JP2018165045A - Reinforced fiber laminate sheet and method of producing resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make prevention of displacement of reinforced fiber layers each other and easiness of deformation compatible in a reinforced fiber laminate sheet.SOLUTION: A reinforced fiber laminate sheet (100) comprises a plurality laminated reinforced fiber layers (1011 to 1013). The plurality of reinforced fiber layer (1011 to 1013) include a plurality of reinforced fiber bundles aligned along one direction respectively, and are restrained each other by being stitched with first yarns (104p1,q1, r1) having softening points (Tp1, q1, r1) and second yarns (104p2, q2, r2) passing through two or more reinforced fiber layers (1011 to 1013) and having softening point (Tp2, q2, r2) higher than that of the first yarns (104p1, q1, r1) or no softening point.SELECTED DRAWING: Figure 3

Description

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

  Conventionally, so-called RTM (Resin Transfer Molding) is known as a molding method of fiber reinforced plastics (also referred to as “FRP”) having excellent productivity. In RTM, a substrate laminate composed of a laminate of multiple reinforcing fiber fabrics is placed in a mold, a matrix resin is injected into the mold, the substrate laminate is impregnated, and the resin is cured. Then, the molded product is demolded.

  The base material laminated body arrange | positioned in a shaping | molding die is previously formed so that it may have a three-dimensional shape according to the shape of the molded product produced | generated. In general, first, the base material laminate is formed into a flat plate shape, and then the base material laminate is shaped into a predetermined three-dimensional shape to create a so-called preform. This preform is placed in a mold.

  As the reinforcing fiber fabric constituting the flat substrate laminate, there are mainly woven fabric and non-crimp fabric (sometimes referred to as “NCF”). These reinforcing fiber fabrics are continuously produced in a certain width by a loom or warp knitting machine, wound around a roll, held, and conveyed. For this reason, when manufacturing a base material laminated body, a required amount of reinforcing fiber fabric is drawn out from a roll, cut into a desired shape, laminated, and a base material laminated body is generated.

  However, in the above-described method, a large amount of end material remaining after cutting out a reinforcing fiber fabric having a desired shape from a reinforcing fiber fabric having a certain width (that is, substantially rectangular). That is, the amount of reinforcing fibers discarded is large. For this reason, the above-described method for producing a reinforcing fiber fabric having a certain width in advance has a problem that the manufacturing cost is high.

  Therefore, instead of cutting out a reinforcing fiber fabric having a product shape from a reinforcing fiber fabric having a certain width (that is, a substantially rectangular shape), reinforcing fibers are applied only to necessary portions so as to obtain a desired shape according to the product shape from the beginning. The fiber placement method, in which bundles are arranged sequentially, has attracted attention. According to the fiber placement method, the amount of scrap material discarded can be significantly reduced.

  As a method for obtaining a three-dimensional base laminate using the fiber placement method, (i) a three-dimensional base laminate is obtained by attaching a reinforcing fiber bundle to a mold having a three-dimensional shape. And (ii) creating a planar reinforcing fiber laminate sheet, then laminating it to form a substrate laminate, and shaping the substrate laminate to form a three-dimensional substrate laminate And a method for obtaining a (preform).

  When a reinforcing fiber bundle is directly attached to a mold having a three-dimensional shape, for example, a reinforcing fiber bundle having tackiness is directly placed on the mold, and the reinforcing fiber layer is fixed to the mold and formed into a molded product shape. I will do it. For this reason, the process of shaping the flat substrate laminate into a three-dimensional shape is unnecessary. However, when arranging the reinforcing fiber bundle on the mold, it is necessary to move the head for arranging the reinforcing fiber bundle along the shape of the mold. For this reason, there are the following problems. That is, when the shape of the mold is complicated, the reinforcing fiber bundle arrangement head and the mold may interfere with each other to dispose the reinforcing fiber bundle. Even if the reinforcing fiber bundle can be arranged along the mold, the reinforcing fiber bundle cannot be arranged at high speed when the shape of the mold is complicated, and the productivity is low.

  On the other hand, in the case of creating a planar reinforcing fiber laminated sheet, the following processing is performed. A reinforcing fiber bundle having tackiness or a dry (non-tacking) reinforcing fiber bundle is arranged in a planar and desired two-dimensional shape along one direction to form one reinforcing fiber layer. Thereafter, a plurality of the reinforcing fiber layers are laminated, and at least a part of the layers is constrained to form a flat reinforcing fiber laminated sheet. As restraining means for reinforcing fiber bundles or reinforcing fiber layers, restraining by adhesion using a resin, restraining by stitching using a suture, and the like are known.

  When a base laminate is manufactured by laminating the produced reinforcing fiber laminate sheets, the reinforcing fibers are fed from the end of the reinforcing fiber layer during transportation or lamination of the reinforcing fiber laminate sheets formed in a desired two-dimensional shape. There was a problem of dropping out. This is because, at the ends of the reinforcing fiber layers formed side by side in a desired two-dimensional shape, the distance at which the end reinforcing fibers are in contact with other reinforcing fibers adjacent to each other may be short.

  Further, when the reinforcing fiber layers are not constrained in the thickness direction, there is a problem that a large shift occurs between the reinforcing fiber layer and the reinforcing fiber layer when the reinforcing fiber laminated sheet is deformed into a three-dimensional shape. there were. On the other hand, in the thickness direction of the reinforcing fiber laminated sheet, for example, when firmly restrained by adhesion using a resin or stitching using a suture, there are the following problems. That is, at the end portion of each reinforcing fiber laminated sheet, there is a problem that deformation conforming to the length and shape of the contour line is suppressed by the above-described constraint, resulting in wrinkles.

  As a means for solving these problems, for example, a technique has been proposed in which a plurality of laminated base materials are integrated in the thickness direction by stitch yarns, and a stitch yarn is partially cut in a multi-axis stitch base material. (See Patent Document 1). In this technology, the stitch yarn is partly cut while giving a constant constraint with the stitch yarn in the thickness direction of the laminated base material, so that when the base material is deformed, each reinforcing fiber laminated sheet has the length and shape of the contour line. It is possible to make a deformation adapted to

  In addition, in a multi-axis stitch base material in which a plurality of laminated base materials are integrated in the thickness direction with an engagement yarn, a technique has been proposed in which the engagement yarn is heated to a melting point temperature or higher (Patent Document 2). reference). In this technique, the engagement yarn is heated to a temperature equal to or higher than the melting point and melted, so that the base material of each layer can be deformed in accordance with the circumference when the base material is deformed.

JP 2007-092232 A JP 2007-160587 A

  In the method of the above-mentioned Patent Document 1, since the stitch yarn is partially cut, the reinforcing fibers at the end of the base material are easily frayed and easily fall off. Further, the reinforcing fibers are easily damaged when the stitch yarn is cut, and it is difficult to maintain high productivity without damaging the reinforcing fibers.

  In the method disclosed in Patent Document 2, one type of engagement thread is used as an engagement thread that stitches the layers of the stacked biaxial stitch base materials together. For this reason, when the temperature is higher than the melting point of the engagement yarn, all the engagement yarns for stitching the layers are melted. As a result, the restraint in the thickness direction of the laminated base material becomes loose, and a shift may occur between the layers.

  The present disclosure has been made to solve at least a part of the problems described above, and can be realized as the following forms or application examples.

(1) According to one aspect of the present invention, a reinforcing fiber laminated sheet is provided. This reinforcing fiber laminated sheet includes a plurality of laminated reinforcing fiber layers. The plurality of reinforcing fiber layers: each including a plurality of reinforcing fiber bundles arranged along one direction; passing through a first yarn having a softening point and two or more of the reinforcing fiber layers; They are constrained to each other by stitching together with a second thread that has a higher softening point or no softening point than the first thread.
According to such an aspect, before or simultaneously with the deformation of the reinforcing fiber laminated sheet, the temperature is higher than the softening point of the first yarn, and the second yarn has a softening point. By raising the temperature of the first yarn to a temperature lower than the softening point of the second yarn, the restraint of the plurality of reinforcing fiber layers by the first and second yarns can be relaxed. For this reason, a reinforcement fiber lamination sheet can be changed easily compared with the reinforcement fiber lamination sheet which cannot relieve restraint of a plurality of reinforcement fiber layers by the 1st and 2nd thread. At that time, the second yarn is still in a state of passing through two or more reinforcing fiber layers. For this reason, the two or more reinforcing fiber layers are restrained more gently by the second yarn than before. For this reason, compared with the aspect in which the means for restraining the reinforcing fiber layers is lost, the reinforcing fiber layers are not easily displaced greatly when the reinforcing fiber laminated sheet is deformed.

(2) In the reinforcing fiber laminate sheet according to the above aspect, the plurality of reinforcing fiber layers are stitched together by the first yarn and the second yarn along at least a part of the outer periphery of the reinforcing fiber laminate sheet. It can be set as the aspect currently performed. If it is set as such an aspect, dropout of the reinforced fiber from the edge part of a reinforced fiber lamination sheet can be prevented effectively.

(3) In the reinforcing fiber laminated sheet of the above aspect, the softening point of the first yarn may be 60 to 120 ° C. If it is set as such an aspect, when conveying or laminating a reinforced fiber lamination sheet, the 1st thread may soften and a plurality of reinforced fiber layers may adhere at an unexpected relative position. Can be reduced. Further, when a reinforcing fiber laminated sheet is impregnated with a thermosetting resin and cured to produce a resin molded product, a thermosetting resin having a fluidity temperature range equal to or higher than the softening point of the first yarn is used. Can be easily selected.

(4) In the reinforcing fiber laminated sheet of the above aspect, the softening point of the second yarn may be 120 to 200 ° C. If it is set as such an aspect, when a reinforced fiber lamination sheet is made to impregnate a thermosetting resin and it hardens | cures and produces | generates a resin molded product, there exist the following advantages. That is, a thermosetting resin having a fluid temperature range lower than the softening point of the second yarn and a curing temperature higher than the softening point of the second yarn can be easily selected.

(5) In the reinforcing fiber laminated sheet of the above aspect, the second yarn may be configured by a reinforcing fiber constituting the reinforcing fiber layer. In such an aspect, the temperature of the first and second yarns is raised to relax the restraint of the plurality of reinforcing fiber layers, and the second remaining in the reinforcing fiber laminated sheet after deforming the reinforcing fiber laminated sheet. The yarn is composed of reinforcing fibers constituting the reinforcing fiber layer. For this reason, even when the structure of the deformed reinforcing fiber laminated sheet can be visually recognized from the outside, the aesthetic appearance can be made beautiful compared to the aspect in which the second yarn is made of another material. In addition, since the reinforcing fibers remain in the stacking direction, the physical properties in the stacking direction can be reinforced as compared with the aspect in which the second yarn is composed of another material.

(6) In the reinforcing fiber laminate sheet of the above aspect, the reinforcing fiber may be an aspect that is a carbon fiber. If it is set as such an aspect, compared with the case where a reinforced fiber is another fiber, the lightweight and highly rigid resin molded product can be manufactured using the said reinforced fiber lamination sheet.

(7) According to another aspect of the present invention, a method for producing a resin molded product is provided.
The production method of this resin molded product is: (a) a step of preparing a reinforcing fiber laminated sheet; the reinforcing fiber laminated sheet comprises a plurality of laminated reinforcing fiber layers; and the plurality of reinforcing fiber layers; Each including a plurality of reinforcing fiber bundles arranged along one direction; passing through a first yarn having a softening point and two or more reinforcing fiber layers, and higher softening than the first yarn A step of preparing reinforcing fiber laminate sheets that are constrained to each other by being stitched together with a second yarn having a point or having no softening point; and (b) softening of the first yarn A step of raising the temperature of the first yarn to a temperature higher than the point, and when the second yarn has a softening point, the temperature of the temperature rise is higher than the softening point of the second yarn. And (c) performing the step (b), and After the step (b), a step of deforming the reinforcing fiber laminated sheet; and a step of solidifying the resin impregnated in (d) of the reinforcing fiber layered sheet after deformation.
According to such an aspect, before or simultaneously with the deformation of the reinforcing fiber laminated sheet, the temperature is higher than the softening point of the first yarn, and the second yarn has a softening point. By raising the temperature of the first yarn to a temperature lower than the softening point of the second yarn, the restraint of the plurality of reinforcing fiber layers by the first and second yarns can be relaxed. For this reason, a reinforcement fiber lamination sheet can be changed easily compared with the reinforcement fiber lamination sheet which cannot relieve restraint of a plurality of reinforcement fiber layers by the 1st and 2nd thread. At that time, the second yarn is still in a state of passing through two or more reinforcing fiber layers. For this reason, the two or more reinforcing fiber layers are restrained more gently than before by the frictional force of the second yarn and each reinforcing fiber layer. For this reason, compared with the aspect in which the means for restraining the reinforcing fiber layers is lost, the reinforcing fiber layers are not easily displaced greatly when the reinforcing fiber laminated sheet is deformed. For this reason, a high-quality resin molded product can be produced.

(8) In the method for producing a resin molded product of the above aspect, in the step (d), the temperature of the resin when the resin is solidified is higher than the softening point of the first yarn. Can do. If it is set as such an aspect, when there exists the 1st thread | yarn which remained in the temperature rising process in the produced | generated resin molded product, possibility that the 1st thread | yarn will be visible can be reduced.

(9) In the method for producing a resin molded product of the above aspect, the second yarn has a softening point; in the step (d): the temperature of the resin when the reinforcing fiber laminated sheet is impregnated with the resin Is lower than the softening point of the second yarn; the temperature of the resin when solidifying the resin is higher than the softening point of the second yarn. In such an embodiment, when the resin is impregnated into the reinforcing fiber laminate sheet, the reinforcing fibers are restrained by the second yarn, so that the reinforcing fiber is flowed by the impregnated resin flow. The layers do not shift. On the other hand, since the second yarn is also melted after the solidifying step, it is possible to reduce the possibility that the second yarn is noticeable in the produced resin molded product.

  The present invention can be realized in various forms other than the production method of the reinforcing fiber laminated sheet and the resin molded product. For example, (i) a reinforcing fiber layer, a preform, and a resin molded product, and (ii) a method for manufacturing the reinforcing fiber layer, the preform, the reinforcing fiber laminated sheet, and the resin molded product, and a method for controlling an apparatus that manufactures the same The present invention can be realized in the form of a computer program for realizing the control method, a non-temporary recording medium on which the computer program is recorded, and the like.

  According to the present disclosure, it is possible to reduce the waste amount of reinforcing fibers, and the reinforcing fibers at the end portions do not drop off during sheet transportation or lamination, and can be deformed along the shape of the mold during shaping. A reinforced fiber laminated sheet with excellent productivity can be obtained.

  Furthermore, according to the reinforcing fiber laminated sheet according to the present disclosure, it is possible to obtain a fiber-reinforced resin molded body having a smooth surface in which the reinforcing fiber bundle is not greatly disturbed and does not have wrinkles.

  As an application of the reinforcing fiber laminated sheet of the present disclosure, creation of a fiber reinforced resin molded body by an RTM molding method can be mentioned. Applications of fiber reinforced resin moldings include, for example, automobile hoods, roofs, doors, fenders, trunk lids, side panels, rear end panels, upper back panels, front bodies, under bodies, various pillars, various members, various frames, various types. Examples include automotive skins, automotive body parts, and automotive structural materials such as beams, various supports, various rails, and various hinges.

It is a perspective view showing one embodiment of a reinforced fiber lamination sheet 100 concerning this indication. 3 is a perspective view schematically showing the configuration of sutures 104p1 and 104p2 that are stitched at a portion P in the vicinity of the outer periphery of a reinforcing fiber laminated sheet 100. FIG. It is sectional drawing which shows typically the state of the 3-3 cross section in FIG. FIG. 4 is a cross-sectional view showing a state of the reinforcing fiber laminate sheet 100 when a part P of the reinforcing fiber laminate sheet 100 of FIG. 3 is heated to a temperature higher than the softening point Tp1 of the suture thread 104p1. 3 is a perspective view schematically showing a configuration of a suture thread 104q2 that stitches a part Q of a reinforcing fiber laminated sheet 100. FIG. It is sectional drawing which shows typically the state of 6-6 cross section in FIG. It is sectional drawing which shows the state of the reinforcement fiber lamination sheet 100 when some Q of the reinforcement fiber lamination sheet 100 of FIG. 6 is heated to the temperature higher than the softening point Tq1 of the suture thread 104q1. 3 is a perspective view schematically showing the configuration of sutures 104r1 and 104r2 that are stitched with a part R of a reinforcing fiber laminated sheet 100. FIG. It is sectional drawing which shows typically the state of the 9-9 cross section in FIG. FIG. 10 is a cross-sectional view showing a state of the reinforcing fiber laminate sheet 100 when a part R of the reinforcing fiber laminate sheet 100 of FIG. 9 is heated to a temperature higher than the softening point Tr1 of the suture thread 104r1. It is a flowchart which shows the production method of the resin molded product which uses the reinforced fiber lamination sheet. It is a top view for demonstrating the relationship between the target shape Fmi of a reinforcing fiber layer, and arrangement | positioning of the some reinforcing fiber bundle 100FBN which comprises the reinforcing fiber layer 1011N. It is a top view for demonstrating the relationship between the target shape Fmi of a reinforced fiber layer, and arrangement | positioning of the some reinforced fiber bundle 100FBW which comprises the reinforced fiber layer 1011W. It is explanatory drawing which shows the sewing method according to the position in the reinforced fiber lamination sheet 100S. It is a figure which shows the state of the reinforced fiber lamination sheet 100S after passing through the process of step S200 and S300 of FIG.

  The reinforcing fiber laminate sheet of the present disclosure is a reinforcing fiber laminate sheet in which a plurality of reinforcing fiber bundles arranged in one direction form one layer, and the layers are laminated in a plurality of layers, and the reinforcing fibers The laminated sheet is a reinforced fiber laminated sheet in which the suture A and the suture B are integrated, and the softening points of the suture A and the suture B are different.

  Next, the form for implementing the reinforcing fiber lamination sheet of this indication is explained, referring to drawings.

A. Reinforced fiber laminate sheet configuration:
FIG. 1 is a perspective view showing an embodiment of a reinforcing fiber laminate sheet 100 according to the present disclosure. The reinforcing fiber laminated sheet 100 is formed by laminating a plurality of reinforcing fiber layers 101. Each reinforcing fiber layer 101 includes a plurality of reinforcing fiber bundles arranged along one direction. Each reinforcing fiber bundle is a bundle of reinforcing fibers composed of a plurality of reinforcing fibers. Each reinforcing fiber layer 101 is cut and arranged in an appropriate length so that the reinforcing fiber laminated sheet 100 has an appropriate shape according to a molded product to be finally formed. Here, in order to facilitate understanding of the technology, an example in which all the reinforcing fiber layers 101 have the same shape is shown.

  A powdery resin binder 102 is attached to one side of the reinforcing fiber layer 101. The resin binder 102 is melted by being heated or being pressurized while being heated. The molten resin binder 102 penetrates into the two adjacent reinforcing fiber layers 101 and then solidifies, whereby the two adjacent reinforcing fiber layers 101 are fixed to each other.

  Note that heating and pressurization are not necessarily performed on the entire reinforcing fiber layer 101. That is, it is possible to heat or press a part of the laminated reinforcing fiber layer 101 to melt only the resin binder 102 existing in the part and then solidify the resin binder 102. In FIG. 1, the resin binder thus melted and solidified is shown as an indeterminate shape as a resin binder 103. In FIG. 1, a resin binder that has not yet been melted is shown as a resin binder 102 in a circular shape.

  The amount of the resin binder 102 present in the interlayer and the surface layer of the reinforcing fiber laminate sheet 100 is in the range of 0.1 to 20 parts by mass, whereas the reinforcing fiber laminate sheet 100 is 100 parts by mass. Is preferred. When the applied amount of the resin binder 102 is smaller than 0.1 parts by mass, it is difficult to hold the shape as a reinforcing fiber sheet even when all the resin binders 102 are finally used to fix adjacent reinforcing fibers. Become. On the other hand, when the applied amount of the resin binder 102 is larger than 20 parts by mass, the resin binder 102 is strongly restrained, and therefore it is difficult to follow the shape of the mold when the reinforcing fiber laminate sheet 100 is deformed into a three-dimensional shape. There is sex. In particular, when the application amount of the resin binder 102 is in the range of 2 to 10 parts by mass, the shape following property to the mold is relatively good while maintaining the shape of the sheet, which is a more preferable embodiment.

  The plurality of reinforcing fiber layers 101 included in the reinforcing fiber laminated sheet 100 are further restrained by stitching with the suture thread 104. That is, the reinforcing fiber laminated sheet 100 stably maintains its form by the resin binder 103 and the suture thread 104. In FIG. 1, the arrangement of the sutures 104 shown in the parts Q and R of the reinforcing fiber laminate sheet 100 is an exemplary arrangement for facilitating understanding of the technology, and the actual reinforcing fiber laminate sheet 100 is shown. It does not accurately reflect the position of the suture 104 in FIG.

  Here, examples of the reinforcing fiber used for constituting the reinforcing fiber bundle include carbon fiber, glass fiber, aramid fiber, metal fiber, alumina fiber, and silicon nitride fiber. In particular, carbon fibers are preferably used because the molded body can be further reduced in weight.

  The reinforcing fiber bundle can also be configured using a plurality of types of reinforcing fibers. The reinforcing fiber bundle can also be composed of synthetic fibers of reinforcing fibers and organic fibers.

  Examples of organic fibers used for reinforcing fiber bundles together with reinforcing fibers include polyamide synthetic fibers, polyolefin synthetic fibers, polyester synthetic fibers, polyphenylsulfone synthetic fibers, polybenzoxazine synthetic fibers, acetates, and acrylonitrile synthetics. Fiber, Modacrylic 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 fiber.

  The suture 104 is, for example, a fiber made of polyethylene, polyamide, polypropylene, polyester, polyphenylene sulfide, polyethersulfone, or the like, a fiber yarn made of inorganic fiber (for example, carbon fiber, glass fiber, metal fiber), or the like. It may be composed of blended yarns of the above fibers.

  The resin binder 102 may be any one that can be fixed to the surface layer of the reinforcing fiber layer 101 and can obtain an effect of fixing the layers of the reinforcing fiber laminated sheet 100. As the resin binder 102, for example, a thermoplastic resin or a thermosetting resin can be employed.

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

  FIG. 2 is a perspective view schematically showing the configuration of the sutures 104p1 and 104p2 that are stitched at a portion P (see FIG. 1) in the vicinity of the outer periphery of the reinforcing fiber laminate sheet 100. FIG. In FIG. 2, a plurality of reinforcing fiber layers 101 constituting the reinforcing fiber laminated sheet 100 are distinguished and shown as reinforcing fiber layers 1011, 1012, and 1013. The reinforcing fiber layer 1011 is a reinforcing fiber layer constituting the surface of the reinforcing fiber laminated sheet 100. The reinforcing fiber layer 1013 is a reinforcing fiber layer constituting the back surface of the reinforcing fiber laminate sheet 100. The reinforcing fiber layer 1012 is a plurality of reinforcing fiber layers disposed between the reinforcing fiber layer 1011 and the reinforcing fiber layer 1013.

  In FIG. 2, the intermediate reinforcing fiber layer 1012 is shown as one reinforcing fiber layer in order to facilitate understanding of the technology. The same applies to FIGS. 5 and 8 to be described later.

  In FIG. 2, the suture thread 104 penetrating the reinforcing fiber laminate sheet 100 and appearing on both sides is shown as a suture thread 104p2. The suture 104 arranged on the reinforcing fiber layer 1013 side is shown as a suture 104p1. The sutures 104p1 and 104p2 stitch the reinforcing fiber layers 1011, 1012 and 1013 of the reinforcing fiber laminated sheet 100 by so-called sewing sewing.

  The reinforcing fiber laminated sheet 100 is stitched so as to surround the inside along the outer circumference with sutures 104p1 and 104p2 at a position P in the vicinity of the outer circumference (see FIG. 1). For this reason, when conveying the reinforcing fiber laminate sheet 100 or when further laminating a plurality of reinforcing fiber laminate sheets 100 to form a base material laminate, the reinforcing fibers fall off from the ends of the reinforcing fiber laminate sheet 100. The possibility can be reduced.

  FIG. 3 is a cross-sectional view schematically showing the state of the 3-3 cross section in FIG. In FIG. 3, the reinforcing fiber bundle constituting the outermost reinforcing fiber layer 1011 is shown as a reinforcing fiber bundle 1011FB. A reinforcing fiber bundle constituting the lowermost reinforcing fiber layer 1013 is shown as a reinforcing fiber bundle 1013FB. A reinforcing fiber bundle constituting the reinforcing fiber layer 1012 of the intermediate layer is shown as a reinforcing fiber bundle 1012FB. In FIG. 3, the shape in a cross section perpendicular to the longitudinal direction of the reinforcing fiber bundle is indicated by an ellipse. The reinforcing fiber bundles constituting the reinforcing fiber layer in contact with each other are arranged so as to form an angle of 90 degrees with each other.

  The sutures 104p2 appear alternately on the surface of the reinforcing fiber layer 1011 and the surface of the reinforcing fiber layer 1013 along the sewing direction, and respectively constitute a loop. However, the distance between both end points of the loop on the surface side of the reinforcing fiber layer 1011 (the point where the suture thread 104p2 is immersed in the reinforcing fiber layer 1011) is equal to both end points of the loop on the surface side of the reinforcing fiber layer 1013 (the suture thread 104p2 is reinforced). This is longer than the interval between the points immersing the fiber layer 1013. Both end points of the loop on the surface side of the reinforcing fiber layer 1013 are at substantially the same position. The suture 104p1 is arranged to pass through the inside of a continuous loop on the reinforcing fiber layer 1013 side of the suture 104p2.

  The suture 104p1 has a softening point Tp1. The suture 104p2 has a softening point Tp2 that is higher than the softening point Tp1. However, the softening point Tp2 of the suture 104p2 is lower than the curing temperature of the thermosetting resin impregnated in the reinforcing fiber laminate sheet 100 in the production of a resin molded product using the reinforcing fiber laminate sheet 100. Here, Tp1 is 85 ° C. and Tp2 is 140 ° C.

  In the present specification, the “softening point” refers to a temperature at which the suture softens / melts when the suture reaches a temperature higher than that temperature. Specifically, when the suture is a crystalline polymer, it indicates the melting point, and when the suture is an amorphous polymer, it indicates the glass transition point.

  FIG. 4 is a cross-sectional view showing a state of the reinforcing fiber laminate sheet 100 when a part P of the reinforcing fiber laminate sheet 100 of FIG. 3 is heated to a temperature higher than the softening point Tp1 of the suture 104p1. When the reinforcing fiber laminate sheet 100 of FIG. 3 is heated to a temperature higher than the softening point Tp1 of the suture 104p1 and lower than the softening point Tp2 of the suture 104p2, the suture 104p1 melts. On the other hand, the suture 104p2 does not melt. That is, there is no suture that restrains the continuous loop on the reinforcing fiber layer 1013 side of the suture 104p2 on the reinforcing fiber layer 1013 side.

  As a result, in the state of FIG. 4, the reinforcing fiber layers 1011, 1012, and 1013 are caused by friction between the suture thread 104 p 2 penetrating the reinforcing fiber layers 1011, 1012, and 1013 and the reinforcing fiber layers 1011, 1012, and 1013. It is restrained by the force and the resin binder 103 disposed in a part of the interlayer. In other words, in the state of FIG. 4, the force that restrains the reinforcing fiber layers 1011, 1012, and 1013 is weaker than in the state of FIG. 3.

  FIG. 5 is a perspective view schematically showing a configuration of the suture thread 104q2 in which a part Q (see FIG. 1) of the reinforcing fiber laminated sheet 100 is sutured. In FIG. 5, the suture thread 104 that penetrates the reinforcing fiber laminated sheet 100 and appears on both sides is shown as suture threads 104q1 and 104q2. The sutures 104q1 and 104q2 respectively sew the reinforcing fiber laminated sheet 100 in a so-called chain stitch pattern.

  FIG. 6 is a cross-sectional view schematically showing the state of the 6-6 cross section in FIG. The sutures 104q2 appear alternately on the surface of the reinforcing fiber layer 1011 and the surface of the reinforcing fiber layer 1013 along the sewing direction, and respectively constitute a loop. However, the loops on the surface side of the reinforcing fiber layer 1011 do not intersect with each other, whereas the loops on the surface side of the reinforcing fiber layer 1013 intersect with each other. That is, the suture thread 104q2 passes through the immediately preceding loop and forms a new loop on the reinforcing fiber layer 1013 side. The suture thread 104q2 sews only a part of the section along the sewing direction. The other part of the section is sutured by the suture 104q1.

  The mode of suturing with the suture 104q1 is the same as that of the suture 104q2. The suture threads 104q1 and 104q2 are partially sewn along the sewing direction. As a result, the sutures 104q1 and 104q2 sew the reinforcing fiber layers 1011, 1012 and 1013 of the reinforcing fiber laminate sheet 100 along the sewing direction.

  Suture 104q1 has a softening point Tq1. The suture 104q2 has a softening point Tq2 higher than the softening point Tq1. However, the softening point Tq2 of the suture thread 104q2 is lower than the curing temperature of the thermosetting resin impregnated in the reinforcing fiber laminate sheet 100 in the production of a resin molded product using the reinforcing fiber laminate sheet 100. Here, the suture 104q1 and the suture 104p1 (see FIGS. 2 to 4) are made of the same material, and Tq1 = Tp1. The suture 104q2 and the suture 104p2 (see FIGS. 2 to 4) are made of the same material, and Tq2 = Tp2.

  FIG. 7 is a cross-sectional view showing a state of the reinforcing fiber laminate sheet 100 when a part Q of the reinforcing fiber laminate sheet 100 of FIG. 6 is heated to a temperature higher than the softening point Tq1 of the suture 104q1. When the reinforcing fiber laminate sheet 100 of FIG. 6 is heated to a temperature higher than the softening point Tq1 of the suture 104q1 and lower than the softening point Tq2 of the suture 104q2, the suture 104q1 is melted. On the other hand, the suture 104q2 does not melt.

  As a result, in the state of FIG. 6, the reinforcing fiber layers 1011, 1012, and 1013 include the suture thread 104 q 2 that penetrates the reinforcing fiber layers 1011, 1012, and 1013, and the resin binder 103 disposed in a part of the layers. , It will be restrained. Then, the reinforcing fiber layers 1011, 1012, and 1013 can be displaced from each other at the portion that is restrained by the suture thread 104 q 1. In other words, in the state of FIG. 6, the force that restrains the reinforcing fiber layers 1011, 1012, and 1013 is weaker than in the state of FIG. 5.

  FIG. 8 is a perspective view schematically showing the configuration of the sutures 104r1 and 104r2 that are stitched with a part R (see FIG. 1) of the reinforcing fiber laminate sheet 100. FIG. In FIG. 8, two adjacent rows of sutures are shown as sutures 104r1 and 104r2. The sutures 104r1 and 104r2 sew the reinforcing fiber laminated sheet 100 by a so-called 1/1 tricot knitting stitch pattern.

  FIG. 9 is a cross-sectional view schematically showing the state of the 9-9 cross section in FIG. The suture 104r2 stitches the reinforcing fiber laminated sheet 100 in a zigzag along the sewing direction (see FIG. 8). The suture thread 104r2 penetrates to the surface side of the reinforcing fiber layer 1013 at a bending point on the surface of the reinforcing fiber layer 1011, forms a loop on the surface of the reinforcing fiber layer 1013, and again on the surface of the reinforcing fiber layer 1011. appear.

  The suture 104r1 also has a configuration similar to that of the suture 104r2 and stitches the reinforcing fiber laminate sheet 100 zigzag along the sewing direction. The suture 104r1 is disposed at a position adjacent to the suture 104r2 (see FIG. 8). More specifically, among the zigzag bending points of the suture 104r1, the bending point near the suture 104r2 and the bending points near the suture 104r1 among the zigzag bending points of the suture 104r2 are sewn. It arrange | positions so that it may be located in the area | region (for example, on a straight line) of the predetermined width along a direction.

  The loops on the surface side of the reinforcing fiber layer 1013 at each bending point are connected. That is, the suture 104r1 forms a loop on the surface side of the next reinforcing fiber layer 1013 through the inside of the loop on the surface side of the reinforcing fiber layer 1013 by the suture 104r2. As a result, the sutures 104r1 and 104r2 sew the reinforcing fiber layers 1011, 1012 and 1013 of the reinforcing fiber laminated sheet 100 along the sewing direction.

  The suture 104r1 has a softening point Tr1. The suture thread 104r2 has a softening point Tr2 that is higher than the softening point Tr1. However, the softening point Tr2 of the suture thread 104r2 is lower than the curing temperature of the thermosetting resin impregnated in the reinforcing fiber laminate sheet 100 in the production of a resin molded product using the reinforcing fiber laminate sheet 100. Here, the suture 104r1 and the suture 104p1 (see FIGS. 2 to 4) are made of the same material, and Tr1 = Tp1. The suture 104r2 and the suture 104p2 (see FIGS. 2 to 4) are made of the same material, and Tr2 = Tp2.

  FIG. 10 is a cross-sectional view showing the state of the reinforcing fiber laminate sheet 100 when a part R of the reinforcing fiber laminate sheet 100 of FIG. 9 is heated to a temperature higher than the softening point Tr1 of the suture 104r1. When the reinforcing fiber laminate sheet 100 of FIG. 6 is heated to a temperature higher than the softening point Tr1 of the suture 104r1 and lower than the softening point Tr2 of the suture 104r2, the suture 104r1 melts. On the other hand, the suture 104r2 does not melt.

  As a result, in the state of FIG. 10, the reinforcing fiber layers 1011, 1012, and 1013 are caused by friction between the suture thread 104 r 2 penetrating the reinforcing fiber layers 1011, 1012, and 1013 and the reinforcing fiber layers 1011, 1012, and 1013. It is restrained by the force and the resin binder 103 disposed in a part of the interlayer. In other words, in the state of FIG. 10, the force that restrains the reinforcing fiber layers 1011, 1012, and 1013 is weaker than in the state of FIG. 9.

  Note that the reinforcing fiber layers 1011, 1012, and 1013 of this embodiment correspond to “a plurality of reinforcing fiber layers” in [Means for Solving the Problems]. The reinforcing fiber bundles 1011FB, 1012FB, and 1013FB correspond to “reinforcing fiber bundles”. 104p1, 104q1, and 104r1 correspond to the “first yarn”. 104p2, 104q2, and 104r2 correspond to the “second yarn”.

B. Manufacturing method of resin molded product:
FIG. 11 is a flowchart showing a method for producing a resin molded product using the reinforcing fiber laminate sheet 100. In step S100, a reinforcing fiber laminated sheet 100 (see FIGS. 1 to 3, 5, 6, 8, and 9) in a state of being stitched by a combination of sutures having different softening points is prepared. More specifically, a plurality of reinforcing fiber laminated sheets 100 each having a preferable shape according to the shape of the product are prepared. And each reinforcement fiber lamination sheet 100 is distribute | arranged to an appropriate relative position, is laminated | stacked, and a base material laminated body is comprised. At this stage, the reinforcing fiber laminated sheets 100 are firmly stitched together by a combination of sutures. For this reason, handling is easy. In other words, the reinforcing fibers are unlikely to fall off from the end of the reinforcing fiber layer during transportation and lamination.

  In addition, in step S100, the laminated | stacked several reinforcement fiber lamination sheet 100 may be further sewn by the method demonstrated in FIGS. In the present specification, the base material laminated body configured as described above is also included in the broader “reinforced fiber laminated sheet”.

  In step S200, the laminated plurality of reinforcing fiber laminate sheets 100 (base material laminate) are higher than the softening point Tp1 (= Tq1 = Tr1) of the sutures 104p1, 104q1, and 104r1, and the sutures 104p2, 104q2, and 104r2. The temperature is raised to a temperature lower than Tp2 (= Tq2 = Tr2). Then, each reinforcing fiber lamination sheet 100 will be in the state shown in FIG.4, FIG.7, and FIG.10. That is, the force which restrains the reinforcement fiber layers 101 in each reinforcement fiber lamination sheet 100 becomes weaker than the state of step S100. However, the relative position between the reinforcing fiber layers 101 is gently restrained by the frictional force between the remaining suture thread and the reinforcing fiber layer.

  In step S300, the plurality of laminated reinforcing fiber laminate sheets 100 (base material laminate) are deformed into a three-dimensional shape in accordance with the three-dimensional shape of the product. In step S200, since the force which restrains reinforcement fiber layers 101 is weakened, in step S300, each reinforcement fiber lamination sheet 100 is easy to deform | transform. For example, at the end of each reinforcing fiber laminate sheet 100 (see P in FIG. 1), deformation adapted to the length and shape of the contour line is not excessively suppressed. As a result, wrinkles at the ends of the reinforcing fiber laminate sheet 100 due to deformation are unlikely to occur. On the other hand, the relative positions of the reinforcing fiber layers 101 are gently restrained by the frictional force between the suture thread and the reinforcing fiber layer (see FIGS. 4, 7, and 10). The relative positional deviation between the reinforcing fiber layers 101 is less likely to occur.

  In step S400, a plurality of reinforcing fiber laminated sheets 100 (preforms) that are laminated and formed into a three-dimensional shape are arranged in the voids of a mold having a three-dimensional shape and impregnated with a matrix resin. A thermosetting resin is used as the matrix resin impregnated in the reinforcing fiber laminate sheet 100. The curing temperature Trc of this thermosetting resin is higher than the softening point Tp1 (= Tq1 = Tr1) of the sutures 104p1, 104q1, and 104r1 and the softening point Tp2 (= Tq2 = Tr2) of the sutures 104p2, 104q2, and 104r2. The temperature Trc is higher than the temperature Tm102 at which the resin binder 102 is melted.

  In step S400, the temperature of the resin and the mold when the reinforcing fiber laminated sheet 100 is impregnated with the resin is lower than the softening point Tp2 (= Tq2 = Tr2) of the sutures 104p2, 104q2, and 104r2. For this reason, when the reinforcing fiber laminated sheet 100 is impregnated with the resin, the sutures 104p2, 104q2, and 104r2 do not melt. As a result, in the plurality of reinforcing fiber laminated sheets 100 (preforms), the relative positions of the reinforcing fiber layers 101 are gently restrained (see FIGS. 4, 7, and 10). Therefore, the possibility of relative displacement between the reinforcing fiber layers 101 due to the flow of the resin is lower than when all the sutures that sew the layers are melted.

  As the matrix resin impregnated in the reinforcing fiber laminated sheet in step S400, for example, a thermosetting resin such as an epoxy resin, a vinyl ester resin, an unsaturated polyester resin, or a phenol resin can be used.

  In step S500, the plurality of reinforcing fiber laminated sheets 100 impregnated with the resin are heated to a temperature equal to or higher than the curing temperature Trc of the thermosetting resin in the mold, and the resin is cured. Thereafter, the plurality of reinforcing fiber laminated sheets 100 impregnated with the resin are cooled and taken out of the mold as a resin molded product.

  The curing temperature Trc of the thermosetting resin is higher than the temperature Tm102 at which the resin binder 102 is melted. For this reason, the resin binder 102 melts in step S500. The temperature Trc is higher than the softening point Tp2 (= Tq2 = Tr2) of the sutures 104p2, 104q2, and 104r2. For this reason, the sutures 104p2, 104q2, and 104r2 are also melted in step S500. Further, if some of the sutures 104p1, 104q1, 104r1 remain undissolved in step S200, they are also melted in step S500. As a result, even when the thermosetting resin is transparent or translucent, the resin binder 102, the sutures 104p2, 104q2, and 104r2 and the sutures 104p1, 104q1, and 104r1 are not visually recognized in the produced resin molded product.

  In addition, step S100 of FIG. 11 in the present embodiment corresponds to “a step of preparing a reinforcing fiber laminated sheet” in [Means for Solving the Problems]. Step S200 corresponds to “a step of raising the temperature of the first yarn to a temperature higher than the softening point of the first yarn”. Step S300 corresponds to “a step of deforming the reinforcing fiber laminated sheet”. Steps S400 and S500 correspond to the “step of impregnating the solidified fiber laminated sheet after deformation with a resin and solidifying it”.

C. Reinforcing fiber layer shape and reinforcing fiber bundle:
FIG. 12 is a plan view for explaining the relationship between the target shape Fmi of the reinforcing fiber layer and the arrangement of the plurality of reinforcing fiber bundles 100FBN constituting the reinforcing fiber layer 1011N. FIG. 13 is a plan view for explaining the relationship between the target shape Fmi of the reinforcing fiber layer and the arrangement of the plurality of reinforcing fiber bundles 100FBW constituting the reinforcing fiber layer 1011W. The shape Fmi shown in FIG. 13 is the same as the shape Fmi shown in FIG.

  The reinforcing fibers constituting the reinforcing fiber bundle 100FBW in FIG. 13 are the same as the reinforcing fibers constituting the reinforcing fiber bundle 100FBN in FIG. The thickness of the reinforcing fiber bundle 100FBW is also the same as the thickness of the reinforcing fiber bundle 100FBN. The width of the reinforcing fiber bundle 100FBW is larger than the width of the reinforcing fiber bundle 100FBN. The thickness of the reinforcing fiber bundle is the dimension of the reinforcing fiber bundle in the lamination direction of the reinforcing fiber layer (the direction perpendicular to the paper surface in FIGS. 12 and 13). The width of the reinforcing fiber bundle is the dimension of the reinforcing fiber bundle in the direction perpendicular to the longitudinal direction of the reinforcing fiber bundle and the lamination direction of the reinforcing fiber layers.

  When the reinforcing fiber bundle 100FBN is thin as shown in FIG. 12, the outer shape of the plurality of reinforcing fiber bundles 100FBN arranged side by side is matched to the product as compared with the case where the reinforcing fiber bundle 100FBW is thick as shown in FIG. It can be made closer to the shape Fmi. For this reason, when processing the reinforcing fiber layers 1011N and 1011W into the target shape Fmi, that is, when cutting and shaping the ends of the reinforcing fiber layers 1011N and 1011W, the amount of discarded reinforcing fibers can be reduced. it can. As a result, the manufacturing cost is reduced. From this point, the number of reinforcing fiber bundles constituting one reinforcing fiber layer is preferably 3000 or more, and more preferably 10,000 or more.

  On the other hand, when the reinforcing fiber bundle 100FBN is thin as shown in FIG. 12, the number of reinforcing fiber layers 1011N to be arranged side by side is larger than when the reinforcing fiber bundle 100FBN is thick as shown in FIG. Therefore, the time required to configure the reinforcing fiber layer 1011N having the shape and size including the target shape Fmi inside the reinforcing fiber bundle 100FBN is similarly set to arrange the reinforcing fiber bundle 100FBW and the reinforcing fiber layer 1011W. This is longer than the time required for the configuration. From this point, the number of reinforcing fiber bundles constituting one reinforcing fiber layer is preferably 60000 or less, and more preferably 40000 or less.

D. Position and method of stitching in reinforcing fiber laminate sheet:
FIG. 14 is an explanatory view showing a stitching method according to the position in the reinforcing fiber laminated sheet 100S. In the reinforcing fiber laminated sheet, like the reinforcing fiber layers 1011 to 1013 shown in FIGS. 1 to 10, the outer shapes of the reinforcing fiber layers do not always match each other. In the reinforcing fiber laminated sheet 100S, all the reinforcing fiber layers 101 overlap in a partial region A1, and only some of the reinforcing fiber layers 101 overlap in other partial regions A2, A3.

  In the reinforcing fiber laminated sheet 100S, the part P1 in the vicinity of the outer contour is stitched with a pair of sutures 104a (see FIGS. 2 to 10) in which one is melted by heating in step S200 of FIG. On the other hand, the inner part P2, that is, the part P2 located on the side opposite to the outer contour of the reinforcing fiber laminate sheet 100S across the part P1, is sutured with the suture 104b that is not melted by heating in step S200 of FIG. Is done.

  FIG. 15 is a diagram showing a state of the reinforcing fiber laminated sheet 100S after the processing of steps S200 and S300 in FIG. In step S200 of FIG. 11, one of the sutures 104a for sewing the part P1 of the reinforcing fiber laminate sheet 100S is melted. As a result, the force that restrains the plurality of reinforcing fiber layers at the site P1 is weak. The suture 104a in this state is indicated by a broken line in FIG. As a result, in step S300 of FIG. 11, the deformation suitable for the length and shape of the contour line is not excessively suppressed by the suture 104a at the end portion of the reinforcing fiber laminate sheet 100S. As a result, wrinkles are less likely to occur due to deformation at the end of the reinforcing fiber laminate sheet 100S.

  On the other hand, in the reinforcing fiber laminate sheet 100S, the suture thread 104b that stitches the inner portion P2 is not melted even after the process of step S200 of FIG. For this reason, the force which restrains a some reinforcing fiber layer in the site | part P2 is not weak compared with the site | part P1. As a result, in step S300 in FIG. 11, the plurality of reinforcing fiber layers are strongly constrained as compared to the end portions in the vicinity of the central portion of the reinforcing fiber laminated sheet 100S. Therefore, the relative positions of the plurality of reinforcing fiber layers do not shift due to resin impregnation.

E. Example:
The reinforcing fiber laminated sheet of the present disclosure will be described based on examples.

Example 1
<Reinforcing fiber>
As the reinforcing fiber bundle, carbon fiber “Torayca” (registered trademark) T800SC manufactured by Toray Industries, Inc., which had been subjected to sizing treatment in advance, was used. A reinforcing fiber bundle having a reinforcing fiber bundle width of 6.5 mm and a reinforcing fiber bundle having 24,000 single fibers was used.

<Applying resin binder>
Using a spraying device, epoxy resin particles (LT3366 manufactured by Huntsman, particle size: 100 μm, melting point: 80 ° C.) are sprayed on a reinforcing fiber bundle, and using an infrared heater, the reinforcing fiber layer of the surface layer has a temperature of 130 ° C. It heated for 30 second in the state, and the epoxy resin particle adhered on the reinforcing fiber bundle.

<Reinforcing fiber layer>
Using a fiber placement head, the reinforcing fiber bundle provided with the resin binder on the gantry was aligned without gaps in one direction, and two reinforcing fiber layers were formed so as to have a rectangular shape of 200 mm × 300 mm.

<Lamination and adhesion>
First, the other reinforcing fiber layer is placed on one of the two reinforcing fiber layers prepared, and the orientation angle of the reinforcing fiber bundle of the reinforcing fiber layer is the same as the reinforcing fiber bundle of the lower reinforcing fiber layer. It arrange | positioned so that it might become 90 degrees with respect to an orientation angle. Thereafter, using an infrared heater, the reinforcing fiber layer on the surface layer was heated for 30 seconds at a temperature of 130 ° C., and the interlayer was fixed to produce a reinforcing fiber sheet. Four reinforcing fiber sheets were produced by the same treatment. In the same manner, for the reinforcing fiber sheet separately prepared, the reinforcing fiber layer on the surface layer was peeled off and the adhesion state between the layers was observed. The molten resin binder was discretely present on the surface of the reinforcing fiber layer, and the layers were adhered. I was able to confirm.

<Suture>
Four reinforcing fiber sheets were laminated so that the outer contours of the four reinforcing fiber sheets coincided, and a reinforcing fiber laminated sheet was prepared by sewing a position 10 mm inside from the end using a sewing machine. A polyamide fiber yarn (melting point: 140 ° C., fineness: 75 dtex) was used as the upper yarn of the sewing machine. Polyamide fiber yarn (melting point: 85 ° C., fineness: 75 dtex) was used as the lower yarn of the sewing machine. The reinforcing fiber laminated sheet prepared by laminating the four reinforcing fiber sheets in this way corresponds to the reinforcing fiber laminated sheet 100 of FIG.

<Shaping>
The prepared reinforcing fiber laminate sheet was placed on a curved shape mold (width: 100 mm, height: 100 mm, length: 1000 mm, curvature: 3000 mm) heated to 100 ° C., and the lower thread was melted. After confirming that the temperature of the mold had dropped to 40 ° C., press shaping was performed. As a result, it was confirmed that the reinforcing fiber laminated sheet could conform to the mold shape without destroying the relative positional relationship between the fiber bundles, and had good shaping performance. Thereafter, the mold was heated to 110 ° C., pressurized at 50 kPa, and held for 30 seconds to prepare a preform.

<Molding>
The preform was placed on the lower mold of an RTM molding double-sided 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 component: manufactured by Momentive, curing agent: manufactured by Toray Industries, Inc., acid anhydride curing agent) is injected into the mold at an injection pressure of 0.5 MPa, impregnated into the preform, and 10 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 significant disturbance in the reinforcing fiber bundle visible on the surface and no wrinkles, and was particularly excellent as a fiber reinforced resin molded product.

(Example 2)
<Reinforcing fiber>
The same reinforcing fiber bundle as in Example 1 was used.

<Applying resin binder>
The same reinforcing fiber bundle as in Example 1 was used.

<Reinforcing fiber layer>
The same reinforcing fiber layer as in Example 1 was used.

<Lamination and adhesion>
Four reinforcing fiber sheets were produced in the same manner as in Example 1.

<Suture>
Four reinforcing fiber sheets are laminated so that the outer contours of the reinforcing fiber sheets coincide with each other, and the position inside 10 mm from the end of the laminated reinforcing fiber sheet layer is sewn with a chain stitch stitch pattern using a handy stitch device. Thus, a reinforcing fiber laminated sheet was prepared. Polyamide fiber yarn (melting point: 140 ° C., fineness: 75 dtex) and polyamide fiber yarn (melting point: 60 ° C., fineness: 110 dtex) were used as sutures.

<Shaping>
The prepared reinforcing fiber laminate sheet was placed on a curved shape mold (width: 100 mm, height: 100 mm, length: 1000 mm, curvature: 3000 mm) heated to 100 ° C., and the lower thread was melted. After confirming that the temperature of the mold had dropped to 40 ° C., press shaping was performed. As a result, it was confirmed that the reinforcing fiber laminated sheet could conform to the mold shape without destroying the relative positional relationship between the fiber bundles, and had good shaping performance. Thereafter, the mold was heated to 110 ° C., pressurized at 50 kPa, and held for 30 seconds to prepare a preform.

<Molding>
Using the above preform, 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 with no significant disturbance in the reinforcing fiber bundle visible on the surface and no wrinkles, and was particularly excellent as a fiber reinforced resin molded product.

F. Variation:
F1. Modification 1:
Although the description is omitted in the description of the above embodiment, the reinforcing fiber bundle (see 1011FB, 1012FB, and 1013FB in FIG. 3) is reinforced by performing pretreatment such as sizing treatment, fiber opening treatment, and binder application in advance. Fiber bundles can be used. By performing the sizing treatment, it is possible to improve the convergence of the reinforcing fiber bundle and suppress the generation of fluff. By performing the fiber opening treatment, the ratio of the thickness and width (aspect ratio) of the reinforcing fiber bundle can be adjusted and set to an aspect ratio suitable for the conditions of the subsequent preform process and RTM molding process. By applying a pretreatment such as binder application, the fixing state between the reinforcing fiber bundles can be made uniform.

F2. Modification 2:
In the above-described embodiment, one reinforcing fiber layer 101 is constituted by a single reinforcing fiber bundle, and adjacent reinforcing fiber layers 101 are laminated so that the directions of the reinforcing fiber bundles are 90 degrees. However, one reinforcing fiber layer may include a reinforcing fiber bundle arranged in parallel and stacked in two or more stages.

F3. Modification 3:
(1) In the above embodiment, a powdered resin binder 102 is used (see FIG. 1). However, the form of the resin binder for restraining the reinforcing fiber layers may be other forms such as a linear form or a non-woven form.

(2) The attachment method in the case of attaching the resin binder to the reinforcing fiber may be, for example, by spreading the resin binder on the reinforcing fiber bundle before attaching the reinforcing fiber layer, and reinforcing by the fiber placement method. After arranging the fiber bundles to form the reinforcing fiber layer, a resin binder may be dispersed and adhered.

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

(4) The melting temperature of the resin binder may be higher or lower than the softening point of the first yarn melted by the temperature increase. The melting temperature of the resin binder may be higher or lower than the softening point of the second yarn that is not melted by the temperature increase.

  However, the melting temperature of the resin binder is preferably higher than the temperature at the time of injecting the resin impregnated into the reinforcing fiber laminated sheet in the production of the resin molded product. If it is set as such an aspect, the possibility that a reinforcement fiber layer will shift | deviate at the time of injection | pouring of resin can be reduced with a resin binder. In addition, when the resin impregnated in the reinforcing fiber laminate sheet in the production of a resin molded product is a thermosetting resin, the melting temperature of the resin binder is preferably lower than the curing temperature of the thermosetting resin. By setting it as such an aspect, the possibility that a resin binder may impair pessimism in a resin molded product can be reduced.

F4. Modification 4:
(1) In the above embodiment, the sutures 104p2, 104q2, and 104r2 for sewing different parts are made of the same material. Therefore, their softening points are the same. Further, the sutures 104p1, 104q1, and 104r1 for sewing different parts are made of the same material. Therefore, their softening points are the same. However, the sutures 104p2, 104q2, and 104r2 that suture different parts and the sutures 104p1, 104q1, and 104r1 may have different softening point temperatures.

  However, a pair of threads that jointly sew one part of the reinforcing fiber laminated sheet or the reinforcing fiber laminated sheet along one sewing direction has a softening point and a higher softening point. Or a yarn having no softening point. And in the same reinforcing fiber laminated sheet, the lowest softening point among the softening points of yarns (see 104p2, q2, r2 in FIGS. 2 to 9) having a softening point higher than the other or not having the softening point. Is preferably higher than the highest softening point among the softening points of the other yarn (see 104p1, q1, r1).

(2) In the above embodiment, the sutures 104p2, 104q2, 104r2 are higher than the softening point Tp1 of the sutures 104p1 (104q1, 104r1), and the curing temperature of the thermosetting resin impregnated in the reinforcing fiber laminate sheet 100 It has a softening point Tp2 lower than Trc. However, the softening point Tp2 of the suture thread 104p2 may be higher than the curing temperature of the thermosetting resin impregnated in the reinforcing fiber laminate sheet. Further, the suture thread 104p2 may have an aspect having no softening point.

  For example, the sutures 104p2, 104q2, and 104r2 as the second thread can also be configured by reinforcing fibers that form the reinforcing fiber layers 1011 to 1013. According to such an embodiment, the temperature of the sutures 104p1, 104q1, 104r1 and the sutures 104p2, 104q2, 104r2 is increased to relax the restraint of the reinforcing fiber layers 1011 to 1013, and the reinforcing fiber laminated sheet 100 is deformed. Later, the sutures 104p2, 104q2, and 104r2 remaining in the reinforcing fiber laminated sheet 100 are constituted by reinforcing fibers that constitute the reinforcing fiber layers 1011 to 1013. For this reason, also when the structure of the deformed reinforcing fiber laminated sheet 100 can be visually recognized from the outside, it is possible to make the beauty beautiful compared to the aspect in which the sutures 104p2, 104q2, and 104r2 are made of other materials. In addition, since the reinforcing fibers remain in the stacking direction of the reinforcing fiber laminate sheet 100, the physical properties in the stacking direction can be enhanced as compared to the aspect in which the sutures 104p2, 104q2, and 104r2 are made of other materials.

(3) In Example 1 above, polyamide fiber yarn having a melting point of 85 ° C. and polyamide fiber yarn having a melting point of 140 ° C. were used as the suture. And the reinforcement fiber lamination sheet was deform | transformed with the curved shape type | mold heated to 100 degreeC. In Example 2, a polyamide fiber yarn having a melting point of 60 ° C. and a polyamide fiber yarn having a melting point of 140 ° C. were used. And the reinforcement fiber lamination sheet was deform | transformed with the curved shape type | mold heated to 100 degreeC. However, the softening point of the suture can be at other temperatures.

  However, the softening point of the first thread having a low softening point of the two types of sutures is preferably 60 ° C to 120 ° C. When the softening point of the first yarn is lower than 60 ° C., the first yarn softens when the reinforcing fiber sheet is transported or laminated, and the reinforcing fiber sheet has an unexpected relative positional relationship. There is a possibility that they will adhere to each other.

  On the other hand, when the softening point of the first yarn is higher than 120 degrees, the resin is injected and impregnated at a temperature higher than 120 degrees when the resin is impregnated into the reinforcing fiber laminated sheet in the production of the resin molded product. This is preferable. In such an embodiment, the required energy is increased, and the production cost is also increased. However, the softening point of the first thread having a low softening point of the two types of sutures may be lower than 60 ° C. or higher than 120 degrees.

The softening point of the second thread having a high softening point among the two types of sutures is preferably 120 ° C to 200 ° C. The injection and impregnation of the resin in the production of the resin molded product (see S400 in FIG. 11) is performed at a temperature lower than the softening point of the second yarn. For this reason, when the softening point of the second yarn is less than 120 ° C., the resin injection and impregnation in step S400 are also performed at less than 120 ° C. Then, in the subsequent resin curing step (see S500 in FIG. 11), the time required for curing the resin from the temperature at which the resin is injected to the resin curing temperature is increased.

  Further, if the softening point of the second yarn is higher than 200 ° C., there is a high possibility that the second yarn will not melt and remain even if the resin is heated to the resin curing temperature in step S500. . If the second yarn is not melted and remains in the resin molded product, the second yarn is visible from the outside, and the appearance of the resin molded product may be impaired. On the other hand, when the second yarn is melted so that the second yarn does not remain in the resin molded product, a reinforcing fiber laminated sheet impregnated with the resin up to the softening point of the second yarn higher than 200 ° C. is used. It is necessary to raise the temperature. For this reason, the energy required to manufacture the resin molded product increases, and the production cost increases. However, the softening point of the second thread having a high softening point among the two types of sutures may be lower than 120 ° C or higher than 200 ° C.

F5. Modification 5:
In the above embodiment, the reinforcing fibers are exemplified by the sewing patterns of sewing knitting (see FIGS. 2 to 4), chain knitting (see FIGS. 5 to 7), and 1/1 tricot knitting (FIGS. 8 to 10). The stitching method of the layers has been described. However, another method may be used as the method for stitching the reinforcing fiber layers. For example, an irregular 1/1 tricot knitting combining a chain knitting and a 1/1 tricot knitting, or a sewing pattern using a one-side stitch machine (chain knitting, 1/1 tricot knitting, anomaly 1). / 1 tricot knitting, blind stitching, double needle, tufting), or a combined stitching pattern.

F6. Modification 6:
In the above-described embodiment, the reinforcing fiber laminated sheet 100 is sewn so as to surround the inside along the outer periphery with the sutures 104p1 and 104p2 at the position P in the vicinity of the outer periphery (see FIG. 1). However, the reinforcing fiber laminate sheet may be sewn with two types of sutures along only the outer circumference along a part of the outer circumference.

F7. Modification 7:
In the above embodiment, after the temperature of the reinforcing fiber laminate sheet 100 (base material laminate) is raised in step S200 of FIG. 11, the reinforcing fiber laminate sheet 100 (base material laminate) is three-dimensionally shaped in step S300. It is deformed to. However, the treatment for raising the temperature of the reinforcing fiber laminate sheet and the reinforcing fiber laminate sheet may be performed simultaneously or partially in parallel with each other in order to relax or release the restraint by the first yarn. If it is set as such an aspect, the manufacture lead time of a resin molded product can be shortened compared with the aspect which performs those processes in a different time interval.

F8. Modification 8:
In the above embodiment, the resin used in step S400 in FIG. 11 is a thermosetting resin. However, thermoplastic resins such as acrylic resins, polyamide resins, and polyolefin resins can also be used as the resin that is impregnated into the reinforcing fiber laminated sheet and solidified. In such an aspect, it is preferable that the temperature of the thermoplastic resin when the reinforcing fiber laminate sheet is impregnated with the thermoplastic resin is higher than the softening point of the first yarn. And when the 2nd thread | yarn has a softening point, it is preferable that the temperature of the thermoplastic resin at the time of making a reinforced fiber laminated sheet impregnate a thermoplastic resin is higher than the softening point of a 2nd thread | yarn.

  This indication is not restricted to the above-mentioned embodiment, an example, and a modification, and can be realized with various composition in the range which does not deviate from the meaning. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each form described in the section for solving the problems solve part or all of the above-described issues. Therefore, in order to achieve part or all of the above-described effects, replacement or combination can be appropriately performed. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 100,100S ... Reinforcement fiber lamination sheet 100FBN, 100FBW ... Reinforcement fiber bundle 101 ... Reinforcement fiber layer 102 ... Resin binder before melting 103 ... Resin binder after melting 104 ... Suture 104a, 104b ... A pair of sutures 104p1, q1, r1 ... suture with low softening point 104p2, q2, r2 ... suture with high softening point 1011 to 1013 ... reinforcing fiber layer 1011FB to 1013FB ... reinforcing fiber bundle 1011N, 1011W ... reinforcing fiber layer A1 ... inside of reinforcing fiber laminated sheet A2, A3 ... Outer region of the reinforcing fiber laminate sheet Fmi ... Target shape of the reinforcing fiber layer P ... Site in the vicinity of the outer periphery of the reinforcing fiber laminate sheet P1 ... Position in the vicinity of the outer periphery of the reinforcing fiber laminate sheet Position inside the sheet Q ... Part of the reinforcing fiber laminate sheet R ... Reinforcement fiber laminate sheet Part of

Claims (9)

A reinforcing fiber laminate sheet,
Provided with a plurality of laminated reinforcing fiber layers,
The plurality of reinforcing fiber layers are:
Each includes a plurality of reinforcing fiber bundles arranged along one direction,
A first yarn having a softening point and a second yarn passing through two or more of the reinforcing fiber layers and having a higher softening point or no softening point than the first yarn, Reinforced fiber laminate sheets that are bound to each other by stitching. The reinforcing fiber laminate sheet according to claim 1,
The reinforcing fiber laminate sheet, wherein the plurality of reinforcing fiber layers are stitched together by the first yarn and the second yarn along at least a part of the outer periphery of the reinforcing fiber laminate sheet. The reinforcing fiber laminate sheet according to claim 1 or 2,
The softening point of the first yarn is a reinforcing fiber laminated sheet having a temperature of 60 to 120 ° C. The reinforcing fiber laminate sheet according to any one of claims 1 to 3,
The softening point of the second yarn is a reinforcing fiber laminated sheet having a temperature of 120 to 200 ° C. The reinforcing fiber laminate sheet according to any one of claims 1 to 3,
The said 2nd thread | yarn is a reinforced fiber lamination sheet comprised by the reinforced fiber which comprises the said reinforced fiber layer. The reinforcing fiber laminate sheet according to any one of claims 1 to 5,
The reinforcing fiber laminate sheet, wherein the reinforcing fiber is a carbon fiber. A method of producing a resin molded product,
(A) a step of preparing a reinforcing fiber laminate sheet,
The reinforcing fiber laminate sheet includes a plurality of laminated reinforcing fiber layers,
The plurality of reinforcing fiber layers are:
Each includes a plurality of reinforcing fiber bundles arranged along one direction,
A first yarn having a softening point and a second yarn passing through two or more of the reinforcing fiber layers and having a higher softening point or no softening point than the first yarn, A step of preparing the reinforcing fiber laminate sheet, which are bound to each other by being stitched;
(B) The step of raising the temperature of the first yarn to a temperature higher than the softening point of the first yarn, and when the second yarn has a softening point, the temperature of the temperature rise is A temperature lower than the softening point of the second yarn,
(C) The step of deforming the reinforcing fiber laminate sheet while performing the step (b) or after the step (b);
(D) A method of producing a resin molded product, comprising: impregnating the reinforced fiber laminated sheet after deformation with a resin and solidifying the resin. The method of claim 7, comprising:
In the step (d),
The method wherein the temperature of the resin when the resin is solidified is higher than the softening point of the first yarn. The method according to claim 7 or 8, comprising:
The second yarn has a softening point;
In the step (d),
The temperature of the resin when the reinforcing fiber laminate sheet is impregnated with the resin is lower than the softening point of the second yarn,
The method wherein the temperature of the resin when the resin is solidified is higher than the softening point of the second yarn.

Images