JP2024052261A - Method for processing fiber-reinforced resin member and composite member - Google Patents

Abstract

[Problem] To provide a method for processing a fiber-reinforced resin member and a composite member capable of suppressing buckling of the fiber-reinforced resin member when the fiber-reinforced resin member is bent. [Solution] A method for bending a fiber-reinforced resin member containing a thermoplastic resin and reinforcing fibers, the method includes the steps of obtaining a composite member 10 in which a buckling suppression member 18 having a laminated structure of a metal layer 16 and an adhesive layer 14 that is peelable from a fiber-reinforced resin member 12 is attached to the fiber-reinforced resin member by the adhesive layer, bending the heated composite member such that at least a portion of the buckling suppression member is bent on the compression side of the portion of the fiber-reinforced resin member that is bent, and removing the buckling suppression member from the bent composite member, and a composite member used therein. [Selected Figure] Figure 2

Description

This disclosure relates to a method for processing fiber-reinforced resin components and composite components.

Fiber-reinforced plastic (FRP), which is made of reinforcing fibers such as glass fiber or carbon fiber and a matrix resin, is expected to be an alternative material to metal components. Metal components can be shaped as desired through secondary processing such as roll forming, and it is expected that the demand for secondary processability of FRP will also increase in the future from the perspective of component productivity.

Various materials and processing methods using fiber-reinforced resins have been proposed.
For example, Patent Document 1 discloses a metal-fiber reinforced resin laminate in which a metal sheet layer and a resin-integrated fiber sheet layer are integrated, the resin-integrated fiber sheet layer includes carbon fiber and a thermoplastic matrix resin, the laminate includes a thermoplastic resin sheet layer disposed between the metal sheet layer and the resin-integrated fiber sheet layer, and the thermoplastic resin sheet layer is a stress relaxation layer. Patent Document 1 describes that the introduction of the stress relaxation layer reduces warping and suppresses peeling of the metal layer.

Patent Document 2 discloses a composite reinforcing rod with a heat-shrinkable tube, which includes a core material in which each constituent fiber thread of the reinforcing fiber is aligned in the thread length direction and bundled into a rod shape, and is embedded and integrated in a matrix resin of a thermoplastic resin or an in-situ polymerized thermoplastic epoxy resin, and a heat-shrinkable tube that is a cylindrical body shorter than the composite reinforcing rod and has an inner diameter larger than the rod diameter of the composite reinforcing rod, and shrinks more in the radial direction than in the longitudinal direction when heated, and the heat-shrinkable tube is loosely fitted into the composite reinforcing rod and disposed at the bending processing portion of the composite reinforcing rod. Patent Document 2 describes that by arranging the heat-shrinkable tube at the processing position, it is possible to prevent the reinforcing fibers from coming apart and becoming peeled off during bending of the fiber-reinforced resin, and to prevent the reinforcing fibers from peeling off and causing wrinkles and deformation in the fiber-reinforced composite material.

Patent Document 3 discloses a method for processing a metal-thermoplastic fiber-reinforced resin material composite member, which includes an integral processing step in which a metal plate having a matrix resin containing a thermoplastic resin and a fiber-reinforced resin material having a reinforcing fiber material arranged on at least one surface is heated to a predetermined temperature at which the fiber-reinforced resin material alone cannot maintain its shape, and then a predetermined pressure is applied through a mold having a predetermined shape to integrally process the metal plate and the fiber-reinforced resin material into a shape that follows the predetermined shape of the mold, and a demolding step in which the integrally processed metal plate and the fiber-reinforced resin material are released from the mold at a predetermined temperature at which the shape of the fiber-reinforced resin material is not yet fully determined, the thermoplastic resin being an amorphous resin other than polycarbonate that has a glass transition temperature Tg, the heating temperature in the integral processing step being lower than the decomposition temperature of the amorphous thermoplastic resin and in a temperature range of (Tg+50) to (Tg+200)°C, and the demolding temperature in the demolding step being lower than the decomposition temperature of the amorphous thermoplastic resin and in a temperature range of (Tg+20) to (Tg+200)°C.

JP 2022-78876 A JP 2020-70506 A JP 2022-33907 A

When bending a fiber-reinforced resin member with a thermoplastic resin matrix, the reinforcing fibers buckle due to differences in the amount of displacement in the thickness direction at the processing position, reducing the strength of the molded product. Figure 11 shows an example of buckling in a bent portion of a fiber-reinforced resin member. As shown in Figure 11, when a fiber-reinforced resin member 22 buckles during bending, a part of the compression side of the bent portion (the side to which compressive stress is applied during bending) is deformed into a raised shape 24.

The technique disclosed in Patent Document 1 does not assume bending of the laminated plate or use with the metal layer removed.
The technique disclosed in Patent Document 2 is unable to prevent buckling of the heat shrinkable tube if the tube is significantly deformed by processing since the heat shrinkable tube has flexibility.
The technology disclosed in Patent Document 3 describes a method of directly bonding a metal plate and a fiber-reinforced resin material to integrate and shape the composite component in a single step, and peeling off the metal component by hydrolyzing the matrix resin, assuming separation during recycling of the composite component. However, it is not assumed that the metal plate will be removed and the composite component will be used again.

The objective of the present disclosure is to provide a method for processing a fiber-reinforced resin member that can suppress buckling of the fiber-reinforced resin member when bending the fiber-reinforced resin member, and a composite member used therein.

Means for solving the above problems include the following aspects.
<1> A method for bending a fiber-reinforced resin member containing a thermoplastic resin and reinforcing fibers,
obtaining a composite member in which a buckling suppression member having a laminated structure of a metal layer and an adhesive layer peelable from the fiber reinforced resin member is attached to the fiber reinforced resin member by the adhesive layer;
Bending the heated composite member such that at least a portion of the buckling suppression member is bent on the compression side of the portion of the fiber reinforced resin member that is bent;
removing the buckling restraint member from the bent composite member;
A method for processing a fiber-reinforced resin member comprising the steps of:
<2> The method for processing a fiber-reinforced resin member according to <1>, wherein the adhesive layer has a thickness of 2 mm or less, and the metal layer has a thickness of 0.05 mm or more.
<3> In the step of bending the composite member, the composite member is heated to a temperature equal to or higher than the glass transition temperature of the thermoplastic resin and bent with a curvature radius of 5.0 mm or more. The method for processing a fiber-reinforced resin member according to <1> or <2>.
<4> The method for processing a fiber-reinforced resin member according to any one of <1> to <3>, wherein an adhesive strength between the fiber-reinforced resin member and the buckling suppression member in the composite member is 4 N/mm or less.
<5> The method for processing a fiber-reinforced resin member according to any one of <1> to <4>, wherein the metal layer is a metal layer containing at least one of copper, aluminum, and stainless steel.
<6> The method for processing a fiber-reinforced resin member according to any one of <1> to <5>, wherein the thermoplastic resin is an amorphous thermoplastic resin having a glass transition temperature of 60° C. or higher.
<7> A fiber-reinforced resin member containing a thermoplastic resin and a reinforcing fiber,
A buckling suppression member having a laminated structure of a metal layer and an adhesive layer that is peelable from the fiber reinforced resin member, and attached to the fiber reinforced resin member by the adhesive layer;
A composite member used in the method for processing a fiber-reinforced resin member according to any one of <1> to <6>.

The present disclosure provides a method for processing a fiber-reinforced resin member that can suppress buckling of the fiber-reinforced resin member when bending the fiber-reinforced resin member, and a composite member used therein.

FIG. 2 is a schematic partial cross-sectional view showing an example of a layer structure of a composite member according to the present disclosure. 1 is a schematic diagram showing an example of a method for processing a fiber-reinforced resin member according to the present disclosure. FIG. 4 is a schematic diagram showing warpage of a fiber reinforced resin member after bending. FIG. 4 is a schematic diagram showing interlayer displacement at an end portion of a fiber-reinforced resin member after bending. FIG. 5 is a schematic diagram showing a method for measuring the adhesive strength between a fiber-reinforced resin member and a buckling suppression member. FIG. FIG. 2 is a schematic diagram showing an example of a bending method using a die. FIG. 2 is a schematic diagram showing the configuration of a composite member used in manual bending in the examples. FIG. 2 is a schematic diagram showing a bending angle. FIG. 13 is a diagram showing the bending strength and bending modulus of CFRP after manual bending under different conditions. FIG. 2 is a schematic diagram showing a main part of a die used in V-bending in the examples. 4 is a schematic diagram showing an example of buckling that occurs on the compression side when a fiber-reinforced resin member is bent; FIG.

Hereinafter, an embodiment that is an example of the present disclosure will be described.
In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In the present specification, the upper limit of a certain numerical range may be replaced by the upper limit of another numerical range, or may be replaced by a value shown in an example. The lower limit of a certain numerical range may be replaced by the lower limit of another numerical range, or may be replaced by a value shown in an example.
In addition, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.

The processing method for a fiber-reinforced resin member according to the present disclosure is a method for bending a fiber-reinforced resin member containing a thermoplastic resin and reinforcing fibers, and includes a step (attaching step) of obtaining a composite member in which a buckling suppression member having a structure in which a metal layer and an adhesive layer that can be peeled off from the fiber-reinforced resin member are laminated to the fiber-reinforced resin member by the adhesive layer, a step (bending step) of bending the heated composite member so that at least a portion of the buckling suppression member bends on the compression side of the portion of the fiber-reinforced resin member that is bent, and a step (removal step) of removing the buckling suppression member from the bent composite member.

Fig. 1 is a schematic diagram showing an example of a layer structure of a composite member used in a processing method for a fiber-reinforced resin member according to the present disclosure. Fig. 2 is a schematic diagram showing an example of a processing method for a fiber-reinforced resin member according to the present disclosure using a composite member having the layer structure shown in Fig. 1.
As shown in FIG. 1, the composite member 10 includes a plate-shaped fiber-reinforced resin member 12 and buckling suppression members 18A, 18B, each of which is formed by laminating a metal layer 16 and an adhesive layer 14, attached to both sides of the plate-shaped fiber-reinforced resin member 12 by the adhesive layer 14.
For example, as shown in Fig. 2(A), the central portion of the composite member 10 is pressed against a round bar jig 30, and a force F is applied from the opposite side to the vicinity of both ends of the composite member 10 to perform bending. This makes it possible to perform bending while suppressing the occurrence of buckling of the fiber reinforced resin member 12. After bending, as shown in Fig. 2(B), the adhesive layer 14 is peeled off from the fiber reinforced resin member 12 to remove the buckling suppression members 18A, 18B. This makes it possible to obtain a fiber reinforced resin member 22 in which buckling is suppressed in the bent portions.
Each step will be described in detail below. In the following description, reference numerals may be omitted. The buckling suppression members 18A and 18B may be referred to as the buckling suppression member 18.

[Attachment process]
First, a composite member 10 is obtained in which a buckling suppression member 18 having a structure in which a metal layer 16 and an adhesive layer 14 that can be peeled off from a fiber-reinforced resin member are laminated together and attached to a fiber-reinforced resin member 12 by the adhesive layer 14.

The composite member 10 shown in Figure 1 has buckling suppression members 18 attached to both sides of a plate-shaped fiber-reinforced resin member 12, but the buckling suppression member may also be a structure in which buckling suppression member 18A is attached only to the compression side of the portion of the fiber-reinforced resin member 12 that is to be bent, i.e., the side of the fiber-reinforced resin member 12 that comes into contact with the jig 30 in Figure 2.
The fiber reinforced resin member and the buckling suppression member will be described below.

<Fiber reinforced resin member>
The fiber reinforced resin member 12 is composed of a thermoplastic resin that is a matrix resin and a fiber reinforced thermoplastic resin that contains reinforcing fibers.

(Thermoplastic resin)
The thermoplastic resin that is the matrix resin of the fiber reinforced resin member is not particularly limited, and examples thereof include phenoxy resin, acrylic resin, polyamide resin, polyvinyl chloride resin, polystyrene resin, ABS resin, polyacetal resin, polycarbonate resin, polyester resin, polyurethane resin, polyolefin (polyethylene, polypropylene, etc.), etc.

The thermoplastic resin contained in the fiber reinforced resin member may be one type alone or a mixture of two or more types.
From the viewpoint of forming a fiber-reinforced resin member by integrating it with the reinforcing fibers and from the viewpoint of making it easier to bend the fiber-reinforced resin member, the thermoplastic resin is preferably an amorphous thermoplastic resin having a glass transition temperature (Tg) of 60 ° C. or more, more preferably an amorphous thermoplastic resin having a Tg of 90 to 250 ° C., and even more preferably an amorphous thermoplastic resin having a Tg of 90 to 160 ° C. that accounts for 50 mass% or more of the thermoplastic resin contained in the fiber-reinforced resin member.
Crystalline thermoplastic resins also have a Tg (for example, Tg of nylon 6 is 60°C), but since the crystallinity is maintained until the melting point is reached, the fluidity is low and secondary processing such as bending cannot be performed. In addition, when the melting point is exceeded, the fluidity becomes very large, so the secondary processability increases, but it is difficult to achieve the accuracy of the resin flow and molding. On the other hand, if the Tg of an amorphous thermoplastic resin is low, it becomes easier to process fiber-reinforced resin members at low temperatures, but on the other hand, the processed members are easily deformed at relatively low temperatures, and the places where they can be used are limited. From this perspective, amorphous thermoplastic resins having a Tg of 60°C or more, particularly in the range of 90 to 250°C, are preferable. The Tg of the thermoplastic resin in this disclosure is a value calculated from the peak value of the second scan measured using a differential scanning calorimeter at a temperature range of 20 to 280°C under a heating condition of 10°C/min.

The thermoplastic resin contained in the fiber reinforced resin member is preferably a phenoxy resin from the viewpoints of strength, affinity with the reinforcing fibers, adhesion to the metal layer, and the like.
Here, the "phenoxy resin" is a linear polymer obtained by a condensation reaction between a dihydric phenol compound and an epihalohydrin, or a polyaddition reaction between a dihydric phenol compound and a difunctional epoxy resin, and is an amorphous thermoplastic resin.

The average molecular weight of the phenoxy resin is, for example, in the range of 10,000 to 200,000 as the weight average molecular weight (Mw), but from the viewpoint of the strength, workability, and processability of the composite material, it is preferably in the range of 20,000 to 100,000, and more preferably in the range of 30,000 to 80,000. If the Mw of the phenoxy resin is too low, the strength of the composite material will be poor, and if it is too high, the workability and processability will tend to be poor. The Mw is measured by gel permeation chromatography (GPC) and is shown as a value converted using a standard polystyrene calibration curve.

Phenoxy resins are produced by known methods from raw material compounds in solution or without solvent, but among the phenoxy resins produced without solvent, those obtained by polymerizing the raw material compounds in situ are also called in-situ polymerized phenoxy resins or thermoplastic epoxy resins.

Phenoxy resin and in situ polymerization type phenoxy resin are both linear polymers made of a difunctional phenol compound and a difunctional epoxy resin. However, the molecular weight and molecular weight distribution of phenoxy resin are controlled within a certain range, and polymerization does not proceed further even when heated, whereas an increase in the molecular weight of in situ polymerization type phenoxy resin is confirmed by heating.
In the present disclosure, any of phenoxy resins produced in a solution, phenoxy resins produced without a solvent, and in-situ polymerized phenoxy resins can be used as the matrix resin of the fiber-reinforced resin member.

Examples of dihydric phenol compounds used in the production of the phenoxy resin are shown below, but as long as they are bifunctional, they are not limited to those shown below. Examples of the bisphenols include bisphenol A, bisphenol F (all manufactured by Nippon Steel Chemical & Material Co., Ltd.), bisphenol fluorene, biscresol fluorene (all manufactured by Osaka Gas Chemical Co., Ltd.), Bis-E, Bis-Z, BisOC-FL, BisP-AP, BisP-CDE, BisP-HTG, BisP-MIBK, BisP-3MZ, SBOC, Bis25X-F (all manufactured by Honshu Chemical Industry Co., Ltd.), and bisphenol S; benzene diols such as hydroquinone, methyl hydroquinone, dibutyl hydroquinone, resorcin, methyl resorcin, catechol, and methyl catechol; naphthalenediols such as naphthalenediol; and biphenols such as biphenol, dimethyl biphenol, and tetramethyl biphenol. Of these, bisphenol compounds or biphenol compounds are preferred.
These dihydric phenol compounds may be used alone or in combination of two or more kinds.

Examples of bifunctional epoxy resins used in the production of the phenoxy resin include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenolacetophenone type epoxy resin, diphenyl sulfide type epoxy resin, diphenyl ether type epoxy resin, and bisphenol fluorene type epoxy resin; biphenol type epoxy resin, diphenyldicyclopentadiene type epoxy resin, alkylene glycol type epoxy resin, dihydroxynaphthalene type epoxy resin, dihydroxybenzene type epoxy resin, and methyl group-substituted products thereof; and bisphenol type epoxy resin, biphenol type epoxy resin, and methyl group-substituted products thereof are preferred.
These difunctional epoxy resins may be used alone or in combination of two or more.

A reaction catalyst (polymerization catalyst) is used in the production of phenoxy resin. The reaction catalyst may be any compound having catalytic ability to promote the reaction between an epoxy group and a phenolic hydroxyl group, and examples of the reaction catalyst include alkali metal compounds, organic phosphorus compounds, tertiary amines, quaternary ammonium salts, cyclic amines, and imidazoles. Among these, it is preferable to use organic phosphorus compounds such as triphenylphosphine (TPP), tri-o-tolylphosphine (TOTP), and tris(p-methoxyphenyl)phosphine (TPAP), and imidazoles such as 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole (TB-Z).
These catalysts may be used alone or in combination of two or more kinds.

A reaction retarder can also be used in the polymerization of phenoxy resin. When mixing the two liquids, the precursor composition is often heated in order to homogenize it and reduce its viscosity as much as possible. It is therefore preferable to slow down the reaction and maintain a low viscosity state, and trialkyl borates such as tri-n-butyl borate, tri-n-octyl borate, and tri-n-dodecyl borate, and triaryl borates such as triphenyl borate are used as reaction retarders. These are used either alone or in combination of two or more.

When the phenoxy resin is produced in a solution, the reaction solvent is not particularly limited as long as it does not inhibit the reaction, and examples of the reaction solvent include organic solvents such as benzene, toluene, xylene, methanol, alcohol, butyl alcohol, methyl ethyl ketone, cyclopentanone, cyclohexanone, butyrolactone, dioxane, tetrahydrofuran, acetophenone, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and sulfolane, and may be a combination of two or more of these, or a mixed solvent of an organic solvent and an inorganic solvent (such as water).

The polymerization reaction is carried out at a temperature at which the catalyst used does not decompose, i.e., 50 to 240°C, and the reaction pressure is usually normal pressure. When it is necessary to remove the heat of reaction, the reaction is carried out by flash evaporation/condensation reflux method of the solvent used, indirect cooling method, or a combination of these methods.
When a low boiling point solvent such as methyl ethyl ketone is used, the reaction temperature can be ensured by carrying out the reaction under high pressure using an autoclave.

The phenoxy resin obtained by this method can be used as a varnish as is, or can be made into a solvent-free solid resin by removing the solvent using an evaporator, etc.

Thereafter, if the phenoxy resin is in a varnish state, it is directly impregnated into the reinforcing fibers and then dried to form a prepreg. If the phenoxy resin is in a solid state, it is impregnated into the reinforcing fiber substrate in a molten state using an impregnation die or the like to form a prepreg.
Furthermore, the solid resin may be made into fibers, films, or powder and woven together with reinforcing fibers (commingled method), or a film and a reinforcing fiber substrate may be layered and pressurized and impregnated using a roll press or the like (film stack method), or the solid resin may be coated onto a reinforcing fiber substrate using a powder coating method to process the resin into an FRP molding material known as semi-preg.

On the other hand, when phenoxy resin is produced without a solvent, the raw material compounds and the reaction catalyst are mixed to form a precursor composition, which is then heated to cause a polyaddition reaction. At this time, in order to optimize the mixture state of the raw materials and the reaction catalyst, the raw materials may be mixed with those that have been heated and melted in advance, or a solvent such as cyclohexanone or methyl ethyl ketone may be added in an amount of up to about 10% by mass.

The conditions for producing a phenoxy resin without a solvent are not significantly different from those for producing a phenoxy resin in a solvent. However, in situ polymerization type phenoxy resin, which can produce a phenoxy resin in situ without using a reactor or the like, is a preferred phenoxy resin because its degree of polymerization can be adjusted within a desired range and it can be impregnated into a reinforcing fiber substrate in the oligomer state to produce a prepreg.
Generally, high temperatures and high pressures are required to impregnate a high molecular weight substance (polymer) into a reinforcing fiber substrate, which can easily cause voids due to poor impregnation or breakage of the reinforcing fibers. When a solvent is used, voids are likely to occur due to residual solvent. However, oligomers have a lower melt viscosity than polymers, so they can be easily impregnated into a reinforcing fiber substrate by heating and melting.

Impregnation into reinforcing fibers is carried out after polymerizing a precursor composition obtained by mixing raw material compounds and a reaction catalyst using a mixer or kneader until the weight average molecular weight (Mw) is in the range of about 100 to 6000, and the precursor composition is heated and melted at 40 to 80°C using an impregnation die or the like and directly impregnated into a reinforcing fiber substrate, or the oligomer is cast onto release paper or the like to form a film, which is then impregnated into a reinforcing fiber substrate at a temperature of 70 to 130°C and a linear pressure of 5 to 25 kg/cm using a roll press or the like (film stack method) to process into a prepreg.
In this case, if necessary, a prepreg having fibers aligned in one direction may be produced using a reinforcing fiber base material having reinforcing fibers aligned in one direction.

(Reinforced Fiber)
The reinforcing fibers contained in the fiber reinforced resin member 12 are not particularly limited and may be continuous fibers or short fibers, but are preferably continuous fibers.
The fiber reinforced resin member 12 may be a UD prepreg in which the fiber direction of the reinforcing fibers is aligned in one direction, a laminate of cross material in which the reinforcing fibers cross vertically and horizontally, or a pultrusion molded product if continuous fibers are used, and a short fiber reinforced resin member in which the fibers are oriented in the planar direction, such as a random mat made by piling up rectangular UD prepregs or felt made by a papermaking method, is preferable if short fibers are used.

From the viewpoint of strength, affinity with thermoplastic resin, and the like, for example, carbon fiber, boron fiber, silicon carbide fiber, glass fiber, aramid fiber, and the like are preferred, and carbon fiber is more preferred. Carbon fibers are generally classified into PAN-based fibers made from polyacrylonitrile and pitch-based fibers made from coal tar pitch or petroleum pitch. Either PAN-based or pitch-based carbon fibers can be used in the present disclosure, and these may be used alone or in combination depending on the purpose and application.

The diameter of the carbon fiber is, for example, 5 to 10 μm. The length of the carbon fiber may be, for example, 10 mm or more, but it is preferable that the fiber is continuous.

The fiber volume content (Vf) of the fiber-reinforced resin member is not particularly limited, but if Vf is too low, the strength improvement due to the reinforcing fibers will be insufficient, and if it is too high, bending may become difficult. Therefore, it is preferable that Vf of the fiber-reinforced resin member is, for example, 40 to 60%.

The fiber reinforced resin member 12 may be composed of one fiber reinforced resin layer, or may be composed of two or more fiber reinforced resin layers.
For example, a laminated structure may be formed in which two or more unidirectional fiber-reinforced resin layers in which the fiber direction of the reinforcing fibers is aligned in one direction are laminated, and the fiber direction is different between adjacent unidirectional fiber-reinforced resin layers in the thickness direction. For example, when a fiber-reinforced resin member is formed by laminating three unidirectional fiber-reinforced resin layers, the fiber directions of each layer relative to the longitudinal direction of the fiber-reinforced resin member are integrated into a laminated structure at 0°, 90°, 0°, or 90°, 0°, 90°, respectively, to form a fiber-reinforced resin member having improved strength in both the longitudinal and width directions. Note that the number of unidirectional fiber-reinforced resin layers to be laminated and the degree of shifting of the fiber direction between adjacent unidirectional fiber-reinforced resin layers (angle difference) are not particularly limited and can be selected according to the application and the required mechanical properties.

Figure 3 is a schematic diagram showing the warping of a fiber-reinforced resin member after bending. As shown in Figure 3, when the center part of a fiber-reinforced resin member is bent, it is preferable that both sides of the bent part are as close to a straight line shape 22A as shown by the dotted line, but they tend to be warped in the opposite direction to the bending direction 22B. However, when a fiber-reinforced resin member having two or more fiber-reinforced resin layers is bent, the layers are displaced according to the bending angle, thereby suppressing warping. Figure 4 shows a schematic diagram of interlayer slippage at the end of the fiber-reinforced resin member 22 after bending. When interlayer slippage occurs between the layers 12A, 12B, and 12C due to bending, the end of the fiber-reinforced resin member 22 becomes inclined with respect to the stacking direction. The occurrence of such interlayer slippage suppresses the occurrence of warping in areas other than the bent part.

The thickness of the fiber-reinforced resin member 12 is not particularly limited and can be selected according to the application, required mechanical properties, etc. For example, it is 2.0 to 9.0 mm.

The shape of the fiber-reinforced resin member 12 is not particularly limited, and may be any shape, such as a plate, strip, rod, column, pipe, or a shape having an irregular cross section such as a T-shape.

<Buckling suppression member>
The buckling suppression member 18 has a structure in which a metal layer 16 and an adhesive layer 14 are laminated together. The buckling suppression member 18 is attached to the fiber reinforced resin member 12 by the adhesive layer 14 so as to be disposed on at least the compression side of the portion of the fiber reinforced resin member 12 that is to be bent.
The buckling suppression member 18 may have at least one metal layer 16 and at least one adhesive layer 14 laminated thereon, and may have a structure in which two or more metal layers 16 and two or more adhesive layers 14 are alternately laminated thereon (a total of four or more layers).

(Metal Layer)
The metal layer 16 significantly affects the rigidity of the buckling suppression member 18 and the shape retention after bending. From this viewpoint, it is preferable that the metal layer 16 is a layer that undergoes plastic deformation when bent together with the laminated adhesive layer 14, causing the buckling suppression member itself to undergo plastic deformation.
Moreover, the metal layer 16 preferably has a bending stiffness per unit width (mm) of 500 Nmm or more from the viewpoint of suppressing buckling of the fiber reinforced resin member 12 when bending the composite member 10. If the bending stiffness per unit width of the metal layer 16 is too high, bending becomes difficult, so the bending stiffness per unit width of the metal layer 16 is preferably 1500 Nmm or less.
The bending rigidity per unit width of the metal layer 16 can be calculated from the following formulas (1) and (2) by measuring the Young's modulus through a tensile test based on JIS Z2241:2011.

The metal material constituting the metal layer 16 is not particularly limited, but is preferably a metal layer containing at least one of copper, aluminum, and stainless steel from the viewpoints of rigidity, bending workability, material cost, etc. For example, the metal layer containing aluminum may be a metal layer of an aluminum alloy.
The metal layer 16 may be made of a shape memory alloy. By bending the composite member 10, the buckling suppression member 18 is also bent together with the fiber reinforced resin member 12. If the metal layer 16 is made of a shape memory alloy, the buckling suppression member 18 that has been peeled off from the composite member 10 after bending can be easily returned to its shape before bending by heating, and can be used repeatedly.

The thickness of the metal layer 16 depends on the material, but from the standpoint of suppressing buckling when bending the composite member 10, preventing peeling, ease of bending, and shape retention after bending, for example, when an aluminum material is used as the metal layer 16, the thickness can be 0.05 to 1.2 mm.
The buckling suppression member 18 may be, for example, an aluminum tape in which an aluminum layer and an adhesive layer are laminated. When the buckling suppression member 18 includes two or more metal layers, the total thickness of the metal layers may be within the above range.

(Adhesive layer)
The adhesive layer 14 constitutes the buckling suppression member 18 together with the metal layer 16, and is a layer that is peelably adhered to the fiber-reinforced resin member 12. The adhesive layer 14 may be composed of an adhesive alone, or may be composed of multiple layers of an adhesive and a substrate, but is preferably elastic from the viewpoint of bending processing. Examples of materials that constitute the adhesive layer 14 include adhesives such as rubber, elastomers, acrylic adhesives, urethane adhesives, and silicone adhesives. Examples of substrates include resin films such as polypropylene, polyethylene terephthalate, polyvinyl chloride, and polyimide, as well as nonwoven fabrics and foams.
Furthermore, the adhesive layer 14 may be, for example, a layer that contains a resin that adheres to the fiber-reinforced resin member 12 and a foaming agent, and that can be peeled off from the fiber-reinforced resin member 12 by heating and foaming after bending processing.

The thickness of the adhesive layer 14 varies depending on the material and configuration, but may be 0.1 mm to 2 mm from the viewpoints of buckling suppression, peeling prevention, ease of bending, shape retention after bending, etc. of the fiber reinforced resin member 12 when bending the composite member 10. When the buckling suppression member 18 includes two or more adhesive layers in which the metal layers 16 and the adhesive layers 14 are alternately laminated, the total thickness of the adhesive layers may be within the above range, but it is preferable that the thickness of the adhesive layer in direct contact with the fiber reinforced resin member 12 is 0.1 to 2 mm.
In addition, from the viewpoints of suppressing buckling of the fiber reinforced resin member 12, preventing peeling, and ease of bending, it is preferable that the adhesive layer 14 has an elastic modulus of 500 MPa or less.
The elastic modulus of the adhesive layer 14 is measured as the tensile elastic modulus using a universal testing machine in accordance with JIS Z7127:1999 Plastics-Test methods for tensile properties-Part 3: Test conditions for films and sheets.

The buckling suppression member 18 is attached to the fiber reinforced resin member 12 by the adhesive layer 14 so as to be disposed on at least the compression side of the portion of the fiber reinforced resin member 12 that is to be bent.
1 and 2, when the fiber reinforced resin member 12 is in a plate shape, the buckling suppression member 18 may be attached to both sides or one side of the fiber reinforced resin member 12. In addition, the buckling suppression member 18 may be provided on the entire surface of both sides or one side of the fiber reinforced resin member 12, or may be attached to a part of the fiber reinforced resin member 12 including a portion that is to be bent.
When the portion of the fiber reinforced resin member 12 to be bent is predetermined, the buckling suppression member 18 may be attached to the compression side of the portion of the fiber reinforced resin member 12 to be bent.
Furthermore, in the case of a composite member 10 in which buckling suppression members 18 are attached to both sides of the fiber-reinforced resin member 12, the position and bending direction of the fiber-reinforced resin member 12 are not limited, improving workability and effectively suppressing not only buckling but also warping of the fiber-reinforced resin member 12 during bending.

The buckling suppression member 18, in which the metal layer 16 and the adhesive layer 14 are laminated, may be attached to the fiber-reinforced resin member 12 by the adhesive layer 14, or after the adhesive layer 14 is attached to the fiber-reinforced resin member 12, a metal plate as the metal layer 16 may be attached to the adhesive layer 14. For example, in the former case, an aluminum adhesive tape in which the aluminum layer and the adhesive layer are integrated may be used, and in the latter case, an aluminum plate may be attached to the fiber-reinforced resin member via a double-sided adhesive tape. Examples of the adhesive layer 14 include acrylic double-sided tape, urethane double-sided tape, and silicone double-sided tape. Examples of commercially available adhesive layers include Nitto HYPERJOINT (registered trademark) series manufactured by Nitto Denko Corporation, Adhesive Transfer Tape 468MP manufactured by 3M Japan Co., Ltd., and Kapton (registered trademark) double-sided tape 760H #25 manufactured by Teraoka Seisakusho Co., Ltd.
The number of layers of metal layers 16 and adhesive layers 14 in buckling suppression member 18 is not limited, and a buckling suppression member having increased rigidity by, for example, laminating two or more sheets of aluminum adhesive tape may be used.

The adhesive strength between the fiber-reinforced resin member and the buckling suppression member is preferably 4 N/mm or less. If the adhesive strength between the fiber-reinforced resin member and the buckling suppression member is 4 N/mm or less, the buckling suppression member can be easily peeled off and removed after bending the composite member into a specified shape.

If the adhesive strength between the fiber-reinforced resin member and the buckling suppression member is too small, the material may peel off at the bending section during bending, making it easier for buckling to occur on the compression side. Therefore, it is preferable that the adhesive strength between the fiber-reinforced resin member and the buckling suppression member be 1.0 N/mm or more.

Figure 5 is a schematic diagram showing a method for measuring the adhesive strength between a fiber-reinforced resin member and a buckling suppression member in a composite member. The buckling suppression member 18 is peeled off from the fiber-reinforced resin member 12 near the end of the test sample S of the composite member 10, and a circular hole 19 is made in the peeled-off portion of the buckling suppression member 18. Both sides of the test sample S are clamped and fixed with a fixing jig 44 so that the test sample S is horizontal. The hook 42 of the tensile tester is hung on the hole 19 of the buckling suppression member 18 and pulled vertically to measure the load at which peeling occurs from the fiber-reinforced resin member 12, and the maximum load at the time of peeling is calculated as the adhesive strength (N/mm) per unit length (mm) in the width direction of the sample S.

The buckling suppression member may have a reinforcing layer in addition to the metal layer and the adhesive layer. The reinforcing layer is, for example, a woven or nonwoven fabric made of glass fiber, and is disposed between the metal layer and the adhesive layer.

In addition, the composite member 10 preferably has a bending rigidity of 2.0×10 ⁵ Nmm ² or less at the bending temperature. When the composite member 10 is in a state in which the fiber reinforced resin member 12 and the buckling suppression member 18 are integrated, if the bending rigidity of the composite member 10 at the bending temperature is 2.0×10 ⁵ Nmm ² or less, the composite member 10 is easy to bend manually. The bending rigidity of the composite member 10 can be adjusted, for example, by the material and thickness of the metal layer 16. The bending rigidity of the composite member 10 is calculated from the following formula (3) by performing a three-point bending test (Method A) at the test processing temperature using a universal testing machine based on JIS K7074:1988.

[Bending process]
After obtaining the composite member 10, the heated composite member 10 is bent so that at least a portion of the buckling suppression member 18 is bent on the compression side of the portion where the fiber reinforced resin member 12 is bent.
The means for performing the bending process is not particularly limited, and may be manual bending or batch processing using a mold. Continuous mechanical processing such as roll forming is also possible, and for example, the bending angle may be changed continuously from the beginning to the end of processing. When performing manual bending, for example, as shown in FIG. 2, the compressed side of the portion of the composite member 10 to be bent is pressed against a jig 30, and the vicinity of both ends of the composite member 10 is pressed by hand from the opposite side to apply a force F to perform bending. This allows bending to a predetermined angle at a predetermined position. In either case, the composite member 10 is bent in a state in which the buckling suppression member 18 is arranged at least on the compressed side of the portion where the fiber reinforced resin member 12 is bent when bending the composite member 10.

Figure 6 shows a schematic example of bending the composite member 10 of the present disclosure into a V-shape using a die. The die is composed of a combination of a die (lower die) 32 having a V-shaped recess and a punch (upper die) 34 having a V-shaped protrusion that fits into the recess of the die 32. The composite member 10 of the present disclosure is placed on the die 32, and the punch 34 is pressed against it to bend the composite member 10. When the buckling suppression member 18 is disposed on only one side of the fiber-reinforced resin member 12, the composite member 10 is disposed on the die 32 so that the buckling suppression member 18 faces the punch 34.

The bending process is performed in a heated state of the composite member 10. The bending process is preferably performed in a state in which the fiber reinforced resin member 12 is heated to a temperature equal to or higher than the glass transition temperature (Tg) of the thermoplastic resin that is the matrix resin, more preferably within a range of Tg+10 to Tg+120°C, even more preferably Tg+50 to Tg+100°C, and most preferably Tg+60 to Tg+90°C.
The composite material 10 may be preheated with an oven or a heat gun before bending, or the bending may be performed while the dies 32, 34 are heated.

Regardless of the bending method, from the viewpoint of suppressing buckling of the fiber reinforced resin member 12 by bending, it is preferable to bend the composite member 10 in which the fiber reinforced resin member 12 and the buckling suppression member 18 are integrated with each other at a radius of curvature of 5.0 mm or more while being heated to a temperature equal to or higher than the glass transition temperature (Tg) of the thermoplastic resin contained in the fiber reinforced resin member 12. There is no particular upper limit to the radius of curvature, but the effect of the present invention is more pronounced if it is less than 1000 mm.

[Removal process]
The buckling suppression member 18 is removed from the bent composite member 10. By removing the buckling suppression member 18 from the composite member 10 after bending, a fiber-reinforced resin member 22 in which buckling is suppressed in the bent portion can be obtained.
For example, after bending, the adhesive layer 14 attached to the fiber reinforced resin member 22 is peeled off from the fiber reinforced resin member 12 to remove the entire buckling suppression member 18 together with the metal layer 16. When peeling, the adhesive layer 14 may be softened by heating to a temperature below the Tg of the matrix resin of the fiber reinforced resin member 22, or may be cooled to a subzero temperature to facilitate peeling.

[Other processes]
The method for processing a fiber-reinforced resin member according to the present disclosure may include other steps, such as a step of cutting the fiber-reinforced resin member into a desired shape or a step of cleaning the fiber-reinforced resin member after the removing step.

The processing method for fiber-reinforced resin members according to the present disclosure suppresses buckling in the bent portion of the fiber-reinforced resin member. Therefore, it is possible to manufacture a fiber-reinforced resin member in which the bending strength of the processed fiber-reinforced resin member is maintained at 80% or more of the bending strength before processing.

The processing method for fiber-reinforced resin members and composite members according to the present disclosure will be described in more detail below with reference to examples. However, the present disclosure is not limited to the following examples.

Fig. 7 is a schematic diagram showing an example of the structure of a composite member manufactured in the examples. The fiber-reinforced resin member 12 in the composite member 100 shown in Fig. 7 is a carbon fiber-reinforced resin plate (CFRP) having a structure in which three unidirectional fiber-reinforced resin layers 12A, 12B, and 12C are laminated by laminating prepregs so that the fiber directions are 90°, 0°, and 90°, respectively, with respect to the longitudinal direction X. Buckling suppression members 18A and 18B, each of which is composed of an adhesive layer and a metal layer, are attached to both sides of the carbon fiber-reinforced resin plate 12.
The materials used in the examples will be described.

<Fiber reinforced resin member>
[Epoxy resin]
A1: Bisphenol A type liquid epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., YD-128)
[Phenol compounds]
B1: Bisphenol A (manufactured by Nippon Steel Chemical & Material Co., Ltd.)
[Polymerization catalyst]
C1: Tri-o-tolylphosphine (manufactured by Hokko Chemical Industry Co., Ltd., trade name: TOTP (registered trademark))
[Reinforced fiber substrate]
E1: PAN-based carbon fiber (Toray Industries, Inc., T700SC-12K-60E)

<Buckling suppression member>
(Metal Layer)
Aluminum plate: A5052, 0.5 mm thick

(Adhesive layer)
Acrylic double-sided tape (manufactured by Nitto Denko Corporation, product name: Nitto HYPERJOINT (registered trademark) H9004, thickness: 0.4 mm)

(metal layer + adhesive layer)
Aluminum tape (Maxell, product name: SLIONTEC No. 8172, thickness: 0.3 mm)

(others)
Glass cloth tape (manufactured by 3M Japan Ltd., product name: Glass Cloth Tape 79, thickness: 0.18 mm)

<Production of fiber reinforced resin member>
A precursor composition (F1) was obtained by kneading 1 part by mass of a cyclohexanone solution in which 188 parts by mass of A1, 112 parts by mass of B1, and 1 part by mass of C1 were dissolved, using a planetary mixer.
Using a reverse roll coater type resin coating device, the precursor composition (F1) was uniformly coated on a silicone-coated release paper at a coating temperature of 40°C to obtain a precursor composition (F1) film with a resin basis weight of 35 g/ ^m2 , a width of 1 m and a length of 100 m.

Next, a reinforcing fiber substrate (E1) in which the reinforcing fibers were aligned in one direction was prepared, and the substrate was sandwiched between films of the precursor composition (F1) on both sides and impregnated with heat and pressure through a press roll at a temperature of 100°C and a linear pressure of 20 kg/cm to produce an in-situ polymerized phenoxy resin prepreg (G1).

A three-layer laminate with a thickness of 5 mm was produced, with the outer layer being an in-situ polymerized phenoxy resin prepreg (G1) laminated so that the fiber direction was 90° to the longitudinal direction and the thickness was 1.0 mm, and the inner layer being laminated so that the fiber direction was 0° to the longitudinal direction and the thickness was 3.0 mm.

This three-layer laminate structure was cut to a size of 300 mmL×16 mmW to prepare a beam-shaped fiber-reinforced resin member as a test sample.
The Tg of the resin of the fiber reinforced resin member was 103°C.

Example 1
(Preparation of composite members)
A composite member was produced by attaching three layers of aluminum tape as a buckling suppression member to one side of a fiber-reinforced resin member.

(Hand bending)
The composite member was preheated for 15 minutes in a thermostatic chamber set at 140° C., and then both ends of the composite member were pressed by hand against a round bar bending jig while the central portion of the composite member on the aluminum tape side was placed in contact with the jig, and the composite member was bent until the bending angle α (the angle after bending with respect to the horizontal shape before bending) became 30 degrees, as shown in FIG. 8 .

(Removal of buckling suppression members)
After the manual bending process, the aluminum tape was entirely peeled off to obtain a bent fiber reinforced resin member 22 .

Example 2
A composite member was produced by attaching a buckling suppression member, which was made of three layers of aluminum tape, to both sides of a fiber-reinforced resin member. After manually bending the composite member in the same manner as in Example 1, all of the aluminum tape was peeled off from both sides of the fiber-reinforced resin member to obtain a bent fiber-reinforced resin member.

Example 3
A composite member was produced by attaching an aluminum plate as a buckling suppression member to one side of a fiber-reinforced resin member via an acrylic double-sided tape. The central part of the aluminum plate side of the composite member was placed against a round bar bending jig and hand-bent in the same manner as in Example 1. The acrylic double-sided tape was then peeled off together with the aluminum plate from the fiber-reinforced resin member to obtain a bent fiber-reinforced resin member.

Example 4
A composite member was produced by attaching aluminum plates as buckling suppression members to both sides of a fiber-reinforced resin member via acrylic double-sided tape. After manually bending the composite member in the same manner as in Example 1, the acrylic double-sided tape was peeled off together with the aluminum plates from both sides of the fiber-reinforced resin member to obtain a bent fiber-reinforced resin member.

Comparative Example 1
A bent fiber-reinforced resin member was obtained by performing manual bending in the same manner as in Example 1, except that the bending was performed without attaching a buckling suppression member to the fiber-reinforced resin member.

Comparative Example 2
The manual bending process was performed in the same manner as in Example 1, except that five layers of glass cloth tape were stacked and attached to one side of the fiber reinforced resin member instead of the buckling suppression member made of three layers of aluminum tape, and then the glass cloth tape was peeled off to obtain a bent fiber reinforced resin member.

[evaluation]
The fiber-reinforced resin members after bending were visually evaluated for buckling, warping, and interlayer misalignment. In addition, the ratio of strength after bending to strength before bending (bending strength retention rate) was measured.

(Anti-buckling)
The presence or absence of convex buckling on the compression side of the bent portion of the fiber reinforced resin member was confirmed.
◯: No buckling ×: Buckling

(Anti-warping)
The presence or absence of warping in the portions other than the bent portion of the fiber-reinforced resin member was confirmed. When a straight member without warping was placed on the unprocessed portion of the tensile side (the side where tensile stress was applied) of the bent portion of the fiber-reinforced resin member and the gap between the straight member and the bent portion was 1 mm or less, it was determined that warping was suppressed.
◯: No warping △: Warping is suppressed ×: Warping is not suppressed

(Interlayer slippage)
The presence or absence of misalignment between layers at the ends of the fiber-reinforced resin member was confirmed. If the three layers of the fiber-reinforced resin member were misaligned and the ends were inclined linearly in the thickness direction, it could be said that the layers were uniformly misaligned and the bending process was ideal.
○: There is a misalignment between layers ×: There is no misalignment between layers

The fiber reinforced resin member was subjected to bending processing by manually pressing it against a bending jig under the following conditions, and evaluation was performed.
Preheat temperature: 140°C
Bending jig radius: 15 mm
Bending angle: 45°
The constituent materials, physical properties, and evaluation results of the buckling suppression member and the composite member are shown in Table 1. The physical properties (flexural rigidity, adhesive strength, elastic modulus) were measured by the methods described above.

Buckling occurred in both Comparative Examples 1 and 2. It is believed that the glass cloth tape used in Comparative Example 2 had almost no rigidity, which is why buckling occurred.
In all of Examples 1 to 4, buckling did not occur.
In Examples 1 and 3, in which a buckling suppression member consisting of three layers of aluminum tape or a buckling suppression member consisting of a combination of acrylic double-sided tape and an aluminum plate was attached to one side (the compression side of the bending process) of the fiber-reinforced resin member, the occurrence of warping was suppressed. In particular, in Examples 2 and 4, in which the members were attached to both sides of the fiber-reinforced resin member, no warping occurred and they were the most effective.

(Strength retention rate)
For the structure of Example 4, after bending, the specimen was bent back to a flat plate to remove the aluminum plate, and then a three-point bending test was carried out to confirm the strength and elastic modulus. The results are shown in Figure 9. The elastic modulus was maintained at almost 100% of the value before bending under all processing conditions.
On the other hand, the strength tends to decrease as the bending angle increases. When the CFRP alone (without aluminum) of Comparative Example 1 was bent to a bending angle α of 45°, the strength decreased to less than 80% of the strength before bending. However, in the case of the composite member, the strength was maintained at 80% or more of the strength before bending, even when bent to a bending angle α of 45°.

<Press V-bend test>
As shown in Fig. 10, a V-shaped (90°) bending test was carried out on a CFRP alone (Comparative Example 3) and a composite member (Example 5) in which aluminum plates were attached to both sides of a CFRP with acrylic double-sided tape, using a mold with an upper mold (bending compression side) having a curvature radius (r) of 9.0 mm and a lower mold (bending tension side) having a curvature radius (r) of 10.0 mm. Each test specimen was a CFRP measuring 90 mm long x 55 mm wide x 5 mm thick.

The V-shaped (90°) bending process was performed by simply applying the weight of the upper die without using the mechanism of the press machine to control the load, and a spacer with a thickness slightly larger than that of the test specimen was used to prevent the molded product from being crushed more than necessary in the thickness direction, which would result in the buckling area being flattened.
After the pressing, the mold was immediately cooled and the test specimen was demolded. In Example 5, in which a composite member was used as the test specimen, the acrylic double-sided tape was all peeled off together with the aluminum plate after demolding to obtain a bent CFRP.
Each bent CFRP was observed for the presence or absence of buckling, interlayer misalignment, and warping.
The results are shown in Table 2.

As shown in Table 2, in Comparative Example 3 in which the CFRP alone was subjected to press V-bending, buckling occurred, there was almost no misalignment between the layers, and warping occurred.
On the other hand, in Example 5, in which a composite material having buckling suppression members attached to both sides of the CFTP was subjected to press V-bending, processing accuracy was improved by preventing buckling, misalignment between layers, and warping, and the appearance was also improved.

10 Composite member 12A, 12B, 12C Unidirectional fiber reinforced resin layer 12 Fiber reinforced resin member 14 Adhesive layer 16 Metal layer 18 Buckling suppression member 22 Fiber reinforced resin member (after bending)

Claims (7)

A method for bending a fiber-reinforced resin member containing a thermoplastic resin and reinforcing fibers, comprising:
obtaining a composite member in which a buckling suppression member having a laminated structure of a metal layer and an adhesive layer peelable from the fiber reinforced resin member is attached to the fiber reinforced resin member by the adhesive layer;
Bending the heated composite member such that at least a portion of the buckling suppression member is bent on the compression side of the portion of the fiber reinforced resin member that is bent;
removing the buckling restraint member from the bent composite member;
A method for processing a fiber-reinforced resin member comprising the steps of: The method for processing a fiber-reinforced resin member according to claim 1, wherein the adhesive layer has a thickness of 2 mm or less, and the metal layer has a thickness of 0.05 mm or more. The method for processing a fiber-reinforced resin member according to claim 1, wherein in the step of bending the composite member, the composite member is bent with a radius of curvature of 5.0 mm or more while being heated to a temperature equal to or higher than the glass transition temperature of the thermoplastic resin. The method for processing a fiber-reinforced resin member according to claim 1, wherein the adhesive strength between the fiber-reinforced resin member and the buckling suppression member in the composite member is 4 N/mm or less. The method for processing a fiber-reinforced resin member according to claim 1, wherein the metal layer is a metal layer containing at least one of copper, aluminum, and stainless steel. The method for processing a fiber-reinforced resin member according to any one of claims 1 to 5, wherein the thermoplastic resin is an amorphous thermoplastic resin having a glass transition temperature of 60°C or higher. A fiber reinforced resin member containing a thermoplastic resin and reinforcing fibers;
A buckling suppression member having a laminated structure of a metal layer and an adhesive layer that is peelable from the fiber reinforced resin member, and attached to the fiber reinforced resin member by the adhesive layer;
A composite member used in the method for processing a fiber-reinforced resin member according to claim 1.