JP2020023182A - Reinforced-fiber base material, reinforced-fiber laminate, and fiber-reinforced resin - Google Patents

Abstract

To provide a reinforced-fiber base material and a reinforced-fiber laminate, which have good impregnation property of a matrix resin and excellent handling property (especially, shape stability), in addition to allow obtaining a fiber-reinforced resin with excellent mechanical properties such as impact resistance and high-temperature mechanical property with good productivity.SOLUTION: There is provided a reinforced-fiber base material in which a resin material is arranged at least on one side surface of a reinforced-fiber assembly selected from any one of [1] reinforced-fiber yarns, [2] a group of reinforced-fiber yarns formed by paralleling reinforced-fiber yarns in parallel, and [3] a reinforced-fiber fabric that is formed by [1] or [2], and the resin material is a reinforced-fiber base material having a Vicat softening temperature in a range of 70 to 200°C.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reinforced fiber base material, a reinforced fiber laminate, and a fiber reinforced resin comprising the same.

  BACKGROUND ART A fiber reinforced resin (FRP) obtained by impregnating a reinforcing fiber with a matrix resin has been mainly used for aviation, space, and sports because it satisfies required characteristics such as excellent mechanical properties and weight reduction. As a typical production method thereof, an autoclave molding method is known. In such a molding method, a prepreg obtained by impregnating a reinforcing fiber bundle group 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 a prepreg has the advantage that an extremely reliable FRP can be obtained, but has the problem of high manufacturing costs.

  On the other hand, as a molding method excellent in productivity of FRP, for example, injection molding such as a resin transfer molding molding method (RTM) is exemplified. In the RTM molding method, a reinforcing fiber base composed of a group of dry reinforcing fiber bundles not pre-impregnated with a matrix resin is laminated on a molding die, and a liquid, low-viscosity matrix resin is injected into the mold. This is a molding method in which a matrix resin is impregnated and solidified to form an FRP.

  Although the injection molding method is excellent in the productivity of FRP, the matrix resin needs to have a low viscosity, so it exhibits sufficient mechanical properties compared to FRP molded from a high viscosity matrix resin used for prepreg. In some cases, it was not possible.

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

JP-T-2012-506499A JP 2008-517812 A

  The present invention solves the problems of the prior art, and specifically, provides a fiber-reinforced resin having good impregnating property of a matrix resin, excellent mechanical properties such as impact resistance and high-temperature mechanical properties. An object of the present invention is to provide a reinforced fiber base material and a reinforced fiber laminate which are not only well obtained but also excellent in handleability (particularly, form stability). Another object of the present invention is to provide a fiber-reinforced resin obtained from such a reinforcing fiber base material and a reinforcing fiber laminate.

The present invention employs the following means in order to solve such a problem. That is,
(1) [1]: Reinforcement fiber yarn, [2]: Reinforcement fiber yarn group in which reinforcement fiber yarns are aligned in parallel, [3]: Reinforcement fiber composed of [1] or [2] A reinforced fiber base material in which a resin material is disposed on at least one surface of a reinforced fiber aggregate selected from any of cloth, wherein the resin material has a Vicat softening temperature in a range of 70 to 200 ° C. A reinforced fiber substrate characterized by the following.
(2) The reinforcing fiber substrate according to (1), wherein the Vicat softening temperature is in a range of 100 to 180 ° C.
(3) The reinforcing fiber substrate according to (1) or (2), wherein the shape of the resin material is porous.
(4) The reinforcing fiber substrate according to any one of (1) to (3), wherein the resin material has a content of 1 to 20% by weight based on the reinforcing fiber substrate.
(5) The reinforcing fiber substrate according to any one of (1) to (4), wherein the resin material is an amorphous polyamide.
(6) The reinforcing fiber substrate according to any one of (1) to (5), wherein the resin material is a semi-aromatic polyamide containing an isophthalic acid component.
(7) The reinforcing fiber substrate according to any one of (1) to (6), wherein the reinforcing fiber yarn group is a sheet having a plurality of reinforcing fiber yarns arranged in parallel.
(8) The reinforcing fiber base material according to any one of (1) to (6), wherein the reinforcing fiber yarn group is in a sheet shape arranged and arranged in parallel by an automated fiber placement device.
(9) A group of reinforcing fiber yarns in which the reinforcing fiber aggregates are arranged in parallel in one direction, and a reinforcing fiber yarn extending in a direction intersecting the reinforcing fiber yarns. The reinforcing fiber substrate according to any one of (1) to (6), which is a unidirectional woven fabric composed of an auxiliary fiber yarn group having a fineness of 1/5 or less.
(10) The reinforcing fiber aggregate is a bidirectional woven fabric composed of the reinforcing fiber yarn group arranged in one direction and the reinforcing fiber yarn group arranged in one direction in different directions. The reinforcing fiber substrate according to any one of (1) to (6).
(11) In the reinforcing fiber fabric, at least two 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 is reduced. The reinforcing fiber substrate according to any one of (1) to (6), which is a stitched fabric stitched and integrated by an auxiliary fiber yarn group that is 1/5 or less of the reinforcing fiber yarn.
(12) A reinforced fiber laminate comprising the reinforced fiber substrate according to any one of (1) to (11) as reinforced fibers.
(13) The reinforcing fiber laminate according to (12), which is integrated by heat fusion or stitching.
(14) A fiber-reinforced resin comprising the reinforcing fiber base according to any one of (1) to (11) or the reinforcing fiber laminate according to (12) or (13) as the reinforcing fiber.
(15) The fiber according to (14), wherein the volume content of the reinforcing fiber is 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. Reinforced resin.
It is.

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

FIG. 1 is a schematic cross-sectional view illustrating one embodiment of a reinforcing fiber base according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic side view which shows one aspect of the manufacturing apparatus of the reinforcing fiber base in this invention. It is a schematic perspective view showing one mode of a reinforcing fiber thread group in the present invention. It is a schematic perspective view showing one mode of a unidirectional textile as a reinforcing fiber aggregate in the present invention. FIG. 1 is a schematic perspective view showing one embodiment of a bidirectional woven fabric as a reinforcing fiber aggregate according to the present invention. It is a schematic perspective view showing one mode of a stitch cloth as a reinforcing fiber aggregate in the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view illustrating one embodiment of a reinforcing fiber base material 11 according to the present invention. The reinforcing fiber base 11 shown in this figure is one in which the resin material 13 is disposed on one surface of the reinforcing fiber assembly 12 and then bonded and integrated.

  The reinforcing fiber base material 11 is a reinforcing fiber aggregate 12 selected from a group consisting of a reinforcing fiber yarn, a group of reinforcing fiber yarns, and a reinforcing fiber cloth or a reinforcing fiber cloth composed of a group of reinforcing fiber yarns. It is important to have the resin material 13 on at least one surface. By providing such a resin material 13 on at least one surface, it is possible to improve the morphological stability such as the width and fiber orientation of the reinforcing fiber base material 11 or to obtain a sheet-like reinforcing fiber base made of a group of reinforcing fiber yarns. It is possible to improve the handling property of the material 11 during transportation or the like.

  In addition, it is possible to impart adhesiveness between the reinforcing fiber aggregates 12 when obtaining a laminate (preform) obtained by laminating the reinforcing fiber base material 11 or the reinforcing fiber aggregates 12 described below, or it is possible to provide a suitable preform. The handleability of the preform can be improved, for example, rigidity can be imparted, and a form stability effect such as prevention of misalignment of reinforcing fibers in the preform can be imparted.

  In particular, the resin material 13 can secure a space for flowing and diffusing a matrix resin, which will be described later, between the layers of the reinforcing fiber assembly 12 (giving the matrix resin a plastic deformability between the layers of the reinforcing fiber assembly 12). When the resin material 13 acts as a stopper for cracks generated between the layers of the reinforcing fiber assembly 12 or the like, it is possible to suppress the damage between the layers of the reinforcing fiber assembly 12 when subjected to an impact, and particularly excellent mechanical properties. (Especially, compressive 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 assembly 12 and not only facilitates impregnation of the matrix resin when subjected to injection molding, but also the The effect of increasing the impregnation rate and improving the productivity of FRP is also exhibited.

  The resin material 13 adheres to the reinforcing fiber assembly 12 and only needs to be present on at least one surface of the reinforcing fiber assembly 12, and exists inside the reinforcing fiber assembly 12 (permeates into the reinforcing fiber yarns). May be. Preferably, 50% by weight or more, more preferably 70% by weight or more, is unevenly distributed on the surface of the reinforcing fiber aggregate 12 for the above-described reason. Further, a binder component may be included for the purpose of bonding the resin material 13 and the reinforcing fiber bundle 12. 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 Can also be used.

  It is important that the resin material 13 has a Vicat softening temperature in the range of 70 to 200 ° C. Here, in the present invention, the Vicat softening temperature (VST) refers to a value measured by the A-50 method according to JIS K7206 (2016). If the VST is lower than 70 ° C., the mechanical properties of the FRP at high temperatures are undesirably reduced. If the VST exceeds 200 ° C., the adhesiveness between the matrix resin and the resin material 13 decreases, and the mechanical properties of FRP (particularly, CAI and ILSS [interlaminar shear strength]) may decrease. Further, the resin material 13 preferably has a Vicat softening temperature in the range of 100 to 180 ° C.

  Further, the form of the resin material 13 is preferably porous. In the present invention, the porous shape refers to a shape in which holes are formed in the thickness direction on a plane, and in such a form, a matrix resin or air flow path in the thickness direction of the reinforcing fiber base material 11 is formed. Not only can it be ensured, but also there is a connection in the plane direction, so that the width stability is improved when the reinforcing fiber yarn is used, and the handling of the sheet-like reinforcing fiber base material 11 composed of the group of reinforcing fiber yarns is carried out. Properties and the morphological stability of the base material when a group of reinforcing fiber yarns or a fabric is used. Examples of the porous resin material 13 include a nonwoven fabric, a mat, a net, a mesh, a fabric, a knit, a short fiber group, a perforated film, and a porous film. Among them, a nonwoven fabric, a mat, or a mesh is preferable because it can be obtained at a low cost, and a matrix resin or an air flow path is also formed in a plane direction, so that the above-mentioned effects are exhibited to a high degree. When the resin material 13 is a non-woven fabric, the form of the constituent fibers includes long fibers and short fibers, and is produced by a method such as melt blowing, spun bonding, air laid, carding, and papermaking, but is not particularly limited. Further, a binder component for binding fibers to each other may be included as an auxiliary component. 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, even more 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, and the flow of the resin may be hindered in the resin impregnation step described below, which is not preferable. Further, if the fiber diameter is 100 μm or more, the thickness between the reinforcing fiber base layers when FRP is formed is increased, and the fiber volume content (Vf) is undesirably reduced.

  The resin material 13 used in the present invention preferably accounts for 1 to 20% by weight of the reinforcing fiber base material 11. Preferably it is 2 to 18% by weight, more preferably 3 to 16% by weight. By arranging the resin material 13 within the above range, the morphological stability of the reinforcing fiber base material 11 is provided, and it is possible to obtain the reinforcing fiber base material 11 having excellent handleability. If the content is less than 1% by weight, not only is the handleability of the reinforcing fiber base material 11 reduced, but also the effect of improving the mechanical properties (particularly, CAI) is undesirably reduced. On the other hand, if it exceeds 20% by weight, the volume content of the reinforcing fibers in the FRP becomes too low, and the heat resistance, the chemical resistance and the compressive strength of the FRP are undesirably reduced.

  The resin material 13 is preferably an amorphous polyamide from the viewpoint of heat resistance, impact resistance, and ease of processing. Here, in the present invention, the term “amorphous” means that the value of the crystal melting enthalpy ΔHm measured by a differential scanning calorimeter (DSC) at a heating rate of 10 ° C./min according to JIS K7121 (1987) is 5 J / g. Less than

  Further, the resin material 13 is preferably a semi-aromatic polyamide containing an isophthalic acid component. Examples of the semi-aromatic polyamide containing an isophthalic acid component include polyamide 2I, polyamide 4I, polyamide 6I, polyamide 9I, polyamide 10I, and polyamide 12I. Among them, polyamide 6I and polyamide 9I from the viewpoint of water absorption and flexibility. , Polyamide 10I, polyamide 12I, and the like having a long methylene chain portion are preferable. Such a resin material 13 can form a layer having high toughness between FRP layers by melting at the time of FRP molding, and can improve mechanical properties (in particular, CAI and ILSS [interlayer shear strength]).

  Further, when the compatibility of the FRP with the matrix resin is low when the resin material 13 is melted during molding, separation occurs at the interface between the resin material 13 and the matrix resin, and the effect of improving the mechanical properties can be obtained satisfactorily. There are things you can't do. Therefore, the absolute value of the solubility parameter difference between the resin material 13 and the matrix resin is preferably 5 or less, more preferably 3 or less. The solubility parameter of the resin material 13 is obtained by the following equation (1). This method is described in "Fukumoto Osamu (1988)" Polyamide Resin Handbook "Nikkan Kogyo Shimbun".

here,
M: molecular weight ρ: density ΔH: amide group interaction 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 method of Fedors. The method is described in F.S. Fedors, Polym. Eng. Sci. , 14 (2), 147 (1974). The reinforcing fiber yarns in the present invention are multifilament yarns such as glass fiber yarns, organic (aramid, PBO, PVA, PE, etc.) fiber yarns, carbon fiber (PAN-based, pitch-based, etc.) yarns and the like. Carbon fibers are excellent in specific strength and specific elastic modulus and hardly absorb water, and therefore are preferably used as reinforcing fibers for aircraft structural materials and automobiles.

  The reinforcing fiber yarn used in the present invention preferably has 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 is preferably a non-twisted yarn having excellent stability in width and thickness of the yarn, and more preferably an opened fiber having excellent fiber orientation.

  Here, the reinforcing fiber base in the present invention is [1]: reinforcing fiber yarn, [2]: reinforcing fiber yarn group in which reinforcing fiber yarns are aligned in parallel, or [3] reinforcing fiber yarn or It is important to form a reinforcing fiber aggregate selected from any one 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 yarn is prepared using, for example, an apparatus illustrated in FIG. Specifically, the reinforcing fiber yarn 22 pulled out from the bobbin 20 is spread by the fiber opening unit 201, adjusted to a desired width by the width regulating roller 202, and then slit in advance to a desired width by the resin material 23 (preferably). Is formed by superimposing with a porous resin material), heating by a heater 203, and pressing by a press roll 204. The fiber opening unit 201 is configured by a vibration roller or the like, and includes a mechanism that applies vibration in a vertical direction or a horizontal direction perpendicular to the traveling direction of the reinforcing fiber yarn 22. Further, the opening unit 201 may include a heater (not shown) for softening the sizing agent attached to the surface of the reinforcing fiber yarn 22. At this time, assuming that the yarn width of the reinforcing fiber yarn 22 drawn out from the bobbin 20 is w0, the width of the reinforcing fiber yarn 22 after opening is widened to w1 (w0 <w1), and then 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 21. In order to improve the width accuracy of the reinforcing fiber base 21, the press roll 204 preferably has a grooved structure.

  The reinforcing fiber substrate 21 produced by such an apparatus has good width and basis weight stability, and also has excellent fiber orientation, so that it can contribute to improvement in the mechanical properties (particularly, compressive strength) of FRP. In addition, it is preferable that the resin material 23 be disposed on both surfaces of the reinforcing fiber yarn group because the form stability of the reinforcing fiber base 21 is further improved.

  Next, [2]: a reinforcing fiber base 21 composed of a group of reinforcing fiber yarns is provided with a plurality of bobbins, for example, in an apparatus illustrated in FIG. 20 and the plurality of reinforcing fiber yarns 22 are drawn out while being aligned in parallel. Here, to align in parallel means to align adjacent reinforcing fiber yarns 22 so that they do not substantially intersect or intersect. Preferably, two adjacent reinforcing fiber yarns have a length of 100 mm. When approximating a straight line in the range of the length, the angle is formed so that the angle formed by the approximated straight line is 5 ° or less, more preferably 2 ° or less. Here, approximating the reinforcing fiber yarn 22 to a straight line means forming a straight line by connecting the starting point and the end point of 100 mm. Adjacent reinforcing fiber yarns 22 may be separated from each other at a certain interval or may overlap each other according to the required basis weight of the reinforcing fiber base material 21. When a certain interval is provided, the interval is preferably not more than 200% of the width of the reinforcing fiber yarn 22, and when overlapping, it may be 100% of the width of the reinforcing fiber yarn 22. It is preferable that the reinforcing fiber yarn group drawn out while being aligned in parallel as described above passes through the fiber opening unit to uniformly distribute the basis weight in the width direction. Further, the reinforcing fiber base 21 made from such a group of reinforcing fiber yarns may be slit if necessary and controlled to an arbitrary width.

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

  As the reinforcing fiber base 22 using the reinforcing fiber yarn 22 and the reinforcing fiber yarn group, an automated fiber placement (AFP) or an automated tape lay-up (ATL) device is suitably used. Such an apparatus is used for the purpose of reducing the disposal rate of the reinforcing fiber base material 21 and automating the laminating process. However, 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 shape stability by connecting in a plane direction, and thus can be suitably used for AFP and ATL.

  Further, as another embodiment of the reinforcing fiber yarn group in the present invention, there is a sheet-like one arranged in parallel by AFP or ATL. FIG. 3 shows an embodiment of a group of reinforcing fiber yarns used in the present invention. The reinforcing fiber yarns 32 are supplied by an AFP head 300 and are arranged in parallel. A porous resin material (not shown) is disposed on the reinforcing fiber thread group 31 so as to overlap with the reinforcing fiber thread group 31, and is bonded by heating with a far-infrared heater or the like, whereby a reinforcing fiber base material can be obtained. Since the sheet-like reinforcing fiber yarn group 31 arranged by AFP or ATL is not restricted in a direction intersecting with the fiber direction, there is a problem that the form of the reinforcing fiber yarn group 31 is collapsed during transportation. In order to solve such a problem, by arranging and bonding the porous resin material, a binding force in a direction intersecting with the fiber direction is generated, and the problem of conveyance can be solved. The spacing between the reinforcing fiber yarns 32 when the reinforcing fiber yarns 32 are aligned and arranged by AFP or ATL is preferably 0.5 to 2 mm. If the interval is less than 0.5 mm, the resin impregnating property during RTM molding may not be sufficient. If the spacing exceeds 2 mm, when a plurality of reinforcing fiber base materials are laminated, the upper reinforcing fibers fall between the lower reinforcing fiber yarns 32, causing undulation in the thickness direction and causing mechanical properties (particularly compression). Strength) may decrease.

  [3] Reinforcing fiber fabrics composed of reinforcing fiber yarns or a group of reinforcing fiber yarns include woven fabrics (unidirectional, bidirectional, multiaxial), knits, braids, and unidirectionally aligned. Sheet (unidirectional sheet), a multiaxial sheet in which two or more unidirectional sheets are stacked, and the like. A plurality of such reinforcing fiber aggregates may be integrated by various joining means such as a resin such as a stitch thread, a knotting thread, a sack cloth, and a binder. In particular, when used as a structure (especially a primary structure) member of a transportation device (especially an aircraft), a unidirectional sheet, a unidirectional woven fabric, or a multiaxial sheet (especially stitched) is preferable.

  FIG. 4 is a schematic perspective view showing one embodiment of a unidirectional woven fabric 41 as a reinforcing fiber cloth used in the present invention. The reinforcing fiber yarns 42 and the warp auxiliary yarns 43 are arranged in the length direction of the reinforcing fiber assembly 41, that is, the warp direction, and the weft auxiliary yarns 44 thinner than the reinforcing fiber yarns 42 are arranged in the weft direction. This is a unidirectional woven fabric in which the yarn 43 and the weft auxiliary yarn 44 intersect and have the weave structure shown in FIG. It is preferable that the auxiliary yarn 43 has low shrinkage, and examples thereof include glass fiber yarn, aramid fiber yarn, and carbon fiber yarn, and the fineness (weight per unit length) of the auxiliary yarn is reinforced fiber. It is preferably 1/5 or less of the yarn. If it exceeds 1/5, the auxiliary yarn becomes thicker, so that the reinforcing fiber yarn is crimped by the auxiliary yarn, and the strength of the reinforcing fiber is slightly reduced when FRP is formed. On the other hand, from the viewpoint of the form stability and the production stability of the reinforcing fiber aggregate, the fineness of the auxiliary yarn is preferably 0.05% or more of the reinforcing fiber yarn. The fineness within the above range is preferable because the reduction in strength is minimized, and the gap between the reinforcing fiber yarns 42 formed by the warp auxiliary yarns at the time of molding becomes a resin flow path, so that the impregnation of the matrix resin can be promoted.

  FIG. 5 is a schematic perspective view showing one embodiment of a bidirectional woven fabric 51 as a reinforcing fiber fabric used in the present invention. The reinforcing fiber yarns 52 are arranged in the length direction of the bidirectional fabric 51, that is, the warp direction, the reinforcing fiber yarns 53 are arranged in the weft direction, and the warp yarns 52 and the weft yarns 53 intersect with each other. It is a bidirectional fabric having a texture.

  FIG. 6 is a schematic perspective view showing one embodiment of a stitch fabric 61 as a reinforcing fiber fabric used in the present invention. From the lower surface of the stitched fabric 61, a large number of reinforcing fiber yarns are arranged in parallel in the oblique direction to the length direction A to form the + α ° layer 62, and then a large number of reinforcing fibers are strengthened in the width direction of the reinforced fabric. The fiber yarns are arranged in parallel to form a 90 ° layer 63, and then a number of reinforcing fiber yarns are arranged in parallel in an oblique direction to form a −α ° layer 64, and then in the longitudinal direction of the reinforced fabric. A number of reinforcing fiber yarns are arranged in parallel to form a 0 ° layer 65, and in a state where four layers having different arrangement directions are laminated, these four layers are stitched and integrated with a stitch thread 66. I have. Examples of the stitching structure formed by the stitch thread 66 for stitching integration include single-ring stitching and 1/1 tricot knitting. The material of the stitch yarn can be selected from polyester resins, polyamide resins, polyethylene resins, vinyl alcohol resins, polyphenylene sulfide resins, polyaramid resins, and compositions thereof. Among them, a polyester resin and a polyamide resin are preferable. From the viewpoint of the shaping property 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 yarn is preferably 1/5 or less of the reinforcing fiber yarn in order to suppress crimping of the reinforcing fiber yarn. Further, it is preferably at least 10 dtex, more preferably at least 30 dtex, from the viewpoint of the form stability and the production stability of the reinforcing fiber aggregate. Furthermore, it is preferable that the stitch yarn has elasticity from the viewpoint of shapeability in a preforming step described later. In FIG. 6, the aggregate of the reinforcing fibers whose cross-sectional shape is shown as an ellipse is one yarn, and it looks as if the stitch yarns 66 are arranged between the reinforcing fiber yarns. The aggregate of the reinforcing fibers inserted at random into the reinforcing fiber yarns and shown in an elliptical shape is formed by the constraint of the stitch yarn 66.

  Here, the configuration of the reinforcing fiber of the multiaxial stitch fabric 61 shown in FIG. 6 has been described as a four-layer configuration of + α ° layer / 90 ° layer / −α ° layer / 0 ° layer, but is not limited thereto. Absent. For example, two layers including a 0 ° layer / 90 ° layer, a + α ° layer / −α ° layer, a 0 ° layer / + α ° layer, a + α ° layer / 0 ° layer / −α ° layer, a + α ° layer / −α Layer / 0 ° layer / 0 ° layer / + α ° layer / 0 ° layer / -α ° layer / 90 ° layer / -α ° layer / 0 ° layer / + α ° layer / 0 ° Like a layer, it may include four directions of 0 °, + α °, −α °, and 90 ° such that many 0 ° layers are included. Further, any of 0 °, + α °, −α °, and 90 ° may be included. Note that the bias angle α ゜ is preferably 45 ° from the viewpoint of stacking stitched fabrics in the length direction of the FRP and effectively performing shear reinforcement with reinforcing fibers.

The preferable weight per layer of the reinforcing fiber base 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 still 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 layers for obtaining a predetermined FRP thickness increases, and the molding workability is poor, which is not preferable. Further, when the basis weight per layer is small, a gap is formed between the reinforcing fiber yarns in the layer and the reinforcing fiber volume content Vf becomes partially non-uniform, and when molded, the reinforcing fiber volume content Vf is increased. Where the Vf is large, the FRP becomes thick, and where 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 spread thinly by a vibrating roller or air jet injection just before weaving, before the integration processing by the stitch yarn, and / or after the processing of the reinforcing fabric, the reinforcing fiber is extended over the entire surface of the reinforcing fabric. Is preferable because the volume ratio becomes uniform and FRP having a smooth surface can be obtained. On the other hand, when it exceeds 800 g / m ² , the impregnating property of the matrix resin is deteriorated, which is not preferable.

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

  Further, the reinforcing fiber laminate in the present invention, in accordance with the form of the desired carbon fiber reinforced resin molded article, imparts a three-dimensional shape to the carbon fiber laminated substrate using a shaping mold or a jig, A preform having a fixed shape can also be used. In particular, when the molding die has a three-dimensional shape, by doing so, it is possible to easily suppress the occurrence of fiber turbulence and wrinkles at the time of mold clamping or at the time of 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. Such a matrix resin is solidified (cured or polymerized) as necessary. Preferable examples of such a matrix resin include, for example, a thermosetting resin, a thermoplastic resin for RIM (Reaction Injection Molding), and among them, an epoxy resin, a phenol resin, a vinyl ester resin, and a non-ionic resin suitable for injection molding. It is preferably at least one selected from a saturated polyester resin, a cyanate ester resin, a bismaleimide resin and a benzoxazine resin.

  Further, since the FRP of the present invention has excellent mechanical properties and is light in weight, its use is intended for primary structural members, secondary structural members, exterior members or interior members in any of aircraft, automobiles and marine transportation equipment. It is preferred that

Next, a method of forming an FRP using the reinforcing fiber base in the present invention will be described.
Among the reinforcing fiber bases in the present invention, the reinforcing fiber bases composed of the reinforcing fiber yarns and the group of the reinforcing fiber yarns are arranged in a desired shape by an AFP or ATL device.

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

  In addition, the sheet-like reinforcing fiber base material formed for each layer may be a reinforcing fiber laminate in which a plurality of layers are stacked and integrated by heat fusion or stitching in order to further improve the handleability. At this time, by setting the arrangement direction of the reinforcing fiber base material of the nth layer after the second layer to a direction different from the arrangement direction of the (n-1) th layer, the reinforcement of a plurality of layers that can be handled in the same manner as a fabric It can be a fiber laminate. The step of integrating the reinforcing fiber bases may be performed on the entire surface where the reinforcing fiber bases overlap, or may be partially performed. When integrated over the entire surface, the reinforced fiber substrate has excellent shape stability. On the other hand, if they are partially integrated, they are likely to be deformed (that is, have good shapeability) during shaping into a molded product shape in a preforming step described later. Therefore, it is preferable to use these arbitrarily depending on the complexity of the shape of the molded product.

  Here, the reinforcing fiber base in the present invention is formed by adding a porous resin to a reinforcing fiber yarn group in which reinforcing fiber yarns (with no resin material attached) are arranged in a desired shape by an AFP or ATL device. It can also include one in which materials are arranged and bonded. This makes it possible to impart properties such as impact resistance to carbon fiber yarns having no properties such as impact resistance.

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

  Further, among the reinforcing fiber substrates in the present invention, the reinforcing fiber substrate comprising a reinforcing fiber aggregate, and the reinforcing fiber laminate including a resin material between layers of the reinforcing fiber yarn group have a desired shape in accordance with the shape of a molded product. Used for cutting.

  The reinforcing fiber base material or the reinforcing fiber laminate thus formed is laminated one by one or a plurality of layers at a desired angle configuration, and then a preforming step is performed to form a preform. In the preforming step, it is desirable to heat the resin material in the range of Vicat softening temperature -30 ° C to Vicat softening temperature + 30 ° C. If the heating temperature is low, the resin material is not sufficiently softened, and the shape of the preform may not be fixed. In addition, when the heating temperature is high, the resin material penetrates the reinforcing fiber base material, and the impregnation property of the matrix resin may deteriorate.

  The molding of the FRP of the present invention is performed by so-called resin injection molding, and RTM (Resin Transfer Molding) molding or VaRTM (Vacuum assisted Resin Transfer Molding) molding is preferably applied. The porous resin material disposed on at least one surface of the reinforcing fiber base in the present invention has a function as a flow path (air path) when discharging air inside the reinforcing fiber base and a function as a resin diffusion medium. Demonstrate. Therefore, it is possible to improve the internal quality of the molded product and to speed up the resin injection process. In addition, since the porous resin material disposed on at least one side of the reinforcing fiber base in the present invention has a connection in a planar direction, it is possible to prevent deformation of the reinforcing fiber base when 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 has a room temperature compressive strength of 240 MPa or more after impact application described in SACMA-SRM-2R-94. preferable. In addition, Vf (unit is vol%) indicates a volume ratio occupied by the reinforcing fibers in the fiber reinforced resin, and is specifically defined by the following formula, 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 substrate (g / cm ² )
ρ: density of reinforcing fiber (g / cm ³ )
T: thickness of fiber reinforced resin (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 effect of reducing the weight is inferior, and if it exceeds 65%, the above-mentioned injection molding becomes difficult, and the mechanical properties (particularly, impact resistance) may decrease. 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, a material that satisfies both the weight-reducing effect and the mechanical properties can be obtained. can do. Fiber reinforced resins satisfying such requirements are used in a wide variety of applications because of their excellent mechanical properties and lightening effects. Although it is not particularly limited, it is used as a primary structural member, a secondary structural member, an exterior member, an interior member, or a part thereof in a transportation device such as an aircraft, an automobile, or a ship, and the effects are maximized.

  Note that SACMA is an abbreviation for Suppliers of Advanced Composite Materials Association, and SACMA-SRM-2R-94 is a test method standard defined here. Cold compressive strength after impact is measured at an impact energy of 270 in-lb under Dry conditions according to SACMA-SRM-2R-94.

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

<Compression strength at high temperature>
It was measured according to SACMA-SRM-1R-94.

[Example 1]
<Reinforcing fiber yarn>
PAN-based carbon fiber, 24,000 filaments, tensile strength: 6.0 GPa, and tensile modulus of elasticity: 294 GPa were used as carbon fiber yarns.

<Resin material>
Hexamethylenediamine and isophthalic acid were polymerized in equimolar ratio to prepare polyamide 6I. The Vicat softening temperature was 130 ° C.

<Porous resin material>
The resin material was formed into a nonwoven fabric by a melt blow 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 following main liquid, and the mixture was uniformly stirred at 80 ° C. to obtain an epoxy resin composition.

Main liquid: 40 parts by weight of tetraglycidyldiaminodiphenylmethane type epoxy (“Araldite” (registered trademark) MY-721, manufactured by Huntsman Japan KK) as an epoxy, liquid bisphenol A type epoxy resin (“EPON” (registered trademark)) 825, 35 parts by weight, manufactured by Mitsubishi Chemical Corporation), 15 parts by weight of diglycidylaniline (GAN, manufactured by Nippon Kayaku Co., Ltd.), and a triglycidylaminophenol type epoxy resin (“jER” (registered trademark) 630; (10 parts by weight, manufactured by Mitsubishi Chemical Corporation) were weighed out and stirred at 70 ° C. for 1 hour to uniformly dissolve.

Curing liquid: 70 parts by weight of a 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 Chemical Fine, Inc.) Also, 10 parts by weight of 4,4′-diaminodiphenyl sulfone (“Seika Cure” S, manufactured by Seika Co., Ltd.) were weighed, stirred at 100 ° C. for 1 hour to homogenize, then cooled to 70 ° C., and cured. As an accelerator, 2 parts by weight of t-butylcatechol (DIC-TBC, manufactured by DIC Corporation) was weighed out, and further stirred at 70 ° C. for 30 minutes to uniformly dissolve.

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

<Reinforced fiber laminate>
Such a reinforcing fiber base material is quasi-isotropically laminated [45/0 / -45 / 90] _3S (24 layers: “3S” here means “3S” in the order of orientation angles shown in []) with an AFP device for CAI measurement. An embodiment in which one set (4 layers × 2 = 8 layers) is combined with the stacked layers and the layers stacked so as to have a symmetrical [Symmetry] arrangement, and three sets of these layers are stacked (8 layers × 3 = 24 layers). The same was applied hereafter.), Laminated on a flat preform mold, heated in a 140 ° C. oven for 1 hour in a state where the bag was sealed with a bag film and a sealant and reduced in pressure to a vacuum. Thereafter, the preform was taken out of the oven, cooled to room temperature, and then released to obtain a reinforced fiber laminate. Further, for measuring the compressive strength at high temperature, the AFP device was used to laminate six layers in the direction of 0 ° on a planar preform mold, and then sealed with a bag film and a sealant and depressurized to a vacuum. Heated in an oven at 1 ° C. for 1 hour. Thereafter, the preform was taken out of the oven, cooled to room temperature, and then released to obtain a reinforced fiber laminate.

<Fiber reinforced resin>
A resin diffusion medium (aluminum wire mesh) is laminated on the obtained reinforcing fiber laminate, and a cavity is formed by sealing a flat molding die and a bag material with a sealant, and forming the cavity in a 100 ° C. oven. I put it. After the temperature of the reinforcing fiber laminate reached 100 ° C., the closed cavity was evacuated to a vacuum, and the matrix resin was injected at only a pressure difference from the atmospheric pressure while maintaining the temperature at 100 ° C. After the impregnation with the resin, the temperature was raised to 180 ° C. while continuing the decompression, left to cure for 2 hours, and demolded, to obtain a FRP flat plate 1a for CAI measurement and a FRP flat plate 1b for high-temperature compressive strength measurement. The VRP of the obtained FRP flat plate 1a was 62%, the CAI was 248 MPa, and the high-temperature compressive strength of the FRP flat plate 1b was 1032 MPa.

[Example 2]
The reinforcing fiber yarn to which the porous resin material is not adhered is drawn into a two-dimensional planar shape using an AFP device to form a reinforcing fiber yarn group, and after the porous resin material is arranged thereon, By heating and bonding with an infrared heater, a planar reinforcing fiber substrate was prepared. The basis weight of the reinforcing fiber base was 162 g / m ² .
Such a reinforcing fiber base material is transported one layer at a time, and is laminated on a planar preform mold in a configuration of pseudo isotropic lamination [45/0 / -45 / 90] _3S (24 layers) for CAI measurement. For measuring the high-temperature compressive strength, the same procedure as in Example 1 was carried out except that the layers were laminated on a planar preform mold in a configuration of six layers in the 0-degree direction. An FRP plate 2b was prepared. The VRP of the obtained FRP flat plate 2a was 61%, the CAI was 244 MPa, and the high-temperature compressive strength of the FRP flat plate 2b was 1019 MPa.

[Example 3]
A unidirectional woven fabric as shown in FIG. 4 was prepared using a reinforcing fiber yarn and an auxiliary yarn (“ECE225 1/0 1Z”, manufactured by Unitika Ltd.), and a porous resin material was arranged on one surface thereof. Thereafter, the mixture was heated and bonded by a far-infrared heater to produce a bonded reinforcing fiber substrate. The basis weight of the reinforcing fiber base was 190 g / m ² .
Such a reinforcing fiber substrate is laminated on a flat preform mold in a configuration of pseudo isotropic lamination [45/0 / -45 / 90] _3S (24 layers) for CAI measurement, and for high-temperature compression strength measurement. Was prepared in the same manner as in Example 1 except that six layers were laminated in a 0-degree direction on a planar preform mold to prepare an FRP flat plate 3a for CAI measurement and a FRP flat plate 3b for high-temperature compressive strength measurement. The Vf of the obtained FRP flat plate 3a was 59%, the CAI was 242 MPa, and the high-temperature compressive strength of the FRP flat plate 3b was 983 MPa.

[Example 4]
Using a reinforcing fiber thread and a stitch thread ("Grilon (registered trademark) K-140" 75 dtex, manufactured by Ms. Chemie Japan Co., Ltd.), arranging a porous resin material between the layers and the lowermost layer, and then suturing with the stitch thread By doing so, a two-layer reinforced fiber substrate of [45 / -45] was prepared. The basis weight of the reinforcing fiber substrate was 268 g / m ² .
An FRP flat plate was prepared in the same manner as in Example 1 except that such a reinforcing fiber base was laminated on a planar preform mold in a configuration of pseudo isotropic lamination [45 / -45 / 0/90] _3S (24 layers). 4 was created. The VRP of the obtained FRP was 59%, and the CAI was 246 MPa.

[Example 5]
An FRP flat plate 5 was prepared in the same manner as in Example 1 except that polyamide 6I / 12 obtained by copolymerizing polyamide 6I and polyamide 12 was prepared as a resin material. The Vicat softening temperature of the resin material was 70 ° C., the Vf of the obtained FRP was 64%, and the CAI was 248 MPa.

[Example 6]
An FRP flat plate 6 was prepared in the same manner as in Example 1 except that polyamide 6/66 obtained by copolymerizing polyamide 6 and polyamide 66 was prepared as a resin material. The Vicat softening temperature of the resin material was 195 ° C., the VRP of the obtained FRP was 54%, and the CAI was 242 MPa.

[Comparative Example 1]
A reinforcing fiber base material was prepared in the same manner as in Example 2 except that the form of the resin material was changed to powder, but the sheet-like reinforcing fiber yarns grouped by AFP were separated during transportation, A molded article could not be obtained.

[Comparative Example 2]
An FRP flat plate 7a for CAI measurement and a FRP flat plate 7b for high-temperature compressive strength measurement were prepared in the same manner as in Example 1 except that polyamide 66 was used as the resin material. The Vicat softening temperature was 237 ° C., the Vf of the FRP flat plate 7a was 52%, the CAI was 210 MPa, and the high-temperature compressive strength of the FRP flat plate 7b was 842 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 aircraft, automobiles, and marine transport equipment. It is also suitable for members for general industrial use such as medical equipment such as a windmill blade, a robot arm and an X-ray top.

11: reinforcing fiber base 12: reinforcing fiber assembly 13: resin material 20: bobbin 21: reinforcing fiber base 22: reinforcing fiber yarn 23: resin material 201: opening unit 202: width regulating roller 203: heater 204: Press roll 31: Reinforcement fiber yarn group 32: Reinforcement fiber yarn 300: AFP head 41: Unidirectional fabric 42: Reinforcement fiber yarn (warp)
43: auxiliary yarn (warp)
44: auxiliary yarn (weft)
51: bidirectional fabric 52: reinforcing fiber yarn (warp)
53: Reinforcing fiber yarn (weft)
61: Stitched fabric 62: Reinforced fabric forming + α ° reinforcing fiber layer 63: Reinforced fabric forming 90 ° reinforcing fiber layer 64: Reinforced fabric forming -α ° reinforcing fiber layer 65: Reinforced fabric formed 0 ° reinforcing fiber layer 66: stitch yarn

Claims (15)

  [1]: a reinforcing fiber yarn, [2]: a reinforcing fiber yarn group in which reinforcing fiber yarns are aligned in parallel, [3]: a reinforcing fiber cloth composed of [1] or [2] A reinforcing fiber base material in which a resin material is disposed on at least one surface of a reinforcing fiber aggregate selected from any one of the above, wherein the resin material has a Vicat softening temperature in a range of 70 to 200 ° C. Reinforced fiber substrate.   The reinforcing fiber substrate according to claim 1, wherein the Vicat softening temperature is in a range of 100 to 180C.   The reinforcing fiber substrate according to claim 1 or 2, wherein the shape of the resin material is porous.   The reinforcing fiber base according to any one of claims 1 to 3, wherein the resin material has a range of 1 to 20% by weight based on the reinforcing fiber base.   The reinforcing fiber substrate according to any one of claims 1 to 4, wherein the resin material is an amorphous polyamide.   The reinforcing fiber substrate according to any one of claims 1 to 5, wherein the resin material is a semi-aromatic polyamide containing an isophthalic acid component.   The reinforcing fiber substrate according to any one of claims 1 to 6, wherein the reinforcing fiber yarn group is in a sheet shape in which a plurality of reinforcing fiber yarns are aligned in parallel.   The reinforcing fiber substrate according to any one of claims 1 to 6, wherein the reinforcing fiber yarn group is a sheet-like material arranged and arranged in parallel by an automated fiber placement device.   The reinforcing fiber aggregate is a group of reinforcing fiber yarns in which reinforcing fiber yarns are aligned in one direction in parallel, and extends in a direction intersecting with the reinforcing fiber yarns. The reinforcing fiber substrate according to any one of claims 1 to 6, which is a unidirectional woven fabric composed of a group of auxiliary fiber yarns that is 1/5 or less.   The said reinforcing fiber aggregate is a bidirectional woven fabric comprised of the said group of reinforcing fiber yarns arranged in one direction and the group of reinforcing fiber yarns arranged in one direction in different directions. 7. The reinforcing fiber substrate according to any one of items 1 to 6.   The reinforcing fiber cloth has at least two layers of a reinforcing fiber yarn group arranged in one direction and a reinforcing fiber yarn group arranged in one direction in a different direction, and at least two layers are cross-laminated, and the fineness is a reinforcing fiber yarn. The reinforcing fiber substrate according to any one of claims 1 to 6, wherein the stitching fabric is a stitched fabric stitched and integrated by a group of auxiliary fiber yarns that is 1/5 or less of the yarn.   A reinforcing fiber laminate comprising the reinforcing fiber substrate according to any one of claims 1 to 11 as a reinforcing fiber.   The reinforcing fiber laminate according to claim 12, which is integrated by heat fusion or stitching.   A fiber-reinforced resin comprising the reinforcing fiber substrate according to any one of claims 1 to 11 or the reinforcing fiber laminate according to claim 12 or 13 as a reinforcing fiber.   The fiber reinforced resin according to claim 14, wherein the reinforcing fiber volume content is 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.

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