JP2007182065A - Multi-axial molding material, preform, frp, and manufacturing method for frp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture FRP which is superior in handleability, resin impregnating ability and formability, and also in mechanical characteristics and quality level, with high productivity. <P>SOLUTION: In a multi-axial molding material, at least two sheets, in which many reinforcing fiber threads are arranged in parallel, constitute a laminate by the lamination in such a manner that the reinforced fiber threads cross one another and the laminate is integrated. A mass per unit area of the reinforced fiber thread of each sheet is in the range of 50-350 g/m<SP>2</SP>; a nonwoven fabric, which is composed of a first thermoplastic resin constituting an FRP matrix, is arranged between the sheets in such a manner that its mass per unit area is in the range of 15-250 g/m<SP>2</SP>; and the laminate is integrated by stitch threads which are composed of a second thermoplastic resin. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention has excellent handling properties, resin impregnation properties, moldability, and excellent FRP with excellent mechanical properties and quality while suppressing disturbance in the orientation of reinforcing fiber yarns that occur during molding. The present invention relates to a multiaxial molding material that can be obtained.

  Conventionally, fiber reinforced plastics (hereinafter abbreviated as FRP) using carbon fibers or glass fibers as reinforced fibers are excellent in specific strength and specific elastic modulus, and thus have been used in various applications. As a method of molding such FRP, a prepreg in which a reinforcing fiber base material is impregnated with a matrix resin in advance is used, this is set in a mold, covered with a bag film, heated and pressurized in an autoclave, and the thermosetting resin is cured. In general, there are widely used autoclave molding methods and vacuum injection molding methods in which a reinforced fiber base material in a dry state is set in a mold, and a liquid thermosetting resin is injected under a reduced pressure (vacuum state) in the mold Are known. However, in the autoclave molding method and the vacuum injection molding method, it is necessary to laminate the base materials, and it is necessary to cover with a bag film and reduce the pressure to a vacuum. In particular, in the vacuum injection molding, it is necessary to inject a thermosetting resin. Further, in these methods, the molding time (cycle time) per process including the above-described steps becomes too long, and it is difficult to adapt to, for example, automobile members having a large number of production.

  To solve this problem, for example, a technique has been proposed in which a lamination process when forming into FRP is omitted by using a multi-axis stitch base material that is laminated in advance and sewed with stitch yarns and integrated. (For example, Patent Document 1). However, such a technique requires a step of injecting a matrix resin (thermosetting resin) separately prepared and further curing it, so that the effect is not sufficient.

  On the other hand, as a means for omitting the resin injection / curing step, a molding material (for example, Patent Document 2) in which synthetic resin fibers serving as a matrix and reinforcing fibers are integrated in advance and used as the multiaxial stitch base, A molding material (for example, Patent Document 3) in which a film serving as a matrix is inserted between layers of a multiaxial stitch base has been proposed.

  However, the method described in Patent Document 2 is inferior in resin impregnation property because it is a molding material in which synthetic resin fibers serving as a matrix are arranged in a reinforcing fiber layer in a multiaxial stitch base, and impregnation with resin Had the problem of requiring high pressure. Further, when the matrix resin is impregnated into the reinforcing fiber, it is important to efficiently release the air existing at the portion to be impregnated out of the system, that is, to form a path of the air to the outside of the system. Because the synthetic resin fibers are pre-integrated with the reinforcing fibers, the path of the air to the outside of the system is narrow and easily clogged during pressurization and heating, and as a result, it tends to remain as voids in the FRP. There was a problem. Furthermore, since it is necessary to previously integrate the synthetic resin fiber with the reinforcing fiber, there is a problem that the cost increases due to an increase in the number of steps.

  The method described in Patent Document 3 has a problem that it is difficult for the sewing thread to penetrate the film. In addition, when a resin film is used, when the laminated sheet is molded into a complicated shape such as a quadratic curved surface, the resin film cannot follow the shape and wrinkles occur, or the reinforcing fibers are bent. There was a problem to do. Furthermore, since the reinforcing fiber layers specifically described in Patent Document 3 are thick and have a large basis weight, there is a problem that it is difficult to completely impregnate a molten resin film (matrix) in the thickness direction. Furthermore, Patent Document 3 does not disclose or suggest any means or method for suppressing the bending of the wrinkles or the reinforcing fibers or improving the impregnation property of the matrix resin.

In addition, with respect to the problem concerning the above-mentioned resin film, a molding material in a prepreg or semi-preg state in which a reinforcing fiber sheet and a thermoplastic resin nonwoven fabric are laminated and heated and pressurized has been proposed (for example, Patent Document 4) ). However, when the reinforcing fiber is impregnated into the prepreg or semi-preg state over the entire surface of the molding material, there is a problem in that the handling property and moldability of the molding material are significantly lowered. And in patent document 4, the means and method are not disclosed or suggested regarding the handleability and moldability in the process of laminating in multiple layers.
That is, in the conventional techniques including Patent Documents 1 to 4, a molding material that has excellent handling properties, resin impregnation properties, and moldability, and can obtain FRP with excellent mechanical properties and quality with high productivity. And no FRP derived from it has been found and such techniques are craved.
US Patent Application Publication No. 2005/0059309 Japanese Patent Application Laid-Open No. 2001-073241 JP 2004-346175 A JP 2003-165851 A

  The problem of the present invention is to solve the problem that wrinkles occur when molding into a complicated shape and the problem of inducing bending of reinforcing fibers, and has excellent handling properties, resin impregnation properties, and moldability properties, An object of the present invention is to provide a multiaxial molding material, a preform, an FRP using the same, and a method for producing the same, which can obtain an FRP having excellent mechanical properties and quality with high productivity.

In order to achieve the above object, the present invention is characterized by the following (1) to (14).
(1) At least two sheets in which a large number of reinforcing fiber yarns are arranged in parallel are laminated so that the reinforcing fiber yarns intersect to form a laminate, and the laminate is integrated. It is a multiaxial molding material, wherein the basis weight of the reinforcing fiber yarns in each sheet is in the range of 50 to 350 g / m ² , and is composed of a first thermoplastic resin that constitutes an FRP matrix at least between the sheets. The non-woven fabric is disposed within a range of 15 to 250 g / m ² , and the laminated body is integrated by stitch yarns composed of a second thermoplastic resin. material.
(2) The melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm1-150) ≦ Tm2 ≦ (Tm1-20) The multiaxial molding material as described in 1).
(3) The above-mentioned (3), wherein the melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm2-150) ≦ Tm1 ≦ (Tm2-20) The multiaxial molding material as described in 1).
(4) The above (1), wherein the melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm2-20) <Tm1 <(Tm2 + 20). The multiaxial molding material described in 1.
(5) The sheet is laminated so that the basis weight of the reinforcing fiber yarns is in a range of 90 to 190 g / m ² and the arrangement direction of the reinforcing fiber yarns is mirror-symmetric within a range of 3 to 12 sheets. The multi-axis molding material according to any one of (1) to (4), wherein the nonwoven fabric has a basis weight in a range of 30 to 80 g / m ² .
(6) The nonwoven fabric composed of the first thermoplastic resin is also disposed in the outermost layer of the laminate, and the nonwoven fabric weight W1 disposed between the layers and the nonwoven fabric weight W2 disposed in the outermost layer Satisfies the relationship of (1.2 × W1) ≦ W2 ≦ (3 × W1), the multiaxial molding material according to any one of (1) to (5) above.
(7) The through holes formed by the stitch yarns penetrating in the laminate thickness direction are regularly arranged within a range of 4 to 25 rows / 25 mm in the longitudinal direction and the width direction of the multiaxial molding material, And the density of a through-hole exists in the range of 60,000-200,000 places / m < ² >, The multiaxial molding material in any one of said (1)-(6) characterized by the above-mentioned.
(8) A preform characterized in that the multiaxial molding material according to any one of (1) to (7) is molded into a shape having a quadric surface.
(9) An FRP molded using the multiaxial molding material according to any one of (1) to (7) or the preform according to (8).
(10) The nonwoven fabric composed of the first thermoplastic resin is melted and solidified to form a matrix, and the stitch yarn composed of the second thermoplastic resin is substantially maintained in its form. FRP as described in said (9) characterized by the above-mentioned.
(11) The non-woven fabric composed of the first thermoplastic resin and the stitch yarn composed of the second thermoplastic resin are melted and solidified to form a matrix, as described in (9) above FRP.
(12) Production of FRP using a multiaxial molding material in which a laminate in which at least two sheets of reinforcing fiber yarns arranged in parallel are laminated so that the reinforcing fiber yarns intersect is integrated A method,
As a multiaxial molding material, it has a nonwoven fabric composed of the first thermoplastic resin that constitutes the FRP matrix at least between the sheets, and the laminate is integrated by stitch yarns composed of the second thermoplastic resin. The melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm1-150) ≦ Tm2 ≦ (Tm1-20). Use
The multiaxial molding material is heated to a temperature not lower than Tm2 and not higher than (Tm1-20) to melt the stitch yarn and mold,
Thereafter, the sheet is heated to a temperature of Tm1 or higher to melt the nonwoven fabric, and each sheet is impregnated with a thermoplastic resin.
(13) Production of FRP using a multiaxial molding material in which a laminate in which at least two sheets of reinforcing fiber yarns arranged in parallel are laminated so that the reinforcing fiber yarns intersect is integrated A method,
As a multiaxial molding material, it has a nonwoven fabric composed of the first thermoplastic resin that constitutes the FRP matrix at least between the sheets, and the laminate is integrated by stitch yarns composed of the second thermoplastic resin. The melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm2-150) ≦ Tm1 ≦ (Tm2-20). Use
A method for producing FRP, wherein the multiaxial molding material is heated to a temperature of Tm1 or more and (Tm2-20) or less, the nonwoven fabric is melted while shaping, and each sheet is impregnated with a thermoplastic resin.
(14) Manufacture of FRP using a multiaxial molding material in which a laminate in which at least two sheets in which a large number of reinforcing fiber yarns are arranged in parallel is laminated so that the reinforcing fiber yarns intersect is integrated A method,
As a multiaxial molding material, it has a nonwoven fabric composed of the first thermoplastic resin that constitutes the FRP matrix at least between the sheets, and the laminate is integrated by stitch yarns composed of the second thermoplastic resin. And the melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm2-20) <Tm1 <(Tm2 + 20),
A method for producing FRP, wherein the multiaxial molding material is heated to a temperature equal to or higher than Tm1 and Tm2, and the stitch yarn and the nonwoven fabric are simultaneously melted to impregnate each sheet with a thermoplastic resin.

  According to the multiaxial molding material of the present invention, a non-woven fabric composed of a matrix resin is arranged between sheets composed of reinforcing fiber yarns to form a laminate, and the laminate is integrated with stitch yarns. Therefore, the preform and FRP can be molded easily and quickly, and the resin-impregnating property is achieved because the through-hole of the stitch yarn becomes a resin flow path when the resin is impregnated in the thickness direction. It will be excellent. When either one of the nonwoven fabric and the stitch yarn is melted, each layer of the laminate is easily shear-deformed while maintaining the form, and even when it is molded using a complex shape mold, Disturbance of the orientation of the reinforcing fiber yarn can be suppressed. Further, when the nonwoven fabric and the stitch yarn are melted at the same time, molding can be performed with higher productivity, and there can be obtained an FRP having no trace of the stitch yarn and particularly excellent in surface smoothness.

  Hereinafter, an exemplary embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic perspective view showing one embodiment of the multiaxial molding material of the present invention. FIG. 2 is a schematic sectional view showing an embodiment of the multiaxial molding material of the present invention.

  As shown in FIG. 1 and FIG. 2, the multiaxial molding material 8 comprises a laminate in which at least two sheets of reinforcing fiber yarns arranged in parallel are laminated so that the reinforcing fiber yarns intersect. ing. Sheet 1 is a layer in which reinforcing fiber yarns are arranged in parallel to the longitudinal direction of the multiaxial molding material, and sheet 2 is a layer in which reinforcing fiber yarns are arranged in parallel to the longitudinal direction of the multiaxial molding material at + 45 °. The sheet 3 is a layer in which reinforcing fiber yarns are arranged in parallel at 90 ° to the longitudinal direction of the multiaxial molding material, and the sheet 4 is composed of reinforcing fiber yarns in the longitudinal direction of the multiaxial molding material. It is a layer arranged in parallel at −45 ° to the direction. Here, the longitudinal direction of the multiaxial molding material refers to a direction in which the multiaxial molding material is taken up by a winding device or a direction in which the multiaxial molding material is taken up by a take-up device. In the multiaxial molding material shown in FIG. 1 and FIG. 2, the number of sheets of reinforcing fiber yarns laminated is 4, but these are examples of the multiaxial molding material of the present invention, The number of stacked layers is not limited to this. A preferred laminated structure in the present invention is mirror-symmetrical lamination so as not to warp when formed into FRP, and the preferred number of laminated sheets is 3 to 12 sheets from the balance between handleability and resin impregnation properties. Within range.

The basis weight of the reinforcing fiber yarn in each of these sheets is in the range of 50 to 350 g / m ² . Preferably it exists in the range of 90-190 g / m < ² >. When the basis weight of the reinforcing fiber yarns in each layer is less than 50 g / m ² , not only is the gap formed between adjacent reinforcing fiber yarns and the quality is inferior, but the gaps cause a decrease in mechanical properties. In addition, when the basis weight of the reinforcing fiber yarns in each layer exceeds 350 g / m ² , a portion where adjacent reinforcing fiber yarns overlap with each other is formed, so that the surface of the multiaxial molding material is uneven and the layer is thick. Therefore, the formability is inferior. Furthermore, when the layer becomes thick, it is necessary to apply an excessive external pressure when the nonwoven fabric composed of the thermoplastic resin is melted and completely impregnated, and the reinforcing fiber yarn is bent by the excessive external pressure, Eventually, the problem of the present invention cannot be solved.

  The multiaxial molding material of the present invention is formed between the respective layers of the laminate composed of reinforcing fiber yarns, that is, between the sheet 1 and the sheet 2 in FIGS. 1 and 2, between the sheet 2 and the sheet 3, Between the sheet | seat 3 and the sheet | seat 4, the nonwoven fabric 5 comprised by the thermoplastic resin (1st thermoplastic resin) which comprises the matrix of FRP is arrange | positioned.

  When the reinforcing fiber yarn is impregnated with the matrix resin, it is important to efficiently release the air existing at the portion to be impregnated out of the system, that is, to form a path of the air to the outside of the system. If air cannot escape efficiently, a problem of remaining as a void in the FRP occurs. Therefore, in the present invention, by disposing at least the nonwoven fabric 5 between the sheets, the gap between the single yarns of the sheets 1 to 4 and the reinforcing fiber yarns in the sheet extending outside the entire surface in the plane direction is out of the air system. This avoids the problem that the path to the outside of the air system is blocked during molding. That is, the present invention has found that the matrix resin can be easily impregnated even by molding at a low pressure by disposing the nonwoven fabric 5 at least between the sheets.

  In the multiaxial molding material shown in FIG. 1 and FIG. 2, the nonwoven fabric 9 is arranged on one side of the outermost layer of the multiaxial molding material. However, the nonwoven fabric may be arranged on both sides of the outermost layer, or in the outermost layer. It is not necessary to arrange a nonwoven fabric. When the non-woven fabric 9 is arranged on at least one of the outermost layers of the multiaxial molding material, the outermost non-woven fabric 9 in each multiaxial molding material is partially melted when a plurality of multiaxial molding materials are laminated. This is preferable because the multiaxial molding materials can be integrated (for example, in the form of a preform). The most preferable embodiment is an embodiment in which both of the outermost layers of the multiaxial molding material are arranged.

The nonwoven fabric disposed between the sheets of reinforcing fiber yarns has a basis weight in the range of 15 to 250 g / m ² . Preferably it is 35-150 g / m < ² >, More preferably, it is 40-100 g / m < ² >. If the basis weight of the non-woven fabric is less than 15 g / m ² , the amount of the thermoplastic resin is relatively insufficient with respect to the amount of the reinforcing fiber yarns, so that the non-woven fabric cannot be sufficiently impregnated. Problems such as tearing or deformation in the manufacturing process of the molding material are likely to occur, and the handleability of the nonwoven fabric is significantly reduced. From the same viewpoint, it is preferably 35 g / m ² or more, more preferably 40 g / m ² . In order to avoid this problem, if the basis weight of the reinforcing fiber yarn sheet is lowered beyond the scope of the present invention, a gap is formed between the reinforcing fiber yarns, so that the strength when FRP is reduced is not only reduced. The quality may also deteriorate. On the other hand, if the basis weight of the nonwoven fabric exceeds 250 g / m ² , the content of the reinforcing fiber yarn is relatively reduced, and sufficient strength cannot be exhibited when the FRP is used. In order to avoid this problem, if the basis weight of the reinforcing fiber yarn sheet is increased beyond the scope of the present invention, the reinforcing fiber yarns are overlapped with each other, resulting in unevenness on the surface, resulting in poor formability and quality. In other words, excessive external pressure is required when impregnating the resin, and the reinforcing fiber yarn may be bent. In addition, the basis weight of the reinforcing fiber yarn and the nonwoven fabric of each sheet is obtained by cutting a sample in accordance with JIS R7602 (1989) 5.5, disassembling the multiaxial molding material by releasing local fusion. The value measured for the reinforcing fiber yarns and the nonwoven fabric of the sheet.

  Furthermore, since the multiaxial molding material of the present invention is a laminated body laminated so that the reinforcing fiber yarns intersect, the orientation of the reinforcing fiber yarns is crushed by layers of reinforcing fiber yarns having different upper and lower orientations. However, it tends to meander in the thickness direction, which may lead to a decrease in mechanical properties. However, by setting the basis weight of the non-woven fabric made of resin within the above range, the non-woven fabric inserted between the sheets can relieve unevenness generated in the upper and lower sheets, and the meandering of the reinforcing fiber yarns can be prevented.

And in the multiaxial molding material of this invention, while the fabric weight of the nonwoven fabric arrange | positioned between sheets shall be in the range of 30-80 g / m < ² >, the fabric weight of a reinforced fiber thread | yarn is in the range of 90-190 g / m < ² >. When a certain sheet is laminated so that the arrangement direction of the reinforcing fiber yarns is mirror-symmetric within the range of 3 to 12, the handling property and formability can be balanced at a high level as a synergistic effect thereof. The resulting FRP is particularly excellent in mechanical properties and quality.

  Further, when surface quality is particularly required for the molded FRP, the basis weight W1 of the nonwoven fabric disposed between the sheets and the basis weight W2 of the nonwoven fabric disposed in the outermost layer is (1.2 × W1) ≦ It is preferable to satisfy the relationship of W2 ≦ (3 × W1). When the basis weight of the nonwoven fabric of the outermost layer is less than 1.2 times the basis weight of the nonwoven fabric arranged between the layers, the unevenness of the outermost layer arranged by reinforcing fiber yarns is not relaxed, and the surface smoothness may be inferior. . Moreover, if the basis weight of the nonwoven fabric of the outermost layer exceeds three times the basis weight of the nonwoven fabric disposed between the layers, the fiber content in the vicinity of the outermost layer is remarkably lowered, so that not only the fiber content becomes non-uniform FPR, The resin arranged in the outer layer tends to flow, and the fiber orientation of the reinforcing fiber in the outermost layer is disturbed to cause a decrease in strength, or the FRP may be warped.

The thermoplastic resin constituting the nonwoven fabric used in the present invention preferably has a melt viscosity of 250 Pa · s or less under the conditions of a melting point Tm + 50 ° C. and a shear rate of 1000 / s. More preferably, it is 200 Pa * s or less, More preferably, it is 150 Pa * s or less. If the melt viscosity exceeds 250 Pa · s, it is difficult to produce a nonwoven fabric by the above-described melt blow method or spun bond method. In addition, when it is melted and impregnated into the reinforcing fiber yarn, not only the impregnation property is inferior, but also high pressure is required for impregnation, so the pressure induces bending and bending of the reinforcing fiber yarn. There is a case. The melting point Tm refers to a value measured by DSC (Differential Scanning Calorimeter) according to JIS K7121 (1987) at a heating rate of 20 ° C./min in an absolutely dry state. For those that do not exhibit a melting point (for example, an amorphous polymer), the glass transition temperature + 100 ° C. obtained by the same measurement is regarded as the melting point for the sake of convenience.
In the present invention, as shown in FIGS. 1 and 2, the laminate is integrated by stitch yarns 6 made of a second thermoplastic resin different from the first thermoplastic resin. The second thermoplastic resin may constitute an FRP matrix as in the case of the first thermoplastic resin, or may not constitute a matrix. The stitch yarn 6 sews a laminated body with a needle 7 to constitute a multiaxial molding material 8.

  Here, through-holes 13 are formed in the laminate by stitch yarns penetrating in the thickness direction of the laminate, and the through-holes 13 serve as resin flow paths when the resin is impregnated. Therefore, the multiaxial molding material of the present invention has excellent resin impregnation properties.

Although there are stitch yarns in the through holes 13, the stitch yarns restrain the reinforcing fiber yarns to maintain their orientation direction (angle), minimize damage to the reinforcing fiber yarns, Considering the balance between the uniform shapeability when molding and the balance with the resin impregnation properties described above, the through-holes in the longitudinal direction and the width direction of the multiaxial molding material are 4-25. It is preferable to arrange regularly within a range of rows / 25 mm. More preferably, it is in the range of 5 to 13 rows / 25 mm in each direction. Note that the longitudinal direction and the width direction do not need to be the same interval. The through hole 13 has a density in the planar direction of the multi-axis molding material 8 is preferably in the range of 30,000～250,000 places / ^{m 2.} More preferably 60,000～200,000 places / ^{m 2,} more preferably in the range of 65,000～150,000 places / ^{m 2.} If the through-holes are less than 4 rows / 25 mm or less than 30,000 locations / m ² , the reinforcing fiber yarns are loosely restrained, resulting in inferior handleability, handling, or forming into FRP. Occasionally bending or bending of reinforcing fiber yarns may be induced. In addition, the through holes function as resin impregnation channels in the thickness direction of the multiaxial molding material, and therefore the number of the through holes is small and the impregnation property is likely to be inferior. On the other hand, if the through-hole exceeds 25 rows / 25 mm or exceeds 250,000 locations / m ² , the resin impregnation property is excellent, but the reinforcing fiber yarn is easily damaged by the needle and not only the mechanical properties are inferior. Constraints on the reinforcing fiber yarns are so tight that the shapeability tends to be inferior.

  In addition, the density of a through-hole shows what multiplied 100 times the through-hole in which the stitch thread has penetrated in the thickness direction from the multiaxial molding material cut out to the square of 10 cm x 10 cm. The number of rows of through-holes per 25 mm in the longitudinal direction or width direction of the multiaxial molding material means that the through holes are regularly arranged in the longitudinal direction or the width direction from the multiaxial molding material cut into a 10 cm × 10 cm square. This shows the number of columns that are counted, and the value obtained by dividing each number by 4 to the first decimal place. The determination of whether or not the through holes are regularly arranged is obtained by calculating the distance between the 25 through holes that are adjacent to each other in the direction of the multiaxial molding material, and the respective distances with respect to the average value. If the individual value is within ± 10%, it is judged as regular. Note that the distances between adjacent through holes do not have to be the same.

  Since the multiaxial molding material of the present invention has the above-described configuration, it is greatly improved in moldability as compared with a molding material (including a prepreg or semi-preg sheet) that is completely fixed in Patent Document 4 in the background art. It is excellent in.

The multiaxial molding material of the present invention is a molding material containing a matrix resin in itself, and is different from a dry intermediate substrate in which a matrix resin prepared separately is injected and cured later. In the dry intermediate substrate, as described above, there are no problems such as resin impregnation property and deterioration of moldability caused by arranging the members constituting the matrix resin in advance. Although the non-woven fabric constituting the matrix can be disposed and the laminating step and the resin injection / curing step can be omitted, the resin impregnation property and the moldability are excellent as described above.
As a method for integrating the laminated body, there is a so-called stitch bonding in which stitch yarn is stitched with a needle using a knitting machine, a sewing machine or the like. Examples of the knitting structure of the stitch yarn include chain knitting, 1/1 tricot knitting, or irregular 1/1 tricot knitting in which chain knitting and 1/1 tricot knitting are combined. In addition to being able to obtain a material with the desired configuration and thickness as a single base material, stitch bonding has the feature that the strength of restraint of each unit can be manipulated freely by optimizing the knitting structure .

  The first thermoplastic resin constituting the nonwoven fabric and the second thermoplastic resin constituting the stitch yarn include the melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin (Tm1- 150) ≦ Tm2 ≦ (Tm1-20) is preferably used (hereinafter referred to as “Aspect A”). The melting point refers to a value measured by DSC (Differential Scanning Calorimeter) according to JIS K7121 (1987) at a heating rate of 20 ° C./min in an absolutely dry state. In the present invention, the glass transition temperature + 100 ° C. obtained by the above measurement method is simply regarded as the melting point for those that do not exhibit a melting point (for example, an amorphous polymer).

  When the melting points of the first thermoplastic resin and the second thermoplastic resin are in the relationship of the aspect A, the stitch yarn can be melted first when the FRP is formed. This makes it easy for each layer composed of reinforcing fiber yarns to undergo shear deformation before the nonwoven fabric is melted and impregnated into the reinforcing fiber yarn layers. In addition, in the case of this aspect A, the previously melted stitch yarn changes its form and remains in the through hole, thereby preventing each layer composed of reinforcing fiber yarns from undergoing excessive shear deformation. The remarkable bending of the fiber orientation can be suppressed. For this reason, even when a mold having a complicated shape (for example, a quadric surface) is used, it is possible to perform molding while suppressing wrinkles generated in the multiaxial molding material. Furthermore, when laminating a plurality of multiaxial molding materials, the nonwoven fabric is not melted, and the stitch yarn composed of the second thermoplastic resin is partially melted to integrate the multiaxial molding materials (for example, This is a preferred embodiment in the present invention.

  As a specific combination satisfying the relationship of the aspect A, for example, the first thermoplastic resin is polyamide 6 or polyamide 66, and the second thermoplastic resin is polyamide 11, polyamide 12 or copolymer polyamide (for example, Polyamide 6/66/12, polyamide 610/12, polyamide 6/66/610/12, polyamide 6/66/612/12, and the like, and the first thermoplastic resin is polyamide 66 and the second A combination in which the thermoplastic resin is polyamide 6, a combination in which the first thermoplastic resin is polyester and the second thermoplastic resin is a copolyester, and the first thermoplastic resin is polyethylene or polypropylene and the second heat A combination in which the plastic resin is a copolymerized polyolefin, and the first thermoplastic resin is polypropylene 2 of thermoplastic resin include combinations is ethylene. In the case of the above combination, the first thermoplastic resin and the second thermoplastic resin are composed of resins having a similar molecular structure, so that both are excellent in compatibility and exhibit excellent mechanical properties in FRP. Can do.

  In addition, when the first thermoplastic resin is a combination of polyphenylene sulfide and the second thermoplastic resin is polyamide, the difference in melting point between the first thermoplastic resin and the second thermoplastic resin can be increased. In particular, there is an advantage of excellent formability.

  From another viewpoint, the melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin are (Tm2-150) as the first thermoplastic resin and the second thermoplastic resin. It is preferable to use those satisfying the relationship of ≦ Tm1 ≦ (Tm2-20) (hereinafter referred to as Aspect B).

  When the melting points of the first thermoplastic resin and the second thermoplastic resin are in the relationship of the mode B, the nonwoven fabric can be melted first when it is molded into FRP. As a result, while the nonwoven fabric is melted and the first thermoplastic resin is impregnated in the reinforcing fiber yarn layer, each layer composed of the reinforcing fiber yarn is reinforced by the unmelted stitch yarn. In addition to preventing disorder of the orientation of the fiber yarns, the first thermoplastic resin that is melted by the through-holes in the sheet thickness direction of the reinforcing fiber yarns formed by the stitch yarns serving as resin impregnation channels There is an unexpected effect of significantly improving the impregnation property. In addition, the improvement of the impregnation property by the through hole can bring about an effect regardless of whether or not the stitch yarn is melted. That is, the effect is exhibited in any of the above-described aspect A and aspect C described later. Specifically, in aspects A and C in which the stitch yarn is melted, the stitch yarn melts first or at the same time. Functions as an impregnation channel. On the other hand, in the aspect B in which the stitch yarn is not melted, the stitch yarn remains in the shape of the yarn, so that the shape of the through hole is reliably maintained, and the function as the impregnation channel is more efficiently performed. That is, this effect is greatly manifested in Aspect B described later. Furthermore, in the aspect B, since the nonwoven fabric is first melted and the resin is impregnated in each layer, the interlayer thickness into which the nonwoven fabric has been inserted becomes thin as shown in FIG. Shear deformation becomes easier and the generation of wrinkles can be suppressed. For this reason, it is possible to obtain a high-quality FRP in which the orientation of the reinforcing fiber yarn is aligned and excellent mechanical properties can be expressed. Furthermore, when the nonwoven fabric composed of the first thermoplastic resin is also disposed on at least one of the outermost layers of the multiaxial molding material, the stitch yarn is melted when laminating a plurality of multiaxial molding materials. Therefore, the non-woven fabric is partially melted so that the multiaxial molding materials can be integrated (for example, a form of a preform). FIG. 3 is a schematic view for easy understanding of the state in which the stitch yarn is loosened. In the stage where the nonwoven fabric is actually melted, the matrix even if the stitch yarn is loose. Immerse in resin.

  As a specific combination of the embodiment B satisfying such a relationship, for example, the first thermoplastic resin is polyamide 11, polyamide 12 or copolymer polyamide (for example, polyamide 6/66/12, polyamide 610/12, polyamide 6 / 66/610/12, etc.) and the second thermoplastic resin is polyamide 6 or polyamide 66, or the first thermoplastic resin is polyamide 6 and the second thermoplastic resin is polyamide 66. A combination in which the first thermoplastic resin is a copolyester and the second thermoplastic resin is a polyester, the first thermoplastic resin is a copolyolefin and the second thermoplastic resin is polyethylene or polypropylene The first thermoplastic resin is polyethylene and the second thermoplastic resin is polypropylene. Combination, and the like that. In the case of the above combination, when a resin similar to the first thermoplastic resin and the second thermoplastic resin is used, the adhesiveness between the two is excellent, and thus excellent mechanical properties can be expressed.

  Further, when the first thermoplastic resin is a polyolefin and the second thermoplastic resin is a combination of polyester, etc., the difference in melting point between the first thermoplastic resin and the second thermoplastic resin can be increased, Since it can be easily impregnated, there is an advantage of excellent moldability.

  From another viewpoint, as the first thermoplastic resin and the second thermoplastic resin, the melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin are (Tm2-20) < It is preferable to use those satisfying the relationship of Tm1 <(Tm2 + 20), that is, the melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin are substantially the same (hereinafter referred to as “Tm1 <(Tm2 + 20)”). , Referred to as aspect C).

  When the melting points of the first thermoplastic resin and the second thermoplastic resin are in the relationship of mode C, the stitch yarn and the nonwoven fabric can be melted almost simultaneously when forming into FRP. In such a multiaxial molding material, since there is no thing that suppresses the disorder of the orientation of the reinforcing fiber yarn other than the stitch yarn melted and changed in form as compared with the aspect A and the aspect B, the mold having a complicated shape Is used, the effect of suppressing the disorder of the orientation of the reinforcing fiber yarn is inferior to that of the modes A and B, but the heating at the time of molding can be made one step, and the molding cycle can be shortened. it can. Moreover, it can shape | mold so that few traces of a stitch thread | yarn may be left by one heating, and FRP excellent in surface smoothness can be obtained. Furthermore, since the first thermoplastic resin and the second thermoplastic resin can be made of the same resin, they are more excellent in compatibility with each other, and can exhibit particularly excellent mechanical properties in FRP.

  As the reinforcing fiber yarn used in the present invention, it is preferable to use those that can be used as reinforcing fiber yarns for composite materials. For example, carbon fiber, graphite fiber, glass fiber, and aramid, paraphenylenebenzobisoxazole, Organic fibers such as polyvinyl alcohol, polyethylene, polyarylate, and polyimide can be used, and one or a combination of two or more of these can be used. Among these, carbon fibers are excellent in specific strength and specific elastic modulus and are preferably used.

  The reinforcing fiber yarn is preferably attached with 0.2 to 2.5% by weight of a sizing agent in order to improve handleability and resistance to needle abrasion during stitching. The fiber yarn to which the sizing agent within the above range is attached can efficiently suppress the generation of fuzz.

The reinforcing fiber yarn can be used either untwisted or twisted, but from the standpoint of mechanical properties such as tensile strength and compressive strength, those having substantially no twist (less than 1 turn / m) are preferable. From this point of view, in the production of the multiaxial molding material of the present invention, the reinforcing fiber yarns may be longitudinally unwound and mixed with unwinding twist, but transversely unraveling and untwisting does not enter. Thus, it is preferable that the reinforcing fiber yarn is present in the multiaxial molding material in a substantially non-twisted state (less than 1 turn / m). By taking a horizontal cut, not only is it easy to reliably obtain a high-quality sheet even in the basis weight within the scope of the present invention, but also the reinforcing fiber volume mixing ratio Vf and mechanical properties can be improved as FRP. it can. In particular, when the basis weight of the sheet is 190 g / m ² or less, a gap (gap) between the reinforcing fiber yarns is easily formed in the sheet, and the sheet quality may be inferior. The above effect is remarkably exhibited when the fineness of the reinforcing fiber yarn is within the range described later. The fineness of the reinforcing fiber yarn is preferably 500 to 7,000 tex, more preferably 1,000 to 2,000 tex. When the fineness is too small, there is almost no problem that the fiber yarn is twisted, and the effect of the present invention may not be exhibited. Further, since the fiber yarn is expensive and a large number of fiber yarns having such fineness are used, the multiaxial substrate itself is also expensive. On the other hand, if the fineness is too large, for example, when obtaining a multi-axis molding material having a low basis weight of reinforcing fiber yarns per layer of 100 g / m ² or less, the yarn width is likely to fluctuate with a slight force and stable. It may be difficult to maintain the finished yarn width.

  As a nonwoven fabric used by this invention, what was manufactured by the card | curd method, the melt blow method, the spun bond method, the papermaking method etc. is mentioned, for example. Such a non-woven fabric may be formed on a support such as a release paper or a film, or may be handled alone, but those that can be handled independently are available at a lower cost. Since the nonwoven fabric produced by the above method is a combination of discontinuous thermoplastic fibers, it has excellent formability when applied to multiaxial molding materials and smooth needle penetration in stitches (continuous stitching). Sex). In addition, a fabric in which continuous fibers are aligned to form a non-woven structure can be given as an example, and one or a combination of two or more of these can also be used. Among these, it is preferable to use those manufactured by the melt blow method or the spunbond method from the viewpoint of material cost and those manufactured by the card method from the viewpoint of moldability.

  The preform of the present invention is formed by laminating the above-mentioned multiaxial molding materials into a shape having a quadric surface. By using the multiaxial molding material of the present invention, a shape having a quadratic curved surface can be molded while preventing wrinkles, and molded into a preform that suppresses the disorder of the orientation of reinforcing fiber yarns. be able to.

  FIG. 4 is a schematic cross-sectional view showing one embodiment of the FRP of the present invention.

  The FRP 12 of the present invention is molded using the above-mentioned multiaxial molding material or preform, and at least the first thermoplastic resin constituting the nonwoven fabric is melted and solidified to form a matrix resin 10. Is. In the case of the multiaxial molding material or preform of the present invention integrated with the matrix resin in advance, the step of injecting the matrix resin as in RTM can be omitted, so the molding cycle can be shortened and the productivity of FRP can be reduced. Excellent. In addition, when the multiaxial molding material or preform of the present invention is used, the shape having a quadratic curved surface can be molded while suppressing the generation of wrinkles, and the FRP that suppresses the disorder of the orientation of the reinforcing fiber yarn can be obtained. Can be molded.

  When such a FRP uses a nonwoven fabric or stitch yarn composed of the thermoplastic resin of the above-mentioned aspect A, after the stitch yarn composed of the second thermoplastic resin is melted, the second thermoplastic resin is first melted. Since the non-woven fabric composed of is melted and solidified to form a matrix, the FRP has no trace of stitch yarn. And as above-mentioned, it can shape | mold while suppressing wrinkles also in a complicated shape, As a result, it can be set as FRP excellent in surface smoothness and a mechanical characteristic. Also, when forming and forming a preform by laminating a plurality of multiaxial molding materials, the multiaxial molding materials can be integrated with each other in advance, so that the molding cycle is short and the productivity is excellent. .

  Moreover, when the nonwoven fabric comprised from the thermoplastic resin of the said aspect B and a stitch thread | yarn are used, the nonwoven fabric comprised from the 1st thermoplastic resin fuse | melted and solidified to comprise a matrix, and 2nd heat The stitch yarn composed of the plastic resin becomes an FRP that substantially maintains its form, and as described above, the stitch yarn that is not melted suppresses the disorder of the orientation of the reinforcing fiber yarn and has excellent mechanics. It becomes FRP which can express a characteristic.

  Furthermore, when the nonwoven fabric and stitch yarn comprised from the thermoplastic resin of the said aspect C are used, the nonwoven fabric comprised from the 1st thermoplastic resin and the stitch yarn comprised from the 2nd thermoplastic resin are At the same time, FRP is formed by melting and solidifying the matrix. And as above-mentioned, a shaping | molding cycle can be shortened and it can be set as FRP excellent in surface smoothness and a mechanical characteristic. In addition, although the stitch thread | yarn is described in FIG. 4, the trace of a stitch thread | yarn does not remain in the multiaxial molding material of aspect A or C.

Such FRP of the present invention can be produced by the following method.
That is, at least between the sheets has a non-woven fabric composed of the first thermoplastic resin constituting the matrix of FRP, and the laminate is integrated by the stitch yarn composed of the second thermoplastic resin, In addition, a multiaxial molding material is used in which the melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm1-150) ≦ Tm2 ≦ (Tm1-20). In this case, the multiaxial molding material is heated to a temperature of Tm2 or more (Tm1-20) or less, and the stitch yarn is melted in a state where the nonwoven fabric is not melted, and then heated to a temperature of Tm1 or more. By melting the nonwoven fabric and impregnating each sheet with a thermoplastic resin, the FRP as described in aspect A can be produced. That is, since the stitch yarn can be melted first before the nonwoven fabric is melted and impregnated in the reinforcing fiber yarn layer, each layer of the laminate is easily shear-deformed and has a complicated shape (for example, a quadratic curved surface). ) Generation of wrinkles can be suppressed.

  Moreover, as a multiaxial molding material, it has a nonwoven fabric comprised from the 1st thermoplastic resin which comprises the matrix of FRP at least between sheets, and a laminated body is comprised with the stitch thread | yarn comprised from the 2nd thermoplastic resin. The melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm2-150) ≦ Tm1 ≦ (Tm2-20). In the case of using a material, the above-described aspect is obtained by heating the multiaxial molding material to a temperature of Tm1 or more (Tm2-20) or less, melting the nonwoven fabric while shaping, and impregnating each sheet with a thermoplastic resin. FRP as described in B can be manufactured. That is, while the nonwoven fabric is melted and the first thermoplastic resin is impregnated into the reinforcing fiber yarn layer, each layer constituted by the reinforcing fiber yarn is restrained by the unmelted stitch yarn. Therefore, disorder of the orientation of the reinforcing fiber yarn can be prevented. Further, since the through-holes in the sheet thickness direction of the reinforcing fiber yarns formed by the stitch yarn serve as the resin impregnation flow path, the molten first thermoplastic resin smoothly impregnates the reinforcing fiber yarn layer. Furthermore, since the nonwoven fabric is melted and impregnated first, the interlayer thickness into which the nonwoven fabric has been originally inserted becomes thin, and the stitch yarn loosens, so that the occurrence of wrinkles can be suppressed due to the shear deformation of each layer. That is, since it is restrained moderately by the stitch yarn, it is possible to obtain a high-quality FRP capable of minimizing the disorder of the orientation of the reinforcing fiber yarn and exhibiting excellent mechanical properties.

  Furthermore, when the nonwoven fabric is melted and each layer is impregnated with a thermoplastic resin, and the stitch yarn is melted by heating to a temperature of Tm2 or higher, the design properties of the FRP are minimized. Therefore, surface quality with excellent FRP can be obtained. For this reason, the process of heating to a temperature of Tm2 or higher is effective for obtaining FRP in which design properties are particularly important.

  Furthermore, as a multiaxial molding material, at least between the sheets, the laminate has a nonwoven fabric composed of a first thermoplastic resin constituting a matrix of FRP, and a laminate is formed by stitch yarns composed of a second thermoplastic resin. The ones that are integrated and the melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm2-20) <Tm1 <(Tm2 + 20) When used, the FRP as described in the above aspect C is obtained by heating the multiaxial molding material to a temperature of Tm1 and Tm2 or more, simultaneously melting the stitch yarn and the nonwoven fabric, and impregnating each sheet with a thermoplastic resin. Can be manufactured. In other words, heating at the time of molding can be performed in one step, the molding cycle can be shortened, and molding can be performed so as to leave almost no trace of stitch yarn by one heating, and the surface smoothness is excellent. FRP can be obtained. Furthermore, since the same resin can be used for the first thermoplastic resin and the second thermoplastic resin, the compatibility of both is further improved, and particularly excellent mechanical properties can be expressed in FRP.

  The means for heating and pressurizing the multiaxial molding material of the present invention is not particularly limited, but it is preferable to use an autoclave, a combination of an oven and atmospheric pressure, a press machine, etc. Among them, the speed of molding time is particularly high. To a press machine is more preferable.

  The following materials were used as raw materials in the examples and comparative examples.

Reinforcing fiber yarn / PAN carbon fiber yarn, 12,000 filaments, fineness 800 tex, tensile strength 4,900 MPa, tensile elastic modulus 240 GPa, 0 turns / m, sizing agent 0.5% by weight.

Stitch yarn / stitch yarn A: Copolyamide, 10 filament, fineness 56 dtex, melting point 115 ° C.
Stitch yarn B: polyamide 66, 10 filament, fineness 33 dtex, melting point 255 ° C.

Nonwoven fabric / nonwoven fabric A: Polyamide 6, basis weight 80 g / m ² , melting point 220 ° C.
Non-woven fabric B: copolymerized polyamide, basis weight 80 g / m ² , melting point 115 ° C.
Non-woven fabric C: Same as non-woven fabric A except that the basis weight is 10 g / m ² .
Non-woven fabric D: Same as non-woven fabric A except that the basis weight is 120 g / m ² .
Non-woven fabric E: Same as non-woven fabric A except that the basis weight is 220 g / m ² .
Non-woven fabric F: Same as Non-woven fabric A except that the weight per unit area is 280 g / m ² .

Example 1
First, a 1.3 m wide laminate was formed by the following procedure. That is, the laminated body which has the nonwoven fabric A in each of between each sheet | seat comprised with the reinforced fiber yarn and outermost layer was formed.
(1) The nonwoven fabric A arranged in the outermost layer was continuously arranged on the belt conveyor so that the longitudinal directions of the nonwoven fabric A and the belt conveyor were parallel. Such a belt conveyor continues to move in the longitudinal direction (0 ° direction) at a constant speed (1 m / min in the present embodiment) while laminating the subsequent layers of reinforcing fiber yarns and the nonwoven fabric. It was intended to be transported continuously.
(2) On the nonwoven fabric A, the reinforcing fiber yarns that have been laterally unwound so as not to mix the untwisted twist are set to −45 ° with respect to the longitudinal direction (the direction in which the belt conveyor conveys, 0 ° direction). A -45 ° sheet was formed in parallel and arranged to be 150 g / m ² . The arrangement of the reinforcing fiber yarns of the −45 ° sheet was performed by a carriage device. The carriage device in this step reciprocates in the -45 ° direction, and is a device that arranges reinforcing fiber yarns on the belt conveyor during the forward movement (or backward movement), and the belt conveyor moves in the longitudinal direction. Control was performed so that the reinforcing fiber yarns do not overlap each other and are arranged next to each other in order in synchronization with the conveying speed.
(3) The second nonwoven fabric A is placed on the −45 ° sheet, and the reinforcing fiber yarns are parallel to the longitudinal direction at + 90 ° with respect to the longitudinal direction in the same manner as in the −45 ° sheet formation. And a + 90 ° sheet was formed so as to be 150 g / m ² .
(4) A third non-woven fabric A is placed on the + 90 ° sheet, and the reinforcing fiber yarns are parallel to the longitudinal direction at + 45 ° in the same manner as in the −45 ° sheet formation. And it arranged so that it might become 150 g / m < ² >, and the +45 degree sheet | seat was formed.
(5) The fourth nonwoven fabric A is arranged on the + 45 ° sheet layer, and the reinforcing fiber yarns are parallel to the longitudinal direction at 0 ° in the same manner as in the −45 ° sheet formation. And a 0 ° sheet was formed by arranging so as to be 150 g / m ² .
(6) The 5th nonwoven fabric A was arrange | positioned on the said 0 degree sheet | seat, and the laminated body was formed.
Subsequently, the laminate on the belt conveyor formed as described above was stitched together with the stitch yarn A and integrated. In such stitches, the stitch yarn A was unwound by an unwinding device and knitted while allowing the needle to penetrate the laminate. The stitch yarn knitting structure is an irregular 1/1 tricot knitting in which chain knitting and 1/1 tricot knitting are combined, and through holes by the stitch yarn are arranged in 5 rows / 25 mm in the longitudinal direction of the multiaxial molding material and 8 in the width direction. They were regularly arranged to be 3 rows / 25 mm. The density of the through holes was 66,666 places / m ² . Nonwoven fabric A was excellent in needle penetrability, and the fibers of the nonwoven fabric were not entangled with the needle. The multiaxial molding material integrated by the stitch yarn A was wound as a multiaxial molding material a by a winding device. (Aspect A)
Subsequently, the multiaxial molding material a (Aspect A) is placed in a mold having a hemispherical quadric surface, and the wrinkles generated while the stitch yarn A is melted while being heated to 150 ° C. are stretched and molded. And pressed (pressed) at 25 MPa for 180 seconds. While being pressurized, the mold temperature was raised to 250 ° C. and held for 180 seconds, the mold temperature was cooled to 50 ° C., and then the pressure was released and demolded to obtain FRP.

  When the cross section cut out from the obtained FRP so as to have a width of 2 cm is observed with an optical microscope, the resin is impregnated into the inside of the reinforcing fiber yarn, and the observation surface of the void is slightly seen near the outermost layer 96% of the resin was impregnated with resin. Further, although the fiber orientation was disordered and the surface was slightly uneven, no wrinkles were observed.

(Example 2)
The stitch yarn A to be used is replaced with the stitch yarn B, the stitch yarn knitting structure is chain knitting, and the through holes by the stitch yarn are 5 rows / 25 mm in the longitudinal direction of the multiaxial molding material and 16.7 rows / 25 mm in the width direction. The multiaxial molding material was formed in the same manner as in Example 1 except that the density of the through holes was 133,333 locations / m ^2, and the multiaxial molding material was formed as a multiaxial molding material b. did. (Aspect B)
Subsequently, the multiaxial molding material b (Aspect B) is placed in a mold having a hemispherical quadratic curved surface, and the wrinkles generated while melting the nonwoven fabric A while heated to 230 ° C. are stretched to follow the mold. The mold was pressurized (pressed) at 25 MPa for 240 seconds, and the mold temperature was cooled to 50 ° C. while being pressurized, and then released and demolded to obtain FRP.

  In the obtained FRP, the resin was impregnated even inside the reinforcing fiber yarn, and 99% of the observation surface was impregnated with the resin. Further, although the surface unevenness was slightly generated, no disorder of fiber orientation or generation of wrinkles was observed.

(Example 3)
A multiaxial molding material was formed in the same manner as in Example 1 except that the nonwoven fabric A to be used was changed to the nonwoven fabric B, and this was designated as a multiaxial molding material c. (Aspect C)
Subsequently, the multiaxial molding material c (Aspect C) is placed in a mold having a hemispherical quadratic curved surface, and the generated wrinkles are stretched while the nonwoven fabric B and the stitch yarn A are melted while being heated to 150 ° C. The mold was followed by pressing, pressing (pressing) at 25 MPa for 180 seconds, cooling the mold temperature to 50 ° C. while applying pressure, and then releasing and releasing the mold to obtain FRP.

  In the obtained FRP, the resin was impregnated to the inside of the reinforcing fiber yarn, and although a void was slightly seen in the vicinity of the outermost layer, 96% of the observation surface was impregnated with the resin. Further, there was almost no trace of the stitch yarn, but there was almost no disorder of fiber orientation or wrinkles. Moreover, it was the most excellent in surface quality compared with FRP in Examples 1 and 2.

Example 4
FRP was molded in the same manner as in Example 1 except that the nonwoven fabric A arranged in the outermost layer was changed to the nonwoven fabric D.

  In the obtained FRP, the resin was impregnated to the inside of the reinforcing fiber yarn, and although a void was slightly seen in the vicinity of the outermost layer, 97% of the observation surface was impregnated with the resin. Although the fiber orientation was slightly disturbed, no wrinkles were observed. Furthermore, the thickness of the surface matrix layer was increased, the unevenness of the surface was relaxed, and the surface smoothness was superior to the FRP of Example 1.

(Example 5)
FRP was molded in the same manner as in Example 1 except that the nonwoven fabric A arranged in the outermost layer was changed to the nonwoven fabric E.

  In the obtained FRP, the resin was impregnated to the inside of the reinforcing fiber yarn, and although a void was slightly seen in the vicinity of the outermost layer, 97% of the observation surface was impregnated with the resin. There were no wrinkles. Furthermore, although the resin in the vicinity of the outermost layer flows to cause slight disturbance in the fiber orientation of the outermost layer, the thickness of the surface matrix layer increases, the unevenness of the surface is relaxed, and the surface smoothness is higher than that of the FRP of Example 4. It was even better.

(Example 6)
In forming each sheet, except that the reinforcing fiber yarns that have been longitudinally unwound so as to mix the untwisted strands are arranged to be 330 g / m ^2, and the nonwoven fabric A to be used is replaced with the nonwoven fabric E. FRP was molded in the same manner as in Example 1. In the obtained FRP, the resin-impregnated portion (void) was slightly seen in the central portion in the thickness direction of the reinforcing fiber yarn sheet, but the resin was impregnated in 93% of the observation surface, and wrinkles were observed. There wasn't.

(Example 7)
The through holes formed by stitch yarns are regularly arranged so that the length of the multiaxial molding material is 2.5 rows / 25 mm in the longitudinal direction and 5 rows / 25 mm in the width direction, and the density of the through holes is 20,000 locations / m. except for using ^2, it was molded FRP in the same manner as in example 2. In the obtained FRP, although the resin non-impregnated portion (void) was slightly seen in the central portion in the reinforcing fiber yarn sheet thickness direction, 91% of the observation surface was impregnated with the resin. Further, slight unevenness on the surface was generated, and disorder of fiber orientation and generation of wrinkles were slightly observed.

(Comparative Example 1)
A multiaxial molding material was formed in the same manner as in Example 1 except that the reinforcing fiber yarns of each sheet were arranged to be 40 g / m ² . The obtained multiaxial molding material was inferior in quality because a gap was formed between adjacent reinforcing fiber yarns. Furthermore, although FRP was shape | molded by the method similar to Example 1, in the obtained FRP, the said clearance gap was not eliminated but the quality was inferior.

(Comparative Example 2)
A multiaxial molding material was formed in the same manner as in Example 1 except that the nonwoven fabric A used was changed to the nonwoven fabric C. Since the nonwoven fabric C has a small basis weight, it is inferior in handleability, and problems such as the nonwoven fabric being torn or deformed and partially thinning during the production of the multiaxial molding material frequently occurred, and stable production could not be performed. The obtained multiaxial molding material was inferior in quality with a non-uniform basis weight such as a thin portion of the nonwoven fabric being seen. Further, FRP was molded by the same method as in Example 1, but the basis weight of the nonwoven fabric C was too small (the amount of the matrix resin was too small), so the absolute amount of the matrix resin was insufficient, and the resin unimpregnated portion was particularly reinforced fiber yarn. It occurred frequently in the central part in the thickness direction of the strip sheet and could not be used as FRP.
(Comparative Example 3)
In forming each sheet, the non-woven fabric E is a non-woven fabric E, in which the reinforcing fiber yarns longitudinally unwound so as to mix the untwisted strands are arranged to be 360 g / m ^2, and the non-woven fabric disposed between the sheets. A multiaxial molding material was formed in the same manner as in Example 1 except for the above point. In addition, in order to make the fiber mixing volume ratio Vf in FRP into the same grade as Example 1, the nonwoven fabric different from Example 1 was used.

  The obtained multiaxial molding material was inferior in surface quality because adjacent reinforcing fiber yarns overlapped to form irregularities on the surface of the multiaxial molding material. Further, when FRP was molded by the same method as in Example 1, the sheet was thick (having a large basis weight), so that the formability was inferior, and the obtained FRP had an unimpregnated portion of the matrix resin (particularly reinforcing fiber). A large portion of the thickness of the yarn sheet) was observed.

(Comparative Example 4)
A multiaxial molding material was formed in the same manner as in Example 1 except that the nonwoven fabric A to be used was replaced with the nonwoven fabric F, and the reinforcing fiber yarns were arranged by longitudinally milling so as to mix the untwisted yarn. Furthermore, although FRP was shape | molded by the method similar to Example 1, the impregnation of resin was satisfactory in the obtained FRP. However, since the basis weight of the nonwoven fabric D is too large (the amount of the matrix resin is too large), the thermoplastic resin (matrix resin) constituting the nonwoven fabric flows too much from the product shape when being pressed (pressed). Along with this resin flow, a large disturbance of fiber orientation occurred. Moreover, the reinforcement fiber mixture rate in FRP became smaller than Example 1, and was inferior to the weight reduction effect as FRP.

(Comparative Example 5)
FRP was molded in the same manner as in Example 1 except that the nonwoven fabric A arranged in the outermost layer was changed to the nonwoven fabric F.

  In the obtained FRP, the resin was impregnated to the inside of the reinforcing fiber yarn, and no generation of wrinkles was observed. However, since the basis weight of the nonwoven fabric F arranged in the outermost layer is too large (the amount of the matrix resin is too much), the thermoplastic resin (matrix resin) constituting the nonwoven fabric near the outermost layer when pressed (pressed) Flowed too much from the product shape, and along with this resin flow, a large disorder of fiber orientation occurred in the outermost layer.

  According to the multiaxial molding material of the present invention, the handling property is excellent, and in the molding of FRP having a complicated shape, it is possible to suppress wrinkles and disorder of the orientation of the reinforcing fiber yarns. Since the impregnation is excellent, a high-quality FRP can be obtained with high productivity. Such a multiaxial molding material can be suitably used for a structural member of a transportation device such as an automobile, an aircraft, a ship, a building member, or the like.

It is a schematic perspective view which shows one embodiment of the multiaxial molding material in this invention. It is a schematic sectional drawing which shows one embodiment of the multiaxial molding material in this invention. It is a schematic sectional drawing which shows one embodiment of the multiaxial molding material of the state in which the nonwoven fabric in this invention was fuse | melted. It is a schematic sectional drawing which shows one embodiment of FRP in this invention.

Explanation of symbols

1: Sheet in which reinforcing fiber yarns are arranged in parallel in the longitudinal direction 2: Sheet in which reinforcing fiber yarns are arranged in parallel at + 45 ° with respect to the longitudinal direction 3: Reinforcing fiber yarns are 90 in the longitudinal direction Sheets arranged in parallel to ° 4: Sheets of reinforcing fiber yarns arranged in parallel to the longitudinal direction at −45 ° 5: Non-woven fabric between layers 6: Stitch yarn 7: Needle 8: Multiaxial molding material 9: Non-woven fabric of outermost layer 10: Matrix resin 11: Multiaxial molding material in which nonwoven fabric is melted 12: FRP
13: Through hole with stitch yarn

Claims (14)

Multi-axial molding in which at least two sheets in which a large number of reinforcing fiber yarns are arranged in parallel are laminated so that the reinforcing fiber yarns intersect to form a laminate, and the laminate is integrated A nonwoven fabric composed of a first thermoplastic resin constituting a matrix of FRP at least between the sheets, wherein the basis weight of the reinforcing fiber yarns in each sheet is in the range of 50 to 350 g / m ^2. A multiaxial molding material, which is disposed within a range of 15 to 250 g / m ² , and wherein the laminate is integrated by stitch yarns composed of a second thermoplastic resin.   The melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy a relationship of (Tm1-150) ≦ Tm2 ≦ (Tm1-20). Multi-axis molding material.   The melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy a relationship of (Tm2-150) ≦ Tm1 ≦ (Tm2-20). Multi-axis molding material.   The multiple melting point according to claim 1, wherein the melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy a relationship of (Tm2-20) <Tm1 <(Tm2 + 20). Shaft molding material. The sheet is laminated such that the basis weight of the reinforcing fiber yarns is in the range of 90 to 190 g / m ² and the arrangement direction of the reinforcing fiber yarns is mirror-symmetric within the range of 3 to 12 sheets. Further, the nonwoven fabric is multi-axial molding material according to claim 1, wherein the basis weight is in the range of 30 to 80 g / m ^2.   The nonwoven fabric comprised by the said 1st thermoplastic resin is arrange | positioned also in the outermost layer of a laminated body, The fabric weight W1 of the nonwoven fabric arrange | positioned between layers, and the fabric weight W2 of the nonwoven fabric arrange | positioned in the outermost layer ( 1.2 × W1) ≦ W2 ≦ (3 × W1) is satisfied, The multiaxial molding material according to any one of claims 1 to 5. The through holes formed by the stitch yarns penetrating in the thickness direction of the laminate are regularly arranged in the range of 4 to 25 rows / 25 mm in the longitudinal direction and the width direction of the multiaxial molding material, and penetrated. The multiaxial molding material according to any one of claims 1 to 6, wherein the pore density is in the range of 60,000 to 200,000 locations / m ² . A preform characterized in that the multiaxial molding material according to claim 1 is molded into a shape having a quadric surface.   An FRP molded using the multiaxial molding material according to any one of claims 1 to 6 or the preform according to claim 8.   The non-woven fabric composed of the first thermoplastic resin is melted and solidified to form a matrix, and the stitch yarn composed of the second thermoplastic resin is substantially maintained in its form. The FRP according to claim 9, characterized in that   10. The FRP according to claim 9, wherein the nonwoven fabric composed of the first thermoplastic resin and the stitch yarn composed of the second thermoplastic resin are melted and solidified to form a matrix. This is an FRP manufacturing method using a multi-axial molding material in which a laminate in which at least two sheets in which a large number of reinforcing fiber yarns are arranged in parallel is laminated so that the reinforcing fiber yarns intersect is integrated. And
As a multiaxial molding material, it has a nonwoven fabric composed of the first thermoplastic resin that constitutes the FRP matrix at least between the sheets, and the laminate is integrated by stitch yarns composed of the second thermoplastic resin. The melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm1-150) ≦ Tm2 ≦ (Tm1-20). Use
The multiaxial molding material is heated to a temperature not lower than Tm2 and not higher than (Tm1-20) to melt the stitch yarn and mold,
Thereafter, the sheet is heated to a temperature of Tm1 or higher to melt the nonwoven fabric, and each sheet is impregnated with a thermoplastic resin. This is an FRP manufacturing method using a multi-axial molding material in which a laminate in which at least two sheets in which a large number of reinforcing fiber yarns are arranged in parallel is laminated so that the reinforcing fiber yarns intersect is integrated. And
As a multiaxial molding material, it has a nonwoven fabric composed of the first thermoplastic resin that constitutes the FRP matrix at least between the sheets, and the laminate is integrated by stitch yarns composed of the second thermoplastic resin. The melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm2-150) ≦ Tm1 ≦ (Tm2-20). Use
A method for producing FRP, wherein the multiaxial molding material is heated to a temperature of Tm1 or more and (Tm2-20) or less, the nonwoven fabric is melted while shaping, and each sheet is impregnated with a thermoplastic resin. This is an FRP manufacturing method using a multi-axial molding material in which a laminate in which at least two sheets in which a large number of reinforcing fiber yarns are arranged in parallel is laminated so that the reinforcing fiber yarns intersect is integrated. And
As a multiaxial molding material, it has a nonwoven fabric composed of the first thermoplastic resin that constitutes the FRP matrix at least between the sheets, and the laminate is integrated by stitch yarns composed of the second thermoplastic resin. And the melting point Tm1 of the first thermoplastic resin and the melting point Tm2 of the second thermoplastic resin satisfy the relationship of (Tm2-20) <Tm1 <(Tm2 + 20),
A method for producing FRP, wherein the multiaxial molding material is heated to a temperature equal to or higher than Tm1 and Tm2, and the stitch yarn and the nonwoven fabric are simultaneously melted to impregnate each sheet with a thermoplastic resin.

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