JP2018001718A - Preform, method for producing preform, and fiber-reinforced plastic using the preform - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preform having both shape retention and impregnation property of a matrix resin, a method for producing a preform capable of shortening the production time, and a fiber reinforced plastic using the above preform. A preform of the present invention includes a laminate in which a plurality of reinforcing fiber sheets are laminated, and a shape-retaining member that retains the shape of the laminate. The shape-retaining member has a penetrating portion that penetrates the laminated body and a shape-imparting portion that abuts on the front surface or the back surface of the laminated body at both ends of the penetrating portion. It is characterized in that at least one of them is bent to form the above-mentioned laminated body. [Selection diagram] Fig. 1

Description

  The present invention relates to a preform for producing a molded product of fiber reinforced plastic, and more specifically, a preform used for resin transfer molding (RTM molding), a method for producing the preform, and the above preform. It relates to the fiber reinforced plastic used.

  Fiber reinforced plastic molded products (hereinafter sometimes referred to as FRP) are lighter than steel and superior in mechanical strength, and can significantly reduce the weight of the vehicle body and contribute to improved fuel efficiency. It has begun to be used as a substitute for steel members.

  The FRP is obtained by laminating a plurality of reinforcing fiber sheets and infiltrating a resin between the reinforcing fibers of the laminated sheets, and is excellent in that the fibers and the matrix resin influence each other. It develops mechanical properties.

Therefore, in order to improve the mechanical performance of FRP, it is necessary not only for the structure of the laminated sheets but also for the matrix resin to sufficiently penetrate between the reinforcing fibers to connect the reinforcing fibers. The quality of the matrix resin impregnation between the reinforcing fibers is important.
In addition, shortening the preform molding process is important to increase the productivity of FRP and reduce costs.

  Patent Document 1 discloses a preform in which a through hole is provided in the thickness direction of a laminate having a thermoplastic resin between layers of a fiber reinforced base material, and the periphery of the through hole is pressed to prevent the fiber reinforced base material from being displaced. Has been. And it is described that the preform is excellent in the impregnation property and handling property of the matrix resin in the production of the fiber reinforced plastic.

Japanese Patent No. 4812262

In the RTM molding, since a preform exists in the mold, the flow resistance of the matrix resin impregnated in the preform is large, and a large impregnation pressure is required to fill the matrix resin in the mold. .
In particular, since the carbon fiber reinforced sheet is slippery in the surface direction, when the impregnation pressure is high, displacement and deflection are likely to occur due to the flowing matrix resin.

  However, in the thing of patent document 1, the shape of a preform is hold | maintained with the thermoplastic resin between the layers of a fiber reinforced base material, and the flow resistance of a matrix resin is given by the thermoplastic resin between the said fibers. Since it increases, the impregnation pressure further increases.

Therefore, when the process temperature is raised and the viscosity of the matrix resin to be impregnated is lowered, the thermoplastic resin is softened and the fiber reinforced base material is displaced or bent, and defects such as unimpregnated portions (voids) of the matrix resin are generated. Is likely to occur.
Therefore, it is difficult to sufficiently impregnate the matrix resin.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is a preform that achieves both shape retention and matrix resin impregnation, and shortens production time. Another object of the present invention is to provide a method for producing a preform, and a fiber reinforced plastic using the preform.

  As a result of intensive studies to achieve the above object, the present inventors have prevented the lamination displacement of the reinforcing fiber sheet by the shape holding member, and the shape holding member retains the shape of the preform. The present inventors have found that both maintaining the shape of the body and preventing the displacement of the reinforcing fiber sheet and improving the impregnation of the matrix resin during the production of the fiber reinforced plastic can be achieved.

That is, the preform of the present invention is a preform including a laminate in which a plurality of reinforcing fiber sheets are laminated, and a shape holding member that holds the shape of the laminate.
And the said shape holding member has the shape provision part which contact | abuts the surface or back surface of the said laminated body, respectively in the penetration part which penetrates the said laminated body, and the both ends of the said penetration part, It is characterized in that at least one of them is bent and the laminate is shaped.

Further, the preform manufacturing method of the present invention includes a laminate in which a plurality of reinforcing fiber sheets are laminated,
It is a manufacturing method of a preform provided with the shape holding member which hold | maintains the shape of the said laminated body.
The shape holding member has a penetrating portion that penetrates the laminate, and shape imparting portions that are in contact with the front surface or the back surface of the laminate, respectively, at both ends of the penetrating portion.
It has the shaping process which bends at least one of the said shape provision part, and shapes the said laminated body.

Furthermore, the fiber-reinforced plastic of the present invention is a laminate in which a plurality of reinforcing fiber sheets are laminated,
A shape holding member for holding the shape of the laminate;
A fiber reinforced plastic comprising a matrix resin between the reinforced fibers of the laminate.
The shape holding member has a penetrating portion that penetrates the laminate, and shape imparting portions that are in contact with the front surface or the back surface of the laminate, respectively, at both ends of the penetrating portion.
The shape imparting portion of the shape holding member is disposed at least at a location where the laminate is bent.

  According to the present invention, the shape holding member prevents the displacement of the reinforcing fiber sheet from being laminated, and the shape imparting portion of the shape holding member that contacts the laminated body holds the shape of the preform. It is possible to provide a preform with improved matrix resin impregnation performance.

It is the schematic which shows an example of the preform of this invention. It is sectional drawing which shows an example of the preform of this invention. It is the schematic which shows an example of the shape holding member of this invention. It is the schematic which shows another example of the shape holding member of this invention. It is a schematic cross section which shows the shaping state in the shape holding member of FIG. It is a figure explaining the state which shape | molds the preform of this invention with a metal mold | die. 2 is an appearance photograph of the preform of Example 1. 3 is an appearance photograph of a preform of Comparative Example 1. 4 is an external appearance photograph of a preform of Comparative Example 2.

The preform of the present invention will be described in detail.
FIG. 1 is a schematic view of the preform of the present invention, and FIG. 2 is a sectional view taken along the line AA ′ in FIG.
1 and 2, 1 is a preform, 2 is a laminate of reinforcing fiber sheets, 3 is a shape holding member, 31 is a penetrating portion of the shape holding member, 32 is a shape giving portion of the shape holding member, and E is a bent portion. It is.

  As shown in FIG. 1, the preform of the present invention includes a laminated body in which a plurality of reinforcing fiber sheets are laminated and a shape holding member.

The shape holding member 3 has a through portion 31 that penetrates the laminated body 2, and the through portion 31 prevents displacement in the surface direction of the reinforcing fiber sheet.
The shape holding member 3 has shape imparting portions 32 a and 32 b at both ends of the penetrating portion 31. And the said shape provision parts 32a and 32b contact | abut to the surface or back surface of the said laminated body 2, respectively, the said laminated body 2 is pinched | interposed by the shape provision parts 32a and 32b, and it prevents that a reinforced fiber sheet spreads in a lamination direction. To do.

As shown in FIG. 2, the shape holding member 3 is disposed at least in the bent portion E of the laminate. The laminate 2 is bent along the shape of the shape imparting portion 32 by bending the shape imparting portions 32a and 32b contacting the front or back surface of the laminate to a desired shape.
The preform 1 can be shaped into a desired shape by changing the shape of the shape imparting portion 32 of the shape holding member to an arbitrary shape such as a mountain fold, a valley fold, or a combination of these.

  It is preferable that the shape holding member 3 is further arranged on the outer peripheral portion of the laminate 2. By disposing the shape holding member 3 on the outer peripheral portion of the laminate 2, it is possible to prevent positional displacement of the reinforcing fiber sheet and fiber fraying at the end of the reinforcing fiber sheet.

  Since the preform 1 is formed by the shape holding member without applying a resin material between the reinforcing fibers, the matrix resin that forms the fiber reinforced plastic with the resin material when the fiber reinforced plastic is manufactured. It is prevented that impregnation of is prevented.

  Therefore, when making fiber reinforced plastics, the impregnation pressure of the matrix resin is low, and it is possible to prevent the reinforcement fiber sheet from being bent and displaced due to the flow of the matrix resin, and to generate defects such as non-impregnated portions (voids) of the matrix resin. Can be prevented.

  And since the fiber reinforced plastic produced from the preform 1 is less likely to have a defective portion, that is, a portion not impregnated with the matrix resin in the molded product, peeling damage due to insufficient matrix resin inside the molded product. Can be prevented and the mechanical properties are improved.

  In addition, since the preform 1 retains its shape with the shape retaining member 3, it is not necessary to melt and solidify the thermoplastic resin at the time of preform molding, and can be shaped in a short period of time, resulting in production efficiency. Will improve.

<Shape retention member>
As shown in FIG. 3 and FIG. 4, the shape holding member 3 has a penetrating portion 31 that penetrates the laminated body, a shape that constrains the laminated body, gives a predetermined shape to the laminated body, and holds the shape. And an imparting unit 32.

Examples of the shape retaining member 3 include staples, rivets, split pins, and fasteners, and staples can be preferably used.
FIG. 2 shows a state formed with staples, and FIG. 5 shows a state formed with rivets or split pins.

  As shown in FIG. 3, the staple is a so-called stapled needle having a U-shape, and includes two needle-like penetrating portions 31 and a shape imparting portion 32 a that connects one end of the two penetrating portions. It has. And after making the said laminated body 2 penetrate the said 2 penetration part, the other end of the 2 penetration part 31 is bent, and the shape provision part 32b is formed.

  Since the shape retaining member 3 is a staple, as shown in FIG. 2, the shape retaining member penetrating portions 31 can be disposed on the flat portions on both sides of the bent portion E of the laminate 2, and the shape imparting portion 32. However, since the shape of the laminated body 2 is hold | maintained across the mountain fold line or valley fold line of the bending part E, shaping property improves.

  In addition, in FIG. 2, although the part which protruded from the laminated body 2 of the penetration part 31 is bent in the same direction as the shape provision part 32a, the shape provision part 32b is formed, but according to the shape etc. of the preform to shape, You may bend | fold the shape provision part 32b in the direction different from the shape provision part 32a, such as a direction opposite to the shape provision part 32a.

Moreover, although the thickness of the said penetration part 31 is based also on the thickness of a laminated body, the matrix resin which comprises a fiber reinforced plastic, etc., it is preferable that it is 0.3 mm-1 mm.
If the thickness is 0.3 mm, the shape of the preform may not be sufficiently maintained. If the thickness exceeds 1 mm, the matrix resin impregnated during the production of the fiber-reinforced plastic may be largely diverted to cause a weld line.

  The cross section of the penetrating part 31 preferably has an aspect ratio of about 3: 5 so that the penetrating part 31 can be bent and the shape imparting part 32b is easily formed. In the present invention, the thickness of the through portion 31 when the cross section of the through portion 31 is flat refers to the longitudinal direction of the cross section.

  As the material constituting the shape retaining member 3, a material that is ductile and plastically deforms without breaking can be used. For example, a metal material such as aluminum, iron, and stainless steel can be preferably used. The shape holding member is preferably one having corrosion resistance by surface treatment or the like.

When the shape holding member 3 is made of a metal material, the process temperature when the preform is impregnated with the matrix resin can be increased.
Therefore, the viscosity of the matrix resin can be lowered, the occurrence of stacking deviations and wrinkles due to the impregnation pressure can be prevented, and the type of the matrix resin is not limited and can be freely selected according to the application.

<Reinforcing fiber sheet>
The reinforcing fiber sheet may be a woven fabric or a non-woven fabric. The weaving method of the woven fabric is plain weaving, satin weaving, twill weaving, nanako weaving, and long fibers arranged in a certain direction. Also good.

  The type of the reinforcing fiber can be appropriately selected according to the type and purpose of the molded product to be used, and either inorganic fiber or organic fiber can be used.

  Examples of the inorganic fibers include carbon fibers, activated carbon fibers, graphite fibers, glass fibers, tungsten carbide fibers, silicon carbide fibers (silicon carbide fibers), ceramic fibers, alumina fibers, natural fibers, mineral fibers such as basalt, and boron fibers. , Boron nitride fiber, boron carbide fiber, and metal fiber.

  Examples of the organic fibers include fibers made of resin materials such as polybenzazole, aramid, PBO (polyparaphenylene benzoxazole), polyphenylene sulfide, polyester, acrylic, polyamide, polyolefin, polyvinyl alcohol, and polyarylate. it can.

In the present invention, it is preferable to use carbon fibers as the reinforcing fibers.
Carbon fiber is lightweight and can provide CFRP with excellent strength.

  The carbon fibers are generally polyacrylonitrile (PAN) based carbon fibers, petroleum / coal pitch based carbon fibers, rayon based carbon fibers, cellulosic carbon fibers, lignin based carbon fibers, phenol based carbon fibers, and vapor growth systems. A carbon fiber etc. can be mentioned.

  The reinforcing fibers can be used alone or in combination of two or more. When two or more types of reinforcing fibers are used, a reinforcing fiber sheet formed of two or more types of reinforcing fibers may be used, or multiple types of reinforcing fiber sheets formed of one type of reinforcing fiber may be used. Good.

<Preform manufacturing method>
Next, the preform manufacturing method of the present invention will be described.
The preform manufacturing method includes an applying step of applying the shape holding member 3 to the laminate 2 in which a plurality of reinforcing fiber sheets are laminated, and pressing the laminate 2 provided with the shape holding member 3 with a mold. And a shaping process.

  In the application step, the laminate 2 in which a plurality of reinforcing fiber sheets are laminated is caused to penetrate the shape holding member 3 including the shape imparting portion 32a at one end of the needle-like penetration portion 31, and the portion protruding from the laminate 2 is penetrated. This is a step of deforming the portion 31 to form the shape imparting portion 32 b at the other end of the penetrating portion 31.

  Specifically, the shape holding member 3 is inserted until the penetrating portion 31 of the shape holding member 3 penetrates the laminate 2, and the shape imparting portion 32a at the one end contacts one surface of the laminate 2, The front end of the penetrating portion 31 is protruded from the other surface of the laminate 2 to prevent a deviation in the surface direction of the laminate 2.

  Then, the protruding portion of the penetrating portion 31 is deformed by bending, crushing, expanding, splitting, or the like to form a shape imparting portion 32b that contacts the other surface of the laminate 2, In this step, the stack 2 is sandwiched and restrained by the applying portions 32a32b.

  The position where the shape retaining member 3 is applied is a position where the shape imparting portion 32 of the shape retaining member is on the bent portion E of the preform.

  In addition, the position and interval at which the shape-retaining member 3 is applied are determined in terms of the shape of the mold for molding the fiber-reinforced plastic, and the shape of the molding so that deformation of the reinforcing fiber sheet due to the matrix resin impregnation pressure can be prevented from being deformed. It is preferable that it is applied in consideration of the flow of the matrix resin.

The said shaping process is a process of pressing and shape | molding the laminated body to which the shape holding member 3 was provided with the metal mold | die 4. FIG.
By pressing the laminated body 2, the shape imparting portions 32 a and 32 b on both sides sandwiching the laminated body are plastically deformed to impart a predetermined shape to the laminated body 2 and to maintain the shape.

  Moreover, the manufacturing method of the preform of this invention can provide the washing | cleaning process of removing resin, such as a sizing agent adhering to the said reinforcing fiber sheet, as needed.

<Fiber reinforced plastic>
The fiber reinforced plastic of the present invention is molded using the preform of the present invention.
The fiber reinforced plastic includes a laminate in which a plurality of reinforcing fiber sheets are laminated, a shape holding member, and a matrix resin between the reinforcing fibers of the laminate, and holds the shape at least where the laminate is bent. The shape-giving part of a member is arrange | positioned.

The fiber-reinforced plastic of the present invention can be produced by placing the preform in a mold and impregnating with a matrix resin. As the mold, a mold different from the mold used in the preform shaping step may be used, or the same mold may be used.
<Resin material>
The matrix resin constituting the fiber reinforced plastic may be either a thermoplastic resin or a thermosetting resin.

  Examples of the thermoplastic resin include polyamide resin, polyolefin resin, polystyrene resin, thermoplastic polyester resin, polyacetal resin (polyoxymethylene resin), polycarbonate resin, (meth) acrylic resin, polyarylate resin, polyphenylene ether resin, polyimide Resin, polyether nitrile resin, phenoxy resin, polyphenylene sulfide resin, polysulfone resin, polyketone resin, polyether ketone resin, thermoplastic urethane resin, fluorine-based resin, thermoplastic polybenzimidazole resin, etc. A resin is preferred.

  Examples of the polyamide resin include polyamide 6 resin (nylon 6), polyamide 11 resin (nylon 11), polyamide 12 resin (nylon 12), polyamide 46 resin (nylon 46), polyamide 66 resin (nylon 66), and polyamide 610. Resin (nylon 610) etc. can be mentioned.

  Examples of the polyolefin resin include polyethylene resin, polypropylene resin, polybutadiene resin, polymethylpentene resin, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, and polyvinyl alcohol resin.

  Examples of the polystyrene resin include polystyrene resin, acrylonitrile-styrene resin (AS resin), acrylonitrile-butadiene-styrene resin (ABS resin), and the like.

  Examples of the polyester resin include polyethylene terephthalate resin, polyethylene naphthalate resin, boribylene terephthalate resin, polytrimethylene terephthalate resin, and liquid crystal polyester.

  These thermoplastic resins may be used alone or in combination of two or more, and may be used in combination with thermoplastic resins having different softening points and melting points, and thermoplastics having different average molecular weights. A resin may be used in combination.

  Examples of the thermosetting resin include epoxy resins, unsaturated polyester resins, vinyl ester resins, phenol resins, guanamine resins, polyimide resins, furan resins, polyurethane resins, polydiallyl phthalate resins, melamine resins, urea resins and amino resins. From the viewpoint of suppressing thermal shrinkage during molding, an epoxy resin can be preferably used.

  Examples of the epoxy resin used for the fiber reinforced plastic include bisphenol A type epoxy resin, phenol novolac type epoxy resin, glycidylamine type epoxy resin and the like as main components. Moreover, as a hardening | curing agent, the hardening | curing agent etc. which combined dichlorophenyl dimethyl urea with dicyandiamide can be mentioned.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the following Example.

[Example 1]
(Preform production)
A continuous reinforcing carbon fiber sheet (Torayca cloth: C06343B: manufactured by Toray Industries, Inc.) was cut into a length of 310 mm and a width of 130 mm to prepare 14 cloths.
Next, the cloth was immersed in pure acetone and allowed to stand overnight, and then thoroughly washed with new pure acetone, and the cloth was placed on a net and allowed to air dry. After drying, it was trimmed to a length of 300 mm and a width of 120 mm.

  Fourteen cloths were laminated, and the outer periphery of the cloth was fixed with staples using a stapler in the usual manner.

  Next, the thickness of the penetrating part is 0.5 mm so that the shape imparting part straddles the mountain fold line or the valley fold line that becomes the bent part E when the cloth is placed on the support and made into a preform. The staple was penetrated, and the penetrating portion of the staple was bent to form a shape imparting portion and restrained.

The laminate provided with the staples was placed in a mold having a shape to be shaped.
A lower aluminum mold used for vacuum molding was used as the mold.

The laminate placed in the mold was evacuated and pressed with an upper mold while preventing displacement, and the shape imparting portion of the stapler was bent and shaped to produce the preform of the present invention.
The preform of Example 1 is shown in FIG.

(Production of fiber reinforced plastic)
The preform is put into an RTM mold, and the inside of the RTM mold is evacuated and dried for a while, and then a nylon 6 monomer solution containing a catalyst and an activator (manufactured by Nagase ChemteX: DENITEITE GAP-1R, DENITEITE GAP- After mixing 1DA), the solution was fed into the mold at 1.0 MPa. Two minutes after completion of liquid feeding, it was taken out to obtain a fiber-reinforced plastic of the present invention.

[Comparative Example 1]
The laminate obtained by alternately laminating the reinforced carbon fiber sheet trimmed in Example 1 and the nylon nonwoven fabric was placed on a hat-shaped mold.
The laminate and the mold are put in a bagging film, evacuated, held at a temperature of 140 ° C. for 10 minutes, the nylon nonwoven fabric is melted, the reinforced carbon fiber sheets are bonded to each other, and then cooled to room temperature. A preform was prepared. The preform of Comparative Example 1 is shown in FIG.

  The preform was put into the RTM mold, and a fiber reinforced plastic was obtained in the same manner as in Example 1.

[Comparative Example 2]
A preform was produced in the same manner as in Comparative Example 1 except that a nylon nonwoven fabric having a width of 1 cm was arranged in a frame shape on the outer periphery of the reinforced carbon fiber sheet trimmed in Example 1 and laminated alternately. The preform of Comparative Example 2 is shown in FIG.

  Further, the preform was put into the RTM mold, and a fiber reinforced plastic was obtained in the same manner as in Example 1.

<Evaluation>
The appearance and cross section of the above Example 1, Comparative Examples 1 and 2 preforms were observed to confirm the shape imparting property and the presence or absence of fiber misalignment.

In Example 1 and Comparative Example 1, peeling of the reinforced carbon fiber sheet and fiber displacement were not confirmed, the shape of the mold was maintained, and handling was easy.
On the other hand, in Comparative Example 2, the reinforced carbon fiber sheet floated in the stacking direction, and fiber misalignment was confirmed at the end of the preform.

  Further, the fiber volume content (Vf) and the flexural modulus of the fiber reinforced plastic molded product produced from the preforms of Example 1 and Comparative Examples 1 and 2 were measured.

  The flexural modulus of the fiber reinforced plastic molded product was measured by using a diamond cutter to cut the molded product into a width of 15 mm and a length of 100 mm to obtain a physical property test piece. With respect to this test piece, the span distance was 80 mm and the test speed was 5 mm / s. A three-point bending test was conducted.

  Moreover, the external appearance and cross section of the fiber reinforced plastics of Example 1 and Comparative Examples 1 and 2 were observed, and the formability such as the shape imparting property and the presence or absence of fiber misalignment was confirmed. The evaluation results are shown in Table 1.

DESCRIPTION OF SYMBOLS 1 Preform 2 Laminated body 3 Shape holding member 31 Penetrating part 32a Shape giving part 32b Shape giving part 4 Mold E Bending part

Claims (9)

A laminate in which a plurality of reinforcing fiber sheets are laminated;
A shape holding member for holding the shape of the laminate,
The shape holding member has a penetrating portion that penetrates the laminate, and shape imparting portions that are in contact with the front surface or the back surface of the laminate, respectively, at both ends of the penetrating portion.
A preform characterized in that at least one of the shape imparting portions is bent to shape the laminate.   The preform according to claim 1, further comprising the shape holding member on an outer peripheral portion of the laminated body.   The preform according to claim 1 or 2, wherein the constituent material of the shape holding member includes a metal material.   The preform according to any one of claims 1 to 3, wherein the shape holding member is a staple. A laminate in which a plurality of reinforcing fiber sheets are laminated;
A shape holding member that holds the shape of the laminate, and a method for producing a preform,
The shape holding member has a penetrating portion that penetrates the laminate, and shape imparting portions that are in contact with the front surface or the back surface of the laminate, respectively, at both ends of the penetrating portion.
A method for producing a preform, comprising a shaping step of bending at least one of the shape imparting portions and shaping the laminate. A laminate in which a plurality of reinforcing fiber sheets are laminated;
A shape holding member for holding the shape of the laminate;
A fiber reinforced plastic comprising a matrix resin between the reinforcing fibers of the laminate,
The shape holding member has a penetrating portion that penetrates the laminate, and shape imparting portions that are in contact with the front surface or the back surface of the laminate, respectively, at both ends of the penetrating portion.
A fiber-reinforced plastic characterized in that a shape imparting portion of the shape holding member is disposed at least at a location where the laminate is bent.   The fiber-reinforced plastic according to claim 6, further comprising the shape holding member on an outer peripheral portion of the laminate.   The fiber-reinforced plastic according to claim 6 or 7, wherein the constituent material of the shape holding member includes a metal material.   The fiber-reinforced plastic according to any one of claims 6 to 8, wherein the shape holding member is a staple.

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