JP6503688B2 - Fiber reinforced composite material - Google Patents

Description

  The present invention relates to a fiber-reinforced composite material having excellent mechanical properties.

  Fiber-reinforced composite materials (FRP) are lightweight and have excellent mechanical properties, and they are used in electric and electronic devices, civil engineering and construction applications, machinery and mechanical parts applications, robot applications, two-wheeled vehicles, automotive applications, space and aviation applications. Are widely used. The reinforcing fibers used in these FRPs include metal fibers such as aluminum fibers and stainless steel fibers, organic fibers such as aramid fibers and PBO fibers, inorganic fibers such as silicon carbide fibers, carbon fibers, etc. Carbon fibers are preferably used from the viewpoints of being particularly excellent in specific strength and specific rigidity and obtaining excellent lightness.

  Here, as a typical form of FRP such as carbon fiber reinforced composite material (CFRP), a prepreg or a preform obtained by laminating the prepreg is press-molded (a molding method for defoaming and shaping under pressure) Molded articles can be mentioned. This prepreg is manufactured by impregnating a resin into a reinforced fiber substrate, in which continuous reinforced fibers are arranged in one direction or woven, but discontinuous reinforced fibers are also used. Ru.

  Molded articles obtained by molding prepregs using continuous reinforcing fibers have excellent mechanical properties, but are not suitable for molding complicated shapes because reinforcing fibers are used as a continuous body, and also prepregs Because of the large influence of the lamination angle on the properties, the economic burden of the lamination process limits the use applications.

  On the other hand, sheet molding compound (SMC) using discontinuous reinforcing fibers and glass mat substrate (GMT) are materials suitable for press molding, but mechanical properties such as specific strength and specific rigidity are low. In view of the difficulty in dealing with thin-walled molded products such as prepregs, and the large flow of resin during molding, so that isotropic mechanical characteristics can not be obtained, and the characteristic variation is large. Usage is limited.

  In addition, since the adhesion between the reinforcing fiber and the matrix resin affects the mechanical properties such as tensile strength of the fiber reinforced composite material, the interface design of the reinforcing fiber and the matrix resin is extremely important in developing the fiber reinforced composite material. It is a difficult task.

  Patent Document 1 proposes a carbon fiber having a carbodiimide reagent attached to the surface, and it is described that the adhesion to a thermoplastic resin to be a matrix resin is excellent and the bending strength is improved. Problems remain in terms of interface strength, and further improvement in strength is desired.

  Patent Document 2 also discloses a technique for a surface modifier for carbon fiber containing an organic compound having two or more carbodiimide bonds in the molecule and a carbon fiber modified with the modifier. Similarly, problems remain in terms of the interfacial strength between the reinforcing fiber and the matrix resin, and it is desirable to further improve the strength of the molded article.

  Further, Patent Document 3 also discloses a resin composition of a fiber as an aliphatic polycarbodiimide resin and an inorganic filler in a polyarylene sulfide resin, but also the tensile strength of a molded article is insufficient, and further Strength improvement is desired.

Unexamined-Japanese-Patent No. 5-106163 Unexamined-Japanese-Patent No. 5-311069 JP 2005-239917 A

  An object of the present invention is to solve the problems of the prior art and to provide a fiber-reinforced composite material excellent in mechanical properties such as tensile strength.

  The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, localize the adhesive compound at the reinforcing fiber interface to control the abundance ratio of the adhesive compound in the vicinity of the reinforcing fiber, and the adhesiveness with the reinforcing fiber. It has been found that the tensile strength of the resulting fiber-reinforced composite material is dramatically improved, and the present invention has been completed.

The fiber reinforced composite material of the present invention for solving such problems comprises the following constitution. That is, it contains at least a thermoplastic resin (A), an adhesive compound (B) and a reinforcing fiber (C), and the adhesive compound (B) is at least selected from the group consisting of a carbodiimide structure, a urea structure and a urethane structure. It is a compound having one or more structures in one molecule, the thermoplastic resin (A) is a polyarylene sulfide , and the reinforcing fiber (C) comprises a carboxyl group, a hydroxyl group, an amino group and an epoxy group. A reinforcing fiber to which a compound having at least one functional group selected from a group and having two or more functional groups in one molecule is attached, and using energy dispersive X-ray spectroscopy (EDX), R (≦ 500 nm) as follows: the presence of the respective regions of R (> 500 nm) C (carbon atoms) / S when evaluating the ratio of (the sulfur atom), adhesive compound represented by the formula (1) (B) Rb is 1.5 or more, a fiber-reinforced composite material.
Rb = R (≦ 500 nm) / R (> 500 nm) (1)
R (≦ 500 nm) = C (≦ 500) / S (≦ 500) : Abundance of the adhesive compound (B) within about 500 nm around the reinforcing fiber (C) R (> 500 nm) = C (> 500) / S (S) > 500) : Abundance of the adhesive compound (B) outside the 500 nm around the reinforcing fiber (C)

  The fiber-reinforced composite material of the present invention can dramatically improve mechanical properties such as tensile strength because the interface strength between reinforcing fibers and matrix resin is high.

It is a schematic diagram which shows an example of the cross section orthogonal to the axial center direction of the single yarn of the reinforcement fiber (C) in the fiber reinforced composite material of this invention.

  As a result of pursuing the local abundance of the adhesive compound in the fiber reinforced composite material, the inventors of the present invention found that the adhesive compound abundance in a specific area in the fiber reinforced composite material is the mechanical property of the fiber reinforced composite material. It is apparent that the fiber-reinforced composite material of the present invention has been reached.

  The fiber-reinforced composite material of the present invention contains, as components, a reinforcing fiber (C), an adhesive compound (B) and a thermoplastic resin (A). First, each component will be described.

  As the reinforcing fiber (C) used in the fiber-reinforced composite material of the present invention, for example, carbon fiber, glass fiber, aramid fiber, alumina fiber, silicon carbide fiber, boron fiber, metal fiber, natural fiber, mineral fiber and the like can be used These may be used alone or in combination of two or more. Among them, carbon fibers such as PAN-based, pitch-based and rayon-based carbon fibers are preferably used from the viewpoints of high specific strength and high specific rigidity and lightening effect. Further, from the viewpoint of enhancing the economic efficiency of the resulting molded product, glass fiber can be preferably used, and in particular, it is preferable to use carbon fiber and glass fiber in combination from the viewpoint of balance between mechanical properties and economic efficiency. Furthermore, from the viewpoint of enhancing the impact absorbability and shapeability of the resulting molded article, aramid fibers can be preferably used, and in particular, it is preferable to use carbon fibers and aramid fibers in combination from the balance of mechanical properties and impact absorbability. Further, from the viewpoint of enhancing the conductivity of the resulting molded article, reinforcing fibers coated with metals such as nickel, copper and ytterbium can also be used.

  As the carbon fiber, a surface oxygen concentration ratio (O / C) which is a ratio of the number of oxygen (O) to the number of carbon (C) on the surface of the fiber measured by X-ray photoelectron spectroscopy (XPS) is 0.05 What is -0.50 is preferable, More preferably, it is 0.08-0.40, More preferably, it is 0.10-0.30. The higher the surface oxygen concentration ratio (O / C), the more functional groups on the surface of the carbon fiber, which can improve the adhesion between the carbon fiber and the sizing agent, while the surface oxygen concentration ratio (O / C) is If it is too high, there is a concern that the crystal structure on the surface of the carbon fiber may be broken, so a fiber-reinforced composite material having particularly excellent mechanical properties can be obtained within the preferable range of surface oxygen concentration ratio (O / C).

The surface oxygen concentration ratio (O / C) of carbon fiber is determined by X-ray photoelectron spectroscopy according to the following procedure. First, carbon fibers from which sizing agents have been removed with a solvent are cut and spread and arranged on a copper sample support, and then the photoelectron escape angle is set to 90 °, and MgK _{α1, 2} are used as X-ray sources, Keep the inside at 1 × 10 ^-8 Torr. The kinetic energy value (K.E.) of the main peak of C1S is adjusted to 969 eV as correction of the peak accompanying charging during measurement. The C1S peak area is E. It calculates | requires by drawing a straight baseline in the range of 952-972 eV. The O1S peak area is determined by E. It is determined by drawing a straight baseline in the range of 714 to 726 eV. Here, the surface oxygen concentration ratio (O / C) is calculated as an atomic ratio from the ratio of the O1S peak area to the C1S peak area using a sensitivity correction value unique to the device.

  The means for controlling the surface oxygen concentration ratio (O / C) is not particularly limited, but, for example, methods such as electrolytic oxidation treatment, chemical oxidation treatment and gas phase oxidation treatment can be employed, among which electrolysis is particularly preferred. Oxidation treatment is preferred.

  Also, the average fiber diameter of the reinforcing fiber (C) is not particularly limited, but is preferably in the range of 1 to 20 μm, and 3 to 15 μm, from the viewpoint of mechanical properties and surface appearance of the obtained fiber reinforced composite material. It is more preferable to be within the range.

  The reinforcing fiber (C) may be used as a reinforcing fiber bundle obtained by bundling a plurality of single yarns from the viewpoint of handleability. The number of single yarns constituting the reinforcing fiber bundle is preferably 100 or more and 350,000 or less, more preferably 1,000 or more and 250,000 or less, more preferably 10,000 or more and 100, from the viewpoint of handling. Or less is more preferable. By setting the number of single yarns constituting the reinforcing fiber bundle in such a range, the fiber-reinforced composite material of the present invention can be obtained economically.

  The number average fiber length of the reinforcing fibers (C) is preferably 0.1 mm to 50 mm. It is more preferable that it is 0.1 mm-20 mm from a viewpoint of the moldability of a fiber reinforced composite material.

  As a method of measuring the number average fiber length, for example, a method in which the resin component contained in the fiber-reinforced composite material is removed by a dissolution method or a burn-out method, and the remaining reinforcing fibers are separated by filtration and measured by a microscope. Alternatively, there is a method in which a fiber reinforced composite material is thinly stretched by a melting method and the reinforcing fibers are observed through transmission. In the measurement, 400 reinforcement fibers were randomly selected, the length was measured with an optical microscope to 1 μm unit, Σ Li / 400 (Li: measured fiber length (i = 1, 2, 3,..., 400) The number average fiber length is calculated from the method of extracting reinforcing fibers from the fiber reinforced composite material by the baking method or the dissolving method, and the method of thinly stretching a molded product by the melting method and observing the reinforcing fibers as There is no particular difference in the results obtained.

  In order to further improve the adhesion of the reinforcing fiber (C) in the fiber-reinforced composite material, the reinforcing fiber (C) contains at least one functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an amino group and an epoxy group. It is preferable that a compound having two or more in one molecule (hereinafter, abbreviated as compound (E)) is attached. Two or more types of functional groups may be mixed in one molecule, and two or more types of compounds having one or more functional groups in one molecule may be used in combination. The compound (E) is preferably an aliphatic compound. By making the compound (E) into an aliphatic compound, the affinity with the reinforcing fiber (C) and the adhesive compound (B) is enhanced, and a fiber-reinforced composite material having excellent mechanical properties is obtained, which is preferable.

  Specific examples of the compound (E) include polyfunctional epoxy resin, acrylic acid type polymer, polyhydric alcohol, polyethylene imine and the like, and in particular, both of the surface functional group of the reinforcing fiber (C) and the adhesive compound (B) Polyfunctional epoxy resins having high reactivity with are preferred.

  As a polyfunctional epoxy resin, trifunctional or more than trifunctional aliphatic epoxy resin, a phenol novolak-type epoxy resin, etc. are mentioned. Among them, trifunctional or higher aliphatic epoxy resins are preferable from the viewpoint of affinity with the fatty carbodiimide compound. The trifunctional or higher aliphatic epoxy resin means an aliphatic epoxy resin having three or more epoxy groups in one molecule.

  Specific examples of the trifunctional or higher aliphatic epoxy resin include, for example, glycerol triglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, arabitol polyglycidyl ether, trimethylolpropane triglycidyl ether And polyglycidyl ethers of aliphatic polyhydric alcohols such as pentaerythritol polyglycidyl ether. Among these aliphatic epoxy resins, glycerol triglycidyl ether and diglycerol poly are preferred because they contain many highly reactive epoxy groups in one molecule, are highly water soluble, and are easy to apply to reinforcing fibers (C). Glycidyl ether and polyglycerol polyglycidyl ether are preferably used in the present invention.

  The acrylic acid-based polymer in the present invention is a polymer of acrylic acid, methacrylic acid and maleic acid, and is a generic term for polymers containing three or more carboxyl groups in one molecule. Specifically, polyacrylic acid, a copolymer of acrylic acid and methacrylic acid, a copolymer of acrylic acid and maleic acid, or a mixture of two or more of these may be mentioned. Furthermore, as long as the number of the functional groups in the molecule is 3 or more in one molecule, the acrylic acid-based polymer may be one in which the carboxyl group is partially neutralized with alkali (that is, as a carboxylate). good. Examples of the alkali include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide and potassium hydroxide, and ammonium hydroxide. As the acrylic acid-based polymer, polyacrylic acid containing more carboxyl groups in one molecule is preferably used.

  Specific examples of polyhydric alcohol in the present invention include polyvinyl alcohol, glycerol, diglycerol, polyglycerol, sorbitol, arabitol, trimethylolpropane, pentaerythritol and the like. As the polyhydric alcohol, polyvinyl alcohol containing more hydroxyl groups in one molecule is preferably used.

  The polyethyleneimine in the present invention is a polyamine obtained by ring-opening polymerization of ethyleneimine and having a branched structure by primary, secondary and tertiary amino groups. As polyethylene imine, polyethylene imine containing more amino groups in one molecule is preferably used.

  It is preferable that the value which remove | divided the mass mean molecular weight by the number of the said functional groups (total of a carboxyl group, a hydroxyl group, an amino group, and an epoxy group) in 1 molecule is 40-150 for a compound (E). With this range, the density of the reaction points with the surface functional group of the reinforcing fiber (C) and the functional group of the adhesive compound (B) can be made more uniform, and the tensile strength of the resulting fiber-reinforced composite material Such mechanical properties can be further enhanced.

  In the fiber-reinforced composite material of the present invention, when the compound (E) is used, the content thereof is 0. 0 to 100 parts by mass of the reinforcing fiber (C) in order to efficiently improve the strength of the fiber-reinforced composite material. It is preferable to set it as 01-5 mass parts, and it is more preferable to set it as 0.1-2 mass parts.

  As a method of attaching the compound (E) to the reinforcing fiber (C), for example, a method of attaching as a sizing agent of the reinforcing fiber (C) can be exemplified. As a means for applying the sizing agent to the reinforcing fiber (C), for example, a method in which the reinforcing fiber (C) is dipped in the sizing agent through a roller, a method in which the sizing agent is atomized and sprayed on the reinforcing fiber (C) Can be mentioned. At this time, it is preferable to control the temperature at the time of applying or diluting the sizing agent with a solvent, yarn tension and the like so that the adhesion amount of the sizing agent to the reinforcing fiber (C) becomes more uniform. Examples of the solvent for diluting the sizing agent include water, methanol, ethanol, dimethylformamide, dimethylacetamide, acetone, toluene and the like, but water is preferable from the viewpoint of easy handling and disaster prevention. Such a solvent is removed by evaporation by heating after applying the sizing agent to the reinforcing fiber (C). When a compound insoluble or sparingly soluble in water is used as a sizing agent, it is preferable to add an emulsifier or surfactant and disperse in water. As an emulsifier or surfactant, an anionic emulsifier, a cationic emulsifier, a nonionic emulsifier etc. can be used. Among these, it is preferable to use a nonionic emulsifier having a small interaction since the effect of the sizing agent is hardly inhibited.

  The adhesive compound (B) used in the fiber-reinforced composite material of the present invention is a compound having two or more structures of at least one selected from the group consisting of a carbodiimide structure, a urea structure and a urethane structure in one molecule. Among them, polycarbodiimide is preferably used from the viewpoint of interfacial adhesion with reinforcing fibers.

  Examples of polycarbodiimides include aliphatic polycarbodiimides and aromatic polycarbodiimides, and aliphatic polycarbodiimides are preferably used from the viewpoint of reactivity with a thermoplastic resin.

Aliphatic polycarbodiimides have the general formula -N = C = N-R _3- (wherein R ₃ is a divalent organic group of an alicyclic compound such as cyclohexylene, or methylene, ethylene, propylene, methyl ethylene) And the like. The repeating unit represented by the divalent organic group of an aliphatic compound such as is a main constituent unit, preferably 70 mol% or more, more preferably 90 mol% or more, and still more preferably 95 It is a homopolymer or copolymer containing mol% or more.

  As the adhesive compound (B) having a urea structure, those obtained by reacting diisocyanate with a diamine containing a compound containing a plurality of amino groups (for example, hydrazine, dihydrazide, etc.) can be used. Alternatively, polyurea, which is an adhesive compound (B) having a plurality of urea structures, can be synthesized by reacting an isocyanate with water to form an unstable carbamic acid. The carbamic acid decomposes to generate carbon dioxide which immediately reacts with the excess isocyanate to form an amino group which forms a urea bridge. Alternatively, it can also be obtained by treating a compound having a carbodiimide structure with water to react the carbodiimide with urea.

  As the adhesive compound (B) having a urethane structure, those obtained by reacting bischloroformate with a diamine can be used. Alternatively, a polyurethane which is an adhesive compound (B) having a plurality of urethane structures can be synthesized by reacting a diisocyanate with a diol such as macroglycol, a polyol, or a combination of macroglycol and a single chain glycol extender. .

  The adhesive compound (B) preferably has a weight average molecular weight of 500 to 10,000, and more preferably 1,000 to 5,000. When the mass average molecular weight of the adhesive compound (B) is in this range, the adhesive compound (B) is relatively easy to flow during heat melting such as molding, and it is too fluid to diffuse so that adhesion is impaired. Since it does not exist, it tends to be localized around the reinforcing fiber (C), and it is presumed that the improvement of mechanical properties such as tensile strength, which is the effect of the present invention, can be achieved at a high level. The mass average molecular weight of the adhesive compound (B) can be determined by an analysis method such as SEC (size exclusion chromatography).

  The thermoplastic resin (A) used in the fiber-reinforced composite material of the present invention has a repeating unit structure of the main chain from the viewpoint of increasing the polarity and increasing the affinity to the reinforcing fiber (C) and the adhesive compound (B). It is necessary to contain an element other than carbon in it, and more specifically polycarbonate, polyester, polyarylene sulfide, polyamide from the viewpoint of the interfacial adhesion with the reinforcing fiber (C) and the formability of the fiber reinforced composite material. It is preferable that it is at least one thermoplastic resin selected from the group consisting of polyoxymethylene, polyether imide, polyether ketone and polyether ether ketone. In addition, the thermoplastic resin (A) has a molecule of at least one functional group selected from the group consisting of a carboxyl group, a hydroxyl group and an amino group from the viewpoint of adhesion with the reinforcing fiber (C) and the adhesive compound (B). It is preferable to have at least one of them.

  The thermoplastic resin (A) preferably has a weight average molecular weight of 10,000 to 80,000, more preferably 10,000 to 60,000, and still more preferably 10,000 to 40,000. is there. The lower the mass average molecular weight of the thermoplastic resin (A), the lower the melt viscosity, and the resulting fiber-reinforced composite material is preferred because it is excellent in molding processability.

  In the fiber-reinforced composite material of the present invention, mechanical properties such as tensile strength of the obtained fiber-reinforced composite material tend to improve as the thermoplastic resin (A) having a smaller mass average molecular weight. The cause of this is that the functional group possessed by the thermoplastic resin (A) chemically reacts with the functional group of the adhesive compound (B), and the smaller the mass average molecular weight of the thermoplastic resin (A) the functional group present at the end It is presumed that the relative increase is due to an increase in the reaction point with the adhesive compound (B). This effect is particularly remarkable when polyarylene sulfide having low adhesion to reinforcing fibers (C) is used as the thermoplastic resin (A). For these reasons, in the fiber-reinforced composite material of the present invention, setting the mass average molecular weight of the thermoplastic resin (A) in the range of 10,000 to 40,000 enhances the mechanical properties of the resulting fiber-reinforced composite material. It is particularly preferable because it can be achieved at the same level and compatible with the molding processability.

  The mass average molecular weight of the thermoplastic resin (A) can be measured by size exclusion chromatography (SEC). In SEC, the mass average molecular weight of the thermoplastic resin (A) is calculated as a mass average molecular weight in terms of polystyrene.

  The fiber-reinforced composite material of the present invention may contain an impact resistance improver such as an elastomer or a rubber component, and other fillers and additives as long as the effects of the present invention are not impaired. Examples of additives include flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet light absorbers, antioxidants, damping agents, antibacterial agents, insect repellents, deodorants, coloring inhibitors, heat stabilizers, mold release And antistatic agents, plasticizers, lubricants, colorants, pigments, dyes, foaming agents, or foam control agents.

  In the fiber-reinforced composite material of the present invention, the adhesive compound (B) is preferably contained in an amount of 0.1 to 10 parts by mass with respect to 100 parts by mass of the thermoplastic resin (A), and 0.1 to 5 parts It is more preferable that the component is contained. When the content of the adhesive compound (B) is in this range, it is an amount sufficient to enhance the affinity between the reinforcing fiber (C) and the thermoplastic resin (A), and the thermoplastic resin (A) It is preferable that the amount thereof is appropriate, and the influence on the cost is also a slight amount, and the mechanical properties of the fiber-reinforced composite material can be efficiently improved. When the content of the adhesive compound (B) is less than 0.1 parts by mass, the amount of the adhesive compound (B) is not sufficient, and the effect of improving mechanical properties such as tensile strength of the obtained fiber-reinforced composite material is small There is a case. When the content of the adhesive compound (B) exceeds 10 parts by mass, the adhesive compound (B) is too large, so the effect of improving mechanical properties such as tensile strength of the obtained fiber-reinforced composite material is small There is a case.

  In the fiber-reinforced composite material of the present invention, the reinforcing fiber (C) is preferably contained in an amount of 10 to 300 parts by mass, preferably 10 to 200 parts by mass, per 100 parts by mass of the thermoplastic resin (A). The content is more preferably 20 to 100 parts by mass, more preferably 20 to 50 parts by mass. When the content of the reinforcing fiber (C) is less than 10 parts by mass, the amount of the reinforcing fiber (C) may not be sufficient, and the effect of improving mechanical properties such as tensile strength of the obtained fiber reinforced composite material may be small. When the content of the reinforcing fiber (C) exceeds 300 parts by mass, the degree of difficulty in combining the reinforcing fiber (C) with the matrix resin containing the thermoplastic resin (A) and the adhesive compound (B) increases. In some cases, the effect of improving mechanical properties such as tensile strength of the fiber-reinforced composite material to be obtained is small.

In the fiber-reinforced composite material of the present invention, the abundance ratio Rb of the adhesive compound (B) represented by the formula (1) needs to be 1.2 or more, and the reinforcing fiber (C) and the adhesive compound (B) From the viewpoint of interfacial adhesion, the abundance ratio Rb is preferably 1.5 or more.
Rb = R (≦ 500 nm) / R (> 500 nm) (1)
R (≦ 500 nm): Abundance of adhesive compound (B) within 500 nm around reinforcing fiber (C) R (> 500 nm): Presence of adhesive compound (B) outside 500 nm around reinforcing fiber (C)

  When the abundance ratio Rb is less than 1.2, the interfacial adhesion between the reinforcing fiber (C) and the adhesive compound (B) is deteriorated, and the mechanical properties of the fiber-reinforced composite material, in particular, the tensile strength affecting the interfacial adhesion is deteriorated. .

  In addition, from the viewpoint of controlling the degree of aggregation of the adhesive compound (B) on the surface of the reinforcing fiber (C), the abundance ratio Rb is preferably 10 or less, more preferably 5 or less, and 3. More preferably, it is 5 or less.

  The abundance ratio Rb is, for example, adhesion using energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), etc. Measure the characteristic elements (nitrogen atom, oxygen atom, etc.), molecules, and bonding states contained in the compound (B) by measuring R (≦ 500 nm) and R (> 500 nm) in the vicinity of the reinforcing fiber (C) to obtain a ratio It can be calculated by taking it. Also, by mapping the abundance ratio, it is possible to know the abundance at each location.

  FIG. 1: represents typically the example observed in the cross section orthogonal to the axial center direction of the single yarn of the reinforced fiber (C) contained about the fiber reinforced composite material of this invention. A region (region 2 within 500 nm around reinforcing fiber (C) in FIG. 1) has a large amount of the adhesive compound (B) at the outer periphery of the cross section of the reinforcing fiber (C) (reinforcing fiber single yarn 1 in FIG. 1) Of the matrix resin containing the adhesive compound (B) and the thermoplastic resin (A), it is composed of a region in which the ratio of the adhesive compound (B) is high. Further, the region where the adhesive compound (B) is present in a small amount (region 3 outside the peripheral 500 nm around the reinforcing fiber (C) in FIG. 1) is a matrix resin containing the adhesive compound (B) and the thermoplastic resin (A) Among these, it comprises from a field with a large rate of thermoplastic resin (A). Here, 500 nm around the reinforcing fiber (C) means that the length (the length 4 from the reinforcing fiber (C) in FIG. 1) obtained by drawing a straight line vertically from the tangent of the reinforcing fiber (C) is 500 nm Show. In order to carry out the measurement of the energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), etc. more accurately, for example, The measurement site area can be largely secured by measuring the cross section of the fiber-reinforced composite material produced by giving an inclination angle from the cross section orthogonal to the axial direction of the single yarn of the reinforcing fiber (C).

  As an example for obtaining the fiber-reinforced composite material of the present invention, a method of melt-kneading using an extruder can be exemplified. As an extruder, a single-screw extruder and a twin-screw extruder can be illustrated, and among them, a twin-screw extruder excellent in kneadability can be preferably used. As a twin-screw extruder, that whose ratio L / D of screw length L and screw diameter D is 20-100 can be illustrated. Furthermore, the screw of the twin-screw extruder is configured by combining screw segments having different length and shape characteristics such as full flight and kneading disks, but from the point of improvement of kneadability and reactivity, one or more screws It is preferable to include a kneading disc of As melt-kneading conditions, the cylinder temperature at the time of melt-kneading is preferably 250 to 400 ° C., more preferably 280 to 350 ° C., and still more preferably 280 to 310 ° C. from the viewpoint of improving kneadability and reactivity. By using the twin-screw extruder having such a configuration, the reaction between functional groups of each component proceeds in the cylinder of the twin-screw extruder, and mechanical properties such as tensile strength of the obtained fiber-reinforced composite material are improved.

  As a first method for obtaining the fiber-reinforced composite material of the present invention using the extruder, a method of melt-kneading reinforcing fiber (C), adhesive compound (B) and thermoplastic resin (A) is used. It can be mentioned. Furthermore, when melt-kneading the reinforcing fiber (C), the adhesive compound (B) and the thermoplastic resin (A), the thermoplastic resin (A) and the adhesive compound (B) are melt-kneaded, and then the reinforcing fiber It is preferable to select the method of complexing with (C). With such a configuration, the adhesive compound in the thermoplastic resin (A) is compared to the method of melt-kneading the thermoplastic resin (A) and then combining the adhesive compound (B) and the reinforcing fiber (C). The diffusion of (B) can be easily controlled, and furthermore, the reinforcing fiber (C) can be compared to a method in which the thermoplastic resin (A) and the reinforcing fiber (C) are melt-kneaded and then the adhesive compound (B) is compounded. The aggregation of the adhesive compound (B) on the surface can be easily controlled, and a fiber-reinforced composite material having a controlled abundance ratio Rb can be produced with high productivity.

  When melt-kneading the reinforcing fiber (C), the adhesive compound (B) and the thermoplastic resin (A), the thermoplastic resin (A) and the adhesive compound (B) are melt-kneaded, and then the reinforcing fiber (C) As a method of making it complex, and the thermoplastic resin (A) and an adhesive compound (B) can be main-fed to an extruder, and the method of side-feeding reinforcing fibers (C) can be illustrated.

  More preferably, a method of carrying out the introduction of the reinforcing fiber (C) as early as possible can be exemplified. By accelerating the introduction of the reinforcing fiber (C), the reinforcing fiber (C) and the adhesive compound (B) approach each other by reaction or interaction, and the adhesive compound (B) reaches 500 nm around the reinforcing fiber (C) The localization in the following manner is preferable because in the fiber-reinforced composite material, the interfacial strength between the reinforcing fiber (C) and the adhesive compound (B) can be increased and mechanical properties such as tensile strength can be improved. For this reason, the range of 20 to 70% of the distance from the position of the main feed to the extruder to the discharge port of the extruder can be exemplified as the side feed position to the extruder, and the range of 20 to 50% is more preferable. In addition, lowering the cylinder temperature of the extruder makes it difficult for the adhesive compound (B) to flow during melting to control the diffusion of the fiber-reinforced composite material in the matrix resin, and around the reinforcing fibers (C). It is also possible to localize the adhesive compound (B). In this method, a melt-kneaded product in which reinforcing fibers (C) are randomly dispersed is obtained, and this melt-kneaded product is suitably used for injection molding and the like by forming it into pellets. In the case of molding by injection molding, moldings of complicated shapes can be produced with high productivity. In addition, lowering the cylinder temperature also during injection molding makes it difficult for the adhesive compound (B) to flow at the time of melting to control the diffusion of the fiber-reinforced composite material in the matrix resin, thereby reinforcing the reinforcing fiber (C It is also possible to localize the adhesive compound (B) in the vicinity of).

  As a second method for obtaining the fiber-reinforced composite material of the present invention using the above-mentioned extruder, a resin composition prepared by melt-kneading the adhesive compound (B) and the thermoplastic resin (A) in advance is a reinforcing fiber ( The method of making it complex with the fiber base material using C) is mentioned. In this case, even when the adhesive compound (B) and the thermoplastic resin (A) are mixed in advance, when the resin composition is compounded with the reinforcing fiber (C), the adhesive compound (B) is a thermoplastic resin It does not react with (A) but is simply kneaded. Therefore, the fiber reinforcement is achieved by the reinforcing fiber (C) and the adhesive compound (B) coming close to each other by reaction or interaction, and the adhesive compound (B) localizing to 500 nm or less around the reinforcing fiber (C). In the composite material, the interfacial strength between the reinforcing fiber (C) and the adhesive compound (B) can be increased, and mechanical properties such as tensile strength can be improved. The shape of the fiber base is, for example, a unidirectional alignment base in which continuous reinforcing fibers are arranged in one direction to form a sheet, woven fabric (cross), non-woven fabric, mat, knitting, braid, yarn, tow, etc. It can be mentioned. The form of the composite includes impregnation, coating, lamination, etc., but since the fiber reinforced composite material having a small number of voids and excellent mechanical properties such as tensile strength and elongation can be obtained, It is preferable that the fiber base material be impregnated. Such a fiber-reinforced composite material can be formed by press molding, stamping, autoclave molding, filament winding molding, transfer molding, and if it is a finely divided substrate, it can also be formed by injection molding. Among them, press molding, stamping molding and injection molding are preferably used in view of the balance between productivity of molded articles and mechanical properties.

  The fiber-reinforced composite material of the present invention is suitable as an electronic device housing, and is suitably used for a computer, a television, a camera, an audio player and the like.

  The fiber-reinforced composite material of the present invention is suitable for electrical and electronic component applications, and connectors, LED lamps, sockets, optical pickups, terminal boards, printed boards, printed boards, speakers, small motors, magnetic heads, power modules, generators, motors, It is suitably used for transformers, current transformers, voltage regulators, rectifiers, inverters and the like.

  The fiber-reinforced composite material of the present invention is suitable for automobile parts and vehicle-related parts, etc., and may be safety belt parts, instrument panels, console boxes, pillars, roof rails, fenders, bumpers, door panels, roof panels, hood panels, trunks. Lid, door mirror stay, spoiler, hood louver, wheel cover, wheel cap, garnish, intake manifold, fuel pump, engine coolant joint, window washer nozzle, wiper, battery peripheral parts, wire harness connector, lamp housing, lamp reflector, lamp It is suitably used for a socket etc.

  The fiber reinforced composite material of the present invention is suitable as a building material, and wall, roof, ceiling material related parts, window material related parts, heat insulating material related parts, floor material related parts, seismic isolation vibration control member related parts for civil engineering buildings , Lifeline related parts etc. are preferably used.

  The fiber reinforced composite material of the present invention is suitable as a sporting goods, and golf club shafts, golf related products such as golf balls, sports racquet related products such as tennis racquets and badminton racquets, American football and baseball, softballs, etc. It is suitably used for sports personal protection products such as masks, helmets, bibs, elbow pads and knee pads, fishing gear related products such as fishing rods, reels and lures, and winter sports related products such as skis and snowboards.

Hereinafter, the present invention will be more specifically described by way of examples. In addition, Example 2, 5-11 is a reference example now, and Example 1, 3, 4 is an Example of this invention.

  First, the evaluation method used in the present invention will be described below.

(1) Number Average Fiber Length of Reinforcing Fiber (C) Contained in Fiber-Reinforced Composite Material A portion of the fiber-reinforced composite material is cut out, and the temperature of melting point + 30 ° C of thermoplastic resin (A), softening temperature + 150 ° C, glass The film was heat-pressed under any of the conditions of transition temperature + 150 ° C (310 ° C if the thermoplastic resin (A) is polyphenylene sulfide and 300 ° C if polycarbonate is a polycarbonate) to obtain a 30 μm thick film. The obtained film was observed at a magnification of 150 with an optical microscope, and the reinforcing fibers dispersed in the film were observed. The length was measured to 1 μm, and the number average fiber length (Ln) was determined by the following equation.
Number average fiber length (Ln) = (ΣLi) / Ntotal
Li: Measured fiber length (i = 1, 2, 3, ..., n)
Ntotal: Total number of fibers measured

(2) Abundance ratio Rb of adhesive compound (B) of fiber reinforced composite material
When the thermoplastic resin (A) was polyphenylene sulfide, it was determined according to the following procedure. First, the ratio of C (carbon atom) / S (sulfur atom) was evaluated for each region of R (≦ 500 nm) and R (> 500 nm) using energy dispersive X-ray spectroscopy (EDX). C / S produced the specimen for observation from a fiber reinforced composite material by FIB micro sampling method using a focused ion beam (FIB) apparatus. Next, the number of carbon atoms and the number of sulfur atoms in a predetermined range were detected according to the following apparatus and conditions, and the obtained number of carbon atoms was divided by the number of sulfur atoms to obtain a sulfur concentration ratio C / S in that range. By this method, it can be determined whether C (carbon atom) is more or less than C / S of polyarylene sulfide at the measurement site, and is there more compounds other than polyarylene sulfide, ie, adhesive compound (B) Since it is possible to know whether the amount is small, it is possible to indirectly know the amount of the adhesive compound (B) at the measurement site, and substituting each C / S into the formula (1) to bond the fiber-reinforced composite material The abundance ratio Rb of the sex compound (B) was determined.
R (≦ 500 nm) = C (≦ 500) / S (≦ 500): Abundance of the adhesive compound (B) within about 500 nm around the reinforcing fiber (C) R (> 500 nm) = C (> 500) / S (S) > 500): Abundance of the adhesive compound (B) outside 500 nm around a reinforcing fiber (C) Rb = R (≦ 500 nm) / R (> 500 nm) (1)
Device: Atomic resolution analysis electron microscope (STEM); JEM-ARM200F (manufactured by JEOL)
Energy dispersive X-ray analyzer; JED-2300 (manufactured by JEOL)
Measurement condition: Acceleration voltage; 200kV
beam spot size; 0.2 nmφ

  When the thermoplastic resin (A) was a polycarbonate, the same evaluation as described above was performed for O (oxygen atom) instead of S (sulfur atom) to measure Rb.

(3) Tensile Test of Fiber-Reinforced Composite Material In accordance with ASTM D638, Type-I test pieces were used, and "Instron (registered trademark)" universal tester (manufactured by Instron) was used as a testing machine.

  Next, materials used in Examples and Comparative Examples of the present invention will be described.

The reinforcing fibers (C) used in any of Examples 1 to 11 or Comparative Examples 1 to 7 are as follows.
(Reinforcing Fiber-1) A continuous carbon fiber strand having a total number of 12,000 single filaments was obtained by performing spinning, baking treatment, and surface oxidation treatment using a copolymer containing polyacrylonitrile as a main component. . The properties of this carbon fiber were as follows.
Tensile strength: 4,900MPa
Tensile modulus of elasticity: 240 GPa
Tensile elongation: 2%
Specific gravity: 1.8
Single yarn diameter: 7 μm
Surface oxygen concentration ratio [O / C]: 0.12
(Reinforcing Fiber-2) A continuous carbon fiber strand having a total number of 12,000 single filaments was obtained by performing spinning, baking treatment, and surface oxidation treatment using a copolymer containing polyacrylonitrile as a main component. . The properties of this carbon fiber were as follows.
Tensile strength: 4,900MPa
Tensile modulus of elasticity: 230 GPa
Tensile elongation: 2%
Specific gravity: 1.8
Single yarn diameter: 7 μm
Surface oxygen concentration ratio [O / C]: 0.06
(Reinforcing Fiber-3) A continuous glass fiber strand made of E-Glass and having a total of 1,600 single filaments. The properties of this reinforcing fiber were as follows.
Tensile strength: 3,400MPa
Tensile modulus of elasticity: 72 GPa
Tensile elongation: 3%
Specific gravity: 2.6
Single thread diameter: 13 μm

Adhesive compounds (B) used in any of Examples 1 to 11 and Comparative Examples 1 to 7 are as follows.
(Adhesive compound-1) Aliphatic polycarbodiimide "Carbodilite (registered trademark)" HMV-8 CA (manufactured by Nisshinbo Chemical Co., Ltd.) (carbodiimide group equivalent 278, mass average molecular weight 3,000)
(Adhesive compound-2) Aromatic polycarbodiimide "Stabacsol (registered trademark)" P (manufactured by Rhine Chemie Co., Ltd.) (mass average molecular weight 4,000)
(Adhesive compound-3) Aromatic polycarbodiimide "Stabacsol (registered trademark)" P400 (manufactured by Rhine Chemie Co., Ltd.) (mass average molecular weight 20,000)
(Adhesive compound 4) N, N'-dicyclohexylcarbodiimide (manufactured by Wako Pure Chemical Industries, Ltd.) (carbodiimide group equivalent 206, mass average molecular weight 206)

The thermoplastic resin (A) used in Examples 1-11 and Comparative Examples 1-7 is as follows.
(Thermoplastic resin-1) Melting point 285 ° C., mass average molecular weight 30,000, acid-terminated product, polyphenylene sulfide (thermoplastic resin-2) having a chloroform extraction amount of 0.5 mass% melting point 285 ° C., mass average molecular weight 45,000 Acid-terminated product, polyphenylene sulfide (thermoplastic resin -3) polycarbonate "Eupilon (registered trademark)" H-4000 (manufactured by Mitsubishi Engineering Plastics Co., Ltd.) with a chloroform extraction amount of 0.5% by mass (glass transition temperature 145 ° C, mass Average molecular weight 34,500)

The compound (E) used as a sizing agent in any of Examples 1-11 or Comparative Examples 1-7 is as follows.
(E-1) Glycerol triglycidyl ether (manufactured by Wako Pure Chemical Industries, Ltd.)
Mass average molecular weight: 260
Number of epoxy groups per molecule: 3
Weight average molecular weight divided by the total number of carboxyl group, amino group, hydroxyl group, epoxy group and hydroxyl group per molecule: 87
(E-2) Bisphenol A diglycidyl ether (manufactured by SIGMA-ALDRICH)
Mass average molecular weight: 340
Number of epoxy groups per molecule: 2
The mass average molecular weight divided by the total number of carboxyl group, amino group, hydroxyl group, epoxy group and hydroxyl group per molecule: 170
(E-3) (3-glycidyloxypropyl) triethoxysilane (manufactured by SIGMA-ALDRICH)
Mass average molecular weight: 278
Number of epoxy groups per molecule: 1
Weight average molecular weight divided by the total number of carboxyl group, amino group, hydroxyl group, epoxy group and hydroxyl group per molecule: 278
(E-4) 80 mol parts of 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-toluene) in a 300 ml separable flask equipped with a stirrer, a thermometer and a cooling condenser TDI) A mixture of 20 molar parts (trade name: TDI 80, manufactured by Mitsui Toatsu Chemicals, Inc.) 22.4 g (0.128 mol), phenyl isocyanate (PhI) 2.20 g (0.0756 mol, TDI 100 molar parts (14 parts by mol), 110 ml of dry toluene were placed in a nitrogen atmosphere and dissolved uniformly with stirring. Next, 0.0913 g (0.000475 mol, 0.37% / TDI) of 3-methyl-1-phenyl-2-phospholene-1-oxide catalyst diluted in 1 ml of the same solvent as the polymerization solvent was added and stirred. While raising the internal temperature to 110 ° C. The generation of carbon dioxide increased with the temperature rise, and the generation of carbon dioxide was observed particularly violently when the internal temperature exceeded 80 ° C. After the internal temperature reached 110 ° C., polymerization was performed for 3.5 hours. After completion of the polymerization, the reaction solution was cooled to room temperature to obtain a transparent carbodiimide copolymer (15% by mass, polystyrene equivalent mass average molecular weight 3,000). This solution was further diluted to 10% by mass with toluene to obtain a sizing mother liquor containing E-4. (Sizing agent identical to the sizing agent described in Example 1 of Patent Document 2 (Japanese Patent Application Laid-Open No. 5-311069))
(E-5) N, N'-dicyclohexylcarbodiimide (manufactured by Wako Pure Chemical Industries, Ltd.) (carbodiimide group equivalent 206, mass average molecular weight 206)

Example 1
Using the reinforcing fibers (C), the adhesive compound (B) and the thermoplastic resin (A) shown in Table 1, a fiber-reinforced composite material was obtained by the following procedure.

  A sizing agent (E-1) is obtained by continuously taking up a fiber bundle of reinforcing fibers (C), immersing in a water-based sizing mother liquor containing 2% by mass of the sizing agent (E-1), and then heat drying at 230 ° C. Reinforcing fiber (C) surface-treated by. The adhesion amount of the sizing agent (E-1) after drying was 1 part by mass with respect to 100 parts by mass of the reinforcing fiber (C). Further, a reinforcing fiber (C) surface-treated with a sizing agent (E-1) was cut into a length of 6 mm to make a chopped strand.

  The adhesive compound (B) and the thermoplastic resin (A) are main-fed, and the chopped strands are side-fed by using a twin screw extruder (JSW TEX-30α, L / D = 31.5). Melt kneading was performed. The side feed was performed at a position 40% of the distance from the main feed position to the extruder to the outlet of the extruder. Melt-kneading is performed at a cylinder temperature of 290 ° C., screw rotation speed of 150 rpm, and a discharge rate of 10 kg / hour, and it is cooled by a water cooling bath while taking out discharges to make a gut, and cutting the gut into a length of 5 mm did.

  The injection molding machine (JSW company J150EII-P) was used, and the test piece for various evaluation was produced by performing injection molding of the said pellet. Injection molding was performed at a cylinder temperature of 320 ° C. and a mold temperature of 150 ° C.

  The obtained test piece is annealed at 150 ° C. for 2 hours, air-cooled and subjected to each test, and the number average fiber length of reinforcing fibers (C) contained in the fiber reinforced composite material, adhesion of the fiber reinforced composite material The tensile strength of the presence ratio Rb of the sex compound (B) and the tensile strength of the fiber reinforced composite material was measured. The results are shown in Table 5.

(Example 2)
Using the reinforcing fibers (C), the adhesive compound (B) and the thermoplastic resin (A) shown in Table 1, a fiber-reinforced composite material was obtained by the following procedure.

  The reinforcing fiber (C) was cut into a length of 6 mm to make a chopped strand.

  The adhesive compound (B) and the thermoplastic resin (A) are main-fed, and the chopped strands are side-fed by using a twin screw extruder (JSW TEX-30α, L / D = 31.5). Melt kneading was performed. The side feed was performed at a position 40% of the distance from the main feed position to the extruder to the outlet of the extruder. Melt-kneading is performed at a cylinder temperature of 290 ° C., screw rotation speed of 150 rpm, and a discharge rate of 10 kg / hour, and it is cooled by a water cooling bath while taking out discharges to make a gut, and cutting the gut into a length of 5 mm did.

  The injection molding machine (JSW company J150EII-P) was used, and the test piece for various evaluation was produced by performing injection molding of the said pellet. Injection molding was performed at a cylinder temperature of 320 ° C. and a mold temperature of 150 ° C.

  The obtained test piece is annealed at 150 ° C. for 2 hours, air-cooled and subjected to each test, and the number average fiber length of reinforcing fibers (C) contained in the fiber reinforced composite material, adhesion of the fiber reinforced composite material The tensile strength of the presence ratio Rb of the sex compound (B) and the tensile strength of the fiber reinforced composite material was measured. The results are shown in Table 1.

(Examples 3 to 11)
Test pieces for various evaluations were produced in the same manner as in Example 1 except that the reinforcing fiber (C), the adhesive compound (B) and the thermoplastic resin (A) were changed as shown in Table 1. Using the prepared test pieces, the number average fiber length of reinforcing fibers (C) contained in the fiber reinforced composite material, the abundance ratio Rb of the adhesive compound (B) of the fiber reinforced composite material, and the tension of the fiber reinforced composite material The tensile strength by the test was measured. The obtained results are summarized in Table 1.

(Comparative example 1)
Using the reinforcing fibers (C) and the thermoplastic resin (A) shown in Table 2, a fiber-reinforced composite material was obtained by the following procedure.

  A sizing agent (E-5) is obtained by continuously taking up a fiber bundle of reinforcing fibers (C), immersing in a water-based sizing mother liquor containing 2% by mass of the sizing agent (E-5), and then heat drying at 230 ° C. Reinforcing fiber (C) surface-treated by. The adhesion amount of the sizing agent (E-5) after drying was 1 part by mass with respect to 100 parts by mass of the reinforcing fiber (C). Furthermore, the reinforcing fiber (C) surface-treated with a sizing agent (E-5) was cut into a length of 6 mm to make a chopped strand.

  The thermoplastic resin (A) was main-fed and the chopped strands were side-fed using a twin-screw extruder (TEX 30α, L / D = 31.5, manufactured by JSW) to melt and knead each component. The side feed was performed at a position 40% of the distance from the main feed position to the extruder to the outlet of the extruder. Melt-kneading is performed at a cylinder temperature of 290 ° C., screw rotation speed of 150 rpm, and a discharge rate of 10 kg / hour, and it is cooled by a water cooling bath while taking out discharges to make a gut, and cutting the gut into a length of 5 mm did.

  The injection molding machine (JSW company J150EII-P) was used, and the test piece for various evaluation was produced by performing injection molding of the said pellet. Injection molding was performed at a cylinder temperature of 320 ° C. and a mold temperature of 150 ° C.

  The obtained test piece is annealed at 150 ° C. for 2 hours, air-cooled and subjected to each test, and the number average fiber length of reinforcing fibers (C) contained in the fiber reinforced composite material, adhesion of the fiber reinforced composite material The tensile strength of the presence ratio Rb of the sex compound (B) and the tensile strength of the fiber reinforced composite material was measured. The results are shown in Table 2.

(Comparative example 2)
Test pieces for various evaluations were produced in the same manner as in Example 1 except that the reinforcing fiber (C), the adhesive compound (B) and the thermoplastic resin (A) were changed as shown in Table 2. Using the prepared test pieces, the number average fiber length of reinforcing fibers (C) contained in the fiber reinforced composite material, the abundance ratio Rb of the adhesive compound (B) of the fiber reinforced composite material, and the tension of the fiber reinforced composite material The tensile strength by the test was measured. The obtained results are shown in Table 2.

(Comparative example 3)
Using the reinforcing fibers (C) and the thermoplastic resin (A) shown in Table 2, a fiber-reinforced composite material was obtained by the following procedure.

  A sizing agent (E-4) is obtained by continuously taking up a fiber bundle of reinforcing fibers (C), immersing in a sizing mother liquor of toluene containing 10% by mass of a sizing agent (E-4), and then heat drying at 260 ° C. Reinforcing fiber (C) surface-treated by. The adhesion amount of the sizing agent (E-4) after drying was 3.1 parts by mass with respect to 100 parts by mass of the reinforcing fiber (C). Furthermore, the reinforcing fiber (C) surface-treated with a sizing agent (E-4) was cut into a length of 6 mm to make a chopped strand.

  The thermoplastic resin (A) was main-fed and the chopped strands were side-fed using a twin-screw extruder (TEX 30α, L / D = 31.5, manufactured by JSW) to melt and knead each component. The side feed was performed at a position 40% of the distance from the main feed position to the extruder to the outlet of the extruder. Melt-kneading is performed at a cylinder temperature of 290 ° C., screw rotation speed of 150 rpm, and a discharge rate of 10 kg / hour, and it is cooled by a water cooling bath while taking out discharges to make a gut, and cutting the gut into a length of 5 mm did.

  The injection molding machine (JSW company J150EII-P) was used, and the test piece for various evaluation was produced by performing injection molding of the said pellet. Injection molding was performed at a cylinder temperature of 320 ° C. and a mold temperature of 150 ° C.

  The obtained test piece is annealed at 150 ° C. for 2 hours, air-cooled and subjected to each test, and the number average fiber length of reinforcing fibers (C) contained in the fiber reinforced composite material, adhesion of the fiber reinforced composite material The tensile strength of the presence ratio Rb of the sex compound (B) and the tensile strength of the fiber reinforced composite material was measured. The results are shown in Table 2.

(Comparative example 4)
Using the reinforcing fibers (C), the adhesive compound (B), and the thermoplastic resin (A) shown in Table 2, a fiber-reinforced composite material was obtained by the following procedure.

  A sizing agent (E-1) is obtained by continuously taking up a fiber bundle of reinforcing fibers (C), immersing in a water-based sizing mother liquor containing 2% by mass of the sizing agent (E-1), and then heat drying at 230 ° C. Reinforcing fiber (C) surface-treated by. The adhesion amount of the sizing agent (E-1) after drying was 1 part by mass with respect to 100 parts by mass of the reinforcing fiber (C). Further, a reinforcing fiber (C) surface-treated with a sizing agent (E-1) was cut into a length of 6 mm to make a chopped strand.

  Adhesive compound (B) and thermoplastic resin (A) shown in Table 2 are mixed for 5 minutes with a Henschel mixer, and this is introduced into a twin screw extruder with a cylinder temperature of 320 ° C., and the chopped strands are the side of the extruder The screw rotation speed and the discharge amount were adjusted so that the resin temperature at the discharge port was 350 ° C. in the twin screw extruder, and melt kneading was performed to obtain pellets. The side feed was performed at a position 40% of the distance from the main feed position to the extruder to the outlet of the extruder.

  The injection molding machine (JSW company J150EII-P) was used, and the test piece for various evaluation was produced by performing injection molding of the said pellet. Injection molding was performed at a cylinder temperature of 320 ° C. and a mold temperature of 150 ° C.

  The obtained test piece is annealed at 150 ° C. for 2 hours, air-cooled and subjected to each test, and the number average fiber length of reinforcing fibers (C) contained in the fiber reinforced composite material, adhesion of the fiber reinforced composite material The tensile strength of the presence ratio Rb of the sex compound (B) and the tensile strength of the fiber reinforced composite material was measured. The results are shown in Table 2.

(Comparative example 5)
Test pieces for various evaluations were produced in the same manner as in Comparative Example 4 except that the reinforcing fiber (C), the adhesive compound (B) and the thermoplastic resin (A) were changed as shown in Table 2. Using the prepared test pieces, the number average fiber length of reinforcing fibers (C) contained in the fiber reinforced composite material, the abundance ratio Rb of the adhesive compound (B) of the fiber reinforced composite material, and the tension of the fiber reinforced composite material The tensile strength by the test was measured. The obtained results are summarized in Table 2.

(Comparative example 6)
Thermoplastic resin (Mold-kneading in a twin-screw extruder is replaced with the main feed of the adhesive compound (B) and the thermoplastic resin (A) and the side feed of the chopped strands composed of the reinforcing fibers (C) Test pieces for various evaluations were prepared in the same manner as in Example 2 except that A) was main-fed and chopped strands consisting of reinforcing fibers (C) and side-feed of the adhesive compound (B) were changed. did. Using the prepared test pieces, the number average fiber length of reinforcing fibers (C) contained in the fiber reinforced composite material, the abundance ratio Rb of the adhesive compound (B) of the fiber reinforced composite material, and the tension of the fiber reinforced composite material The tensile strength by the test was measured. The obtained results are summarized in Table 2.

(Comparative example 7)
Thermoplastic resin (Mold-kneading in a twin-screw extruder is replaced with the main feed of the adhesive compound (B) and the thermoplastic resin (A) and the side feed of the chopped strands composed of the reinforcing fibers (C) Test pieces for various evaluations were prepared in the same manner as in Example 2 except that the chopped strands consisting of A) and the reinforcing fibers (C) were main-fed and side-fed was changed to the adhesive compound (B). did. Using the prepared test pieces, the number average fiber length of reinforcing fibers (C) contained in the fiber reinforced composite material, the abundance ratio Rb of the adhesive compound (B) of the fiber reinforced composite material, and the tension of the fiber reinforced composite material The tensile strength by the test was measured. The obtained results are summarized in Table 2.

  According to the comparison between Examples 1 to 10 and Comparative Examples 1 to 4 and the comparison between Example 11 and Comparative Example 5, the fiber reinforced composite material of the present invention has an abundance ratio Rb of the adhesive compound (B) of 1.2. As described above, it is understood that the interfacial adhesion between the reinforcing fiber and the matrix resin is enhanced by localizing the adhesive compound around the reinforcing fiber in the fiber-reinforced composite material, and the tensile strength of the obtained fiber-reinforced composite material is excellent.

  From the comparison of Examples 2, 3 and 5, according to the fiber-reinforced composite material of the present invention, the sizing agent for reinforcing fiber (C) was further added after the abundance ratio Rb of the adhesive compound (B) was 1.2 or more. A compound having at least one functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an amino group and an epoxy group as a compound (E) is attached to one molecule to form a reinforced fiber and a matrix resin It can be seen that it is possible to further enhance the interfacial adhesion of the above, and the tensile strength of the resulting fiber-reinforced composite material is excellent. In particular, the value of the mass average molecular weight divided by the number of the functional groups (total number of carboxyl group, hydroxyl group, amino group and epoxy group) in one molecule is 40 to 150, using E-1 for the compound (E) It turns out that it is excellent in the tensile strength of the fiber reinforced composite material obtained by being in a range.

  From the comparison of Examples 3, 7 and 8 and Comparative Example 2, the fiber-reinforced composite material of the present invention is further characterized in that the adhesive compound (B) is added after the abundance ratio Rb of the adhesive compound (B) is 1.2 or more. It can be understood that the tensile strength of the obtained fiber-reinforced composite material is excellent by using an aliphatic polycarbodiimide.

  From the comparison of Examples 3, 4 and 11, according to the fiber-reinforced composite material of the present invention, carbon fibers were further added to the reinforcing fiber (C) after setting the abundance ratio Rb of the adhesive compound (B) to 1.2 or more. By using it, it is understood that the effect of the improvement in the interfacial adhesion between the reinforcing fiber and the matrix resin is exhibited particularly high, and the tensile strength of the obtained fiber reinforced composite material is excellent.

  From the comparison of Examples 3 and 4, the fiber-reinforced composite material of the present invention further uses carbon fiber as the reinforcing fiber (C) after setting the abundance ratio Rb of the adhesive compound (B) to 1.2 or more. It turns out that it is excellent in the tensile strength of the fiber reinforced composite material obtained by making surface oxygen concentration ratio into the range of 0.10-0.30.

  From the comparison of Example 2 and Comparative Examples 6 and 7, by selecting the melt-kneading method in which the thermoplastic resin (A) and the adhesive compound (B) are melt-kneaded and then compounded with the reinforcing fiber (C), It is easy to control the diffusion of the adhesive compound (B) into the thermoplastic resin (A) and the cohesion to the surface of the reinforcing fiber (C), so it is easy to control the abundance ratio Rb to 1.2 or more, and the tensile strength It can be seen that a fiber-reinforced composite material excellent in the above is obtained with high productivity.

  The fiber-reinforced composite material of the present invention can dramatically improve mechanical properties such as tensile strength as compared with conventional products. Therefore, the fiber-reinforced composite material of the present invention can be suitably used for electronic device casings, applications of electric and electronic parts, parts for automobiles and parts for vehicles, construction materials, sports goods and the like.

1 reinforcing fiber single yarn 2 area within 500 nm around reinforcing fiber (C) 3 area outside reinforcing fiber (C) around 500 nm 4 length from reinforcing fiber (C)

Claims (9)

At least one member containing a thermoplastic resin (A), an adhesive compound (B) and a reinforcing fiber (C), and the adhesive compound (B) selected from the group consisting of a carbodiimide structure, a urea structure and a urethane structure And a thermoplastic resin (A) is a polyarylene sulfide , and the reinforcing fiber (C) is a compound comprising a carboxyl group, a hydroxyl group, an amino group and an epoxy group. It is a reinforcing fiber to which a compound having two or more functional groups at least one kind selected is attached in one molecule, and R (≦ 500 nm) and R as shown below using energy dispersive X-ray spectroscopy (EDX) (> 500 nm) C (carbon atoms) for each region of the / S when evaluating the ratio of (the sulfur atom), the abundance ratio Rb of the adhesive compound of the formula (1) (B) is 1 It is 5 or more, a fiber-reinforced composite material.
Rb = R (≦ 500 nm) / R (> 500 nm) (1)
R (≦ 500 nm) = C (≦ 500) / S (≦ 500) : Abundance of the adhesive compound (B) within about 500 nm around the reinforcing fiber (C) R (> 500 nm) = C (> 500) / S (S) > 500) : Abundance of the adhesive compound (B) outside the 500 nm around the reinforcing fiber (C) The fiber reinforced composite material according to claim 1 , wherein the adhesive compound (B) has a weight average molecular weight of 500 to 10,000. The fiber reinforced composite material according to claim 1 or 2 , wherein the adhesive compound (B) is polycarbodiimide. The fiber reinforced composite material according to claim 1 or 2 , wherein the adhesive compound (B) is an aliphatic polycarbodiimide. The thermoplastic resin according to any one of claims 1 to 4 , wherein the thermoplastic resin (A) has at least one functional group selected from the group consisting of a carboxyl group, a hydroxyl group and an amino group in its molecule. The fiber reinforced composite material of description. The fiber reinforced resin composition according to any one of claims 1 to 5 , wherein the thermoplastic resin (A) has a weight average molecular weight of 10,000 to 80,000. Number average fiber length of the reinforcing fibers (C) is 0.1 to 50 mm, fiber-reinforced composite material according to any one of claims 1-6. The reinforcing fiber (C) is carbon fiber, fiber reinforced composite material according to any one of claims 1-7. The fiber reinforced composite material according to claim 8 , wherein the carbon fiber has a surface oxygen concentration ratio O / C of 0.05 to 0.50 as measured by X-ray photoelectron spectroscopy (XPS).