JP6946666B2 - Reinforced fiber laminated sheet and fiber reinforced resin molded product - Google Patents

Description

The present invention relates to a reinforcing fiber laminated sheet, and particularly to a reinforcing fiber laminated sheet suitable for RTM molding.

Conventionally, as a method for molding fiber reinforced plastics (sometimes referred to as FRP) having excellent productivity, a base material laminate made of dry reinforced fiber cloth is placed in a molding mold, and a matrix resin is used. A so-called RTM molding method is known in which a molded product is demolded after being injected into a mold and impregnated in a laminated body of a reinforcing fiber base material to cure a resin.

Then, in general, the reinforcing fiber base material laminate (for example, a plurality of reinforcing fiber base materials) is first shaped into a predetermined shape to prepare a preform of the reinforcing fiber base material laminate which is the pre-molding frame of FRP. Then, a molding method (RTM molding method) is adopted in which the preform is placed in a molding mold, a matrix resin is injected into the mold, and the resin impregnated in the base material is cured.

As the reinforcing fiber fabric used in such an RTM molding method, a woven fabric or a non-crimp fabric (sometimes referred to as NCF) is often used. These reinforcing fiber fabrics are continuously produced in a constant width by a loom or a warp knitting machine and wound on a roll, and when the above-mentioned preform is produced, the reinforcing fiber fabric is required from the roll. The amount is drawn out, cut into a desired shape, and laminated.

However, in the method of pulling out the required amount of the reinforcing fiber base material from the roll and cutting it into a shape corresponding to the product in this way, there are many scraps of the reinforcing fiber cloth remaining after cutting out the product shape, and the amount of waste of the reinforcing fiber is large. There was a problem that it increased and contributed to the increase in manufacturing cost.

Therefore, the fiber placement method, which significantly reduces the amount of waste by sequentially arranging reinforcing fiber bundles at necessary places instead of cutting from rolls, is attracting attention.

As the fiber placement method, a method of directly attaching the reinforcing fiber bundle to the three-dimensional shape type and a method of producing a flat reinforcing fiber sheet are known.

When the reinforcing fiber bundle is directly attached to the three-dimensional shape mold, for example, a reinforcing fiber bundle having a tack property is used as the reinforcing fiber bundle, and this reinforcing fiber bundle is directly arranged on the mold to form a reinforcing fiber bundle layer. Since it is formed into a molded product shape while being fixed, the step of producing a preform becomes unnecessary. However, when arranging the reinforcing fiber bundle, it is necessary to move the reinforcing fiber bundle arranging head along the mold shape. Therefore, when the mold shape is complicated, the reinforcing fiber bundle arranging head and the mold interfere with each other. Therefore, there is a problem that the reinforcing fiber bundle cannot be arranged, or at least the reinforcing fiber bundle cannot be arranged at high speed, and the productivity is lowered.

On the other hand, in the case of producing a flat sheet, a tacky reinforcing fiber bundle or a dry reinforcing fiber bundle is unidirectionally and flatly arranged in a desired shape to form one reinforcing fiber bundle layer. Then, the sheet form is formed by restraining the adjacent reinforcing fiber bundles or laminating a plurality of the layers to restrain the layers. In this case, since the reinforcing fiber bundle arrangement head does not need to perform a complicated operation of moving in the out-of-plane direction, the reinforcing fiber bundle can be arranged at high speed. As a means of restraining the reinforcing fiber bundle (layer) for forming the sheet form, restraint by adhesion using a resin, restraint by suturing using a suture, and the like are known.

For example, a method has been proposed in which reinforcing fiber bundles are aligned in one direction to form one layer, and heat-bonded with a thermoplastic resin veil sandwiched between laminated layers to form a sheet form (Patent Document). See 1.). In the proposed method, the reinforcing fiber bundle can be restrained easily and with high production efficiency by arranging the thermoplastic resin veils between the layers and heat-bonding them. However, when the reinforcing fiber bundle is arranged on a flat surface and then restrained by using a resin, it is in the form of a base material (particularly in the case of a unidirectional fabric) like a woven fabric or NCF at the time of shaping in a subsequent process. It was difficult to deform along the shape of the mold while maintaining the fiber orientation, fiber spacing, etc.) and the alignment (straightness) of the reinforcing fiber bundles.

Separately, a method is proposed in which a plurality of reinforcing fiber bundles are arranged in one direction at predetermined positions on the sheet-shaped base base material, and the reinforcing fiber bundles are randomly point-bonded on the base base material to form a sheet form. (See Patent Document 2). However, in this proposed method, the reinforcing fiber bundle can be restrained with high production efficiency, and the reinforcing fiber bundle and the base base material are randomly point-bonded, so that the reinforcing fiber bundle is more easily deformed than when the entire surface is bonded. Although it is excellent in terms of points, it has been difficult to sufficiently maintain the alignment of the reinforcing fiber bundles when shaping into a complicated shape that requires large deformation.

Furthermore, it is a method of stacking multiple layers of unidirectional fibers and restraining them with sutures, and using the stitch type, spacing, density, material, weight and tension as parameters, the area and mold shape that firmly maintain the sheet shape It has been proposed to use a sheet having a region excellent in deformation along the line (see Patent Document 3). In this proposed method, since the layers are restrained by sutures, the layers are not adhered, and the restraint condition can be controlled for each area such as loosening the restraint at the place where large deformation is required, so that the mold shape followability is excellent. Sheets can be made. Further, since a plurality of stitch threads can be sewn at the same time using a warp knitting machine, a piece of cloth having a constant width can be made into a sheet with high production efficiency. However, in this proposal, when a flat sheet is produced by using the fiber placement method, since reinforcing fiber bundles having different lengths are arranged, the end of the fabric is stabbed with a sword and fixed. It is not possible to grip each of the reinforcing fiber bundles as in the warp knitting machine in which the above method is adopted. Therefore, in this proposal, there is a problem that the restraint by the suture using a warp knitting machine or the like cannot be performed on the arranged reinforcing fiber bundle, and the reinforcing fiber sheet cannot be formed. Further, when restraining with sutures using a one-side stitch machine instead of using a warp knitting machine, only one stitch thread can be sewn to one head, which is sufficient to maintain the sheet shape. When a large amount of stitch thread is sewn, there is a problem that productivity is lowered.

Special Table 2013-532739 Japanese Unexamined Patent Publication No. 2014-159999 Japanese Patent Publication No. 2011-530014

As described above, in the so-called fiber placement method, the reinforcing fiber bundles are sequentially arranged at desired locations, so that the amount of reinforcing fibers discarded can be significantly reduced. In particular, when the reinforcing fibers are arranged in a planar shape, the arrangement speed of the reinforcing fibers can be increased, so that the productivity is also excellent. However, when the reinforcing fiber bundles are arranged on a flat surface and the formed reinforcing fiber bundle layers are fixed and integrated with a binder, the fiber alignment is performed at the time of shaping into a mold, especially when the base material is greatly deformed. It was difficult to maintain. On the other hand, even if an attempt is made to integrate using a suture, it is difficult to restrain the reinforcing fiber bundle layer with the suture as in the case of suturing with a warp knitting machine, and it is difficult to produce a reinforcing fiber laminated sheet itself. rice field. Alternatively, there is a problem that productivity is lowered when suturing with a one-side stitch machine.

Therefore, an object of the present invention is that, in view of the current state of the prior art, the amount of reinforcing fibers discarded can be significantly reduced, and the reinforcing fibers are deformed along the shape of the mold while maintaining the form as a base material at the time of shaping. It is an object of the present invention to provide a highly productive reinforcing fiber laminated sheet.

Another object of the present invention is to provide a fiber-reinforced resin molded product using the above-mentioned reinforcing fiber laminated sheet.

As described above, in the fiber placement method, there are a method using a resin binder and a method using a suture as a means for restraining the layers of the fiber bundle, and both are the degree of restraint (the amount of the binder sprayed and the amount of the suture stitch thread). It is known that as the number increases, the restraint becomes stronger, and the alignment maintenance of the fiber bundle and the shapeability to the mold are inferior. However, the present inventors, contrary to the expectation that the degree of restraint is further increased by the addition of the restraint means by using the two restraining means of the resin binder and the suture at the same time, the fibers are more than the restraint of the resin binder alone. We came to the conclusion that the alignment of the bundle is maintained and the shapeability to the mold is excellent. Furthermore, we have come to the idea that by narrowing down the stitching by stitching to the necessary places, the decrease in productivity when stitching with a one-side stitch machine can be minimized.

The present invention is intended to solve the above-mentioned problems, and in the reinforcing fiber laminated sheet of the present invention, a plurality of reinforcing fiber bundles aligned in one direction form one layer, and the plurality of the above-mentioned layers are present. It is a layer-laminated reinforcing fiber laminated sheet, in which layers are fixed by a resin binder in at least a part of the reinforcing fiber laminated sheet, and a plurality of layers are fixed by a suture thread in at least a part of the reinforcing fiber laminated sheet. Layers are sewn together, and the layers are fixed only by the resin binders that are discretely present on the surface of the reinforcing fiber layer, and the layers are separated by the resin binders that are discretely present on the surface of the reinforcing fiber layer. It is a reinforcing fiber laminated sheet which is fixed and has a region where a plurality of layers are sewn by a suture thread. Further, it is a reinforcing fiber laminated sheet in which a plurality of reinforcing fiber bundles aligned in one direction form one layer, and the layers are laminated in a plurality of layers, and layers are interposed in at least a part of the reinforcing fiber laminated sheet. A plurality of layers are sewn with sutures at least a part of the reinforcing fiber laminated sheet, and the layers are separated only by the resin binders discretely existing on the surface of the reinforcing fiber layer. It is a reinforcing fiber laminated sheet characterized by having a region to be fixed and a region in which a plurality of layers are sewn only by sutures.

According to a preferred embodiment of the reinforcing fiber laminated sheet of the present invention, the outer peripheral shape of the reinforcing fiber laminated sheet is A) a shape surrounded only by five or more straight lines (for example, a pentagon or a hexagon), b). A shape surrounded by at least one straight line and at least one curve (for example, a semicircular shape or a capsule shape), or / and a shape surrounded by only at least one curve (for example, a circle or Elliptical shape, etc.).

In the present invention, it is possible to obtain a fiber-reinforced resin molded product composed of the reinforcing fiber laminated sheet and the matrix resin according to any one of the above.

According to the present invention, the amount of waste of reinforcing fibers can be significantly reduced, and the shape as a sheet and the fiber bundles are maintained at the time of shaping and deformed along the shape of the mold to improve shapeability. A reinforcing fiber laminated sheet that can be made to be obtained can be obtained.

Further, according to the reinforcing fiber laminated sheet according to the present invention, it is possible to obtain a fiber-reinforced resin molded product having a smooth surface in which the reinforcing fiber bundle is not greatly disturbed and wrinkles are not present.

FIG. 1 is a perspective view showing an embodiment of a reinforcing fiber laminated sheet according to the present invention. FIG. 2 is a perspective view for explaining an example of the arrangement of the reinforcing fiber bundles constituting the reinforcing fiber bundle layer of the reinforcing fiber laminated sheet according to the present invention. FIG. 3 is a cross-sectional view showing an embodiment of the reinforcing fiber laminated sheet according to the present invention. FIG. 4 is a cross-sectional view showing another embodiment of the reinforcing fiber laminated sheet according to the present invention. FIG. 5 is a cross-sectional view showing another embodiment of the reinforcing fiber laminated sheet according to the present invention. FIG. 6 is a plan view showing an embodiment of a region in which a large deformation of the reinforcing fiber laminated sheet according to the present invention is required. FIG. 7 is a plan view for explaining the outer peripheral shape of the reinforcing fiber laminated sheet according to the present invention.

The reinforcing fiber laminated sheet of the present invention is a reinforcing fiber laminated sheet in which one or a plurality of reinforcing fiber bundles aligned in one direction form one layer, and the said layers are laminated in a plurality of layers. It is a reinforcing fiber laminated sheet in which layers are fixed by a resin binder in at least a part of the reinforcing fiber laminated sheet, and a plurality of layers are sewn by sutures in at least a part of the reinforcing fiber laminated sheet.

Next, a mode for carrying out the reinforcing fiber laminated sheet of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the reinforcing fiber laminated sheet 100 according to the present invention. FIG. 1 (a) represents the reinforcing fiber laminated sheet 100, and FIG. 1 (b) illustrates the layer structure of a part (“P” portion of FIG. 1 (a)) of the reinforcing fiber laminated sheet 100. It is represented as. The reinforcing fiber laminated sheet 100 is formed by laminating a plurality of reinforcing fiber bundle layers 101. The reinforcing fiber bundle layer 101 is composed of a plurality of reinforcing fiber bundles aligned in one direction, and is formed in a desired shape. More preferably, the reinforcing fiber bundle layer 101 is formed into a desired shape by arranging the reinforcing fiber bundles in parallel and in a plane with a predetermined length by using a fiber placement method.

A resin binder 102 is attached to at least one surface of the reinforcing fiber bundle layer 101, and the resin binder 102 is laminated so as to exist between all layers. The reinforcing fiber laminated sheet 100 contributes to adhesion between layers by heating and / or pressurizing the reinforcing fiber bundle layer 101 and / or the resin binder 102, thereby melting and solidifying the resin binder 102. The so-called "resin binder that fixes the layers" 103 is formed, and the sheet morphology is maintained by restraining at least a part of the sheet by suturing with the "resin binder that fixes the layers" 103 and the suture thread 104. ing. The resin binder 102 and the "resin binder that fixes the layers" 103 need only be present between all the layers, and can be further present on the surface layer.

Examples of the reinforcing fibers used here include carbon fibers, glass fibers, aramid fibers, metal fibers, alumina fibers and silicon nitride fibers, and carbon fibers can be made even lighter in particular. Is preferably used. Further, as the reinforcing fiber bundle, a reinforcing fiber bundle composed of a plurality of types of reinforcing fibers or synthetic yarns of reinforcing fibers and organic fibers can also be used.

Examples of the organic fiber used in this case include polyamide-based synthetic fiber, polyolefin-based synthetic fiber, polyester-based synthetic fiber, polyphenylsulphon-based synthetic fiber, polybenzoxazine-based synthetic fiber, acetate, acrylonitrile-based synthetic fiber, and modacryl fiber. Polyvinyl chloride synthetic fiber, polyvinylidene chloride synthetic fiber, polyvinyl alcohol synthetic fiber, polyurethane fiber, polyclar fiber, protein-acrylonitrile copolymer fiber, fluorine fiber, polyglycolic acid fiber, phenol fiber, and para aramid Examples include fibers.

Further, the preferable outer peripheral shape of the reinforcing fiber laminated sheet of the present invention is A) a shape surrounded by only five or more straight lines (for example, a pentagon or a hexagon), B) at least one straight line and at least one. A shape surrounded by a curve (for example, a semicircular shape, a capsule shape, etc.) or / and a shape surrounded by at least one curve (for example, a circle, an ellipse, etc.).

For example, the automobile member shape 701 as shown in FIG. 7 (a) satisfies any of the above conditions A), B) and C), while the rectangular shape shown in FIG. 7 (b). Since the 702 and the parallelogram shape 703 are surrounded by four straight lines, they do not satisfy any of the above conditions A), B), and C).

Further, FIG. 7 (c) shows an enlarged view of the “Q” portion of FIG. 7 (b). Here, the outer peripheral shape includes a substantially shape, and even if the end portion of the reinforcing fiber bundle having a rectangular shape is displaced as shown in FIG. 7 (c), the outer peripheral shape is considered to be a rectangular shape. It shall be.

FIG. 2 is a perspective view for explaining an example of the arrangement of the reinforcing fiber bundles constituting the reinforcing fiber bundle layer of the reinforcing fiber laminated sheet according to the present invention.

FIG. 2 shows an example of arrangement of the reinforcing fiber bundles constituting the reinforcing fiber bundle layer 201. FIG. 2A shows an example in which the reinforcing fiber bundle 202 is thin and FIG. 2B shows an example in which the reinforcing fiber bundle 202 is thick with respect to the desired shape 203.

As shown in FIG. 2A, as the reinforcing fiber bundle becomes thinner, the shape of the reinforcing fiber bundle layer 201 can be closer to the desired shape 203, and the amount of waste of fibers can be reduced, but the number of fibers is larger. Since the reinforcing fiber bundle 202 is arranged, it takes time to arrange the reinforcing fiber bundle 202, which lowers the productivity.

On the other hand, as shown in FIG. 2B, the thicker the reinforcing fiber bundle is, the faster the reinforcing fiber bundle 202 can be arranged, but the shape of the reinforcing fiber bundle layer 201 protrudes from the desired shape 203, and the reinforcement is strengthened. It increases the amount of fiber waste and leads to an increase in manufacturing costs. In view of these, the number of single fibers of the reinforcing fibers constituting the reinforcing fiber bundle 202 is preferably 3000 to 60,000, and more preferably 10,000 to 60,000.

As the reinforcing fiber bundle 202, for example, a reinforcing fiber bundle that has been previously subjected to pretreatment such as sizing treatment, fiber opening treatment, and binder application can also be used. For example, by applying the sizing treatment, the focusing property of the reinforcing fiber bundle can be improved and the generation of fluff can be suppressed. Further, by performing the fiber opening treatment, the thickness-width ratio (aspect ratio) of the reinforcing fiber bundle is adjusted and set to an aspect ratio suitable for the conditions of the preform process and the RTM molding process of the subsequent process. Can be done. Further, by performing a pretreatment such as adding a binder, the state of fixation between the reinforcing fiber bundles can be made uniform.

The resin binder 102 can be fixed to the surface layer of the reinforcing fiber bundle layer 101, and can obtain an action of fixing the layers of the reinforcing fiber laminated sheet 100. For example, a thermoplastic resin or a thermosetting resin can be used. Can be mentioned.

Examples of the thermoplastic resin include resins such as polyamide, polysulfone, polyetherimide, polyphenylene ether, polyimide and polyamideimide. Examples of the thermosetting resin include epoxy resin, vinyl ester resin, unsaturated polyester resin, and phenol resin.

The amount of the resin binder 102 present between the layers and the surface layer of the reinforcing fiber laminated sheet 100 is in the range of 0.1 to 20 parts by mass, while the reinforcing fiber laminated sheet 100 is 100 parts by mass. It is preferable to have. When the amount of the resin binder 102 applied as the fixing material is smaller than 0.1 parts by mass, it becomes difficult to maintain the shape as the reinforcing fiber laminated sheet. On the other hand, when the amount of the resin binder 102 applied as the fixing material is larger than 20 parts by mass, the resin binder 102 is strongly restrained and may hinder the shape followability to the mold.

In particular, when the amount of the resin binder 102 applied is in the range of 2 to 10 parts by mass, the shape followability to the mold is relatively good while maintaining the shape of the sheet, which is a more preferable embodiment. The form of the resin binder 102 may be, for example, powdery or linear, and may also be used as a non-woven fabric form.

As a method of adhering the resin binder 102 to the reinforcing fibers, for example, the resin binder 102 may be sprayed and adhered to the reinforcing fiber bundle as a pretreatment, and the resin binder 102 is sprayed after being aligned by the fiber placement method. It can also be attached.

As a method of fixing the layers of the reinforcing fiber laminated sheet 100 with the resin binder 102, for example, the resin binder 102 is heated and melted by using an infrared heater in a state where the resin binder 102 is present between the layers of the reinforcing fiber laminated sheet 100. Examples thereof include a method and a method of heating and pressurizing the entire surface of the reinforcing fiber laminated sheet 100 with a heated metal flat plate.

The material of the suture thread 104 used in the present invention is, for example, from fibers made of polyethylene, polyamide, polypropylene, polyester, polyphenylene sulfide, polyether sulfone, etc., and inorganic fibers (for example, carbon fibers, glass fibers, metal fibers). Examples thereof include fibrous yarns made of these fibers or blended yarns of these fibers.

FIG. 3 is a cross-sectional view of an embodiment of the reinforcing fiber laminated sheet according to the present invention.

In FIG. 3, the reinforcing fiber laminated sheet 300 has a region 305 for maintaining the sheet shape and a region 306 for which large deformation is required following the shape of the mold at the time of shaping. In the region 305 that maintains the sheet form, the layers between the reinforcing fiber bundle layers 301 are bonded and restrained by the molten resin binder 303. The reinforcing fiber laminated sheet 300 can maintain the sheet form by fixing the layers of the reinforcing fiber bundle layer 301 with the molten resin binder 303.

In the region 306 where large deformation is required, the layers of the reinforcing fiber bundle layers 301 are adhered to each other by the resin binder 303 that fixes the layers, and the reinforcing fiber bundle layers 301 are sewn together by the suture thread 304. .. In the region 306 where large deformation is required, in addition to the restraint of the resin binder 303 that fixes the layers, the restraint by the suture thread 304 causes a large shear deformation locally at the time of deformation, and the resin binder 303. Even if the resin is broken, the suture thread 304 remains, so that the shape of the mold can be followed while maintaining the alignment of the fiber bundles. Further, since the layers are fixed by the resin binder 303 that fixes the layers, it is possible to prevent the reinforcing fiber bundles from being misaligned due to being flown through the resin in the resin injection step, which is a subsequent step.

FIG. 4 is a cross-sectional view of another embodiment of the reinforcing fiber laminated sheet 400 according to the present invention.

The reinforcing fiber laminated sheet The reinforcing fiber laminated sheet has a region 405 for maintaining the sheet morphology and a region 406 for which large deformation is required following the shape of the mold at the time of shaping. Further, the resin binder 402 or the molten resin binder 403 is present between the layers over the entire surface direction of the reinforcing fiber laminated sheet 400.

The resin binder 402 or the resin binder 403 that fixes the layers does not necessarily have to exist in a region other than the region 405 that maintains the sheet morphology, but it is excellent in maintaining the morphology of the reinforcing fiber bundle layer 401 and the reinforcing fiber laminated sheet. From the viewpoint of easy spraying of the resin onto the 400, it is preferable that the resin binder 402 or the resin binder 403 that fixes the layers is present between the layers over the entire surface direction of the reinforcing fiber laminated sheet 400.

FIG. 5 is another embodiment of the cross section of the reinforcing fiber laminated sheet 500 according to the present invention. The reinforcing fiber laminated sheet 500 has a region 505 that maintains the sheet shape and a region 506 that is required to have a large deformation following the shape of the mold at the time of shaping. Further, a resin binder 502 or a resin binder 503 for fixing the layers is present between the layers over the entire surface direction of the reinforcing fiber laminated sheet 500. In the region 506 where large deformation is required, since the suture thread 504 is restrained, the suture thread 504 can follow the mold shape while maintaining the alignment of the reinforcing fiber bundles at the time of deformation.

In the region 506 where the large deformation is required, the layers may be restrained by the suture thread 504, and the layers may not be fixed by the resin binder 502, or the layers may be fixed by the resin binder 503 that fixes the layers. It is also permissible to be done. When the layers are not fixed by the resin binder 502, when the reinforcing fiber laminated sheet 500 follows the mold shape, it is easy to maintain the alignment of the reinforcing fiber bundles in a shape that requires a large deformation. Are better. When the layers are fixed by the resin binder 503 that fixes the layers, it is possible to prevent the reinforcing fiber bundles from being misaligned due to being flown through the resin in the resin injection step, which is a subsequent step. FIG. 6 is a diagram showing another embodiment of the region where large deformation is required according to the present invention.

FIG. 6 (a) shows the reinforcing fiber bundle layer 601, and FIGS. 6 (b) and 6 (c) show a part of the reinforcing fiber bundle layer 601 that requires large deformation (FIG. 6). 6 (a) is an enlarged view of (M) portion). In the example of the shape of FIG. 6, the “M” portion of FIG. 6A needs to be greatly deformed along the mold shape when deformed into the three-dimensional shape, and the reinforcing fiber bundle layer 601 is wrinkled during the deformation. This is a portion that needs to be largely compressed and deformed in the x direction in FIG. 6 so as not to occur.

In FIG. 6, as the suture pattern of the suture thread 604, for example, a chain knitting, a 1/1 tricot knitting, an irregular 1/1 tricot knitting in which a chain knitting and a 1/1 tricot knitting are combined, or a one-side stitch machine is used. Examples of the suture pattern (chain knitting, 1/1 tricot knitting, irregular 1/1 tricot knitting, blind stitch, double needle, tufting) or a suture pattern in which these are combined can be mentioned. An example is given, and FIG. 6 (c) gives an example of the 1/1 tricot edition.

The pitch p of the suture thread 604 represents the distance traveled in the stitch direction (x direction in FIG. 6) while the stitch needle moves for one cycle in the thickness direction of the reinforcing fiber laminated sheet. The pitch p of the suture thread 604 is preferably 2.5 mm or more and 20 mm or less. When the pitch p is less than 2.5 mm, the suture density of the produced reinforcing fiber laminated sheet becomes too high, and the suture inhibits the deformation of the reinforcing fibers at the time of shaping, so that sufficient shapeability can be obtained. Hard to get rid of. Further, when the pitch p is larger than 20 mm, the suture density of the produced reinforcing fiber laminated sheet becomes too low, and it becomes difficult to maintain the desired fiber bundle alignment.

The distance w between the sutures 604 represents the distance between the sutures 604 that are adjacent to each other in the stitch orthogonal direction (y direction in FIG. 6). The distance w between the sutures 604 is preferably 5 mm or more and 500 mm or less. When the distance w between the sutures 604 is less than 5 mm, the suture density of the produced reinforcing fiber laminated sheet becomes too high, and the sutures 604 hinder the deformation of the reinforcing fibers at the time of shaping. It is difficult to obtain followability (formability). When the distance w between the sutures 604 is larger than 500 mm, the suture density of the produced reinforcing fiber laminated sheet becomes too low, and it becomes difficult to maintain the desired fiber bundle alignment.

When a fiber-reinforced resin molded body is produced using the above-mentioned reinforcing fiber laminated sheet and a matrix resin, the matrix resin used is, for example, thermosetting such as epoxy resin, vinyl ester resin, unsaturated polyester resin, and phenol resin. Not limited to resins, thermoplastic resins such as acrylic resins, polyamide resins, and polyolefin resins can also be used.

The use of the reinforced fiber laminated sheet of the present invention is used when producing a fiber reinforced resin molded body by an RTM molding method, and the use of the fiber reinforced resin molded body is, for example, a hood, a roof, a door, a fender, a trunk. Lid, side panel, rear end panel, upper back panel, front body, underbody, various pillars, various members, various frames, various beams, various supports, various rails, various hinges, automobile outer panels, automobile body parts, and Used for automobile structural materials.

Next, the reinforcing fiber laminated sheet of the present invention will be described based on Examples.

(Example 1)
<Reinforcing fiber>
As the reinforcing fiber bundle, carbon fiber "Trading Card" (registered trademark) T700SC manufactured by Toray Industries, Inc., which had been subjected to a sizing treatment in advance, was used. In the examples, a reinforcing fiber bundle having a width of 6 mm and a single fiber number of 12000 in the reinforcing fiber bundle was used.

<Reinforcing fiber bundle layer>
Using a fiber placement head, the reinforcing fiber bundles were aligned in one direction without gaps on the gantry, and two reinforcing fiber bundle layers were produced so that the outer peripheral shape became a circular shape with a diameter of 700 mm.

<Resin binder>
A resin binder non-woven fabric manufactured by Japan Vilene Co., Ltd. (product number: EF15, main component: polyamide, basis weight: 15 g / m ² ) was prepared so that the outer peripheral shape was a circular shape with a diameter of 700 mm.

<Lamination and sticking>
First, the resin binder non-woven fabric was laminated on one of the prepared reinforcing fiber layers. Next, the remaining reinforcing fiber layers were arranged and laminated on this so that the fiber orientation angle difference was 90 °. Then, using an infrared heater, the surface reinforcing fiber bundle layer was heated at a temperature of 130 ° C. for 30 seconds to fix the layers. At this time, when the reinforcing fiber layer was separately peeled off and the bonding state between the layers was observed, it was confirmed that the molten resin binders were discretely present on the surface of the reinforcing fiber layer and were bonded between the layers.

<Suture>
Using a one-side stitch machine, the regions (150 mm × 300 mm, two locations) of the reinforcing fiber bundle layer that require large deformation were sutured and integrated. Polyester fiber yarn (total fineness: 30 dtex) was used as the stitch yarn, and the stitch pattern was chain knitting (pitch p: 10 mm, spacing between stitch yarns w: 50 mm).

<Excipient>
The prepared sheet was placed on an elliptical hemispherical shape (height: 30 mm and 60 mm), and press shaping was performed. As a result, it was confirmed that in the mold having a height of 30 mm, the reinforcing fiber laminated sheet can follow the mold shape without losing the alignment of the fiber bundles and has good shaping performance. In addition, in the mold with a height of 60 mm, the reinforcing fiber laminated sheet showed some irregularities in the alignment of the fiber bundles in the region where large deformation was required, but it could generally follow the shape of the mold and had good shaping performance. It was confirmed that it had. Then, the upper and lower molds were heated to a temperature of 110 ° C., pressurized at 50 kPa, and held for 30 seconds to prepare a preform.

<Molding>
This preform was placed on a lower mold of a double-sided RTM molding mold maintained at a temperature of 110 ° C., the upper mold was closed, and the air in the mold was discharged by a vacuum pump. Next, a two-component epoxy resin (main agent: manufactured by Momentive, curing agent: manufactured by Toray Industries, Inc., acid anhydride-based curing agent) is injected into the mold at an injection pressure of 0.5 MPa to impregnate the preform with 10 It was left for a minute. In this way, a fiber reinforced resin molded product was obtained.

The obtained fiber-reinforced resin molded product had a smooth surface with no major disturbance in the fiber bundles visible on the surface and no wrinkles, and was particularly excellent as a fiber-reinforced resin molded product.

(Example 2)
A reinforcing fiber laminated sheet was produced by the same method as in Example 1 except that the carbon fiber PX35 manufactured by ZOLDEK Co., Ltd., which had been subjected to a sizing treatment in advance, was used as the reinforcing fiber bundle. In this example, a reinforcing fiber bundle having a width of 25 mm and a single fiber number of 50,000 in the reinforcing fiber bundle was used.

<Excipient>
The prepared reinforcing fiber laminated sheet was placed on the elliptical hemispherical shape (height: 30 mm and 60 mm), and press shaping was performed. As a result, it was confirmed that in the mold having a height of 30 mm, the reinforcing fiber laminated sheet can follow the mold shape without losing the alignment of the fiber bundles and has good shaping performance. In addition, in the mold with a height of 60 mm, the reinforcing fiber laminated sheet showed some irregularities in the alignment of the fiber bundles in the region where large deformation was required, but it could generally follow the shape of the mold and had good shaping performance. It was confirmed that it had. Then, the upper and lower molds were heated to a temperature of 110 ° C., pressurized at 50 kPa, and held for 30 seconds to prepare a preform.

<Molding>
This preform was placed on a lower mold of a double-sided RTM molding mold maintained at a temperature of 110 ° C., the upper mold was closed, and the air in the mold was discharged by a vacuum pump. Next, a liquid epoxy resin manufactured by Toray Industries, Inc. was injected into the mold at an injection pressure of 0.5 MPa, impregnated into the preform, and left to stand for 10 minutes. In this way, a fiber reinforced resin molded product was obtained.

The obtained fiber-reinforced resin molded product had a smooth surface with no major disturbance in the fiber bundles visible on the surface and no wrinkles, and was particularly excellent as a fiber-reinforced resin molded product.

(Example 3)
<Reinforcing fiber>
As the reinforcing fiber bundle, carbon fiber "Trading Card" (registered trademark) T700SC manufactured by Toray Industries, Inc., which had been previously subjected to sizing treatment and binder addition, was used. In this example, a reinforcing fiber bundle having a width of 6 mm and a single fiber number of 12000 in the reinforcing fiber bundle was used. The binder was adhered on the reinforcing fiber bundle using a granular binder (manufactured by Toray Industries, Inc.) containing a thermoplastic resin as a main component so that the adhesion amount per 1000 m was 30 g.

<Fiber placement process>
Using a fiber placement head, the reinforcing fiber bundles were aligned in one direction without gaps on the gantry, and two reinforcing fiber bundle layers were produced so that the outer peripheral shape became a circular shape with a diameter of 700 mm.

<Laminating and fixing process>
Next, one of the reinforcing fiber bundle layers was adsorbed and transported, and was arranged and laminated on the other reinforcing fiber bundle layer so that the orientation angle difference was 90 °. After that, of the two reinforcing fiber bundle layers arranged and laminated using a flat plate (aluminum, 300 mm × 300 mm) heated to a temperature of 110 ° C., a region (150 mm × 300 mm, 2) that requires particularly large deformation. The entire region except (place) was heated at a pressure of 50 kPa for 30 seconds to fix the layers.

<Suture process>
Using a one-side stitch machine, the regions (150 mm × 300 mm, two locations) of the reinforcing fiber bundle layer that require particularly large deformation were sutured and integrated. Polyester fiber yarn (total fineness: 30 dtex) was used as the stitch yarn, and the stitch pattern was chain knitting (pitch p: 10 mm, spacing between stitch yarns w: 50 mm).

<Shaping process>
The prepared sheet was placed on an elliptical hemispherical shape (height: 30 mm and 60 mm), and press shaping was performed. As a result, it was confirmed that the reinforcing fiber laminated sheet can follow the mold shape without losing the alignment of the fiber bundles in both the molds having a height of 30 mm and 60 mm, and has good shaping performance. Then, the upper and lower molds were heated to a temperature of 110 ° C., pressurized at 50 kPa, and held for 30 seconds to prepare a preform.

<Molding process>
A fiber-reinforced resin molded product was obtained in the same manner as in Example 1. The obtained fiber-reinforced resin molded product had a smooth surface without wrinkles, although the reinforcing fiber bundle was slightly disturbed especially in the region requiring large deformation, and was used as a fiber-reinforced resin molded product. It was excellent.

(Comparative Example 1)
A reinforcing fiber laminated sheet was produced by the same method as in Example 1 except that the suturing step was not performed.

<Shaping process>
The prepared reinforcing fiber laminated sheet was placed on the elliptical hemispherical shape (height: 30 mm and 60 mm), and press shaping was performed. As a result, it was confirmed that the reinforcing fiber laminated sheet had wrinkles at places where large deformation was required. Then, the upper and lower molds were heated to a temperature of 110 ° C., pressurized at 50 kPa, and held for 30 seconds to prepare a preform.

<Molding process>
A fiber-reinforced resin molded product was obtained in the same manner as in Example 1. In the obtained fiber-reinforced resin molded product, the appearance of the reinforcing fiber bundle was observed without the resin impregnating at the place where the preform was wrinkled, and a good fiber-reinforced resin molded product could not be obtained.

(Comparative Example 2)
Using the same reinforcing fibers as in Example 1, the fiber placement step was carried out in the same way as in Example 1.

<Laminating and fixing process>
Next, one of the reinforcing fiber bundle layers was adsorbed and transported, and the reinforcing fiber bundle layer was arranged and laminated on the other reinforcing fiber bundle layer so that the orientation angle difference was 90 °.

<Suture process>
An attempt was made to suture the regions (150 mm × 300 mm, two locations) of the reinforcing fiber bundle layer that require large deformation using a one-side stitch machine. Polyester fiber yarn (total fineness: 30 dtex) was used as the stitch yarn, and the stitch pattern was chain knitting (pitch p: 10 mm, spacing between stitch yarns w: 50 mm). When suturing was performed, there was no area where the layers were fixed with the resin binder in advance, so when the needle was inserted between the layers by suturing, the arrangement of the reinforcing fibers was disturbed, and more fluffing occurred, and the reinforcing fibers were sewn. The laminated sheet could not be obtained.

Table 1 summarizes the main conditions and evaluation results in the examples and comparative examples.

In the evaluation column of Table 1, the evaluation symbols for shaping and molding mean the following. Shaped A and B and molded A and B are accepted.
-Shaping A: For molds that require large deformation, the reinforcing fibers were aligned and could be shaped without wrinkles.
-Shaping B: For the mold that needs to be deformed, the alignment of the reinforcing fibers was maintained and the shaping could be performed without wrinkles.
-Formation C: The alignment of the reinforcing fibers was disturbed with respect to the mold that required deformation. Or wrinkles have occurred.
-Molding A: No disorder was observed in the reinforcing fiber bundle, and molding was possible without impregnation of the resin.
-Molding B: Although the reinforcing fiber bundle was slightly disturbed, it could be molded without being impregnated with resin.
-Molding C: The reinforcing fiber bundle was greatly disturbed. Alternatively, the resin was not impregnated.

In Examples 1 to 3, it was possible to obtain products that passed evaluation A or B in terms of both shaping and molding results. On the other hand, in Comparative Example 1, only products that failed the evaluation C in both the shaping and molding results could be obtained, and in Comparative Example 2, the reinforcing fiber laminated sheet could not be produced.

100, 300, 400, 500: Reinforcing fiber laminated sheet 101, 201, 301, 401, 501, 601: Reinforcing fiber bundle layer 102, 402, 502: Resin binder 103, 303, 403, 503: Resin binder for fixing layers 104, 304, 404, 504, 604: Suture 305, 405, 505: Regions for maintaining sheet morphology 306, 406, 506, 606: Regions requiring large deformation 202: Reinforcing fiber bundle 203: Desired shape 701: Automobile member shape 702: Rectangular shape 703: Parallelogram shape

Claims (4)

A plurality of reinforcing fiber bundles aligned in one direction form one layer, and the layers are laminated in a plurality of layers, and at least a part of the reinforcing fiber laminated sheet has a resin binder between the layers. In addition, a plurality of layers are sewn by suture threads in at least a part of the reinforcing fiber laminated sheet, and the layers are fixed only by resin binders discretely existing on the surface of the reinforcing fiber layer. Reinforcing fiber having a region in which the layers are fixed by resin binders discretely existing on the surface of the reinforcing fiber layer and a region in which a plurality of layers are sewn by a suture thread. Laminated sheet. A plurality of reinforcing fiber bundles aligned in one direction form one layer, and the layers are laminated in a plurality of layers, and at least a part of the reinforcing fiber laminated sheet has a resin binder between the layers. In addition, a plurality of layers are sutured by sutures in at least a part of the reinforcing fiber laminated sheet, and the layers are fixed only by resin binders discretely existing on the surface of the reinforcing fiber layer. A reinforcing fiber laminated sheet having a region in which a plurality of layers are sewn only by a suture thread. The reinforcing fiber laminated sheet according to claim 1 or 2 , wherein the outer peripheral shape of the reinforcing fiber laminated sheet satisfies any of the following conditions.
A) A shape surrounded by only 5 or more straight lines.
B) A shape surrounded by at least one straight line and at least one curve.
C) A shape surrounded by at least one curve. A fiber-reinforced resin molded product composed of the reinforcing fiber laminated sheet according to any one of claims 1 to 3 and a matrix resin.

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