JP2010143009A - Plate-like composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plate-like metal/plastic composite material which exhibits excellent durability even in an environment wherein a low temperature or a high temperature is repeated. <P>SOLUTION: In the composite material, a plate-like fiber-reinforced plastic material containing fibers at least 10 mm in length in a thermosetting resin is jointed to the surface of a plate-like metallic material through a thermoplastic resin adhesive layer. When the average thickness of the plate-like metallic material is t<SB>M</SB>(mm), the average thickness of the adhesive layer is t<SB>C</SB>(mm), and the elongation of the thermoplastic resin constituting the adhesive layer is δ(%), the following formulas (1) and (2) are satisfied: (1) t<SB>C</SB>×δ≥0.16 and (2) t<SB>C</SB>/t<SB>M</SB>≥0.01. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plate-like composite material in which a plate-like metal material and a plate-like fiber reinforced plastic material are joined with an adhesive.

  A composite material made by joining metal and fiber reinforced plastic can greatly improve the specific strength (tensile strength / specific gravity ratio) compared to the case of a single metal material. It is becoming widespread as a structural member for ships and the like.

  Known fiber-reinforced plastics include those obtained by dispersing and blending short fibers in a matrix of a resin composition, and those obtained by embedding long fibers in a resin. There are various types of fibers depending on the application, but carbon fibers and glass fibers are typical examples of fibers having excellent strength characteristics. The plate-like fiber reinforced plastic material using such high-strength fibers has a very high strength and is particularly advantageous for improving the specific strength of the plate-like metal material.

  Patent Document 1 describes a light metal / CFRP hybrid structural material in which light metal and fiber reinforced plastic are integrated with an adhesive to improve corrosion resistance, strength and impact energy absorption performance. Patent Document 2 describes a multilayer laminate having excellent corrosion resistance, impact resistance, and vibration damping properties, in which a fiber reinforced plastic based on a thermoplastic resin is laminated on a metal plate. Patent Document 3 describes a high-strength metal-resin composite structure in which a metal and a fiber-reinforced plastic are joined via a foamed resin.

WO99 / 10168 republication gazette Japanese Patent Laid-Open No. 6-115007 JP 2007-196545 A

  Conventionally, when a metal / fiber reinforced plastic is bonded with an adhesive to form a metal / plastic composite material, it is common to use a thermosetting resin such as an epoxy resin for the adhesive. The thermosetting resin is hard and has high strength, which is advantageous in improving the strength level of the composite material. However, metal / plastic composite materials applied to uses such as automobile parts are often used in an environment (low temperature / high temperature repeat environment) in which they are repeatedly exposed to low temperatures (normal temperatures) and high temperatures. According to the investigation by the inventors, when a conventional metal / plastic composite material is applied to a member or a body member in an engine room of an automobile, material deformation or peeling between the metal / plastic occurs due to repeated low and high temperature environments. I found out there was a fear. The reason for this is that there is a large difference in the coefficient of thermal expansion between the metal and the resin. The short-term use of racing cars, etc. can achieve the purpose of reducing the weight and increasing the strength of conventional metal / plastic composite materials. However, when applied to ordinary passenger cars, etc., it must withstand long-term use and is durable. I have anxiety in terms of sex.

  On the other hand, as shown in Patent Document 3, when metal and plastic are joined with foamed resin, deformation does not occur in heating and cooling during joining. However, when applied to a part where the temperature rising / falling cycle frequently occurs in a short cycle, such as the interior of an automobile, stress due to the difference in thermal expansion characteristics between the metal and the plastic is repeatedly applied to the foamed resin layer, There is a concern that the foamed resin layer may cause a decrease in strength due to deterioration over time. Further, the foamed resin layer becomes thick in order to foam the resin, and it becomes difficult to apply it to a site where a thin material is required.

  An object of the present invention is to provide a plate-like metal / plastic composite material that exhibits excellent durability even in a low temperature / high temperature repeated environment.

  As described above, material deformation and delamination between metal and plastic, which are problematic when metal / plastic composite materials are used in low-temperature and high-temperature repeated environments, are mainly caused by the difference in thermal expansion between metal and plastic. . As a result of detailed studies, the inventors used a thermoplastic resin having a good elongation rate as an adhesive for joining metal and plastic, and secured a product of the elongation rate and the thickness of the adhesive layer above a certain level. At the same time, by increasing the thickness of the adhesive layer according to the plate thickness of the metal material, the strain caused by the difference in thermal expansion between the metal and plastic can be bonded while maintaining the high strength required as a composite material. It was found that it can be absorbed in the agent layer. The present invention has been completed based on such findings.

That is, in the present invention, a plate-like fiber reinforced plastic material containing fibers having a length of 10 mm or more in a thermosetting resin is bonded to the surface of the plate-like metal material via a thermoplastic resin adhesive layer. The composite material, wherein the average thickness of the plate-like metal material is t _M (mm), the average thickness of the adhesive layer is t _C (mm), and the elongation of the thermoplastic resin constituting the adhesive layer is δ (% ), A plate-shaped composite material satisfying the following formulas (1) and (2) is provided.
t _C × δ ≧ 0.16 (1)
t _C / t _M ≧ 0.01 (2)

Here, the plate-like composite material may have a structure in which one plate-like metal material and one piece of plate-like fiber reinforced plastic material are joined, or plate-like fiber reinforced plastic on both sides of one plate-like metal material. A sandwich structure in which materials are joined or a structure in which a plurality of plate-like metal materials and a plurality of plate-like fiber reinforced plastic materials are alternately laminated can also be employed. In the case of a structure having a plurality of adhesive layers and metal material layers, the total thickness of each layer may be adopted as t _C and t _{M in the} formulas (1) and (2). Further, in the case of a structure having a plurality of adhesive layers, when the value of the elongation δ of the resin constituting each adhesive layer is different, a value obtained by calculating t _C × δ for each adhesive layer and totaling them May be adopted as the value on the left side of equation (1).

  As the plate-like fiber reinforced plastic material, it is particularly effective to use a material having a tensile strength of 2000 MPa or more. For example, a prepreg sheet obtained by flattening a long fiber bundle made of carbon fibers with a binder of a thermosetting resin composition is used as a raw material, and the thermosetting resin is cured. In many cases, the plate-like fiber-reinforced plastic material has anisotropy in strength characteristics depending on the orientation of the fibers. Here, “the tensile strength is 2000 MPa or more” means that the value when the tensile test is performed in the direction in which the maximum tensile strength is obtained may be 2000 MPa or more.

  The ratio of the average thickness of the plate-like fiber reinforced plastic material occupying the plate thickness of the composite material (the average value of the total thickness in the case of having a plurality of layers of plate-like fiber reinforced plastic material) is 60 to 80%, adhesion It is more preferable that the ratio of the average thickness of the agent layer (in the case of having a plurality of adhesive layers, the average value of the total thickness) is less than 10%.

  According to the present invention, in a composite material obtained by joining a plate-like metal material and a plate-like fiber reinforced plastic material, the durability in a low-temperature / high-temperature repeat environment is remarkably ensured while ensuring the original specific high strength. An improvement was realized. Therefore, this composite material can be applied not only to special applications such as racing cars, but also to general automobiles (utility vehicles) that require long-term durability.

  FIG. 1 schematically shows a cross-sectional structure of the plate-shaped composite material of the present invention. The plate-like metal material 1 and the plate-like fiber reinforced plastic material 2 are joined together via the adhesive layer 3, and they are integrated to form a plate-like composite material 10. In FIG. 1, the thickness of the adhesive layer 3 is exaggerated. Here, the plate-like composite material 10 in which the plate-like fiber reinforced plastic material 2 is joined to one side of the plate-like metal material 1 is illustrated, but the plate-like fiber reinforced plastic material 2 is joined to both sides of the plate-like metal material 1, A plate-like composite material 10 having a sandwich structure in which the plate-like metal material 1 is bonded to both surfaces of the plate-like fiber reinforced plastic material 2 can also be constructed. Further, the plate-like metal material 1 and the plate-like fiber reinforced plastic material 2 may be alternately laminated and joined.

[Plate metal material]
As the plate-like metal material used for the composite material of the present invention, various metal materials such as a steel plate, a copper alloy plate, and an aluminum alloy plate can be considered depending on the application. Examples of the steel plate include general plain steel plates, high-tensile steel plates, various plated steel plates using these steel plates as plating base plates, and stainless steel plates.

Among them, the hot-dip Zn-Al-Mg-based steel sheet is superior in corrosion resistance compared to conventional galvanized steel sheets, and has a great effect of suppressing peeling between metal / fiber reinforced plastics caused by corrosion even in severe corrosive environments. . The following can be illustrated as a plating layer composition of a hot-dip Zn-Al-Mg based steel sheet.
(Plating layer composition); by mass: Al: 3-22%, Mg: 0.5-8%, Ti: 0.1% or less, B: 0.05% or less, Si: 2% or less And the total content of Ca, Sr, Na, Ni, Co, Sn, Cu, Cr, Mn, rare earth elements, Y, Zr is limited to 1% or less (including 0%), The content of Fe is limited to 2.5% or less, and the plating layer is composed of the balance Zn and inevitable impurities. In this case, it is effective that the coating adhesion amount is about ²⁰ to 300 g / m ² per one side of the steel sheet.

  As the stainless steel plate, for example, an existing steel type having a composition corresponding to a steel type specified in JIS G4305: 2005 can be adopted. Specifically, SUS304 type which is an austenitic general-purpose steel type, SUS430 type which is a ferritic general-purpose steel type, and the like can be mentioned. In addition, as a steel type not corresponding to JIS, for example, in the case of austenite, in the austenitic steel type described in Table 2 of JIS G4305: 2005, the content of the components specified in Table 2 is satisfied, and B : One or more of 0.05% or less, V: 0.5% or less, Zr: 0.5% or less, Al: 0.5% or less, Cu: 3% or less, N: 0.5% or less And a steel type in which the total content of Ca, Mg, Y and REM is 0 to 0.01%, and the balance is Fe and inevitable impurities. In the case of a ferrite type, in the ferritic steel types described in Table 4 of JIS G4305: 2005, the content of the components specified in Table 4 is satisfied, and further B: 0.05% or less and V: 0.00% in mass%. 5% or less, Al: 0.5% or less, Cu: 1% or less, the total content of Ca, Mg, Y, REM is 0 to 0.01%, the balance is Fe and The steel grade which is an unavoidable impurity is mentioned.

  Further, by subjecting the plate-shaped metal material to a chemical conversion treatment, the adhesiveness with the adhesive is improved, and a higher strength composite material can be obtained. In particular, in the case of a steel plate, an effect of suppressing peeling between the metal plate and the long fiber reinforced plastic plate due to improved corrosion resistance is also expected. Chemical conversion coatings include organic coatings, chromates, urethane and acrylic resins containing inorganic rust inhibitors such as chromates, titanium salts, phosphates, silane coupling agents and silica sols, An inorganic chemical conversion treatment film in which an additive such as a silane coupling agent or silica sol is blended with an inorganic component such as titanium salt or phosphate can be applied. In particular, a chemical conversion coating such as titanium salt containing valve metal is extremely effective in improving the corrosion resistance of a steel sheet, and good corrosion resistance is exhibited even in a composite material.

[Plate fiber reinforced plastic material]
As the plate-like fiber reinforced plastic material to be joined to the plate-like metal material, a short fiber having a length of 10 mm or more or a material containing a long fiber in a thermosetting resin is applied. Here, the “long fiber” is a fiber continuously connected from one end to the other end of each plate-like fiber reinforced plastic material to be bonded to the plate-like metal material. On the other hand, “short fiber” is a fiber having a terminal portion inside a plate-like fiber reinforced plastic material. A fiber reinforced plastic material consisting only of short fibers having a fiber length of less than 10 mm tends to be insufficient for the purpose of remarkably improving the specific strength of the metal material, and is not suitable for the present invention.

  Examples of fiber types include inorganic fibers such as carbon fibers, graphite fibers, silicon carbide fibers, alumina fibers, boron fibers, and glass fibers, and organic fibers such as aramid fibers, ultrahigh molecular weight polyethylene fibers, and high-strength polyacrylate fibers. It is done.

  A thermosetting resin is employed as the type of plastic. Examples thereof include resins such as epoxy, melamine, phenol, and copolymers thereof. In a fiber reinforced plastic using a thermal “plastic” resin, when an impact is applied at a high temperature, the resin is softened, so that the fiber is not sufficiently fixed and sufficient strength cannot be obtained. For this reason, in this invention, it is necessary to use the fiber reinforced plastic material which fixed the fiber with the thermosetting resin.

  When short fibers are used, a plate-like fiber-reinforced plastic material can be obtained by a method in which short fibers are dispersed in a resin composition, then formed into a sheet and cured by heat treatment. When long fibers are used, it is preferable to use a “prepreg sheet” in which a long fiber bundle is previously flattened with a binder of a thermosetting resin composition. Among them, a prepreg sheet obtained by flattening a long fiber bundle of carbon fibers by impregnating with a liquid of a thermosetting resin composition is preferable. In this case, the carbon long fibers may be oriented in one direction, or may be a woven fabric in which the fibers are oriented in the warp direction and the weft direction.

  Production of a plate-like fiber reinforced plastic material using a prepreg sheet is relatively simple. That is, when the thermosetting resin composition impregnated in the prepreg sheet is cured by heating, a plate-like fiber reinforced plastic material can be immediately formed. One prepreg sheet may be used as it is, or a plurality of prepreg sheets laminated may be integrated by hot pressing. If necessary, the amount ratio of the thermosetting resin to the fiber can be adjusted by adding the thermosetting resin composition before the curing treatment.

  As the plate-like fiber reinforced plastic material, a material having a high strength sufficient to improve the specific strength of the metal material that is a bonding partner is applied. As a result of various studies, those exhibiting a tensile strength of 2000 MPa or more in a certain direction are preferable. If it has an extremely high tensile strength in at least one direction, deformation when subjected to an impact from the outside is suppressed, and for example, in a body use of an automobile, the resistance to dents is significantly increased. The strength of the plate-like fiber reinforced plastic material can be controlled mainly by the orientation direction of the fibers and the ratio of the fibers in the resin. The average thickness of the plate-like fiber reinforced plastic material can be adjusted within a range of about 0.1 to 10 mm, for example.

[Adhesive layer]
An adhesive made of a thermoplastic resin is applied to join the plate-like metal material and the plate-like fiber reinforced plastic material. Examples of the resin include polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyvinyl acetate, acrylic, polyphenylene sulfide polycarbonate, polyethersulfone, polyamide, polybutylene terephthalate, and copolymers thereof. Among them, ethylene vinyl alcohol-vinyl acetate copolymers having a polar group such as a hydroxy group and a carboxyl group in the skeleton, and polyethylene terephthalate and polybutylene terephthalate which are condensates of polyvalent carboxylic acids and polyalcohols. Is particularly excellent in adhesion to metals and plastics.

The adhesive layer composed of this adhesive serves to join the plate-like metal material and the plate-like fiber reinforced plastic material, and has a role of absorbing strain caused by the difference in thermal expansion between the two. Plastic has a larger coefficient of thermal expansion than metal materials. The adhesive layer has sufficient thickness to sufficiently relieve the stress between the “plate-like metal material / adhesive layer” caused by the difference in thermal expansion and the stress between the “plate-like fiber reinforced plastic material / adhesive layer”. There is a need to. The thickness also depends on the elongation percentage of the resin constituting the adhesive. That is, in order to obtain the same stress relaxation effect, the thickness of the adhesive layer can be reduced if the resin has a high elongation rate, and conversely, if the resin has a low elongation rate, the thickness of the adhesive layer can be reduced. It needs to be thick. As a result of various studies, setting the thickness of the adhesive layer according to the type of resin so as to satisfy the following formula (1) can reduce the stress caused by the difference in thermal expansion between the metal material and the fiber-reinforced plastic material. It was found to be extremely effective in mitigating.
t _C × δ ≧ 0.16 (1)
Here, t _C is the average thickness (mm) of the adhesive layer, and δ is the elongation δ (%) of the thermoplastic resin constituting the adhesive layer. The elongation δ corresponds to the tensile elongation at the maximum tensile load, and data measured according to JIS K7161 can be adopted.

On the other hand, the plate-like metal material and the plate-like fiber reinforced plastic material itself are caused by the stress of the “plate-like metal material / adhesive layer” caused by the difference in thermal expansion and the stress of the “plate-like fiber reinforced plastic material / adhesive layer”. It is affected by material deformation behavior due to expansion during temperature rise and shrinkage during temperature fall. According to the study by the inventors, it is particularly effective to improve the durability as a composite material to ensure a sufficient thickness of the adhesive layer according to the thickness of the plate-like metal material. I found it. That is, when the thickness of the plate-like metal material is small, it easily follows the deformation of the plate-like fiber reinforced plastic material, and the amount of strain to be absorbed by the adhesive layer is reduced. May be relatively thin. Conversely, as the thickness of the plate-like metal material increases, it becomes more difficult to follow the deformation of the plate-like fiber reinforced plastic material.As a result, the amount of strain to be absorbed by the adhesive layer increases, so the thickness of the adhesive layer is reduced. It needs to be bigger. As a result of detailed examination, it is extremely effective to satisfy the following expression (2).
t _C / t _M ≧ 0.01 (2)
Here, t _M is the average thickness (mm) of the sheet metal material, and t _C is the average thickness (mm) of the adhesive layer.

  When the above formula (1) or (2) is not satisfied, the deformation of the adhesive layer cannot follow the deformation of the material due to the difference in thermal expansion coefficient between the plate-like metal material and the plate-like fiber reinforced plastic material. May occur, the adhesive layer may cohesively break, and sufficient bonding strength may not be ensured.

[Thickness ratio of each layer in plate-like composite material]
The ratio of the average thickness of the plate-like fiber reinforced plastic material occupying the plate thickness of the plate-like composite material (in the case of having a plurality of plate-like fiber reinforced plastic material layers) is 60 to 80% It is more preferable that If the thickness ratio of the plate-like fiber reinforced plastic material is set to 60% or more, the specific strength is greatly improved by increasing the strength and reducing the thickness of the metal material compared to the case of a single metal material. I found it easy. However, if this ratio becomes excessively high, the cost merit is reduced, so it is preferable to set the ratio to 80% or less.

  Moreover, it is more preferable that the ratio of the average thickness of the adhesive layer occupying the plate thickness of the plate-shaped composite material (the average value of the total thickness in the case of having a plurality of adhesive layers) is less than 10%. Since the adhesive layer made of a thermoplastic resin hardly contributes to the strength of the plate-shaped composite material, when the thickness ratio is 10% or more, the strength level of the plate-shaped composite material is likely to be lowered.

<< Production of plate-like composite material >>
A plate-shaped composite material of the type shown in FIG. 1 was produced as follows.

[Plate metal material]
The metal plate shown in Table 1 was prepared. “Tensile strength” in Table 1 is a tensile test value in the rolling direction, and was measured according to JIS Z2241. The metal plate A is obtained by forming a chemical conversion treatment film under the following conditions of “chemical conversion treatment 1”. The other metal plates are not subjected to chemical conversion treatment.
(Chemical conversion treatment condition 1)
Treatment solution; Aqueous solution containing ammonium fluoride titanate 50 g / L, 85% phosphoric acid 20 g / L, magnesium phosphate 10 g / L Treatment method: Treatment solution is adjusted so that the amount of Ti metal equivalent adhesion is 40 mg / m ^2. After applying to the surface of the metal plate with a bar coater, it is dried at a plate temperature of 120 ° C.

〔adhesive〕
The adhesive shown in Table 2 was prepared. “Tensile elongation” in Table 2 is the elongation at the maximum tensile load, and the data measured according to JIS K7161 after the adhesive was cured.

[Plate fiber reinforced plastic material]
A carbon fiber prepreg sheet (manufactured by Mitsubishi Rayon Co., Ltd .; Pyrofil TR350C100) was prepared. This sheet is obtained by impregnating a long fiber bundle of carbon fibers oriented in one direction with an epoxy resin composition, which is a thermosetting resin, and flattening the sheet. A predetermined number of prepreg sheets shown in Table 3 were laminated so that the directions of the long carbon fibers were in the same direction, and were subjected to a heat treatment at 130 ° C., a pressure of 0.033 MPa, for 120 minutes by hot pressing, to obtain an epoxy. The resin was cured to obtain a plate-like fiber reinforced plastic material. Table 3 shows the average thickness and tensile strength of each plate-like fiber reinforced plastic material. This “tensile strength” was measured according to JIS K7146. This tensile test was performed in a direction corresponding to the longitudinal direction of the long fibers.

[Plate-shaped composite material]
The plate-like metal material shown in Table 1 and the plate-like fiber reinforced plastic material shown in Table 3 were joined using the adhesive shown in Table 2 to produce a plate-like composite material of the type shown in FIG. The combinations of plate metal material, adhesive layer and plate fiber reinforced plastic material are listed in Table 4. Both were joined so that the rolling direction of the plate-like metal material and the fiber direction of the plate-like fiber-reinforced plastic material (the direction in which the strength shown in Table 3 was obtained) coincided. The bonding method was as follows according to the type of adhesive.

When using a thermoplastic resin adhesive (other than the epoxy in Table 2), heat the adhesive to a temperature of the melting temperature + 20 ° C., and use the bar coater or sol coater to remove the melted adhesive liquid. A predetermined amount is applied to the substrate, cooled to room temperature, and then a plate-like fiber reinforced plastic material is placed on the adhesive layer, followed by heat treatment with an adhesive melting temperature + 20 ° C. and a pressure of 0.033 MPa for 120 seconds by hot pressing. By applying, the plate-like metal material and the plate-like fiber reinforced plastic material were integrated through an adhesive to obtain a plate-like composite material.
When using an epoxy adhesive, apply a predetermined amount of adhesive solution with a curing agent to the surface of the plate-shaped metal material using a bar coater or sol coater, and then apply a plate on the adhesive application surface before the adhesive is cured. The plate-like metal reinforced plastic material is placed and pressed at a pressure of 0.033 MPa for 120 minutes to integrate the plate-like metal material and the plate-like fiber-reinforced plastic material via an adhesive, and the plate-like composite material is Obtained.

<Characteristic evaluation of plate-like composite material>
〔Tensile strength〕
The tensile strength was measured according to JIS K7146. The tensile direction was the rolling direction of the sheet metal material. Those having a tensile strength of 950 MPa or more were determined to be acceptable. In particular, those having a pressure of 1900 MPa or more are evaluated to be extremely excellent in strength characteristics.

[Specific strength]
The specific strength was calculated by dividing the value obtained by converting the tensile strength into kg / m ² by the specific gravity of the plate-like composite material. If this specific strength 16 × 10 ⁶ or more, a number of so marked effect on increasing the strength or weight reduction can be expected than in the case of the metal material alone in applications, those specific strength 16 × 10 ⁶ or more It was determined to pass.

[Heat-resistant deformation]
A test piece of 200 mm × 150 mm was cut out from each plate-shaped composite material and subjected to the following two types of tests.
Heating test; Hold in an oven at 70 ° C. for 120 minutes Cycle test; 50 cycles of heating / cooling cycle of “immersion in hot water at 70 ° C. for 10 minutes → immersion in cold water at 4 ° C. for 10 minutes”

The test piece after each test was placed on a flat board, and steepness (= mountain height / test piece length 200 mm × 100) was measured in order to evaluate the warpage of the plate. The measured values were evaluated according to the following criteria, and both the heating test and the cycle test were judged to have no problem in many applications if they were more than ○ evaluations.
◎: Steepness; less than 0.2% ○: Steepness; 0.2% or more and less than 1.0% △: Steepness; 1.0% or more and less than 1.5% ▲: Steepness; 1.5% or more X: Peeling of the plate metal material and the plate fiber reinforced plastic material occurred

Based on the above test results, all of the tensile strength, specific strength, and heat distortion resistance were accepted as a comprehensive evaluation; judged as acceptable and designated as ◎ (excellent) and ◯ (good). Other than that, comprehensive evaluation;
The results are shown in Table 4.

  As can be seen from Table 4, all of the examples of the present invention were excellent in the above characteristics, and the overall evaluation was determined to be acceptable. Among them, the thickness ratio of the plate-like fiber reinforced plastic material occupying the plate thickness is 0.6 to 0.8, and the thickness ratio of the adhesive layer is less than 0.1 (Sample Nos. 2, 5, 8, 9, 10, 11, 16) are extremely excellent in strength characteristics. In Sample Nos. 18 and 19, the thickness ratio of the plate-like fiber reinforced plastic material exceeds 0.8, which increases the cost depending on the application.

  In contrast, sample Nos. 1, 3, 4, and 12 which are comparative examples do not satisfy the formula (1) or (2), and sample Nos. 13 and 15 use a thermosetting resin for the adhesive layer. These were all inferior in heat distortion resistance.

The figure which illustrated typically the cross-sectional structure of the plate-shaped composite material of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plate-shaped metal material 2 Plate-shaped fiber reinforced plastic material 3 Adhesive layer 10 Plate-shaped composite material

Claims (4)

A composite material in which a plate-like fiber reinforced plastic material containing a fiber having a length of 10 mm or more in a thermosetting resin is bonded to the surface of a plate-like metal material via a thermoplastic resin adhesive layer. When the average thickness of the sheet metal material is t _M (mm), the average thickness of the adhesive layer is t _C (mm), and the elongation of the thermoplastic resin constituting the adhesive layer is δ (%), A plate-shaped composite material satisfying the following formulas (1) and (2).
t _C × δ ≧ 0.16 (1)
t _C / t _M ≧ 0.01 (2)   The plate-like composite material according to claim 1, wherein the plate-like fiber reinforced plastic material has a tensile strength of 2000 MPa or more.   The plate-like fiber reinforced plastic material is obtained by using a prepreg sheet obtained by flattening a long fiber bundle made of carbon fibers with a binder of a thermosetting resin composition as a material, and curing the thermosetting resin. The plate-like composite material according to 1 or 2.   The plate-like composite material according to any one of claims 1 to 3, wherein the thickness ratio of the plate-like fiber reinforced plastic material occupying the plate thickness is 60 to 80%, and the thickness ratio of the adhesive layer is less than 10%.

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