JP4543696B2 - FIBER-REINFORCED COMPOSITE MATERIAL, ITS MANUFACTURING METHOD, AND INTEGRATED MOLDED ARTICLE - Google Patents

Description

  The present invention relates to a fiber reinforced composite material (FRP) in which a matrix resin is reinforced with continuous reinforcing fibers and a method for producing the same, and more particularly, when an integrated molded product using the fiber reinforced composite material is discarded. The present invention provides a fiber-reinforced composite material that can be easily peeled and disassembled and can be separated very easily for reuse, and a method for producing the same. The integrated molded product using the fiber reinforced composite material is used for parts, members, or casings of electric / electronic devices, OA devices, home appliances, automobiles or building materials.

  Fiber reinforced plastics are excellent in moldability, thin wall, light weight, high rigidity, productivity, and economical efficiency. Electrical / electronic equipment parts, automotive equipment parts, personal computers, OA equipment, AV equipment, mobile phones, telephones, facsimiles, home appliances. It is frequently used for parts and casings of electrical and electronic equipment such as toy supplies. However, for example, fiber reinforced plastic plates in a form in which long fiber groups of reinforcing fibers are arranged in layers are materials that are particularly thin-walled, lightweight, and highly rigid. It was unsuitable for easy production.

  On the other hand, metal materials such as Mg alloys can be used for electronic devices such as personal computers, mobile phones, personal digital assistants, office automation equipment, automobiles, building materials, etc. It came to be used. However, even when trying to use metal materials for all parts, Mg alloy has a problem that the specific gravity is larger than fiber reinforced plastic and a sufficient weight reduction effect cannot be obtained, and the cost is increased.

  Therefore, there is a demand for a technique for integrally bonding a composite material such as a fiber reinforced plastic plate to a metal member or another injection molded product. In a molded product in which members made of different materials are integrated, the adhesiveness at the joint becomes a very important problem in terms of function.

  As an integration method, a method using an adhesive has been generally employed.

  For example, Patent Document 1 discloses an electronic device casing in which a metal frame and an injection-molded rib are bonded with an epoxy resin-based paint.

However, the method using the adhesive of Patent Document 1 requires an adhesive preparation step and a coating step, so that it is difficult to reduce the production cost and sufficient reliability of the adhesive strength is not obtained. is the current situation. Furthermore, when disposing of the integrally molded product, it is difficult to separate different materials, and even if they can be separated, there is a problem that reuse is difficult due to contamination of the remaining adhesive.
JP 2001-298277 A (first page, fourth line)

  The object of the present invention is to provide a fiber-reinforced composite material and an integrally molded article that are free from such problems of the prior art and excellent in adhesion to other members and mechanical properties. It is another object of the present invention to be able to easily disassemble and reuse a member of an integrally molded product after it has been used.

That is, the present invention is a fiber reinforced composite material comprising a reinforced fiber and a thermosetting resin composition , wherein a film made of the thermoplastic resin composition is formed on at least a part of the surface of the fiber reinforced composite material . The solubility parameter δ (SP value) of the thermoplastic resin constituting the thermoplastic resin composition is 9 to 16, and at least a part of the reinforcing fibers is embedded in the thermosetting resin composition with respect to the same fiber. a fiber-reinforced composite material that have a both a part portion to be buried in the thermoplastic resin composition.

The present invention also relates to a thermoplastic resin composition comprising a thermoplastic resin having a solubility parameter δ (SP value) of 9 to 16 on at least a part of the surface of a thermosetting prepreg laminate comprising reinforcing fibers and a thermosetting resin composition. a lamination step of placing an object, by forming a parallel with the curing reaction of the thermosetting resin constituting the thermosetting resin composition by melting the thermoplastic resin composition film, among the reinforcing fibers Characterized in that at least a part thereof includes a thermoforming step of providing a structure having both a portion embedded in the thermosetting resin composition and a portion embedded in the thermoplastic resin composition with respect to the same fiber. A method for producing a fiber-reinforced composite material.

  In addition, the present invention is an integrally molded product in which the fiber-reinforced composite material of the present invention and another structural member are integrally bonded.

  The fiber-reinforced composite material of the present invention can be easily integrated with other members and has excellent adhesive strength between the members to be joined.

  Further, the integrally molded product of the present invention is excellent in mechanical properties and light weight, and can be easily disassembled when discarded. In addition to excellent electromagnetic shielding properties, it is thin, lightweight, and highly rigid. As a casing for electrical and electronic devices such as personal computers, displays, and personal digital assistants, and parts, members, and casings for automobiles and building materials. Is preferred.

  The fiber-reinforced composite material of the present invention comprises reinforcing fibers and a thermosetting resin composition.

  Examples of reinforcing fibers include metal fibers such as aluminum, brass, and stainless steel, polyacrylonitrile-based, rayon-based, lignin-based, pitch-based carbon fibers, graphite fibers, insulating fibers such as glass, aramid, PBO, Examples thereof include organic fibers such as polyphenylene sulfide, polyester, acrylic, nylon, and polyethylene, and inorganic fibers such as silicon carbide and silicon nitride. These fibers may be subjected to a surface treatment. Examples of the surface treatment include a treatment with a coupling agent, a treatment with a sizing agent, and an adhesion treatment of an additive in addition to a treatment for depositing a metal as a conductor. Moreover, these reinforcing fibers may be used individually by 1 type, and may use 2 or more types together.

  Among these, carbon fiber, particularly polyacrylonitrile-based carbon fiber is preferably used from the viewpoint of the balance of specific strength, specific rigidity, light weight, and conductivity, and in particular, at a low cost.

  The carbon fiber has a surface oxygen concentration {O / C}, which is a ratio of the number of oxygen (O) and carbon (C) atoms on the fiber surface measured by X-ray photoelectron spectroscopy, of 0.05 to 0.00. 3 is preferable, more preferably 0.06 to 0.25, and still more preferably 0.07 to 0.2. When the surface oxygen concentration {O / C} is 0.05 or more, the amount of polar functional groups on the surface of the carbon fiber can be secured, and the affinity with the thermoplastic resin composition can be increased and strong adhesion can be obtained. . Moreover, since it is 0.3 or less, the fall of the intensity | strength of carbon fiber itself by oxidation is small.

  Moreover, as a form of a reinforced fiber, what has an average length of 10 mm or more is laminated | stacked and arrange | positioned at a layer form is preferable when expressing the reinforcement effect of a reinforced fiber efficiently. As the form of the reinforcing fiber layer, a form in which cloths, filaments, blades, filament bundles, spun yarns and the like are arranged in one direction can be suitably used. In the case of stacking layers in a form aligned in one direction, it is preferable to stack the layers while shifting the direction for each layer in order to reduce the strength anisotropy of the stacked body. Moreover, the form of these layers may be used individually by 1 type, or may use 2 or more types together.

  The ratio of the reinforcing fiber to the fiber-reinforced composite material of the present invention is preferably 5 to 75% by volume, more preferably 10 to 65% by volume from the viewpoints of moldability, mechanical properties, and electromagnetic shielding properties.

  As a thermosetting resin which comprises a thermosetting resin, it is preferable that a glass transition temperature is 60 degreeC or more, It is more preferable that it is 80 degreeC or more, It is further more preferable that it is 100 degreeC or more. Since the integrated molded product is a housing that mainly stores the heating element, its use environment is usually around 40 ° C, and the glass transition temperature is 60 ° C or higher, so it has excellent mechanical properties. Fiber reinforced composite material.

  Examples of thermosetting resins include unsaturated polyesters, vinyl esters, epoxies, phenols (resol type), urea melamine, polyimides, copolymers, modified products, or resins blended with two or more. can do. Among these, those containing at least an epoxy resin are preferable from the viewpoint of mechanical properties of the fiber-reinforced composite material.

  In order to improve impact resistance, an elastomer or a rubber component may be added to the thermosetting resin composition.

  It is important that the fiber-reinforced composite material of the present invention has a film formed of a thermoplastic resin composition formed on at least a part of its surface. By the said film, the outstanding adhesiveness with respect to another member can be obtained.

In the fiber-reinforced composite material of the present invention, it is important that the solubility parameter δ (SP value) of the thermoplastic resin constituting the thermoplastic resin composition of the coating is 9 to 16, preferably 10 to 15, More preferably, it is 11-14. By making it within the above range, the cohesive strength of the molecular chain of the thermoplastic resin is large, the thermoplastic resin composition itself is not easily broken, and the affinity with the reinforcing fiber is further increased, thereby providing a strong adhesive strength. Can be expressed.

  Examples of the thermoplastic resin that can achieve the solubility parameter δ include bonds having higher polarity than hydrocarbon skeletons such as amide bonds, ester bonds, urethane bonds, ether bonds, amino groups, hydroxyl groups, carboxyl groups, and aromatic rings, and functional groups. Mention may be made of groups or structures. Examples of the thermoplastic resin composition containing an amide bond, an ester bond, a urethane bond, a hydroxyl group, and the like include polyamide resins, polyester resins, polycarbonate resins, and EVA resins. Examples of those containing an aromatic ring include styrene resins and PPS resins. The resin is not limited to being used alone, but may be a copolymer, a modified body, a resin blended with at least two of these, or the like.

  Moreover, as a weight average molecular weight of the thermoplastic resin which comprises the thermoplastic resin composition of a film, 2,000-200,000 are preferable, 5,000-150,000 are more preferable, 10,000-100,000 are preferable. Is more preferable. By making it within the above range, intermolecular forces and entanglement of molecular chains increase, and the strength of the thermoplastic resin itself increases, making it difficult for the thermoplastic resin itself to be easily broken, and when the thermoplastic resin melts. It becomes easy to impregnate the reinforcing fiber, and a strong adhesive force can be expressed.

  Moreover, as a glass transition temperature of the thermoplastic resin which comprises the thermoplastic resin composition of a film, 15-300 degreeC is preferable, More preferably, it is 40-250 degreeC, More preferably, it is 80-200 degreeC. If the glass transition temperature is within the above temperature range, the thermoplastic resin composition is unlikely to be in a rubber state near room temperature, which is a normal use temperature, and exhibits strong adhesiveness. Can be lowered.

  Further, the melting point of the thermoplastic resin constituting the thermoplastic resin composition of the coating is preferably 100 ° C. or higher from the practicality of the molded product, and preferably melted at a temperature at which the thermosetting resin is cured. Therefore, 350 degrees C or less is preferable. More preferably, it is 100-250 degreeC, More preferably, it is 150-220 degreeC.

In the fiber-reinforced composite material of the present invention, at least a part of the reinforcing fibers has both a portion embedded in the thermosetting resin composition and a portion embedded in the thermoplastic resin composition of the coating with respect to the same fiber. Tei Ru. The same fiber is buried in both layers of the thermoplastic resin composition and the thermoplastic resin composition, so that the adhesion interface is reinforced by the effect of skewering, so that strong adhesion can be obtained.

  The state in the vicinity of the adhesive interface can be observed with an optical microscope, SEM, or TEM. In observation, in order to facilitate visual distinction, resin may be dyed.

In the fiber reinforced composite material of the present invention, the absolute value (| Ep-Es |) of the difference between the total surface free energy Ep of the thermoplastic resin composition and the total surface free energy Es of the thermosetting resin composition is 10 mJ. preferably / m ² or less and more preferably 7 mJ / m ^2, more preferably not more than 5 mJ / m ^2. The fact that the total surface free energy of the two to be bonded is close means that the affinity for each other is high, and the thermoplastic resin composition peels from the thermosetting resin composition by setting it to 10 mJ / m ² or less. Can be prevented.

In the fiber-reinforced composite material of the present invention, the absolute value (| Ep−Ef |) of the difference between the total surface free energy Ep of the thermoplastic resin composition and the total surface free energy Ef of the reinforcing fiber is 10 mJ / m ² or less. Preferably, it is 7 mJ / m ² or less, more preferably 5 mJ / m ² or less. By setting it as 10 mJ / m < ² > or less, it can prevent that a thermoplastic resin composition will peel from a reinforced fiber.

  The thermoplastic resin composition for the film may contain a filler or an additive depending on the application. As fillers or additives, inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping agents, antibacterial agents, insect repellents, deodorants, coloring inhibitors, heat There are stabilizers, mold release agents, antistatic agents, plasticizers, lubricants, colorants, pigments, foaming agents, coupling agents and the like.

  In particular, the addition of a flame retardant for applications that require flame retardancy, and the addition of a conductivity imparting agent for applications that require electrical conductivity are preferably employed. Examples of flame retardants that can be used include flame retardants such as halogen compounds, antimony compounds, phosphorus compounds, nitrogen compounds, silicone compounds, fluorine compounds, phenol compounds, and metal hydroxides. Among these, from the viewpoint of suppressing environmental burden, phosphorus compounds such as ammonium polyphosphate, polyphosphazene, phosphate, phosphonate, phosphinate, phosphine oxide, and red phosphorus can be preferably used. Examples of the conductivity-imparting agent that can be used include carbon black, amorphous carbon powder, natural graphite powder, artificial graphite powder, expanded graphite powder, pitch microbeads, vapor grown carbon fiber, and carbon nanotube.

  As an average thickness of a film, 0.1-1000 micrometers is preferable, More preferably, it is 0.5-500 micrometers, More preferably, it is 1-100 micrometers. If the average thickness of the coating is within the above range, it is sufficient to obtain strong adhesion. The average thickness of the coating can be measured by observing the cross section of the coating with an optical microscope, SEM, or TEM.

The fiber-reinforced composite material of the present invention has a vertical adhesive strength of 10 MPa or more at 40 ° C. and 10 MPa at 140 ° C. when a nylon 6 resin containing 30% by weight of carbon fiber single fiber is injection molded on the coating. It is good that it is less than. For example, as one of the main applications of the integrally molded product of the present invention, in a housing that stores a heating element, since the use environment is usually around 40 ° C., the adhesive strength that can withstand use in that environment is 10 MPa. It is important to ensure the above, preferably 13 MPa or more, more preferably 18 MPa or more. On the other hand, the adhesive strength at 140 ° C. as the temperature higher than the normal use environment is less than 10 MPa, preferably 8 MPa or less, more preferably 6 MPa or less, so that different members are preheated when the integrally molded product is used. Can be easily separated and collected and reused. The glass transition temperature of the thermosetting resin under normal atmospheric conditions (normal pressure, 50% RH) is approximately 130 to 150 ° C., and is generally not used at higher temperatures. A major feature of the present invention is that the bond strength is lowered and the fiber-reinforced composite material and other molded articles are easily decomposed. Further, as a standard material as another member to be bonded to the fiber-reinforced composite material of the present invention, nylon 6 resin containing 30% by weight of carbon fiber short fibers is adopted. Further details will be described later in Examples.

  The fiber-reinforced composite material of the present invention has at least one substantially flat portion in order to adapt to its shape, because one of its main uses is, for example, a casing of an electric / electronic device as an electromagnetic wave shield molded product. Furthermore, it is more preferable that 50% or more of the surface having the maximum area of the fiber-reinforced composite material forms a substantially flat surface. When a case of an electric or electronic device is assumed as an application, the average thickness of the laminate is preferably 0.1 to 3 mm, more preferably 0.3 to 2 mm from the viewpoint of thinness and lightness. Preferably, it is 0.4 to 1.6 mm, more preferably 0.5 to 1.2 mm. Here, the average thickness of the laminated body is an average value of measured values of at least five points evenly distributed in the substantially planar portion. In the measurement of the average thickness, parts that are intentionally given a shape such as a rib part, a hinge part, and a convex concave part are excluded.

  In addition, the fiber-reinforced composite material of the present invention assumes flexural elasticity based on ASTM D790 from the viewpoint of protecting a member to be mounted from breakage, bending, and deformation of a molded product, assuming use as a casing of an electric / electronic device. The rate is preferably 20 GPa or more, more preferably 30 GPa or more. When the fiber reinforced composite material has anisotropy of flexural modulus in the plane, the minimum value is evaluated. Further details of the measurement method will be described later in Examples.

  The fiber reinforced composite material of the present invention preferably has a radio wave shielding property at a frequency of 1 GHz measured by the Advantest method of 30 dB or more, more preferably 40 dB or more, and further preferably 50 dB or more. Further details of the measuring method will be described later in Examples.

  Next, the integrally molded article of the present invention is formed by integrally bonding the fiber-reinforced composite material of the present invention and another structural member via a film made of a thermoplastic resin composition. By being coupled through the coating, it is possible to obtain strong integrity. Furthermore, it has peelability and decomposability in an atmosphere at a high temperature, specifically, at a temperature higher than the melting point or softening point of the thermoplastic resin film of the fiber-reinforced composite material of the present invention which is a part of the constituent elements. This makes it very easy to separate and separate each member during disposal. This is an excellent characteristic that can greatly reduce the effort for reusing the discarded molded product.

  The bonded surface preferably has a coating of the fiber-reinforced composite material of the present invention on 50% by area or more of the bonded surface, more preferably 70% or more of the bonded surface area, and an adhesive layer on the entire bonded surface. It is particularly preferred to have

  In addition, it is also preferable to use a combination of fitting, fitting and the like in an auxiliary manner.

  The “other member” may be, for example, a metal material such as aluminum, iron, magnesium, titanium, and alloys thereof, the fiber-reinforced composite materials of the present invention, or a thermoplastic resin composition. It may be.

  In addition, it is preferable to use a thermoplastic resin composition reinforced with reinforcing fibers as “another member” because a light weight that cannot be realized when a metal material is employed is obtained.

  Examples of the thermoplastic resin used in the “other member” include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polyester such as liquid crystal polyester, In addition to polyolefins such as polyethylene (PE), polypropylene (PP), and polybutylene, and styrene resins, polyoxymethylene (POM), polyamide (PA), polycarbonate (PC), polymethylene methacrylate (PMMA), polychlorinated Vinyl (PVC), polyphenylene sulfide (PPS), polyphenylene ether (PPE), modified PPE, polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polysulfone (PSU) , Modified PSU, polyethersulfone, polyketone (PK), polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyarylate (PAR), polyethernitrile (PEN), phenol Fluororesins such as polyresin, phenoxy resin, polytetrafluoroethylene, thermoplastic elastomers such as polystyrene, polyolefin, polyurethane, polyester, polyamide, polybutadiene, polyisoprene, fluorine, etc. Copolymers, modified products, and resins obtained by blending two or more of them may be used. In particular, PPS resin is used from the viewpoint of heat resistance and chemical resistance, polycarbonate resin and styrene resin are used from the viewpoint of molded product appearance and dimensional stability, and polyamide resin is used from the viewpoint of strength and impact resistance of the molded product. More preferably used.

  Further, other elastomers or rubber components may be added to improve impact resistance. Moreover, according to a use etc., you may contain another filler and additive in the range which does not impair the objective of this invention. For example, inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping agents, antibacterial agents, insect repellents, deodorants, anti-coloring agents, heat stabilizers, release agents , Antistatic agents, plasticizers, lubricants, colorants, pigments, dyes, foaming agents, antifoaming agents, coupling agents and the like. Examples of the conductivity-imparting agent include carbon black, amorphous carbon powder, natural graphite powder, artificial graphite powder, expanded graphite powder, pitch microbeads, vapor-grown carbon fiber, and carbon nanotube. It is preferably used for the purpose of further enhancement.

  The material of the reinforcing fiber used in “another structural member” can be selected based on the same idea as the reinforcing fiber in the above-described fiber-reinforced composite material of the present invention. However, when the “another structural member” is formed by injection molding, it is preferable that the reinforcing fibers are short fibers and are uniformly dispersed in the thermoplastic resin composition. In this case, the blending ratio of the thermoplastic resin and the reinforcing fiber is such that when the reinforcing fiber is a carbon fiber, the thermoplastic resin is 25 to 95% by weight and the carbon fiber from the viewpoint of a balance with moldability, strength, and lightness. Is preferably 5 to 75% by weight, more preferably 35 to 85% by weight of the thermoplastic resin and 15 to 65% by weight of the carbon fiber.

  Assuming an application as a casing of an electric / electronic device, “another structural member” preferably has a volume resistivity of 100 Ω · cm or less, more preferably 70 Ω · cm or less, and 50 Ω · cm or less. Further preferred.

  In the integrally molded product of the present invention, those obtained by laminating reinforcing fibers, which is a preferred embodiment of the fiber-reinforced composite material of the present invention, have an electromagnetic shielding property, assuming use as a casing of an electric / electronic device. In view of the above, it is preferable that the fiber-reinforced composite material of the present invention constitutes at least a part of the top surface of the casing, more preferably constitutes 50% or more of the projected area of the top surface, and the projected area of the top surface. It is particularly preferable to constitute 70% or more. Here, the projected area is a scale representing the size of the molded product surface obtained from the outer dimensions of the molded product.

  The shape of the integrally molded product of the present invention may include a curved surface, a rib, a hinge, a boss, and a hollow portion. Further, the molded product may be subjected to surface decoration treatment by plating, painting, vapor deposition, insert, stamping, laser irradiation, or the like.

  Applications of the integrally molded product of the present invention include, for example, personal computers, displays, OA equipment, mobile phones, portable information terminals, facsimile machines, compact discs, portable MDs, portable radio cassettes, PDAs (mobile information terminals such as electronic notebooks). , Video cameras, digital still cameras, optical equipment, audio equipment, air conditioners, lighting equipment, entertainment equipment, toy products, other electrical appliances such as household appliances, internal parts such as trays and chassis, cases, and mechanical parts Applications for building materials such as panels, motor parts, alternator terminals, alternator connectors, IC regulators, light meter potentiometer bases, suspension parts, exhaust gas valves and other valves, fuel-related, exhaust and intake pipes, air intakes Snorkel, intake manifold, various arms, various frames, various hinges, various bearings, fuel pump, gasoline tank, CNG tank, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor, coolant sensor, oil temperature sensor , Brake pad wear sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake butt wear sensor, thermostat base for air conditioner, heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, Wiper motor related parts, distributor, starter switch, starter relay, transmission wire Harness, window washer nozzle, air conditioner panel switch board, coil for fuel related electromagnetic valve, connector for fuse, battery tray, AT bracket, headlamp support, pedal housing, handle, door beam, protector, chassis, frame, armrest, horn terminal, Step motor rotor, lamp socket, lamp reflector, lamp housing, brake piston, noise shield, radiator support, spare tire cover, seat shell, solenoid bobbin, engine oil filter, ignition device case, under cover, scuff plate, pillar trim, propeller shaft, Wheel, fender, fascia, bumper, bumper beam, bonnet, aero parts, platform Cars such as foam, cowl louvers, roofs, instrument panels, spoilers and various modules, aircraft-related parts, parts and skins, landing gear pods, winglets, spoilers, edges, ladders, elevators, failings, ribs, etc. Examples include related parts, members, and outer plates. In particular, the integrally molded product of the present invention is suitable as an electromagnetic shielding molded product, making use of its excellent electromagnetic shielding properties, and is suitable for casings and external members for electric and electronic equipment, and also has a thin and wide projected area. It is suitable as a casing of a required notebook type personal computer or portable information terminal.

Next, in the method for producing a fiber-reinforced composite material of the present invention, the solubility parameter δ (SP value) is 9 to 16 on at least a part of the surface of the thermosetting prepreg laminate including the reinforcing fiber and the thermosetting resin composition. of the laminate placing a thermoplastic resin composition comprising a thermoplastic resin, a parallel with the curing reaction of the thermosetting resin constituting the thermosetting resin composition by melting the thermoplastic resin composition film By forming , at least a part of the reinforcing fibers provides a structure having both a portion embedded in the thermosetting resin composition and a portion embedded in the thermoplastic resin composition with respect to the same fiber. A thermoforming process. That is, the thermoplastic resin is disposed in a film shape on the surface layer of the thermosetting resin composition before curing, and then cured at a temperature equal to or higher than the melting point of the thermoplastic resin, whereby the thermosetting resin composition and the thermoplastic resin are cured. It is possible to obtain the fiber-reinforced composite material of the present invention in a state of being well adhered.

  The reinforcing fibers can be aligned with drum winds or the like.

  As a means for forming a laminate, for example, hand lay-up molding method, spray-up molding method, vacuum back molding method, pressure molding method, autoclave molding method, press molding method, transfer molding method, etc. From this viewpoint, a vacuum back molding method, a press molding method, a transfer molding method and the like are preferably used.

  As a method of dispersing the reinforcing fibers in the thermoplastic resin in “another structural member”, for example, a known method of melt-kneading the thermoplastic resin and the reinforcing fibers can be employed. Examples of molding means for “another structural member” include injection molding, extrusion molding, and press molding. In particular, injection molding is highly industrially suitable and has a rib, hinge, and boss. It is preferably used because a molded product having a complicated shape can be easily mass-produced.

  Examples of the procedure for integrating the fiber-reinforced composite material of the present invention and “another structural member” include the following construction methods 1 to 3.

  Construction method 1: A construction method in which the fiber-reinforced composite material of the present invention is molded in advance and both are integrated simultaneously with the molding of “another structural member”. For example, the fiber-reinforced composite material of the present invention is manufactured in advance by press molding, processed into a predetermined size, post-processed, inserted into an injection mold, and then integrated by injection molding “another structural member”. How to make.

  Construction method 2: A construction method in which “another structural member” is formed in advance and both are integrated simultaneously with the formation of the fiber-reinforced composite material of the present invention. For example, “another structural member” manufactured in advance by injection molding and post-processed is inserted into a press die, and then a prepreg to be a fiber-reinforced composite material of the present invention is laid up, and the melting point of the thermoplastic resin or higher The method of integrating by vacuum back molding at the temperature of.

  Construction method 3: A construction method in which the fiber-reinforced composite material of the present invention and “another structural member” are separately separately molded and integrated with each other. For example, the fiber-reinforced composite material of the present invention that has been manufactured in advance by press molding, processed to a predetermined size, and post-processed, and “another structural member” that has been manufactured and post-processed by injection molding in the same manner as method 2 are used. To integrate them.

  As a means for joining the fiber reinforced composite material of the present invention and “another structural member” to produce the integrated molded product of the present invention, for example, the thermoplastic resin composition of the coating in the fiber reinforced composite material of the present invention is used. Adhering and bonding the fiber reinforced composite material of the present invention and the “another structural member” by pasting the “another structural member” at a process temperature equal to or higher than the melting point of the thermoplastic resin to be configured and then cooling. Integration can be achieved at the same time.

Examples and comparative examples are shown below (the same applies to the evaluation and measurement methods of the reference examples) . In the blending ratios shown in the examples and comparative examples, “%” without any special note means% by weight.

(Evaluation and measurement method)
(1) Vertical adhesive strength evaluation Using a molded product obtained by melting and bonding a thermoplastic molding material based on nylon resin at a temperature equal to or higher than its melting point on the target bonding surface of a fiber reinforced composite material. Do it. Specific examples are shown below.

(Material of the adherend)
Nylon 6 resin CM1001 manufactured by Toray Industries, Inc. is supplied from a main hopper as a thermoplastic resin to the Nippon Steel Works TEX-30α type twin screw extruder (screw diameter 30 mm, L / D = 32). Toray Co., Ltd. chopped carbon fiber “Torayca” TS-12 (chopped yarn length 6 mm) is supplied from the downstream side hopper, kneaded sufficiently at a barrel temperature of 260 ° C. and a screw speed of 150 rpm, and further downstream vacuum Deaeration was performed from the vent. The supply was adjusted by a weight feeder so that the carbon fiber content was 30% by weight. Molten resin was discharged from a die port (inner diameter 5 mm), and the obtained strand was cooled and then cut with a cutter to obtain a pellet-shaped molding material. The obtained pellets were dried at 90 ° C. for 3 hours by hot air drying and further at 80 ° C. for 6 hours under vacuum, and sufficiently dried to a moisture content of 0.1% or less.

(injection molding)
Next, using a J350EIII type injection molding machine manufactured by Nippon Steel Co., Ltd., the fiber reinforced composite material of each Example / Comparative Example is placed in the mold, and the surface having the coating made of the thermoplastic resin composition is used as the injection molding material. It was mounted so that it could be integrated, and the material of the adherend member was injection molded at a temperature of 280 ° C. so that the thickness of the injection molding material portion was 3 mm, to obtain an integrated molded product as shown in FIG.

(Tensile test)
A vertical adhesive strength evaluation sample (b in FIG. 6) was cut out from the integrated molded product at a 10 mm square. Using an “Instron” (registered trademark) 5565 type universal material testing machine (manufactured by Instron Japan Co., Ltd.) as a measuring device, the sample is fixed with a jig (a in FIG. 6), and 40 ° C. At two temperatures of 140 ° C., a tensile test was performed by pulling the adhesive surfaces from both surfaces in a 90 ° direction at a tensile speed of 1.27 mm / min, and the maximum load was divided by the adhesion area to obtain a vertical adhesive strength (MPa )
The number of samples was n = 5.

  A molded product that could be held by an Instron chuck was sandwiched between the chucks and subjected to a tensile test. For those that could not be gripped, an adhesive (ThreeBond 1782, manufactured by ThreeBond Co., Ltd.) was applied to the molded body and left at 23 ± 5 ° C. for 4 hours and then at 50 ± 5% RH for 4 hours to adhere to the jig. For the test result, only the value at which the bonded and integrated part was peeled off was adopted, and the result of peeling off the jig and the molded product was deleted.

(2) Adhesive strength based on ISO4587 Two test pieces TP1 were cut out per sample from the fiber reinforced composite material of each Example / Comparative Example based on the provisions of ISO4587. The shape and dimensions were set to a length (TP1L in FIG. 4) of 100 mm and a width (TP1W in FIG. 4) of 25 mm in accordance with ISO4587. When it is difficult to cut out a test piece having this size, a size obtained by proportionally reducing the size may be used instead.
The prepared two test pieces TP1 were faced to each other so that the respective coatings of the thermoplastic resin composition became the joints. The length of this joint (BPL in FIG. 4) was 12.5 mm. Both test pieces TP1 are heated to a temperature at which the resin of the thermoplastic resin composition is sufficiently melted (temperature higher by 10 ° C. than the melting point), and both are bonded at a pressure of 50 MPa for 1 minute, and cooled while being clamped. And what joined both was made into the tensile test piece.

As a tensile tester, “Instron” (trademark) 5565 type universal material testing machine (manufactured by Instron Japan Co., Ltd.) was used, and at two temperatures of 40 ° C. and 140 ° C. during the test, A tensile test was performed at a tensile speed of 1.27 mm / min. It was confirmed that the fracture occurred in the vicinity of the joining position (near the boundary), and the value obtained by dividing the strength (unit: kN) by the surface area of the joined portion was defined as the adhesive strength (unit: MPa).
The number of samples was n = 5.

(3) Flexural modulus Evaluated according to ASTM D790. Four test pieces cut out from substantially flat portions of the fiber reinforced composite material at different angles of 0 degrees, 45 degrees, 90 degrees, and 135 degrees with respect to the longitudinal direction of the fiber reinforced composite material were prepared. When the shape of a rib part, a hinge part, an uneven | corrugated | grooved part, etc. is attached | subjected to the test piece intentionally, the measurement of the thickness of a test piece is performed except this part. The minimum value of the flexural modulus obtained from these test pieces was adopted as the flexural modulus referred to herein.

(4) Electromagnetic wave shielding property It evaluated by the Advantest method. A 120 mm × 120 mm flat plate was cut out from the fiber-reinforced composite material of each Example / Comparative Example to obtain a test piece. In the evaluation, the test piece was in an absolutely dry state (moisture content of 0.1% or less), and a conductive paste (Dotite manufactured by Fujikura Kasei Co., Ltd.) was applied to the four sides to sufficiently dry the conductive paste.

  The test piece was sandwiched in a shield box, and the radio wave shielding property (unit: dB) at a frequency of 1 GHz was measured with a spectrum analyzer to obtain an electromagnetic wave shielding property. The higher the radio wave shielding property, the better the electromagnetic wave shielding property.

(5) Volume Specific Electrical Resistance A test piece having a width of 12.7 mm and a length of 65 mm was cut out from “another structural member” and subjected to measurement in an absolutely dry state (moisture content of 0.1% or less). First, apply a conductive paste (Dotite manufactured by Fujikura Kasei Co., Ltd.) to the cross-sections at both ends of the test piece, dry the conductive paste sufficiently, and press both sides of the test piece to the electrode. The resistance value was measured with a digital multimeter (manufactured by FLUKE). The value obtained by subtracting the contact resistance of the measuring instrument, jig, etc. from the electrical resistance value, multiplied by the area of the conductive paste coating surface, and dividing that value by the length of the test piece is the volume specific electrical resistance value (unit: Ω Cm).

(6) Determination of Solubility Parameter δ (SP Value) In the present invention, the solubility parameter δ (SP value) refers to the value of the repeating unit of the polymer at 25 ° C. determined by the method of Fedors. The method is described in RFFedors, Polym. Eng. Sci., 14 (2), 147 (1974). That is, in the structural formula of the desired compound, it is determined by the following formula from the evaporation energy and molar volume data of atoms and atomic groups.
δ = (ΣΔei / ΣΔvi) ^1/2
In the formula, Δei and Δvi represent the evaporation energy and molar volume of an atom or atomic group, respectively. The structural formula of the compound to be determined is determined using a general structural analysis technique such as IR, NMR, and mass spectrum.

(7) Total surface free energy Total surface free energy was evaluated as follows.

(A) Total surface free energy (Es) of thermosetting resin composition
40 g of an uncured thermosetting resin composition used in each example and comparative example was placed in a “Teflon (registered trademark)” container (50 × 50 × 50 mm) and heated at 150 ° C. for 30 minutes. Cured to obtain a cured resin.

  After this epoxy resin cured product was cut into a size of 30 mm in length and 15 mm in width, the surface was polished using a polishing machine (Refine Tech Co., Ltd. Refine Polisher 200 and Automax AMO-210) to obtain a particle size of # 600. For 5 minutes, particle size # 800 for 5 minutes, particle size # 1000 for 15 minutes, particle size # 1200 for 20 minutes, particle size # 1500 for 30 minutes, and dry polishing in order at a rotational speed of 100 rpm. Thereafter, the abrasive particles METAPOLISH (Fujimi Incorporated No. 1) were polished with a polishing buff pan cloth (Refinetech Co., Ltd.) for 5 minutes while flowing simultaneously with water. Thereafter, polishing particles METAPOLISH (Fujimi Incorporated No. 5) were polished with a polishing buff suede cloth (Refinetech Co., Ltd.) at 100 rpm for 5 minutes while flowing simultaneously with water.

  50 μl of each liquid of water, ethylene glycol, and tricresol phosphate was dropped on the flat plate, and the droplets formed on the flat plate were observed, and the contact angle θs formed between the flat plate and the droplets was measured (see FIG. 5). .

  Substituting the obtained contact angle θs together with the surface tension component of each liquid into the approximate expression of Owens (the polar component and the nonpolar component of the surface tension unique to each liquid, and the formula constituted by the contact angle θs) to X and Y After plotting, the polar component of the surface free energy of the thermosetting resin composition is determined by the square of the slope a when linearly approximated by the least square method.

Similarly, the nonpolar component of the surface free energy of the thermosetting resin composition is determined from the Y section at that time. What added both was made into the total surface free energy of the thermoplastic resin which comprises a thermosetting resin composition.
Y = a · X + b
X = (polar component of liquid surface tension (unit: mJ / m ² )) ^1/2 / (nonpolar component of liquid surface tension (unit: mJ / m ² )) ^1/2
Y = (1 + COSθs) · (polar component of liquid surface tension (unit: mJ / m ² )) / 2 (nonpolar component of liquid surface tension (mJ / m ² )) ^1/2
Polar component of surface free energy of thermosetting resin composition = a ²
Nonpolar component of surface free energy of thermosetting resin composition = b ²
Total surface free energy (Es) of thermosetting resin composition = a ² + b ²
The polar component and nonpolar component of the surface tension of each liquid are as follows.
Purified water Surface tension 72.8 mJ / m ² , polar component 51.0 mJ / m ² , nonpolar component 21.8 mJ / m ²
・ Ethylene glycol surface tension 48.0 mJ / m ² , polar component 19.0 mJ / m ² , nonpolar component 29.0 mJ / m ²
・ Tricresol phosphate surface tension 40.9mJ / m ² , polar component 1.7mJ / m ² , nonpolar component 39.2mJ / m ²
(B) Total surface free energy (Ep) of thermoplastic resin composition
The thermoplastic resin composition used for forming the coating film in each Example / Comparative Example was heated for 3 minutes while applying a pressure of 6 MPa at 180 ° C. and then cooled to produce a flat plate having a length of 30 mm, a width of 15 mm, and a thickness of 2 mm. did.

  The surface of this flat plate was polished under the same conditions as in (A) above. 50 μl of each liquid of water, ethylene glycol, and tricresol phosphate is dropped on the flat plate, and the droplets formed on the flat plate are observed, and the contact angle θp formed by the flat plate and the droplets is measured.

  In the same manner as in the above (A), calculation is performed by substituting the obtained contact angle θp into an approximate expression of Owens to obtain the total surface free energy of the thermoplastic resin composition.

(C) Surface free energy of reinforcing fiber (Ef)
It describes about the case where carbon fiber is used for reinforcement fiber.

  A single fiber of carbon fiber was calculated by using an Owens approximate expression based on each contact angle measured by Wilhelmi method in each liquid of purified water, ethylene glycol, and tricresol phosphate.

  First, one single fiber was taken out from the carbon fiber bundle using DataPhysics DCAT11, cut into 8 pieces with a length of 12 ± 2 mm, and then placed in a dedicated holder FH12 (a flat plate whose surface was coated with an adhesive substance). Affixed in parallel with a fiber spacing of 2 to 3 mm. Thereafter, the tips of the single fibers are cut and set on the DCAT 11 of the holder. In the measurement, the cell containing each liquid is brought close to the lower ends of the eight single fibers at a speed of 0.2 mm / s and immersed from the tip of the single fibers to 5 mm. Thereafter, the single fiber is pulled up at a speed of 0.2 mm / s. Repeat this operation four or more times. The force F received by the single fiber when immersed in the liquid is measured with an electronic balance. Using this value, the contact angle θf is calculated by the following equation.

COSθf = (force F (unit: mN) received by eight single fibers) / ((8 (number of single fibers) × circumference of single fibers (unit: m)) × surface tension of liquid (unit: mJ / m) ² ))
In addition, the measurement was implemented about the single fiber extracted from the different place of three carbon fiber bundles. That is, the average value of contact angles for a total of 24 single fibers was obtained for one carbon fiber bundle.

  Substituting the obtained contact angle θf into the Owens approximate expression (polar and nonpolar components of the surface tension specific to each liquid, and further the contact angle θf) together with the surface tension component of each liquid X, Y Then, the polar component of the surface free energy of the reinforcing fiber is obtained by the square of the slope a when linearly approximated by the least square method.

Similarly, the nonpolar component of the surface free energy of the reinforcing fiber is obtained from the Y section at that time. The sum of both is defined as the total surface free energy of the reinforcing fiber.
Y = a · X + b
X = (polar component of liquid surface tension (unit: mJ / m ² )) ^1/2 / (nonpolar component of liquid surface tension (unit: mJ / m ² )) ^1/2
Y = (1 + COSθf). (Polar component of liquid surface tension (unit: mJ / m ² )) / 2 (nonpolar component of liquid surface tension (unit: mJ / m ² )) ^1/2
Polar component of surface free energy of reinforcing fiber = a ²
Nonpolar component of surface free energy of reinforcing fiber = b ²
Surface free energy (Ef) of reinforcing fiber = a ² + b ²
The absolute value of the difference in total surface energy was calculated using Es, Ep, and Ef obtained from the above.

(8) Evaluation of glass transition temperature and melting point Measured by differential scanning calorimetry (DSC) according to JIS K7121 at a heating rate of 10 ° C./min, and the glass transition temperature was specified from the endothermic peak of the measurement piece. . In collecting the sample, the thermosetting resin layer of the fiber reinforced composite material was cut out without separating the reinforcing fiber group.

(9) {O / C} evaluation of carbon fiber surface Evaluation was made by a known technique by X-ray photoelectron spectroscopy.

(10) Weight average molecular weight evaluation It evaluated using the well-known technique by a gel permeation chromatography.

(11) Evaluation of average thickness of coating FIG. 7 shows a schematic diagram of a cross section of the laminate. From the TEM observation photograph of the cross section of the laminate, the thickness from the surface of the thermoplastic resin composition layer c to the interface f of the thermosetting resin composition is measured. The measurement is performed at 10 locations, and the average value is taken as the average film thickness.

( Reference Example 1)
An embodiment of the method for producing a fiber-reinforced composite material of the present invention will be described with reference to the exploded perspective view of the model housing for electric / electronic equipment shown in FIG.

In the figure, the following was prepared as a fiber reinforced composite material. That is, a carbon fiber woven fabric having a length of 350 mm and a width of 300 mm (Toray Industries Co., Ltd., TORAYCA fabric CO6343) is laminated with a 57% by volume carbon fiber prepreg impregnated with an epoxy resin, and a nylon spunbond is further formed on the outermost surface. A nonwoven fabric sheet (trade name: Dynac LNS-0050 basis weight 50 g / m ² , melting point 135 ° C., solubility parameter δ (SP value) 13.0, weight average molecular weight 18000 manufactured by Kureha Chemical Co., Ltd.) was laminated. Next, a vacuum bag was formed, and cured by heating at 140 ° C. for 1 hour to obtain a fiber-reinforced composite material (I) having a thickness of 0.9 mm. On the surface of this fiber reinforced composite material, the nonwoven fabric was melted and adhered in the form of a film, and the film thickness was 25 μm. The crow transition temperature of the fiber reinforced composite material was 130 ° C. The absolute value of the difference in total surface free energy between the thermosetting resin composition of the fiber reinforced composite material and the film-like thermoplastic resin composition was 9. The absolute value of the difference in total surface free energy between the reinforcing fiber of the fiber-reinforced composite material and the film-shaped thermoplastic resin composition was 8. The fiber-reinforced composite material had a vertical adhesive strength of 21 MPa in a 40 ° C. atmosphere and 2 MPa in a 140 ° C. atmosphere.

  Next, using a J350EIII type injection molding machine manufactured by Nippon Steel Co., Ltd., the fiber reinforced composite material (I) was placed in the mold, and the thermoplastic resin described in the section of the thermoplastic resin pellet for the test was used. In use, another structural member (II) shown in FIG. 3 was injection molded. The obtained integrally molded product (III) obtained a casing in which (I) and (II) were firmly and integrally joined.

  And when the bending elastic modulus, electromagnetic wave shielding property, etc. of this housing were measured by the above-mentioned method, the bending elastic modulus was 55 GPa, the electromagnetic wave shielding property was 55 dB, and the housing standing wall portion which is another structural member (II). The volume resistivity was 4.5 Ω · cm.

( Reference Example 2)
180 ° C. curable prepreg (consisting of a reinforcing fiber group consisting of a large number of carbon filaments arranged in one direction (Toray Industries, Inc., {O / C} = 0.08), and the content of the reinforcing fiber group is , A prepreg having a weight ratio (Wf) of 70% and a volume ratio (Vf) of 61%) and a nylon film (type 1401 thickness 50 μm, melting point 210 ° C., solubility parameter δ (SP value) 13. 4. Using a weight average molecular weight of 20000, manufactured by Toray Synthetic Film Co., Ltd.), before press molding, preheat at 225 ° C. for 3 minutes on a hot plate to melt the nylon film, and then press molding machine The mixture was heated at 150 ° C. for 30 minutes while applying a pressure of 6 MPa to obtain a fiber-reinforced composite material (I) having an average thickness of 0.9 mm. On the surface of this fiber reinforced composite material, the nylon film was melted and adhered in the form of a film, and the film thickness was 40 μm. The crow transition temperature of the fiber reinforced composite material was 180 ° C. The absolute value of the difference in total surface free energy between the thermosetting resin composition of the fiber reinforced composite material and the film-like thermoplastic resin composition was 8. The absolute value of the difference in total surface free energy between the reinforcing fiber of the fiber-reinforced composite material and the film-shaped thermoplastic resin composition was 7. The fiber-reinforced composite material had a vertical adhesive strength of 15 MPa in a 40 ° C. atmosphere and 8 MPa in a 140 ° C. atmosphere.

A casing was molded from this fiber-reinforced composite material in the same manner as in Reference Example 1, and a casing that was firmly joined integrally was obtained. When the bending elastic modulus and electromagnetic wave shielding property of the housing were measured in the same manner as in Reference Example 1, the bending elastic modulus was 54 GPa, the electromagnetic wave shielding property was 53 dB, and the volume of the standing wall portion of the housing which is another structural member (II). The specific resistance was 4.0 Ω · cm.

(Example 1 )
The matrix resin is an epoxy resin (thermosetting resin) and consists of a group of reinforcing fibers composed of a large number of carbon filaments (Toray Industries, Inc., trading card, {O / C} = 0.08) arranged in one direction. From the prepreg in which the content of the reinforcing fiber group is 70% by weight (Wf) and 61% by volume (Vf), the fiber direction is 45 °, −45 °, 90 ° with the length direction as 0 ° direction. 5 sheets of prepreg sheets cut into a length of 350 mm and a width of 300 mm so as to be −45 ° and 45 ° are prepared, and the fiber directions are 45 °, −45 °, 90 °, −45 °, and 45 ° from the top. Then, a laminated prepreg sheet was produced.

On the other hand, as a thermoplastic resin composition, a terpolymer polyamide resin (manufactured by Toray Industries, Inc., ternary copolymer polyamide resin CM4000, polyamide 6/66/610, melting point 150 ° C., solubility parameter δ (SP value) 13. 3, a non-woven fabric having a width of 1,000 mm made of a weight average molecular weight of 20000). The basis weight of this nonwoven fabric was 30 g / m ² . From this heat bonding substrate, a rectangular heat bonding substrate having a length of 350 mm and a width of 300 mm was prepared. Two base materials for thermal bonding were stacked and laminated on the upper surface of the laminated prepreg sheet so that the length direction and the width direction coincided with each other.

  Next, press molding was performed. In a press molding machine, preheating was performed at 160 ° C. for 5 minutes to melt the base material for thermal bonding, and then the thermosetting resin was cured by heating at 150 ° C. for 30 minutes while applying a pressure of 6 MPa. After completion of curing, the mixture was cooled at room temperature and demolded to produce a fiber-reinforced composite material having a thermoplastic resin composition layer formed on the surface of a laminate having an average thickness of 0.7 mm. The glass transition temperature of this fiber reinforced composite material was 130 ° C. The absolute value of the difference in total surface free energy between the thermosetting resin composition of the fiber reinforced composite material and the film-like thermoplastic resin composition was 5. The absolute value of the difference in total surface free energy between the reinforced fiber of the fiber reinforced composite material and the film-like thermoplastic resin composition was 4. The bond strength of this fiber reinforced composite material based on ISO4587 was 20 MPa in a 40 ° C. atmosphere and 8 MPa in a 140 ° C. atmosphere. Furthermore, this fiber reinforced composite material had a flexural modulus of 25 GPa and an electromagnetic wave shielding property of 55 dB.

  When the obtained fiber reinforced composite material was subjected to cross-sectional observation by TEM and SEM, it was found that continuous filaments were arranged in the thermoplastic resin layer. That is, it was shown that the reinforced fiber exists in the thermosetting resin layer and the thermoplastic resin layer of the fiber reinforced composite material and reinforces the interface between the two resins.

(Example 2 )
The matrix resin is an epoxy resin (thermosetting resin) and consists of a group of reinforcing fibers composed of a large number of carbon filaments (Toray Industries, Inc., trading card, {O / C} = 0.08) arranged in one direction. From the prepreg in which the content of the reinforcing fiber group is 70% by weight (Wf) and 61% by volume (Vf), the fiber direction is 45 °, −45 °, 90 ° with the length direction as 0 ° direction. 5 sheets of prepreg sheets cut into a length of 350 mm and a width of 300 mm so as to be −45 ° and 45 ° are prepared, and the fiber directions are 45 °, −45 °, 90 °, −45 °, and 45 ° from the top. Then, a laminated prepreg sheet was produced.

On the other hand, as a thermoplastic resin composition, pellets of a copolyester resin (manufactured by Toyobo Co., Ltd., copolyester resin Byron GM400, melting point 143 ° C., solubility parameter δ (SP value) 10.7, weight average molecular weight 25000) are used. A film-like base material for thermal bonding having a basis weight of 80 g / m ² was produced by pressing at 200 ° C. for 3 minutes while applying a pressure of 18 MPa. This heat bonding base material was cut into a rectangular shape having a length of 350 mm and a width of 300 mm, and was laminated on the upper surface of the laminated prepreg sheet so that the length direction and the width direction coincided.

  Next, press molding was performed. In a press molding machine, preheating was performed at 160 ° C. for 5 minutes to melt the base material for thermal bonding, and then the thermosetting resin was cured by heating at 150 ° C. for 30 minutes while applying a pressure of 6 MPa. After completion of curing, the mixture was cooled at room temperature and demolded to produce a fiber-reinforced composite material having a thermoplastic resin composition layer formed on the surface of a laminate having an average thickness of 0.7 mm. The glass transition temperature of this fiber reinforced composite material was 130 ° C. The absolute value of the difference in total surface free energy between the thermosetting resin composition of the fiber reinforced composite material and the film-like thermoplastic resin composition was 5. The absolute value of the difference in total surface free energy between the reinforced fiber of the fiber reinforced composite material and the film-like thermoplastic resin composition was 4. The bond strength based on ISO4587 of this fiber-reinforced composite material was 18 MPa in a 40 ° C. atmosphere and 6 MPa in a 140 ° C. atmosphere. Furthermore, this fiber reinforced composite material had a flexural modulus of 25 GPa and an electromagnetic wave shielding property of 55 dB.

  When the obtained fiber reinforced composite material was subjected to cross-sectional observation by TEM and SEM, it was found that continuous filaments were arranged in the thermoplastic resin layer. That is, it was shown that the reinforced fiber exists in the thermosetting resin layer and the thermoplastic resin layer of the fiber reinforced composite material and reinforces the interface between the two resins.

(Comparative Example 1)
A fiber-reinforced composite material (I) was obtained in the same manner as in Reference Example 1 except that a nylon spunbond nonwoven fabric was not used. Adhesion obtained by applying and bonding two-part acrylic adhesive 3921/3926 manufactured by ThreeBond Co., Ltd. using the obtained fiber reinforced composite material (I) as an adhesive, leaving it to stand for 24 hours at room temperature, and bonding firmly A strength specimen was obtained. The vertical adhesive strength was 25 MPa at 40 ° C. and 17 MPa at 140 ° C.

Separately another structural member by placing a metal spacer having the same shape as the fiber reinforced composite material (I) in the same manner as in Reference Example 1 in place of the fiber-reinforced composite material (I) in an injection molding die (II ) Was injection molded. The two-component acrylic adhesive 3921/3926 manufactured by ThreeBond Co., Ltd. was applied as an adhesive to the obtained fiber-reinforced composite material (I) and another structural member (II), and then bonded and left to stand for 24 hours at room temperature. As a result, a strongly bonded housing was obtained. As a result of evaluation in the same manner as in Reference Example 1, the elastic modulus was 56 GPa, the electromagnetic wave shielding property was 55 dB, and the volume resistivity of the standing wall portion was 4.0 Ω · cm.

(Comparative Example 2)
In Example 1 , without applying preheating, while applying a pressure of 6 MPa, heating was performed at 150 ° C. for 30 minutes to perform press molding, and after curing, cooling at room temperature, demolding, and average thickness A fiber-reinforced composite material in which a thermoplastic resin composition was formed on a 0.7 mm laminate was produced. The glass transition temperature of this fiber reinforced composite material was 130 ° C. The absolute value of the difference in total surface free energy between the thermosetting resin composition of the fiber reinforced composite material and the film-like thermoplastic resin composition was 5. The absolute value of the difference in total surface free energy between the reinforced fiber of the fiber reinforced composite material and the film-like thermoplastic resin composition was 4. The vertical adhesive strength of this fiber reinforced composite material was 1 MPa in a 40 ° C. atmosphere and 0.4 MPa in a 140 ° C. atmosphere. Furthermore, this fiber reinforced composite material had a flexural modulus of 25 GPa and an electromagnetic wave shielding property of 55 dB.

The obtained fiber-reinforced composite material was subjected to cross-sectional observation by TEM and SEM in the same manner as in Example 1 , but it was found that continuous filaments were not arranged in the thermoplastic resin layer.

(Comparative Example 3)
The matrix resin is an epoxy resin (thermosetting resin) and consists of a group of reinforcing fibers composed of a large number of carbon filaments (Toray Industries, Inc., trading card, {O / C} = 0.08) arranged in one direction. From the prepreg in which the content of the reinforcing fiber group is 70% by weight (Wf) and 61% by volume (Vf), the fiber direction is 45 °, −45 °, 90 ° with the length direction as 0 ° direction. 5 sheets of prepreg sheets cut into a length of 350 mm and a width of 300 mm so as to be −45 ° and 45 ° are prepared, and the fiber directions are 45 °, −45 °, 90 °, −45 °, and 45 ° from the top. Then, a laminated prepreg sheet was produced.
On the other hand, pellets of polypropylene resin (manufactured by Mitsui Sumitomo Polyolefin Co., Ltd., melting point 165 ° C., solubility parameter δ (SP value) 8.3) were used as the thermoplastic resin composition, and 3 at 200 ° C. while applying a pressure of 18 MPa. The substrate was pressed for a minute to produce a film-like base material for thermal bonding having a basis weight of 80 g / m ² . This heat bonding base material was cut into a rectangular shape having a length of 350 mm and a width of 300 mm, and was laminated on the upper surface of the laminated prepreg sheet so that the length direction and the width direction coincided.

  Next, press molding was performed. In a press molding machine, preheating was performed at 180 ° C. for 5 minutes to melt the base material for thermal bonding, and then the thermosetting resin was cured by heating at 150 ° C. for 30 minutes while applying a pressure of 6 MPa. After completion of curing, the mixture was cooled at room temperature and demolded to produce a fiber-reinforced composite material in which a thermoplastic resin composition was formed on a laminate having an average thickness of 0.7 mm. The glass transition temperature of this fiber reinforced composite material was 130 ° C. The absolute value of the difference in total surface free energy between the thermosetting resin composition of the fiber reinforced composite material and the film-like thermoplastic resin composition was 7. The absolute value of the difference in total surface free energy between the reinforcing fiber of the fiber-reinforced composite material and the film-shaped thermoplastic resin composition was 7. The vertical adhesive strength of this fiber reinforced composite material was 1.5 MPa in a 40 ° C. atmosphere and 1 MPa in a 140 ° C. atmosphere. Furthermore, this fiber reinforced composite material had a flexural modulus of 25 GPa and an electromagnetic wave shielding property of 55 dB.

  When the obtained fiber reinforced composite material was subjected to cross-sectional observation by TEM and SEM, it was found that continuous filaments were arranged in the thermoplastic resin layer. That is, it was shown that the reinforced fiber exists in the thermosetting resin layer and the thermoplastic resin layer of the fiber reinforced composite material and reinforces the interface between the two resins.

From Examples 1 and 2, Reference Examples 1 and 2 and Comparative Examples 1 to 3, the following was revealed.

In the integrated molded products of Examples 1 and 2 and Reference Examples 1 and 2, the fiber-reinforced composite material is firmly bonded, and the adhesive strength value at room temperature is also excellent. In addition, it is clear that the adhesive strength is greatly reduced in a 140 ° C. atmosphere, and is easily peeled and decomposed, and the thermosetting resin composition and the thermoplastic resin composition are easily separated and excellent in reusability. . The case bonded with the acrylic adhesive of Comparative Example 1 is excellent in adhesive strength at 40 ° C., but still has high adhesive strength even at 140 ° C., and it is difficult to disassemble each resin composition. It is not easy to reuse.

In the fiber reinforced composite materials of Examples 1 and 2 , the two fiber reinforced composite materials are firmly bonded, and the adhesive strength value is also excellent. In the fiber reinforced composite materials of Comparative Examples 2 and 3, the adhesion between the two fiber reinforced composite materials is weak, and the value of the adhesive strength is also low.

It is a perspective view of one Example which used the integrated molded product (III) of this invention as the electronic device housing | casing which is an electromagnetic wave shield molded product. It is a perspective view of the molded product used for vertical adhesive strength evaluation of this invention. It is a disassembled perspective view for demonstrating the manufacturing process of one Example which used the electromagnetic wave shield molded article (III) of this invention as the model housing | casing of an electrical / electronic device. It is an adhesive strength evaluation test piece shape based on ISO4587 of the fiber reinforced composite material of the present invention. The contact angle θ between the flat plate and the solvent is illustrated. It is a schematic diagram of the vertical adhesive strength evaluation apparatus of the fiber reinforced composite material of this invention. The average thickness of the film of the fiber reinforced composite material of this invention is typically illustrated.

Explanation of symbols

I: Fiber reinforced composite material constituting electromagnetic wave shield molding (I)
II: Another structural member constituting the electromagnetic wave shield molding (II)
III: Integrated electromagnetic shield (III)
TP1: Specimen TP1L: Length TP1W of Specimen TP1: Width of Specimen TP1 BP: Test piece joint BPL: Specimen joint length a: Tensile jig b: Integrated molded product c: Heat Plastic resin composition d: Reinforcing fiber e: Thermosetting resin composition f: Interface between thermoplastic resin composition and thermosetting resin composition

Claims (23)

A fiber reinforced composite material comprising a reinforced fiber and a thermosetting resin composition, wherein a film made of the thermoplastic resin composition is formed on at least a part of the surface thereof, and the thermoplastic resin composition of the film The solubility parameter δ (SP value) of the thermoplastic resin constituting the resin is 9 to 16, and at least a part of the reinforcing fibers is embedded in the thermosetting resin composition with respect to the same fibers and the heat A fiber-reinforced composite material having both a portion embedded in a plastic resin composition. The fiber-reinforced composite material according to claim 1, wherein the thermoplastic resin is a polyamide-based resin and / or a polyester-based resin. The fiber-reinforced composite material according to claim 1 or 2, wherein the reinforcing fibers are carbon fibers. The surface oxygen concentration {O / C} which is the ratio of the number of oxygen (O) and carbon (C) atoms on the surface of the carbon fiber measured by X-ray photoelectron spectroscopy of the carbon fiber is 0.05 to 0.3. The fiber-reinforced composite material according to claim 3, wherein The fiber reinforced composite material according to any one of claims 1 to 4, wherein an average length of the reinforcing fibers is 10 mm or more, and the long fiber group is laminated and arranged in a layered manner. The fiber-reinforced composite material according to any one of claims 1 to 5, wherein a content of the reinforcing fiber is 5 to 75% by volume. The fiber reinforced composite material according to any one of claims 1 to 6, wherein a glass transition temperature of a thermosetting resin constituting the thermosetting resin composition is 60 ° C or higher. The fiber-reinforced composite material according to any one of claims 1 to 7, wherein the thermosetting resin composition contains at least an epoxy resin. The fiber reinforced composite material according to any one of claims 1 to 8, wherein a glass transition temperature of a thermoplastic resin constituting the thermoplastic resin composition is 15 to 300 ° C. The fiber-reinforced composite material according to any one of claims 1 to 9, wherein a melting point of the thermoplastic resin constituting the thermoplastic resin composition is 100 to 350 ° C. The fiber reinforced composite material according to any one of claims 1 to 10, wherein the thermoplastic resin constituting the thermoplastic resin composition has a weight average molecular weight of 2,000 to 200,000. The fiber reinforced composite material according to any one of claims 1 to 11, wherein an average thickness of a film made of the thermoplastic resin composition is 0.1 to 1000 µm. The fiber-reinforced composite material according to any one of claims 1 to 12, having an average thickness of 0.1 to 3 mm. The fiber-reinforced composite material according to any one of claims 1 to 13, wherein the flexural modulus based on ASTM D790 is 20 GPa or more. The fiber-reinforced composite material according to any one of claims 1 to 14, wherein the radio wave shielding property at a frequency of 1 GHz measured by the Advantest method is 30 dB or more. Lamination in which a thermoplastic resin composition containing a thermoplastic resin having a solubility parameter δ (SP value) of 9 to 16 is disposed on at least a part of the surface of a thermosetting prepreg laminate including reinforcing fibers and a thermosetting resin composition At least a part of the reinforcing fibers is formed by melting the thermoplastic resin composition and forming a coating in parallel with the step and the curing reaction of the thermosetting resin constituting the thermosetting resin composition. And a thermoforming step of providing a structure having both a portion embedded in the thermosetting resin composition and a portion embedded in the thermoplastic resin composition with respect to the same fiber. Manufacturing method. An integrated molded article, wherein the fiber-reinforced composite material according to any one of claims 1 to 15 and another structural member are integrally bonded through a film made of the thermoplastic resin composition. The integrally molded article according to claim 17, wherein the “another structural member” is a metal material. The integrated molded article according to claim 17 , wherein the “another structural member” is the fiber-reinforced composite material according to claim 1. The integrated molded article according to claim 17 , wherein the “another structural member” is a molded article made of a thermoplastic resin composition. The integrated molded article according to claim 20, wherein the molded article made of the thermoplastic resin composition further contains carbon fibers. The integral molded article according to any one of claims 17 to 21, wherein the volume resistivity of the "other structural member" is 100 Ω · cm or less. The integrated molded product according to any one of claims 17 to 22, which is used for any one of a part, a member or a casing of an electric / electronic device, an OA device, a home appliance, an automobile or a building material.

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