JP2008132775A - Multilayer substrate and preform - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer substrate excellent in curve followability while reinforcing fiber yarns are oriented multidirectionally, and a preform comprising the same. <P>SOLUTION: The multilayer substrate has a constitution that reinforced fiber yarns are arranged in parallel in a sheet form to form a reinforced fiber layer, and multiple layers of the reinforced fiber layer are integrated in a state that the multiple layers are laminated at angles different in an array direction of the reinforced fiber yarns constituting each reinforced fiber layer. The multilayer substrate is configured such that (1) 80 wt.% or more reinforcing fiber yarns constituting the reinforced fiber layer have a cutting end in a direction traversing the reinforcing fiber yarns, and the length of the reinforcing fiber yarns having the cutting end is a finite length of 10-300 mm, or (2) 80 wt.% or more reinforcing fiber yarns constituting the reinforced fiber layer are spun yarns consisting of discontinuous fibers having a finite length of 10-300 mm, the fineness of the spun yarn is 300-5,000 tex, and a yarn width/thickness ratio is 2-20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multilayer base material composed of reinforcing fiber yarns. More specifically, the present invention uses a multi-layer base material in which reinforcing fiber yarns are arranged in multiple directions in the plane and integrated by bonding with stitch yarns or resin materials, and fiber reinforced resin (hereinafter referred to as FRP). In particular, the present invention relates to a multilayer substrate excellent in moldability and a preform comprising the multilayer substrate.

  Conventionally, reinforced fiber yarns such as carbon fibers have high specific strength and specific elastic modulus, so they have been widely used for FRP as well as aircraft and general industries, including sports / leisure products that have a large weight reduction effect. .

  In recent years, in order to reduce the molding cost of FRP in these fields, a multilayer base material in which reinforcing fiber yarns are arranged in multiple directions in a plane and integrated by adhesion of stitch yarns or resin materials has been proposed. Since these multilayer base materials are arranged with reinforced fiber yarns oriented in multiple directions in the plane, quasi-isotropic properties can be obtained, and multiple reinforced fiber layers can be integrated, There are advantages such as a reduction in stacking operation cost.

  However, the multiaxial stitch base material in which the reinforcing fiber yarns are aligned in multiple directions in the plane and integrated with the stitch yarn has a quadratic curved surface because the multiple reinforcing fiber layers are constrained by the stitch yarn. There is a problem that it is a material that is very difficult to mold into a shape. In other words, even if this multi-axis stitch base material is inserted into male and female molds and forced to draw deeply, it cannot be molded, or even if it can be molded, it will be wrinkled or removed. At this time, since the multi-axis stitch base material tries to recover to the original flat state, there is a problem that an accurate shape cannot be maintained.

  In order to improve this problem, a multiaxial stitch base material using a stitch yarn which is a low melting point polymer (see Patent Document 1) or a multiaxial stitch base material using a stitch yarn which is a polymer having a different melting point (Patent Document) 2) is proposed. Since these multiaxial stitch base materials are composed of a low melting point polymer and stitch yarn, the multiaxial stitch base material is heated at the time of molding to improve the apparent moldability by melting the stitch yarn. Can be made. However, when the stitch yarn is completely melted, there is no problem that the reinforcing fiber yarn is restrained, and the reinforcing fiber layer is separated so that the shape cannot be maintained and cannot be handled.

On the other hand, in a reinforced fiber fabric, as a method for improving the shapeability, it has been proposed to improve the shapeability by opening a cut in the fabric prepreg (see Patent Document 3). ). This proposal has a problem that wrinkles easily occur unless the resin is impregnated with a resin such as a prepreg because the deformation behavior at the time of forming differs between the cut and the periphery of the cut. In addition, it has been proposed to improve the formability using a woven fabric made of spun yarn (see Patent Document 4). Although this fabric is a fabric with a low basis weight of 100 g / m ² or less using a spun yarn of fineness, the shapeability is excellent, but when the fabric weight is increased, the shapeability is reduced. There's a problem. In this way, a material excellent in formability has not been obtained not only in a multiaxial stitch base material but also in a reinforcing fiber fabric, and the multiaxial base material obtained by such a conventional technique is applied to a quadratic curved surface. If the followability is inferior and the follower is forced to follow the curved surface, the reinforcing fibers are scattered, the fiber meandering and the amount of fiber are dense, and not only the high mechanical properties can be exhibited when molded into FRP, but also the surface smoothness There was a problem that it was not possible to obtain an excellent molded product.
JP 2002-227066 A JP 2002-227068 A JP-A 63-267523 JP-A-10-280246

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and provide a multilayer substrate excellent in curved surface followability while a reinforcing fiber yarn is oriented in multiple directions and a preform comprising the same.

  In order to achieve the above object, the present invention employs the following configuration. That is, in the multilayer base material of the present invention, the reinforcing fiber yarns are arranged in a sheet shape in parallel to form a reinforcing fiber layer, and a plurality of the reinforcing fiber layers constitute the reinforcing fiber layers. In a multi-layered base material that is integrated in a state where the arrangement direction of the stripes is laminated at different angles, 80% by weight or more of the reinforcing fiber yarns constituting the reinforcing fiber layer are cut in a direction crossing the reinforcing fiber yarns. A multilayer base material characterized by having a finite length of 10 to 300 mm in length of reinforcing fiber yarns having ends and cut ends.

  The multilayer base material of the present invention is a reinforcing fiber yarn in which reinforcing fiber yarns are arranged in a sheet form in parallel to form a reinforcing fiber layer, and a plurality of layers of the reinforcing fiber layers constitute each reinforcing fiber layer. In a multi-layered base material integrated in a state in which the arrangement directions of the stripes are laminated at different angles, 80% by weight or more of the reinforcing fiber yarns constituting the reinforcing fiber layer is a finite-length discontinuity of 10 to 300 mm It is a spun yarn comprising fibers, and the total fineness of the spun yarn is 300 to 5,000 tex, and the yarn width / thickness ratio is 2 to 20, which is a multilayer base material.

  According to a preferred aspect of the multilayer base material of the present invention, the cut ends of the reinforcing fiber yarns are arranged at an interval of at least 10 to 300 mm in the length direction of the reinforcing fiber yarns.

  According to the preferable aspect of the multilayer base material of this invention, a multilayer base material is integrated by the resin material arrange | positioned between the layers of a stitch yarn or a reinforced fiber layer.

  According to a preferred aspect of the multilayer base material of the present invention, the length of the cut end per one position in the sheet-like reinforcing fiber layer is 1 which is the smaller one of the stitch length S or the gauge length G of the stitch yarn. ~ 5 times.

  According to a preferred aspect of the multilayer base material of the present invention, the length of the cut end per location in the sheet-like reinforcing fiber layer is 2 to 15 times the average yarn width per yarn of the reinforcing fiber yarn. It is.

  According to a preferred aspect of the multilayer base material of the present invention, the number of twists of the spun yarn is 200 turns / m or less, and the spun yarn is substantially untwisted and covered with the auxiliary yarn to be converged. It will be.

  According to a preferred aspect of the multilayer base material of the present invention, the spun yarn is substantially untwisted and focused by a binder.

  According to a preferred aspect of the multilayer base material of the present invention, the reinforcing fiber yarn is a reinforcing fiber yarn in which 80% by weight or more has a cut end, or the above-mentioned 80% by weight or more is a spun yarn composed of discontinuous fibers. A reinforcing fiber layer in which strips are arranged in parallel is integrated with a resin material.

According to a preferred embodiment of the multilayer base material of the present invention, the basis weight per one layer of the sheet-like reinforcing fiber layer is 100 to 1,000 g / m ² .

  The multilayer substrate of the present invention can be shaped into a molded product such as a preform. Specifically, the multilayer base material may be formed into a molded product such as a preform by being molded into a shape having a secondary curved surface by being laminated by one sheet or a plurality of sheets.

  According to the present invention, in the multilayer substrate, the reinforcing fiber yarns are restrained by stitch yarns or resin materials, and 80% or more of the reinforcing fiber yarns constituting the reinforcing fiber layer cross the reinforcing fiber yarns. And the reinforcing fiber yarn having the cut end has a finite length of 10 to 300 mm, or 80% by weight or more of the reinforcing fiber yarn has a finite length of 10 to 300 mm. Therefore, when the multilayer base material is formed into a quadratic curved surface, the cut end of the reinforcing fiber yarn is opened, or the multilayer base material is formed by discontinuity of discontinuous fibers in the spun yarn. Formability can be improved by extending in a pseudo manner.

  In the case of spun yarn composed of discontinuous fibers, the total fineness is 300 to 5,000 tex, and the yarn width / thickness ratio is 2 to 20, so it is used as a reinforcing fiber yarn for a multilayer base material. In addition, a multilayer substrate having a smooth surface can be obtained.

  Furthermore, the preform obtained from the multilayer base material can be molded in a state where the reinforcing fiber yarns constituting the sheet-like reinforcing fiber layer at the time of molding are integrated with stitch yarns or resin materials. It can be molded without being loosened, and when molded into FRP, not only exhibits high mechanical properties such as high strength and elastic modulus, but also achieves excellent appearance quality.

  Hereinafter, the multilayer substrate of the present invention will be described in more detail based on the drawings.

  FIG. 1 is a partially cutaway schematic perspective view for illustrating a multilayer base material of the present invention. FIG. 1 shows a cut end in a direction crossing a reinforcing fiber yarn as one embodiment according to the present invention. A multi-axis stitch base material which is a multilayer base material having 17 (only the second layer is shown) will be described as an example. As shown in FIG. 1, the multilayer base material 1 includes a plurality of reinforcing fiber yarns 2 arranged in parallel from the lower surface in a first oblique direction oblique to the longitudinal direction A of the multilayer base material 1. The reinforcing fiber layer 3 of + α ° is constituted, and then the second layer is a reinforcing fiber of 90 ° with respect to the longitudinal direction A by arranging a plurality of reinforcing fiber yarns 4 in parallel in the width direction of the multilayer substrate 1 The layer 5 is formed, and then the third layer is formed of a plurality of reinforcing fiber yarns 6 arranged in parallel in an oblique direction of the multilayer base material 1 to form a reinforcing fiber layer 7 of -α ° with respect to the length direction A. Then, the fourth layer is composed of a plurality of reinforcing fiber yarns 8 arranged in parallel in the length direction of the multilayer base material 1 to form a 0 ° reinforcing fiber layer 9, and then the fifth layer is the multilayer base material 1. A plurality of reinforcing fiber yarns 10 are arranged in parallel in the oblique direction to form a reinforcing fiber layer 11 of −α ° with respect to the length direction A, and then the sixth layer extends in the width direction of the multilayer substrate 1. Many The reinforcing fiber yarns 12 are arranged in parallel to form a reinforcing fiber layer 13 of 90 ° with respect to the longitudinal direction A, and then the seventh layer is a plurality of reinforcing fiber yarns in the diagonal direction of the multilayer substrate 1. The strips 14 are arranged in parallel to form a reinforcing fiber layer 15 of + α ° with respect to the longitudinal direction A, and the first to seventh layers having different arrangement directions are laminated to form a laminate. is doing.

  The stitch yarn 16 is arranged in the length direction of the multilayer base material 1 on the surface of the laminated body, that is, on the upper portion of the reinforcing fiber yarn 14 of the reinforcing fiber layer 15 of + α ° with respect to the length direction A of the multilayer base material 1. Then, a laminated body composed of seven reinforcing fiber layers 3, 5, 7, 9, 11, 13, and 15 is stitched and integrated with the stitch yarn 16 in a 1/1 tricot knitting structure. Here, the knitting structure of the stitch yarn in the stitch is not limited to the tricot knitting structure, and may be another knitting structure such as a single ring stitch structure.

  In the multilayer substrate 1, the reinforcing fiber yarns 2, 4, 6, 8, 10, 12, and 14 constituting the sheet-like reinforcing fiber layer are (1) reinforcing fiber yarns constituting the sheet-like reinforcing fiber layer. 80% by weight or more has a cut end 17 in a direction crossing the reinforcing fiber yarn, and the reinforcing fiber yarn having the cut end 17 has a finite length of 10 to 300 mm, or (2) a sheet shape 80% by weight or more of the reinforcing fiber yarn constituting the reinforcing fiber layer is a spun yarn comprising discontinuous fibers having a finite length of 10 to 300 mm, and the total fineness of the spun yarn is 300 to 5,000 tex, And the yarn width / thickness ratio is 2-20.

  As means for integrating a plurality of sheet-like reinforcing fiber layers in the multilayer material 1, integration by stitches using stitch yarns, integration by adhesion of resin materials arranged between sheet-like reinforcing fiber layers, and Although means such as integration by entanglement of fibers by needle punching can be mentioned, preferable means are integration by stitching using a stitch yarn and integration by adhesion using a resin material.

  According to stitch integration using stitch yarn, the restraint state of the reinforcing fiber yarn can be adjusted by adjusting the pitch and interval of the stitch according to the shape of the product to be molded, making it easy to mold can do. Moreover, even if integration is performed using adhesion using a resin material, the adhesive strength between the layers of the reinforcing fiber layers constituting the multilayer base material can be adjusted by adjusting the amount of resin to be attached to the surface of the sheet-like reinforcing fiber layer. At the same time, the preform can be easily processed by adjusting the heating temperature for shaping.

  FIG. 2 is a schematic partial cross-sectional view showing a seven-layer portion in the AA ′ cross section of FIG. 1 before forming the multilayer base material 1 of FIG. 1 into a quadratic curved surface. 3 is an enlarged view of a part of the schematic partial cross-sectional view shown in FIG. FIG. 4 is a schematic partial cross-sectional view of a preform 20 obtained by shaping the multilayer base material of FIG. 1 into a curved shape.

  In the laminated base material 1 of FIG. 2, a direction in which 80% by weight or more of the reinforcing fiber yarns constituting the sheet-like reinforcing fiber layers 3, 5, 7, 9, 11, 13, 15 cross the reinforcing fiber yarns. The reinforcing fiber yarn having the cut end 17 (only the second layer is shown) and having the cut end 17 has a finite length of 10 to 300 mm. That is, 80% by weight or more of the reinforcing fiber yarn has a cut end, and the reinforcing fiber yarn having the cut end has a finite length of 10 to 300 mm. Therefore, the multilayer substrate 1 of FIG. As shown in FIG. 3, when trying to mold into a quadratic curved surface shape, it became discontinuous by cutting starting from the cutting point of the cutting end 17 (only the second layer is shown) in the direction crossing the reinforcing fiber yarn shown in FIG. When the reinforcing fiber yarn moves while the interval between the cut ends of the reinforcing fiber yarns is widened, it can be formed into a quadratic curved surface shape.

  Here, 80% by weight or more of the reinforcing fiber yarn has a cut end, as long as at least 80% by weight has a cut end, and may be 100% by weight. By doing so, it becomes easier to form a quadric surface.

  In the multilayer substrate of the present invention, the reinforcing fiber yarn constituting the sheet-like reinforcing fiber layer has a cut end in a direction crossing the reinforcing fiber yarn, and the reinforcing fiber yarn having the cut end is 10 to 300 mm. It is of finite length. When the length of the reinforcing fiber yarn is less than 10 mm, the cutting length is too small, and there are few places where the reinforcing fiber yarn is restrained by the stitch yarn or the resin material, and the reinforcing fiber yarn easily falls off the multilayer base material. On the other hand, if the length of the reinforcing fiber yarn exceeds 300 mm, the number of places where the reinforcing fiber yarn is restrained by the stitch yarn or the resin material increases. Although it does not fall off, the reinforcing fiber yarns do not slip appropriately at the locations where the intervals are too large, and shaping becomes difficult. Therefore, the reinforcing fiber yarn has a finite length in the range of 10 to 300 mm. A more preferable length of the reinforcing fiber yarn is 10 to 100 mm. Within this range, the effect of the present invention can be most effectively exhibited by appropriately sliding the reinforcing fiber yarn. The thickness of the reinforcing fiber yarn used in the present invention is preferably a multifilament having a total fineness of about 300 to 5,000 tex. The number of filaments of the reinforcing fiber yarn is preferably about 3,000 to 80,000.

  Another embodiment of the multilayer substrate of the present invention is a spun yarn in which 80% by weight or more of the reinforcing fiber yarns constituting the sheet-like reinforcing fiber layer are composed of discontinuous fibers having a finite length of 10 to 300 mm. is there. 80% by weight or more of the reinforcing fiber yarns constituting the sheet-like reinforcing fiber layer, that is, most of the reinforcing fiber yarns are spun yarns, and the spun yarns are composed of 10-300 mm finite-length discontinuous fibers. Therefore, the deformation performance can be increased by allowing the spun yarn to pass through appropriately when shaping the multilayer substrate.

  Here, the spun yarn in which 80% by weight or more of the reinforcing fiber yarn is made of discontinuous fibers may be a spun yarn in which at least 80% by weight or more is made of discontinuous fibers, and may be 100% by weight. . By doing so, it becomes easier to form a quadric surface.

  Here, if the length of the discontinuous fibers constituting the spun yarn is less than 10 mm, the fiber length is short, so that the spun yarn is easily dropped from the multilayer base material. On the other hand, when the length of the discontinuous fiber exceeds 300 mm, there is no fear of dropping off from the multilayer base material, but since the fiber length is too long, it is difficult to slip out and shaping is difficult. Therefore, the fiber length of the discontinuous fibers constituting the spun yarn is a finite length in the range of 10 to 300 mm. A more preferable length of the discontinuous fiber is 10 to 100 mm, and if it is within this range, the reinforcing fiber yarn can be appropriately pulled out and the effect of the present invention can be most effectively exhibited.

  Further, in the case of spun yarn in which 80% by weight or more of the reinforcing fiber yarns constituting the sheet-like reinforcing fiber layer are made of discontinuous fibers having a finite length of 10 to 300 mm, the total fineness of the spun yarn is 300 to 5, If the yarn width / thickness ratio of the spun yarn is 2 to 20, the surface irregularity of the multilayer base material can be reduced because the spun yarn has a flat shape despite the thick reinforcing fiber yarn. it can.

  If the total fineness of the spun yarn is less than 300 tex, the fineness is too small and a large number of reinforcing fiber yarns are required. On the other hand, if the total fineness of the spun yarn exceeds 5,000 tex, the fineness is too large and the width of the reinforcing fiber yarn is controlled. It becomes difficult to do. Further, when the yarn width / thickness ratio of the spun yarn is less than 2, the cross-sectional shape of the spun yarn is close to a circle, so that the surface unevenness becomes large when a multilayer base material is used. On the other hand, if the yarn width / thickness ratio of the spun yarn exceeds 20, it becomes difficult to maintain the shape of the flat yarn. Therefore, the total fineness of the spun yarn is 300 to 5,000 tex, and the yarn width / thickness ratio is in the range of 2 to 20.

  Here, the yarn width and the yarn thickness are measured in a state where the yarn is taken out from the multilayer base material so that the cross-sectional shape of the reinforcing fiber yarn does not change. The measurement method may be a contact type using a caliper, a micrometer, etc. However, since the cross-sectional shape of the thread is likely to change during measurement, measurement is preferably performed by a non-contact type using a displacement sensor or the like. . Here, regarding the yarn width and the yarn thickness, the minimum diameter in the section of the extracted yarn is defined as the yarn thickness, and the maximum diameter is defined as the yarn width.

  In the present invention, 80% or more of the reinforcing fiber yarns have cut ends in the direction crossing the reinforcing fiber yarns, so that most of the reinforcing fiber yarns have cut ends, so that the deformation performance can be increased. Since the distance between the cut end and the cut end in the length direction of the reinforcing fiber yarn is a finite length of 10 to 300 mm, only the cut end interval at a specific location does not widen, and it is possible to cope with molding in various shapes. Can do.

  Moreover, the integration by the above-mentioned stitch is mentioned as a preferable aspect of the integration of the multilayer base material in the present invention. In the case of stitching, only a part of the stitch yarn is cut when the cut end is provided in the direction crossing the reinforcing fiber yarn, so that the reinforcing fiber yarn constituting each layer of the reinforcing fiber layer is separated. Therefore, it is possible to mold while maintaining integration as a multilayer base material. Here, when the reinforcing fiber yarns are scattered, the stitches that restrain the reinforcing fiber yarns are eliminated, so that the reinforcing fiber yarns may come off from the surface of the multilayer substrate, The meandering of the fibers and the density of the reinforcing fibers in the layer occur. Usually, when trying to mold a multi-layer base material in which a plurality of sheet-like reinforcing fiber layers made of reinforcing fiber yarns are integrated with stitch yarns into a quadratic curved surface shape, the reinforcing fiber yarns are restrained by the stitch yarns. Therefore, the reinforcing fiber yarn cannot move, and even if the multilayer base material is to be deformed, the reinforcing fiber is stuck, making it difficult to follow the quadric surface. Therefore, the reinforcing fiber yarn has a cut end in a direction crossing the reinforcing fiber yarn, and the reinforcing fiber yarn having the cut end has a finite length of 10 to 300 mm. It is possible to move the reinforcing fiber yarn by sliding the reinforcing fiber bundle so that the interval between the cut portions of the reinforcing fiber yarn is widened as necessary, and the deformation of the reinforcing fiber yarn is not limited even though it is a multilayer substrate. The amount can be increased.

  Further, as another preferred embodiment of the integration of the multilayer base material in the present invention, a plurality of reinforcing fiber layers are integrated by adhesion of the resin material arranged between the above-mentioned sheet-like reinforcing fiber layers. . In this aspect, the multilayer substrate is maintained in its form because the reinforcing fiber layer constituting the multilayer substrate is bonded by the resin material at room temperature, but the multilayer substrate is heated to remove the resin material. By softening, the multilayer substrate can be shaped.

  Even in this case, the length of the reinforcing fiber yarn is a finite length in the range of 10 to 300 mm. When the length of the reinforcing fiber yarn is less than 10 mm, the cutting length is too small and the number of cut ends increases, and the reinforcing fiber yarn is easily dropped from the multilayer substrate when handling the multilayer substrate. On the other hand, if the length of the reinforcing fiber yarn exceeds 300 mm, the number of cut ends decreases, so that the reinforcing fiber yarn does not fall off from the multilayer base material, but is strengthened at the point where the interval is too large and cut. The fiber yarn does not slip properly, making shaping difficult. Therefore, even in the multilayer base material integrated by bonding, the length of the reinforcing fiber yarn has a finite length in the range of 10 to 300 mm. A more preferable length of the reinforcing fiber yarn is 10 to 100 mm. If it is within this range, the reinforcing fiber yarn can pass through appropriately, and the effect of the present invention can be exhibited most effectively.

  Examples of the resin material used here include a thermosetting resin, a thermoplastic resin, or a mixture thereof, and the form thereof may be any form such as liquid, powder, fiber, and nonwoven fabric. When only adhesiveness is required as a multilayer substrate, a thermosetting resin or a thermoplastic resin may be used alone, but when impact resistance is required, it has moderate toughness. However, since it has appropriate adhesiveness to the reinforcing fiber layer, it is preferable to use a mixture of a thermoplastic resin having excellent toughness and a thermosetting resin that is easily reduced in viscosity and easy to adhere to the reinforcing fiber layer.

  Examples of the thermosetting resin include an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, and a phenol resin. The thermoplastic resin includes polyvinyl acetate, polycarbonate, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyarylate, polyester, polyamideimide, polyimide, polyetherimide, polysulfone, polyethersulfone, polyetherether. Examples include ketones, polyaramides, polybenzimidazoles, polyethylene, polypropylene, cellulose acetate, and cellulose butyrate.

  Here, the adhesion amount of the resin material is preferably 0.5 to 15% by weight with respect to the weight of the plurality of sheet-like reinforcing fiber layers which are composed of and integrated with reinforcing fiber yarns. If the adhesion amount is within this range, the reinforcing fiber yarns can be integrated into a reinforcing fiber yarn or reinforcing fiber layer having an appropriate stiffness. If the adhesion amount of the resin material is less than 0.5% by weight, it is difficult to unite the fibers, and if the adhesion amount exceeds 15% by weight, the amount of resin is too large to make it difficult to pass through the reinforcing fiber bundle. Become. Therefore, the adhesion amount of the resin material is preferably 0.5 to 15% by weight with respect to the weight of the reinforcing fiber bundle or the sheet composed of the reinforcing fiber bundle.

  In another preferred embodiment of the present invention, the cut ends of the reinforcing fiber yarns constituting the sheet-like reinforcing fiber layer are arranged so as to have an interval of at least 10 to 300 mm in the length direction of the reinforcing fiber yarns. Has been.

  If the distance between the cut ends in the length direction of the reinforcing fiber yarn, that is, the length of the reinforcing fiber yarn having the cut end is less than 10 mm, the cut length is too small and the reinforcing fiber yarn is made of stitch yarn or resin material. There are few places which restrain a line, and it becomes easy for a reinforcing fiber yarn to fall off from a multilayer substrate. On the other hand, if the distance between the cut end and the cut end in the length direction of the reinforcing fiber yarn exceeds 300 mm, the number of places where the reinforcing fiber yarn is restrained by the stitch yarn or the resin material increases. Although it does not fall off from the stitch base material, the reinforcing fiber yarns do not slip appropriately at the locations where the interval is too large and cut, and shaping may be difficult. Therefore, it is preferable that the distance between the cut ends of the reinforcing fiber yarns is in the range of 10 to 300 mm. The distance between the cut end and the cut end is more preferably 10 to 100 mm. By doing so, it becomes easier to form a quadratic curved surface.

  As another preferred embodiment of the present invention, the length (cutting width) of the cut end per place in the sheet-like reinforcing fiber layer is preferably any of stitch length S or gauge length G of the stitch yarn. 1 to 5 times smaller intervals. If the length of the cut end (cut width) is less than one of the smaller intervals of the stitch length S or the gauge length G, the reinforcing fiber yarn cannot be restrained by the stitch yarn and is likely to fall off. Become. In addition, since the number of stitch yarns to be cut increases when the length of the cut end (cut width) exceeds five times, the restriction of the reinforcing fiber yarns in the multilayer base material is reduced, and the reinforcing fiber yarns are It becomes easy to drop off from the multilayer substrate. Therefore, it is preferable that the length (cutting width) of the cut end per place in the sheet-like reinforcing fiber layer is 1 to 5 times the smaller one of the stitch length S or the gauge length G of the stitch yarn. .

  The stitch length S referred to here is an interval between stitches that are continuous in the longitudinal direction of the multilayer base material, and corresponds to a length per loop course. The gauge length G is a stitch interval in the width direction of the multilayer base material, and corresponds to a distance obtained by dividing the knitting width by the number of wells.

  Further, as another preferred embodiment of the present invention, the length of the cut end per place in the sheet-like reinforcing fiber layer, that is, the distance between the cut end and the adjacent cut end (cut width) is preferably Is 2 to 15 times the average yarn width per yarn of the reinforcing fiber yarn. If the length of the cut end (cutting width) is less than twice the yarn width, at least one reinforcing fiber yarn is completely cut even if there is a variation in the yarn width, resulting in a quadratic curved surface. When forming into a preform by shaping, the shapeability can be improved by moving the reinforcing fiber yarn by moving the reinforcing fiber yarn by opening the cut end portion of the reinforcing fiber yarn. On the other hand, if the length of the cut end (cut width) exceeds 15 times, it becomes easier to form when forming into a secondary curved surface to form a preform, but the reinforcing fiber is wide at the location of the cut end. Since the length continuously cut in the direction becomes too large, the mechanical properties are deteriorated when a composite material is used. Therefore, it is preferable that the length of the cut end per place in the sheet-like reinforcing fiber layer is 2 to 15 times the average yarn width per yarn of the reinforcing fiber yarn.

  Here, the cutting of the reinforcing fiber yarns in the base material may be cut at different places for each of the sheet-like reinforcing fiber layers, or may be cut by a notch penetrating in the thickness direction of the multilayer base material. Absent.

  As another preferred embodiment of the present invention, in a spun yarn comprising discontinuous fibers having a finite length of 10 to 300 mm, the number of twists is 200 turns / m or less, and an untwisted spun yarn may be used. . If the number of twists is 200 turns / m or less, the spun yarn can be easily removed with a small load because the number of twists is small, and a base material with excellent formability can be obtained.

  As another preferred embodiment of the present invention, the spun yarn composed of short fibers that are discontinuous fibers is substantially untwisted and can be bundled by covering with an auxiliary yarn. . Since the spun yarn is covered with the auxiliary yarn in a non-twisted state, and the spun yarn is not twisted, the flattening treatment is easily performed by pressurizing the spun yarn via a nip roller or the like. be able to. Furthermore, if the auxiliary yarn to be covered is a thermoplastic resin fiber yarn, the shape of the spun yarn can be maintained in a flat state by heat melting in the covering state.

  Here, the fibers constituting the auxiliary yarn to be covered may be any of inorganic fibers such as glass fibers and carbon fibers, and organic fibers such as nylon, polyester, and polyurethane. Copolymer nylon fibers are preferably used because of their good adhesion to matrix resins in fiber reinforced resins such as saturated polyester resins. The total fineness of the auxiliary yarn to be covered is preferably in the range of 10 to 500 dtex.

  As another preferred embodiment of the present invention, a spun yarn composed of short fibers which are discontinuous fibers can be substantially untwisted and bundled with a binder. By bundling with a binder in a non-twisted state, the handleability of the yarn is good when producing a multi-layer substrate, and after producing the multi-layer substrate, this binder is melted or removed, so that the spun yarn can be obtained. It can be made to pass through moderately, and the moldability of the multilayer substrate can be improved.

  Here, the binder may be in any form such as liquid or powder. If the binder is liquid, the yarn can be focused by applying a polymer such as water-soluble polyvinyl alcohol, water-soluble polyvinyl pyrrolidone and soluble polyester to the spun yarn and then drying it. If the binder is powder, the yarn can be bundled by heating the thermoplastic resin or a mixed polymer of the thermoplastic resin and the thermosetting resin to adhere to the spun yarn.

  In another preferred embodiment of the present invention, reinforcing fiber yarns having 80% by weight or more having cut ends or reinforcing fiber yarns that are spun yarns having 80% by weight or more of discontinuous fibers are arranged in parallel. The reinforced fiber layer thus made is integrated with a resin material.

  By arranging the reinforcing fiber yarns constituting the reinforcing fiber layer in parallel and integrating them with the resin material, the reinforcing fiber yarns that are parallel when manufacturing the multilayer substrate are handled with the resin material. When it is going to improve a property or to shape | mold a multilayer base material, it can be shape | molded easily by heating a multilayer base material and softening a resin material.

  The resin material used here is the same as the resin material disposed between the reinforcing fiber layers described above, and is a thermosetting resin, a thermoplastic resin, or a mixture thereof, and is in any form such as liquid, powder, fiber, and nonwoven fabric. It does not matter. When the resin material is a fiber, a reinforcing fiber constituting a reinforcing fiber layer is formed by using a covering yarn obtained by covering a thermoplastic fiber yarn with an inorganic fiber yarn or a core-sheath yarn comprising two types of yarns having different melting points as an adhesive yarn. They can be arranged in the width direction at a predetermined interval in a direction perpendicular to the direction in which the yarns are arranged, and can be integrated by thermal fusion.

Moreover, as another preferable embodiment in the present invention, the basis weight per layer of the sheet-like reinforcing fiber layer constituting the multilayer base material is preferably 100 to 1,000 g / m ² . If the basis weight of the reinforcing fiber layer is less than 100 g / m ² , the basis weight is small and the number of laminated layers increases, so the number of cut ends of the reinforcing fiber yarns increases and the workability decreases. On the other hand, if the basis weight of the reinforcing fiber layer exceeds 1,000 g / m ² , the number of laminated layers decreases, and the workability is improved, but the influence of cutting the reinforcing fiber yarn is likely to be noticeable. Therefore, the basis weight per layer of the reinforcing fiber layer constituting the multilayer base material is preferably 100 to 1,000 g / m ² .

  1 to 3 show a multilayer base material and a preform composed of one multilayer base material. In the present invention, the multilayer base material 1 is referred to as a single unit (hereinafter referred to as a multilayer base unit). And a multilayer substrate obtained by stacking a plurality of sheets and further integrating them with stitch yarns or the like. By adopting such an embodiment, even if one multilayer substrate unit is composed of a plurality of sheet-like reinforcing fiber layers, the reinforcing fiber yarns constituting each reinforcing fiber layer have cut ends. Not only can the position of the reinforcing fiber yarns be shifted within each layer, but also the positions of the multilayer substrate units can be shifted between the layers of the multilayer substrate unit, thereby further enhancing the formability to a quadratic curved surface shape. be able to. In addition to the above effects, the multi-layer base unit that is excellent in formability alone is further laminated and integrated, so that the handleability is excellent while maintaining the formability as a multi-layer base. A preform molded into a shape having a next curved surface (in some cases, a deep-drawn portion) can be obtained.

  As the above-mentioned multi-layer base unit having excellent formability, the reinforcing fiber yarn is 0 ° / 90 in which the multi-layer base material is laminated in the longitudinal direction (0 ° direction) and the vertical direction (90 ° direction). A biaxial multi-layer substrate is preferred. The multilayer substrate unit having such a configuration is very excellent in formability as a multilayer substrate unit alone. That is, when trying to obtain a reinforced fiber base material with excellent deformation performance, the crossing angle of the reinforcing fiber yarns is large and the deformation performance of the base material can be increased as the fiber arrangement direction is smaller. It is preferably a multilayer base material in which reinforcing fiber yarns are oriented on two axes of / 90 °.

  Further, when the multilayer base material is a stitch, the influence of inhibiting the deformation due to the presence of the stitch yarn can be reduced by making the arrangement direction of the reinforcing fiber yarns and the stitch line the same direction. For this reason, the laminated base unit is a biaxial axis of 0 ° / 90 ° in which reinforcing fiber yarns are laminated in the longitudinal direction (0 ° direction) and the vertical direction (90 ° direction) of the base material. A substrate is preferred.

  As the stitch yarn used in the present invention, a stitch yarn made of polyester fiber, nylon fiber, polyaramid fiber, vinylon fiber, glass fiber, carbon fiber, or the like can be selected.

  Moreover, it is preferable that the arrangement | sequence space | interval of the stitch thread | yarn in the multiaxial stitch base material which is a multilayer base material is about 2-20 mm, and a pitch is about 2-20 mm. More preferably, the arrangement interval of the stitch yarns is 2 to 10 mm, and the pitch is 2 to 10 mm.

  If the arrangement interval or pitch of the stitch yarns is smaller than this, the reinforcement of the reinforcing fiber yarns by the stitch yarns becomes strong, the formability of the formed preform is lowered, and the followability to the curved surface shape is impaired. In addition, if the arrangement interval or pitch is larger than this, the preform formability is improved, and deep drawing can be performed, but it becomes difficult to maintain the form of the preform by increasing the stitch interval, Within the range constrained by the stitch yarn, the reinforcing fiber yarn is partially bent or uneven, and the fibers are unevenly distributed.

  Moreover, if the thickness of the stitch yarn is too thin, it becomes easy to break the yarn when stitching, and if it is too thick, the stitch yarn is located on the surface of the multilayer base material, so that the FRP surface after molding is uneven. Become. Therefore, the total fineness of the stitch yarn is preferably 3 to 50 tex. The total fineness of the stitch yarn is more preferably 7 to 40 tex.

  The stitch yarn may be in any form such as a monofilament or spun yarn, but is preferably a multifilament yarn in order to obtain the smoothness of the surface of the multilayer substrate. This is because, in the case of multifilament yarn, by pressing the preform at the time of shaping or molding, the arrangement position of each filament moves and the thickness of the multifilament yarn can be reduced.

  Moreover, as a preferable resin material for adhesion | attachment of the reinforced fiber layer attached to the reinforced fiber layer surface used by this invention, a thermosetting resin, a thermoplastic resin, or mixtures thereof are mentioned. When only adhesiveness as a preform is required, a thermosetting resin or a thermoplastic resin may be used alone, but when impact resistance is required, thermoplastic with excellent toughness When a mixture of a resin and a thermosetting resin that can be easily reduced in viscosity and easily bonded to the reinforcing fiber base is used, appropriate adhesiveness to the reinforcing fiber layer can be imparted while having appropriate toughness.

  Examples of the thermosetting resin include epoxy resins, unsaturated polyester resins, vinyl ester resins, and phenol resins. The thermoplastic resin includes polyvinyl acetate, polycarbonate, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyarylate, polyester, polyamideimide, polyimide, polyetherimide, polysulfone, polyethersulfone, polyetherether. Examples include ketones, polyaramides, polybenzimidazoles, polyethylene, polypropylene, cellulose acetate, and cellulose butyrate.

  The form of adhesion of the resin material to the reinforcing fiber layer is dot-like, linear, or discontinuous linear. In order to adhere the resin material in the form of dots, a powdery resin material may be sprayed on the surface of the reinforcing fiber base and heat-sealed. In addition, in order to attach the resin material in a linear or discontinuous linear shape, a fabric made of continuous fibers such as a nonwoven fabric or a woven fabric made of the resin material is once produced, and then the fabric made of the resin material is reinforced fiber base material It is good to stick on the surface and heat-seal. By doing in this way, it has moderate adhesiveness in preform production, and does not hinder the impregnation of the resin in the thickness direction of the reinforcing fiber base during FRP molding.

  Examples of the reinforcing fiber yarn used in the present invention include a yarn made of glass fiber, polyaramid fiber, or carbon fiber. Among them, the carbon fiber yarn has good adhesion to the matrix resin and has a high tensile strength and tensile strength. Since the elastic modulus is high and the weight of the FRP molded body can be reduced, it is preferably used.

  Here, the carbon fiber is carbonized carbon fiber obtained by carbonizing polyacrylonitrile (hereinafter referred to as PAN-based carbon fiber) or pitch precursor (pitch fiber obtained from coal tar or heavy petroleum oil as a raw material). Any of the carbon fibers (pitch-based carbon fibers) obtained in this way may be used.

  The total thickness of the reinforcing fiber yarn used in the present invention is preferably about 300 to 5,000 tex. In particular, when a thick reinforcing fiber yarn is used, the reinforcing fiber yarn becomes cheap, and an inexpensive multilayer substrate can be obtained. However, if the basis weight of the reinforcing fiber yarn per reinforcing fiber layer is small, a gap is formed between the yarns in the layer, and the fiber density is partially reduced when integrated with stitch yarn or resin material. When it is molded, the FRP is thick where the fiber density is high, and the FRP is thin where the fiber density is low, resulting in an FRP with an uneven surface. Furthermore, when using thick reinforcing fiber yarns with a total fineness of 700 to 5,000 tex, before integrating them with stitch yarns or resin materials, the reinforcing fiber yarns can be swung by a roller or air jet sprayed. This is a preferable mode because the density of the reinforcing fiber yarns becomes uniform over the entire surface in a plane and an FRP having a smooth surface is obtained.

  The structure of the reinforcing fiber yarn of the multilayer substrate shown in FIG. 1 is composed of seven layers of + α ° layer / 90 ° layer / −α ° layer / 0 ° layer / −α ° layer / 90 ° layer / + α ° layer. However, the present invention is not limited to this, and at least the bias (± α °) of the −α ° layer and the + α ° layer with respect to the length direction of the multilayer base material. It is only necessary that the reinforcing fiber layer has a layer structure in the direction. Further, the layer structure of the reinforcing fiber layer in the multilayer base material is preferably mirror-symmetrically laminated so as not to warp when formed into FRP.

Further, the order of the layer structure of the reinforcing fiber layer is not limited to the order of -α ° / 90 ° / + α ° / 0 ° / + α ° / 90 ° / -α °, but is 0 ° / -α ° / It can be appropriately designed such as + α ° / 90 ° / + α ° / −α ° / 0 °. In addition, if a -α ° reinforced fiber layer and a + α ° reinforced fiber layer are made of a multi-layer base material in which reinforcing fiber yarns are arranged only in the bias direction, the multi-layer base material is easily reinforced when pulled in the length direction. The form is unstable, for example, the direction of the fiber yarn is shifted and the width direction of the multilayer base material is narrowed. In such a case, for example, auxiliary yarns made of thin glass fibers, carbon fibers, polyaramid fibers, etc. are arranged in the direction of 0 ° or 90 ° in an amount of about ²⁰ to 100 g / m ² , and a reinforcing fiber layer of −α ° and + α The form can be stabilized by integrating the reinforcing fiber layer of ° with stitch yarn or adhesive resin.

  The multilayer base material of the present invention does not necessarily need to be composed of a laminate of reinforcing fiber layers in which reinforcing fiber yarns are arranged in one direction to form a layer structure, and a woven fabric or chopped strand as long as it does not impair the formability -You may have layers, such as a mat | matte, a continuous strand mat | matte.

  The bias angle α ° is preferably in the range of 45 ° ± 10 °, more preferably 45 ° from the viewpoint of effectively laminating the multilayer base material in the length direction of the FRP molded body and effectively performing shear reinforcement with reinforcing fibers. .

  In the present invention, as a method of providing a cut end so that the reinforcing fiber yarns have a finite length, a method of cutting by a manual operation or a cutting machine using a cutter (Method A), a blade is disposed at a predetermined position. Examples thereof include a method of punching with a punching blade (Method B) and a method of continuously cutting through a rotating roller having a blade disposed at a predetermined position (Method C). When the cut ends are simply provided on the reinforcing fiber yarn (Method A), when manufacturing in large quantities in consideration of production efficiency (Method B), when further mass production is performed (Method C) Is suitable. The cut ends can be provided so that the reinforcing fiber yarns have a predetermined finite length by making cuts in each layer or making cuts in a multilayer state.

  In addition, the preform of the present invention can be produced by molding a multilayer base material into a shape having a secondary curved surface by laminating one or a plurality of multilayer substrates as shown in FIG. By adopting such an embodiment, in each layer, the reinforcing fiber yarn has a cut end and is composed of discontinuous fibers of a finite length, so that it is handled while maintaining the formability as a multilayer substrate. Excellent in shape and excellent in shaping to a quadric surface.

  The multilayer base material and preform of the present invention are used as a reinforcing material for FRP used in other general industries such as repair / reinforcement of structures, transportation equipment such as automobiles, ships, airplanes, bicycles, sports equipment and FRP types. Preferably used.

(Example 1)
As the reinforcing fiber yarn, the tensile strength is 4,900 MPa, the tensile elastic modulus is 230 GPa, and the number of filaments is 12,000 PAN-based carbon fiber yarn (manufactured by Toray Industries, Inc., registered trademark: “Torayca”, The total fineness: 800 tex) was used, and the polyester yarn having a total fineness of 5.6 tex consisting of 24 filaments (registered trademark: “Tetron”, product number: 56T-24-262) made of 24 filaments was used. A fiber reinforced layer composed of PAN-based carbon fiber yarns is used, and the PAN-based carbon fiber yarns are −45 ° / 90 ° / + 45 ° / 0 ° / + 45 ° / 90 ° / − with respect to the longitudinal direction of the multilayer substrate. A multilayer base material A was prepared by arranging and laminating at 45 ° and integrating them with stitch yarns. Here, in each of the reinforcing fiber layers made of carbon fiber yarns that are reinforcing fiber yarns, the arrangement density of the carbon fiber yarns is 3.75 pieces / cm, and the basis weight of the carbon fiber yarns is 300 g / m ² . At the same time, the arrangement interval of the stitch yarns was 5 mm, and the stitch pitch was 5 mm.

  In addition, the carbon fiber yarn of each layer of the reinforcing fiber layer constituting the multilayer substrate has a cut end in a direction crossing the carbon fiber yarn at 80% by weight in each layer, and the carbon fiber yarn having this cut end. The fiber length was set to 50 mm so as to have cut ends at intervals of 50 mm. Here, the cut ends were provided by cutting manually by using a cutter for each layer, and seven layers were laminated. The cut length of the carbon fiber yarn is 21.3 mm (8 reinforcing fiber yarns) cut every 26.7 mm (10 reinforcing fiber yarns), thereby cutting 80% by weight of the reinforcing fiber yarns. It has an end. The cut end length was 4.3 times the stitch interval and 8 times the average yarn width.

  And this multilayer base material A was cut | judged to the magnitude | size of 100 cm x 100 cm, Then, two sheets were piled up. This was sandwiched between a male mold having a curved surface with a curvature radius of 30 cm and a female mold having a curved surface with a curvature radius of 30.5 cm to obtain a preform A molded into a curved shape. In this preform A, 20% by weight of the carbon fiber yarns constituting the multilayer base material are continuous fibers, and the remaining 80% by weight of the reinforcing fiber yarns have cut ends at intervals of 50 mm. As a result, the preform could be produced without generating wrinkles.

(Example 2)
In Example 1, a multilayer substrate B and a preform B were obtained in the same manner as in Example 1 except that the following points were changed.
1) The stitch yarn arrangement interval is 10 mm, and the stitch pitch is 10 mm.
2) The carbon fiber yarn of each layer of the reinforcing fiber layer constituting the multilayer substrate has a cut end in the direction crossing the carbon fiber yarn at 90% by weight in each layer, and the carbon fiber yarn having this cut end. The cut ends are spaced at intervals of 200 mm so that the fiber length is 200 mm.
3) The cut length of the carbon fiber yarn is cut by 24.0 mm (9 reinforcing fiber yarns) every 26.7 mm (10 reinforcing fiber yarns), thereby cutting 90% by weight of the reinforcing fiber yarns. Have an edge.

  In the obtained multilayer base material B, the cut end length was 2.4 times the stitch interval and 9.0 times the average yarn width. And this multilayer base material B was made like Example 1, and the preform B shape | molded by the curved-surface shape was obtained. In this preform B, 10% by weight of the carbon fiber yarns constituting the multilayer base material are continuous fibers, and the remaining 90% by weight of the reinforcing fiber yarns have cut ends at intervals of 250 mm. As a result, the preform could be produced without generating wrinkles.

(Example 3)
In Example 1, a continuous PAN-based carbon fiber yarn having a tensile strength of 4,900 MPa, a tensile elastic modulus of 230 GPa, and a filament number of 12,000 (manufactured by Toray Industries, Inc., registered trademark: “Torayca”) PAN-based carbon fiber having a tensile strength of 4,900 MPa and a tensile elastic modulus of 230 GPa (manufactured by Toray Industries, Inc., registered trademark: “Torayca”) was cut from a discontinuous fiber having a length of 50 mm. Using a spun yarn having a twist number of 100 turns / m (total fineness 800 tex), two (20% by weight) continuous fiber yarns in 10 layers and 8 (80% by weight) become spun yarns in each layer. A multilayer substrate C and a preform C were obtained in the same manner as in Example 1 except that the above arrangement was made. Here, the spun yarn was nipped between the rollers so as to have a yarn width / thickness ratio of 10, and flattened.

  In the preform C, 20% by weight of the carbon fiber yarns constituting the multilayer base material are continuous fibers, and the remaining 80% by weight is made of spun yarn, so that the short fibers constituting the spun yarn are allowed to pass through. However, since a large load was required, the preform C could be produced without generating wrinkles. Further, since the flattening treatment was performed so that the yarn width / thickness ratio was 10, the yarn thickness was almost the same as that of the continuous fiber, so that a preform with a smooth surface was obtained.

Example 4
In Example 2, a spun yarn having a twist number of 150 turns / m (total fineness: 800 tex) made of discontinuous fibers obtained by cutting carbon fibers into a length of 50 mm was used, and one piece (10% by weight) per ten pieces in each layer. A multilayer substrate D and a preform D were obtained in the same manner as in Example 2 except that 9 continuous fibers (90% by weight) were arranged so as to become spun yarns. Here, the spun yarn was nipped between the rollers so that the yarn width / thickness ratio was 10, and flattened.

  In Preform D, 10% by weight of the carbon fiber yarns constituting the multilayer substrate were continuous fibers, the remaining 90% by weight was made of spun yarn, and the number of twists was as small as 50 turns / m. Therefore, the preform D could be produced without causing wrinkles or the like because the staple fibers constituting the spun yarn easily slipped out. In addition, since the flattening treatment was performed so that the yarn width / thickness ratio was 10, the yarn thickness was almost the same as that of the continuous fiber, so that a preform with a smooth surface was obtained.

(Example 5)
In Example 1, a multilayer substrate E and a preform E were obtained in the same manner as in Example 1 except that the reinforcing fiber layer was integrated by a resin material. Here, the resin material used for adhesion is polyethersulfone (manufactured by Sumitomo Chemical Co., Ltd., registered trademark: “Sumika Excel”, product number: 5003P) and epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., registered trademark: “Epicoat”). "Product number: 21 parts by weight of 806, manufactured by Nippon Kayaku Co., Ltd., trade name: 12.5 parts by weight of NC-3000, and product name: TEPIC-P4 parts by weight of Nissan Chemical Industries, Ltd., 100" Is a powder of an adhesive resin obtained by pulverizing a mixed resin having a mixing ratio of 60:40) and sprayed on the surface of the reinforcing fiber layer, followed by heat-sealing. A multilayer substrate E was produced. The adhesion amount of the resin material to the reinforcing fiber layer was 20 g / m ² . In the preform E, 20% by weight of the carbon fiber yarn constituting the multilayer base material is continuous fiber, and the remaining 80% by weight has a cut end and each sheet is bonded with an adhesive resin. By heating and softening the resin material, it was possible to fabricate the preform without causing wrinkles and the like by sliding the reinforcing fiber yarns and widening the distance between the cut ends.

(Example 6)
In Example 1, a continuous PAN-based carbon fiber yarn having a tensile strength of 4,900 MPa, a tensile elastic modulus of 230 GPa, and a filament number of 12,000 (manufactured by Toray Industries, Inc., registered trademark: “Torayca”) , Total fineness: 800 tex), a tensile strength of 4,900 MPa, and a spinning fiber made of discontinuous fibers obtained by cutting carbon fibers having a tensile modulus of 230 GPa (manufactured by Toray Industries, Inc., registered trademark: “Torayca”) into a length of 50 mm. In the same manner as in Example 1, the multilayer substrate F was used except that the yarn (total fineness 800 tex) was used and that 20% by weight was continuous fiber yarn and 80% by weight was spun yarn in each layer. A preform F was obtained. This spun yarn is untwisted, and a copolymer nylon yarn (manufactured by Toray Industries, registered trademark: “Elder”, product number: 56T-10-G100) having a melting point of 110 ° C. and a total fineness of 5.6 tex is 200 turns / m. And then flattening so that the yarn width / thickness ratio is 10, and maintaining the shape by melting and bonding the copolymer nylon yarn, and at the time of molding, the molding is performed while heating to a temperature of 120 ° C. went. In the preform F, 20% of the carbon fiber yarns constituting the multilayer base material F are continuous fiber yarns, and the remaining 80% are made of spun yarns covered with thermoplastic resin fibers, and the covering yarns are melted. However, by forming the preform, the preform could be produced without causing wrinkles or the like because the short fibers constituting the spun yarn were displaced while passing through. Further, by performing the flattening treatment so that the yarn width / thickness ratio is 10, the yarn thickness is almost the same as that of the continuous fiber yarn, so that a preform with a smooth surface was obtained.

(Example 7)
In Example 1, a continuous PAN-based carbon fiber yarn having a tensile strength of 4,900 MPa, a tensile elastic modulus of 230 GPa, and a filament number of 12,000 (manufactured by Toray Industries, Inc., registered trademark: “Torayca”) , Total fineness: 800 tex), a tensile strength of 4,900 MPa, and a spinning fiber made of discontinuous fibers obtained by cutting carbon fibers having a tensile modulus of 230 GPa (manufactured by Toray Industries, Inc., registered trademark: “Torayca”) into a length of 50 mm. In the same manner as in Example 1, except that the yarn (total fineness 800 tex) was used and that 10% by weight was continuous fiber yarn and 90% by weight was spun yarn in each layer, A preform G was obtained. This spun yarn is untwisted, and a powder of an adhesive resin (glass transition point: 62 ° C.) obtained by pulverizing a mixed resin having a blending ratio of polyethersulfone and epoxy resin of 60:40 is adhered to the surface of the spun yarn. A flattening process was performed so that the width / thickness ratio was 10, and the adhesive resin was melt-bonded to maintain the shape, and at the time of molding, molding was performed while heating to a temperature of 120 ° C. In the preform G, 10% by weight of the carbon fiber yarns constituting the multilayer base material are continuous fiber yarns, and the remaining 90% by weight is spun by a mixture of thermoplastic resin / thermosetting resin particles. By forming while mixing the mixed particles, the preform can be produced without wrinkles due to the short fibers (discontinuous fibers) that make up the spun yarn slipping while slipping out. It was. Further, since the flattening treatment was performed so that the yarn width / thickness ratio was 10, the yarn thickness was almost the same as that of the continuous fiber, so that a preform with a smooth surface was obtained.

(Comparative Example 1)
A multilayer substrate H and a preform H were produced in the same manner as in Example 1, except that the reinforcing fiber yarn was not provided with a cut end. In the preform H, the continuous reinforcing fiber yarns were restrained by the stitch yarns, and the reinforcing fiber yarns were not able to move. Therefore, the curved surface shape could not be followed, and many wrinkles were generated.

(Comparative Example 2)
In Example 1, continuous fiber yarns and reinforcing fiber yarns having cut ends were alternately arranged every 8 pieces, and the ratio was 50% by weight. Multilayer substrate I and preform I were produced. The cut end length was 4.3 times the stitch interval and 8 times the yarn width. In Preform I, although it was able to be molded into a curved surface shape, the carbon fiber yarn could not move partially, and since there was a clogged portion, the shape after molding could not be maintained.

(Comparative Example 3)
In Example 1, the same as in Example 1, except that the reinforcing fiber yarns having cut ends were manually cut using a cutter for each layer at intervals of 4 mm so that the fiber length was 4 mm. Multilayer substrate J and preform J were produced. The length of the cut end was 0.8 times the stitch interval and 1.5 times the yarn width. In the preform J, although the length of the carbon fiber having a cut end that was able to be shaped into a curved surface was 4 mm, which was smaller than the stitch interval, many carbon fiber yarns dropped from the multilayer base material.

  Table 1 shows the results of the above Examples and Comparative Examples.

  As is clear from the results shown in Tables 1 and 2, the preforms of Examples 1 to 7 constitute the reinforcing fiber layer while restraining the reinforcing fiber yarns with stitch yarns or resin materials in the multilayer base material. 80% by weight or more of the reinforcing fiber yarn has a cut end in a direction crossing the reinforcing fiber yarn, and the reinforcing fiber yarn having the cut end has a finite length of 10 to 300 mm, or its reinforcement Since 80% by weight or more of the fiber yarn is a spun yarn composed of 10 to 300 mm of finite-length discontinuous fibers, when the multilayer base material is shaped into a quadric surface, the cut ends of the reinforcing fiber yarns are The shapeability could be improved by opening or by the pseudo extension of the multilayer substrate due to the discontinuity of discontinuous fibers in the spun yarn. On the other hand, in the preform of Comparative Example 1, the reinforcing fiber yarn in which the multilayer base material is continuous is constrained by the stitch yarn, and the reinforcing fiber yarn cannot be moved, so that it cannot follow the curved surface shape. A lot of sputum occurred. In the preform of Comparative Example 2, the multilayer base material was formed into a curved surface shape because the ratio of the continuous fiber yarns and the reinforcing fiber yarns having cut ends was 50% by weight. Since the carbon fiber yarn could not move and there was a pinched part, the shape after shaping could not be maintained. Further, in the preform of Comparative Example 3, although the multilayer base material could be shaped into a curved shape, the length of the carbon fiber having a cut end was 4 mm, which was smaller than the stitch interval. Numerous yarn dropouts occurred.

  In the multilayer base material and preform of the present invention, 80% by weight or more of the reinforcing fiber yarns constituting the multilayer base material have cut ends in the direction crossing the reinforcing fiber yarns, and the reinforcing fiber yarns having the cut ends are Preform manufacturing process because 80% by weight of the reinforcing fiber yarn constituting the multilayer base material is a spun yarn composed of 10-300 mm finite length discontinuous fibers. Can be shaped into a curved surface without causing wrinkles or separation of reinforcing fibers.

  The preform of the present invention does not cause wrinkles in the multi-layer substrate during molding, and the reinforcing fibers are straightly oriented. Therefore, when molded into FRP, it exhibits high mechanical properties such as high strength and elastic modulus. In addition to this, excellent appearance quality can be achieved. Such a preform is suitably used as a reinforcing material for FRP used in other general industries such as repair / reinforcement of structures, transportation equipment such as automobiles, ships, airplanes, bicycles, sports equipment, and FRP types.

FIG. 1 is a partially cutaway schematic perspective view for illustrating the multilayer substrate of the present invention. FIG. 2 is a schematic partial cross-sectional view taken along the line AA ′ of the multilayer substrate of FIG. 3 is an enlarged view of the schematic partial cross-sectional view of FIG. FIG. 4 is a schematic partial sectional view of a preform obtained by shaping the multilayer base material of FIG. 1 into a curved shape.

Explanation of symbols

1: Multi-layer base material 2: Reinforcing fiber yarn constituting + α ° reinforcing fiber layer 3: + α ° reinforcing fiber layer 4: Reinforcing fiber yarn constituting 90 ° reinforcing fiber layer 5: Reinforcing fiber of 90 ° Layer 6: Reinforcing fiber yarn constituting -α ° reinforcing fiber layer 7: -α ° reinforcing fiber layer 8: 0 Reinforcing fiber yarn constituting 0 ° reinforcing fiber layer 9: 0 Reinforcing fiber layer 10 : -Α ° reinforcing fiber layer constituting a reinforcing fiber layer 11: -α ° reinforcing fiber layer 12: 90 ° reinforcing fiber layer constituting a reinforcing fiber layer 13: 90 ° reinforcing fiber layer 14: + α Reinforcing fiber yarns constituting the reinforcing fiber layer of 15 °: Reinforcing fiber layer of + α ° 16: Stitch yarn 17: Cut end 20: Preform B: Longitudinal direction AA ′ of the multilayer base material: Sectional reference line

Claims (13)

  The reinforcing fiber yarns are arranged in parallel in a sheet form to form a reinforcing fiber layer, and a plurality of layers of the reinforcing fiber layers are laminated at different angles in the arrangement direction of the reinforcing fiber yarns constituting each reinforcing fiber layer. In the multi-layered base material integrated in a state where the reinforcing fiber layer constitutes the reinforcing fiber layer, 80% or more by weight of the reinforcing fiber yarn has a cut end in a direction crossing the reinforcing fiber yarn, and has the cut end. A multilayer substrate characterized in that the length of the reinforcing fiber yarn is a finite length of 10 to 300 mm.   The reinforcing fiber yarns are arranged in parallel in a sheet form to form a reinforcing fiber layer, and a plurality of layers of the reinforcing fiber layers are laminated at different angles in the arrangement direction of the reinforcing fiber yarns constituting each reinforcing fiber layer. In the multi-layered base material integrated in the state, 80% by weight or more of the reinforcing fiber yarns constituting the reinforcing fiber layer are spun yarns composed of discontinuous fibers having a finite length of 10 to 300 mm, A multi-layer substrate having a total fineness of spun yarn of 300 to 5,000 tex and a yarn width / thickness ratio of 2 to 20.   The multilayer base material according to claim 1, wherein the cut ends of the reinforcing fiber yarns are arranged at an interval of at least 10 to 300 mm in the length direction of the reinforcing fiber yarns.   The multilayer substrate according to any one of claims 1 to 3, wherein the multilayer substrate is integrated by stitch yarns.   The multilayer base material according to any one of claims 1 to 3, wherein the multilayer base material is integrated by a resin material disposed between layers of the sheet-like reinforcing fiber layers.   5. The multilayer base material according to claim 4, wherein the length of the cut end per place is 1 to 5 times the smaller interval between the stitch length S and the gauge length G of the stitch yarn.   The multilayer base according to any one of claims 1, 3 to 6, wherein the length of the cut end per place is 2 to 15 times the average yarn width per yarn of the reinforcing fiber yarn. Wood.   6. The multilayer substrate according to claim 2, wherein the number of twists of the spun yarn is 200 turns / m or less.   6. The multilayer base material according to claim 2, wherein the spun yarn is substantially untwisted and is covered and converged with an auxiliary yarn.   6. The multilayer base material according to claim 2, wherein the spun yarn is substantially untwisted and focused by a binder.   A sheet-like reinforcing fiber layer in which 80% by weight or more of reinforcing fiber yarns having cut ends or 80% by weight or more of reinforcing fiber yarns, which are spun yarns composed of discontinuous fibers, are arranged in parallel is a resin. The multilayer substrate according to any one of claims 1 to 10, wherein the multilayer substrate is integrated with a material. Multilayer substrate according to any one of claims 1 to 11 mass per unit area per reinforcing fiber layers one layer is characterized by a 100~1,000g / m ^2.   A preform formed by forming a multilayer base material according to any one of claims 1 to 12 into a shape having a secondary curved surface by laminating one or more.

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