or more, more preferably 30 dtex or more. Further, from the viewpoint of formability in the preforming step described later, it is preferable that the stitch thread has elasticity. In FIG. 6, the aggregate of the reinforcing fibers whose cross-sectional shape is shown in an elliptical shape is one thread, and it seems that the stitch threads 66 are arranged between the reinforcing fiber threads, but the stitch threads 66 are It is randomly inserted into the reinforcing fiber thread, and the aggregate of the reinforcing fibers shown in an elliptical shape is formed by the restraint of the stitch thread 66.

Here, the structure of the reinforcing fiber of the multi-axis stitch fabric 61 shown in FIG. 6 has been described as a four-layer structure of + α ° layer / 90 ° layer / −α ° layer / 0 ° layer, but the structure is not limited to this. not. For example, two layers consisting of 0 ° layer / 90 ° layer, + α ° layer / −α ° layer, 0 ° layer / + α ° layer, + α ° layer / 0 ° layer / −α ° layer, + α ° layer / −α Three layers consisting of ° layer / 0 ° layer, 0 ° layer / + α ° layer / 0 ° layer / -α ° layer / 90 ° layer / -α ° layer / 0 ° layer / + α ° layer / 0 ° Like the layer, it may include four directions of 0 °, + α °, −α °, and 90 ° so as to include many 0 ° layers. Further, it may contain any of 0 °, + α °, −α °, and 90 °. The bias angle α ° is preferably 45 ° from the viewpoint of laminating stitch fabrics in the length direction of the FRP and effectively performing shear reinforcement with reinforcing fibers.

The preferred basis weight per layer of the reinforcing fiber base material in the present invention is in the range of 50 to 800 g / m ² . It is more preferably in the range of 100 to 500 g / m ² , and even more preferably in the range of 120 to 300 g / m ² . If it is less than 50 g / m ² , the number of laminated sheets for obtaining a predetermined thickness of FRP increases, and the workability of molding is poor, which is not preferable. Further, if the texture per layer is small, a gap is formed between the reinforcing fiber threads in the layer, the reinforcing fiber volume content Vf becomes partially non-uniform, and when molded, the reinforcing fiber volume content is partially non-uniform. Where the Vf is large, the FRP becomes thick, and when the reinforcing fiber volume content Vf is small, the FRP becomes thin, resulting in an FRP having an uneven surface. In such a case, if the reinforcing fiber yarn is thinly spread by a vibrating roller or air jet injection just before weaving, before the integrated processing with the stitch thread, and / and after the reinforcing fabric processing, the reinforcing fiber is spread over the entire surface of the reinforcing fabric. It is preferable because FRP having a uniform volume ratio and a smooth surface can be obtained. Further, if it exceeds 800 g / m ² , the impregnation property of the matrix resin deteriorates, which is not preferable.

Next, the reinforcing fiber laminate in the present invention will be described. Prior to FRP molding, a plurality of reinforcing fiber base materials in the present invention are laminated until a desired thickness is reached to form a reinforcing fiber laminated body. In the present invention, it is preferable that the reinforcing fiber laminate is integrated by heat fusion or stitching in order to impart handleability and morphological stability.

Further, the reinforced fiber laminate in the present invention is given a three-dimensional shape to the carbon fiber laminated base material by using a shaping mold, a jig, or the like according to the form of the target carbon fiber reinforced resin molded body. It can also be a preform with a fixed shape. In particular, when the molding die has a three-dimensional shape, by doing so, it is possible to easily suppress the occurrence of fiber disorder and wrinkles during mold clamping or resin injection / impregnation.

Next, the FRP of the present invention will be described. The FRP of the present invention is obtained by impregnating the above-mentioned reinforcing fiber laminate with a matrix resin. The matrix resin is solidified (cured or polymerized) as needed. Preferred examples of such a matrix resin include, for example, a thermosetting resin, a thermoplastic resin for RIM (Reaction Injection Molding), and the like, among which epoxy resin, phenol resin, vinyl ester resin, etc., which are suitable for resin injection molding, are used. It is preferably at least one selected from unsaturated polyester resin, cyanate ester resin, bismaleimide resin and benzoxazine resin.

Further, since the FRP of the present invention has excellent mechanical properties and is lightweight, its use is as a primary structural member, a secondary structural member, an exterior member or an interior member in any of transportation equipment of aircraft, automobiles and ships. Is preferable.

Next, a method for forming an FRP using a reinforcing fiber base material in the present invention will be described.

Among the reinforcing fiber base materials in the present invention, the reinforcing fiber base material composed of the reinforcing fiber threads and the reinforcing fiber thread group is aligned and arranged in a desired shape by an AFP or an ATL device.

Such an arrangement step may be performed in a two-dimensional planar shape or may be performed in a three-dimensional shape. In the case of a two-dimensional plane shape, by arranging a reinforcing fiber base material for each layer and then arranging and adhering a porous resin material, a sheet-shaped reinforcing fiber base material that can be easily transported for each layer can be obtained. It can be created and can be transported to a separately prepared shaping mold without breaking the shape in the aligned and arranged state. It is preferable that the porous resin material to be arranged at this time has at least a partial notch because the shapeability in the preforming step described later becomes better. Further, as the transporting means, a transporting means by a method such as static electricity, suction, or needle stick can be used.

Further, the sheet-shaped reinforcing fiber base material prepared for each layer may be a reinforcing fiber laminate in which a plurality of layers are laminated and integrated by heat fusion or stitching in order to further improve the handleability. At this time, by setting the arrangement direction of the nth layer of the reinforcing fiber base material of the second and subsequent layers to be different from the arrangement direction of the n-1th layer, the reinforcement of a plurality of layers that can be treated in the same manner as the cloth. It can be a fiber laminate. The step of integrating the reinforcing fiber base materials may be performed on the entire surface where the reinforcing fiber base materials are overlapped, or may be performed partially. When integrated on the entire surface, the morphological stability of the reinforcing fiber base material is excellent. On the other hand, if it is partially integrated, it is easily deformed (that is, has good shapeability) when it is shaped into a molded product shape in the preforming step described later. Therefore, it is preferable to use these arbitrarily depending on the complexity of the molded product shape.

Here, the reinforcing fiber base material in the present invention is a porous resin in a group of reinforcing fiber threads in which reinforcing fiber threads (without resin material attached) are aligned and arranged in a desired shape by an AFP or ATL device. It can also include materials that have been placed and bonded. As a result, it is possible to impart characteristics such as impact resistance to carbon fiber yarns that do not have characteristics such as impact resistance.

Further, after arranging the first layer of the reinforcing fiber base material, the arrangement of the second and subsequent layers may be repeated on the same plane. In such an arrangement process, a heater is provided at the head portion of the AFP or ATL device, and the reinforcing fiber base material of the second and subsequent layers is arranged while melting the resin material on the surface of the reinforcing fiber base material, whereby the reinforcing fiber base material is arranged. And the integration process can be integrated. At this time, by setting the arrangement direction of the nth layer of the reinforcing fiber base material of the second and subsequent layers to be different from the arrangement direction of the n-1th layer, the reinforcement of a plurality of layers that can be treated in the same manner as the cloth. It can be a fiber laminate.

Further, among the reinforcing fiber base materials in the present invention, the reinforcing fiber base material made of the reinforcing fiber aggregate and the reinforcing fiber laminate containing the resin material between the layers of the reinforcing fiber thread group have a desired shape according to the shape of the molded product. It is used by cutting it into.

The reinforcing fiber base material or the reinforcing fiber laminate thus prepared can be prepared by laminating one layer at a time or a plurality of layers at a desired angle configuration, and then performing a preforming step to prepare a preform.

The molding of FRP of the present invention is carried out by so-called resin injection molding, and RTM (Resin Transfer Molding) molding and VaRTM (Vacum assisted Resin Transfer Molding) molding are preferably applied. The porous resin material arranged on at least one side of the reinforcing fiber base material in the present invention functions as a flow path (air path) when the air inside the reinforcing fiber base material is discharged and as a resin diffusion medium. Demonstrate. Therefore, it is possible to improve the internal quality of the molded product and speed up the resin injection process. Further, since the porous resin material arranged on at least one surface of the reinforcing fiber base material in the present invention has a connection in the plane direction, it is possible to prevent the reinforcing fiber base material from being deformed when the resin is injected at a high pressure.

The FRP of the present invention has a reinforcing fiber volume content (Vf) in the range of 53 to 65%, and the room temperature compressive strength after impact application described in SACMA-SRM-2R-94 is 240 MPa or more. preferable. Note that Vf (unit is vol%) refers to the volume ratio occupied by the reinforcing fibers in the fiber reinforced resin, and is specifically defined by the following equation, and the symbols used here are as shown below.
Vf = (W × 100) / (ρ × T)
W: Weight of reinforcing fiber per 1 cm ² of reinforcing fiber base material (g / cm ² )
ρ: Reinforcing fiber density (g / cm ³ )
T: Thickness of fiber reinforced plastic (cm)

When the Vf of the fiber reinforced resin is in the range of 53 to 65%, the excellent mechanical properties of the fiber reinforced resin can be maximized. If Vf is less than 53%, the weight reduction effect is inferior, and if it exceeds 65%, molding by the above-mentioned resin injection molding becomes difficult and mechanical properties (particularly impact resistance) may be deteriorated. That is, in such a Vf range, when the room temperature compressive strength after impact application described in SACMA-SRM-2R-94 of the fiber reinforced resin is 240 MPa or more, the material satisfies both the weight reduction effect and the mechanical properties. can do. Fiber reinforced plastics that meet these requirements are used in a wide variety of applications due to their excellent mechanical properties and weight reduction effect. Although not particularly limited, it is used for a primary structural member, a secondary structural member, an exterior member, an interior member, or parts thereof in transportation equipment such as an aircraft, an automobile, or a ship, and exerts its effect to the maximum extent.

In addition, SACMA is an abbreviation for Supporters of Advanced Composites Association, and SACMA-SRM-2R-94 is a standard of the test method defined here. The room temperature compressive strength after impact is measured at 270 inch pounds of impact energy under Dry conditions according to SACMA-SRM-2R-94.

Hereinafter, the present invention will be further described with reference to examples. The raw materials and molding methods used in the examples and comparative examples are as follows. The present invention is not limited to these Examples and Comparative Examples.

<Compressive strength at high temperature and water absorption>
A test piece was prepared according to SACMA-SRM-1R-94, immersed in warm water at 70 ° C. for 14 days, and then subjected to a compression test in an atmosphere of 70 ° C.

[Example 1]
<Reinforcing fiber thread>
As the carbon fiber threads, PAN-based carbon fibers, 24,000 filaments, tensile strength: 6.0 GPa, and tensile elastic modulus: 294 GPa were used.

<Resin material>
Hexamethylenediamine and terephthalic acid were polymerized in an equimolar ratio to prepare a polyamide 6T.

<Porous resin material>
The above resin material was made into a non-woven fabric by a spunbond device. The basis weight was 10 g / m ² .

<Matrix resin>
39 parts by weight of the following curing liquid was added to 100 parts by weight of the next main liquid, and the mixture was uniformly stirred at 80 ° C. to obtain an epoxy resin composition.
Main liquid: As epoxy, tetraglycidyldiaminodiphenylmethane type epoxy ("Araldite" (registered trademark) MY-721, manufactured by Huntsman Japan Co., Ltd.) 40 parts by weight, liquid bisphenol A type epoxy resin ("EPON" (registered trademark)) 825, 35 parts by weight of Mitsubishi Chemical Co., Ltd., 15 parts by weight of diglycidyl aniline (GAN, manufactured by Nippon Kayaku Co., Ltd.), and triglycidyl aminophenol type epoxy resin (“jER” (registered trademark) 630, 10 parts by weight (manufactured by Mitsubishi Chemical Corporation) were weighed and stirred at 70 ° C. for 1 hour to uniformly dissolve them.

Curing solution: 70 parts by weight of modified aromatic polyamine (“jER Cure” (registered trademark) W, manufactured by Mitsubishi Chemical Corporation), 20 parts by weight of 3,3'-diaminodiphenyl sulfone (manufactured by Mitsui Chemicals Fine Co., Ltd.), Then, weigh 10 parts by weight of 4,4'-diaminodiphenyl sulfone ("Seika Cure" S, manufactured by Seika Co., Ltd.), stir at 100 ° C for 1 hour to make it uniform, and then lower the temperature to 70 ° C to cure. As an accelerator, 2 parts by weight of t-butyl catechol (DIC-TBC, manufactured by DIC Co., Ltd.) was weighed and further stirred at 70 ° C. for 30 minutes to uniformly dissolve.

<Reinforcing fiber base material>
Using the apparatus shown in FIG. 2, a tape-shaped reinforcing fiber base material having a width of 1/4 inch was prepared. The basis weight of the reinforcing fiber base material was 162 g / m ² .

<Reinforcing fiber laminate>
Such a reinforcing fiber base material is pseudo-isotropically laminated [45/0 / -45/90] _3S (24 layers: where "3S" is used in the order of orientation angles shown in []) for CAI measurement using an AFP device. One set (4 layers x 2 = 8 layers) was formed by combining the stacked ones and the ones laminated so as to have a symmetrical arrangement, and three sets of these were laminated (8 layers x 3 = 24 layers). After laminating on a flat preform mold having the same structure as shown below), the mixture was sealed with a bag film and a sealant and depressurized to a vacuum, and then heated in an oven at 140 ° C. for 1 hour. Then, it was taken out from an oven, the preform mold was cooled to room temperature, and then the pressure was released to obtain a reinforcing fiber laminate. For high-temperature compressive strength measurement, the AFP device is used to stack 6 layers in the 0-degree direction on a flat preform mold, which is then sealed with a bag film and sealant and depressurized to vacuum. It was heated in an oven at ° C for 1 hour. Then, it was taken out from an oven, the preform mold was cooled to room temperature, and then the pressure was released to obtain a reinforcing fiber laminate.

<Fiber reinforced plastic>
A resin diffusion medium (aluminum wire mesh) is laminated on the obtained reinforcing fiber laminate, and a cavity is formed by sealing the flat molded mold and the bag material with a sealant, and the cavity is formed in an oven at 100 ° C. I put it in. After the temperature of the reinforcing fiber laminate reached 100 ° C., the closed cavity was reduced to vacuum, and the matrix resin was injected only by the differential pressure from the atmospheric pressure while keeping the temperature at 100 ° C. After the resin was impregnated, the temperature was raised to 180 ° C. while continuing to reduce the pressure, and the mixture was allowed to stand for 2 hours to be cured and demolded to obtain an FRP flat plate 1a for CAI measurement and an FRP flat plate 1b for measuring compressive strength at high temperature. The Vf of the obtained FRP flat plate 1a was 57%, the CAI was 140 MPa, and the compressive strength of the FRP flat plate 1b at high temperature and water absorption was 1100 MPa.

[Comparative Example 1]
Using the apparatus shown in FIG. 2, the FRP flat plate for CAI measurement was prepared in the same manner as in Example 1 except that the resin material was not introduced when the tape-shaped reinforcing fiber base material having a width of 1/4 inch was prepared. 2a and FRP flat plate 2b for measuring compressive strength at high temperature and water absorption were obtained. The Vf of the obtained FRP flat plate 1a was 62%, the CAI was 100 MPa, and the compressive strength of the FRP flat plate 1b at high temperature and water absorption was 1190 MPa.

Since the FRP of the present invention has excellent mechanical properties and is lightweight, its use is limited to primary structural members, secondary structural members, exterior members or interior members in any of the transportation equipment of aircraft, automobiles and ships. It is also suitable for general industrial use members such as windmill blades, robot arms and X-ray top plates for medical equipment.

11: Reinforcing fiber base material 12: Reinforcing fiber aggregate 13: Resin material 20: Bobin 21: Reinforcing fiber base material 22: Reinforcing fiber thread 23: Resin material 201: Fiber opening unit 202: Width regulation roller 203: Heater 204: Press roll 31: Reinforcing fiber thread group 32: Reinforcing fiber thread 300: AFP head 41: One-way fabric 42: Reinforcing fiber thread (warp)
43: Auxiliary thread (warp)
44: Auxiliary thread (warp and weft)
51: Bidirectional woven fabric 52: Reinforcing fiber threads (warps)
53: Reinforcing fiber threads (warp and weft)
61: Stitched fabric 62: + α ° reinforcing fiber layer forming the reinforcing fabric 63: 90 ° reinforcing fiber layer forming the reinforcing fabric 64: Forming the reinforcing fabric-α ° reinforcing fiber layer 65: Forming the reinforcing fabric 0 ° Reinforcing Fiber Layer 66: Stitch Thread

Claims (11)

[1]: Reinforcing fiber thread, [2]: Reinforcing fiber thread group formed by arranging reinforcing fiber threads in parallel, [3]: Reinforcing fiber cloth composed of [1] or [2]. A reinforcing fiber base material in which a resin material is arranged on at least one surface of a reinforcing fiber aggregate selected from any of the above, wherein the resin material is a semi-aromatic polyamide containing a terephthalic acid component. Reinforcing fiber base material for resin injection molding. The reinforcing fiber base material for resin injection molding according to claim 1, wherein the resin material has a porous shape. The reinforcing fiber base material for resin injection molding according to claim 1 or 2, wherein the resin material is contained in the range of 1 to 20% by weight with respect to the reinforcing fiber base material. The reinforcing fiber base material for resin injection molding according to any one of claims 1 to 3, wherein the reinforcing fiber thread group is in the form of a sheet in which a plurality of reinforcing fiber threads are arranged in parallel. The reinforcing fiber base material for resin injection molding according to any one of claims 1 to 3, wherein the reinforcing fiber thread group is in the form of a sheet arranged and arranged in parallel by an automated fiber placement device. The fineness of the reinforcing fiber thread is such that the reinforcing fiber aggregate extends in a direction intersecting the reinforcing fiber thread group formed by aligning the reinforcing fiber threads in parallel in one direction and the reinforcing fiber thread. The reinforcing fiber base material for resin injection molding according to any one of claims 1 to 3, which is a unidirectional fabric composed of a group of auxiliary fiber threads having a size of 1/5 or less. Claim 1 is a bidirectional woven fabric in which the reinforcing fiber aggregate is composed of the reinforcing fiber thread group arranged in one direction and the reinforcing fiber thread group arranged in one direction in different directions. The reinforcing fiber base material for resin injection molding according to any one of 3 to 3. At least two or more layers of the reinforcing fiber yarn group arranged in one direction and the reinforcing fiber yarn group arranged in one direction in different directions are cross-laminated, and the fineness of the reinforcing fiber fabric is increased. The reinforcing fiber base material for resin injection molding according to any one of claims 1 to 3, which is a stitch fabric stitched and integrated by a group of auxiliary fiber threads having 1/5 or less of the threads. A reinforcing fiber laminate for resin injection molding containing the reinforcing fiber base material for resin injection molding according to any one of claims 1 to 8 as a reinforcing fiber. The reinforcing fiber laminate for resin injection molding according to claim 9, which is integrated by heat fusion or stitching. A fiber-reinforced resin containing the reinforcing fiber base material for resin injection molding according to any one of claims 1 to 8 or the reinforcing fiber laminate for resin injection molding according to claim 9 or 10.

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