Fiber-reinforced resins and integrally molded products

Abstract

The objective of the present invention is to provide a fiber-reinforced resin that can be welded to other members through a thermoplastic resin, and is less likely to be damaged even when welded at a high temperature.　The fiber-reinforced resin includes a reinforced fiber, and has an epoxy resin cured product region and a thermoplastic resin region formed on the surface thereof, wherein an aromatic ring percentage of an epoxy resin cured product constituting the epoxy resin cured product region is 50% to 90%.

Description

[Technical Field]

[0001] The present invention relates to fiber-reinforced resin and an integrated molded product in which the fiber-reinforced resin is welded to other components. [Background technology]

[0002] Fiber-reinforced resins, which use thermosetting resins such as epoxy resin as a matrix and combine them with reinforcing fibers such as carbon fiber and glass fiber, are lightweight yet possess excellent mechanical properties such as strength and rigidity, as well as heat resistance and corrosion resistance. Therefore, they have been applied in numerous fields, including aerospace, automobiles, railway vehicles, ships, civil engineering and construction, sporting goods, and electronic components. However, fiber-reinforced resins using thermosetting resins are unsuitable for molding complex shapes. To manufacture complex parts and structures, it was necessary to mold relatively simple fiber-reinforced resin components and then integrate them with other components (hereinafter simply referred to as "other components") made of the same or different materials as the fiber-reinforced resin.

[0003] Mechanical joining methods, such as using bolts, rivets, and screws, and joining methods using adhesives, are employed to integrate fiber-reinforced resin with other components. However, mechanical joining methods require pre-processing of the joining area, such as drilling holes, leading to problems such as longer manufacturing times and increased manufacturing costs, as well as a decrease in material strength due to processing. Joining methods using adhesives require bonding and curing processes, including adhesive preparation and application, leading to problems such as longer manufacturing times and difficulty in obtaining sufficient reliability in terms of adhesive strength.

[0004] As a solution to these problems, fiber-reinforced resins have recently been developed in which a thermoplastic resin layer is formed on the surface of a fiber-reinforced resin using a thermosetting resin (Patent Document 1). Such fiber-reinforced resins can be easily joined to other components by welding via the thermoplastic resin layer. [Prior art documents] [Patent Documents]

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Especially in applications where heat resistance is required, when a high melting point resin such as a super engineering plastic is used as the thermoplastic resin layer of a fiber reinforced resin having such a thermoplastic resin layer, it is necessary to raise the temperature to 300 °C or higher for welding with other members. At that time, the surrounding epoxy resin will also be exposed to 300 °C or higher. Since the epoxy resin tends to rapidly decompose from around 300 °C, when welding is carried out at a high temperature around 300 °C, there is a concern that damage will occur due to the decomposition of the epoxy resin.

[0007] An object of the present invention is to provide a fiber reinforced resin that can be welded to other members through a thermoplastic resin and is less likely to be damaged even when such high-temperature welding is carried out.

Means for Solving the Problems

[0008] In order to solve such problems, the fiber reinforced resin of the present invention is a fiber reinforced resin containing reinforcing fibers and having an epoxy resin cured product region and a thermoplastic resin region formed on the surface, and the aromatic ring ratio of the epoxy resin cured product constituting the epoxy resin cured product region is 50% or more and 90% or less.

Effects of the Invention

[0009] By using the fiber reinforced resin of the present invention, damage is less likely to occur during welding between the thermoplastic resin region and other members, and an integrally molded product having excellent tensile shear joint strength can be produced.

Brief Description of the Drawings

[0010] [Figure 1] This is a schematic diagram of a cross-section perpendicular to the surface of the fiber-reinforced resin of the present invention, which will assist in explaining the measurement methods for the average roughness length RSm and average roughness height Rc, which will be described later. [Modes for carrying out the invention]

[0011] In this specification, "~" represents a range that includes the numbers at both ends.

[0012] The fiber-reinforced resin of the present invention is a fiber-reinforced resin that contains reinforcing fibers and has an epoxy resin cured region and a thermoplastic resin region formed on its surface, wherein the proportion of aromatic rings in all molecules constituting the epoxy resin cured region is 50% or more and 90% or less.

[0013] The fiber-reinforced resin of the present invention has a thermoplastic resin region formed on its surface, which allows other components to be welded to the thermoplastic resin region on the surface to produce an integrated molded product. The "other components" are not particularly limited, but include components containing thermoplastic resin and components made of metal materials, and the other components may also be the fiber-reinforced resin of the present invention. The other components used when welding to the thermoplastic resin region on the surface of the fiber-reinforced resin of the present invention to form an integrated molded product are sometimes referred to as the adherends. There are no particular limitations on the thermoplastic resins included in this thermoplastic resin range. Examples include polyester resins (polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, liquid crystal polyester, etc.), polyolefin resins (polyethylene, polypropylene, polybutylene, etc.), styrene resins, urethane resins, as well as polyoxymethylene, polyamide resins (aliphatic polyamides such as polyamide 6 and polyamide 66, semi-aromatic polyamides, alicyclic polyamides, etc.), polycarbonate, polymethyl methacrylate, polyvinyl chloride, polyphenylene sulfide, polyphenylene ether, modified polyphenylene ether, polyimide, polyamide-imide, polyetherimide, polysulfone, modified polysulfone, polyethersulfone, polyketone, polyarylene ether ketone (polyether ketone, polyether ether ketone, polyether ketone ketone, etc.), polyarylate, polyether nitrile, phenolic resins, phenoxy resins, and others. Furthermore, these thermoplastic resins may be copolymers or modified versions of the above-mentioned resins, and / or resins blended from two or more types. Among these, polyketones, polyetherketones, polyetheretherketones, polyarylene ether ketones such as polyetherketone and polyetherketoneketone, alicyclic polyamides, semi-aromatic polyamides, polyphenylene sulfide, polyetherimide, polyethersulfone, polysulfone, modified polysulfone, and polyamideimide are particularly preferred because they yield fiber-reinforced resins with excellent heat resistance.

[0014] In particular, in the fiber-reinforced resin of the present invention, it is preferable that the epoxy resin cured region and the thermoplastic resin region on the surface, described later, are adjacent to each other in a layered manner. Being adjacent in a layered manner means, for example, as shown in Figure 1, in a cross section obtained by cutting perpendicular to the plane direction of the prepreg, the thermoplastic resin region 2 and the epoxy resin cured region 3, which are continuous in the planar direction, exist in close contact while forming an interface 5. If the thermoplastic resin does not exist in a continuous layered manner but in particulate, fibrous, nonwoven fabric, etc., the proportion of the area where the epoxy resin is exposed on the surface increases, and the coverage rate of the thermoplastic resin on the outermost surface decreases, so the weldability tends to decrease.

[0015] The basis weight for thermoplastic resins is 10 g / m². 2 A value greater than or equal to this is preferable because it exhibits excellent bonding strength with the adherend. The basis weight of the thermoplastic resin region is more preferably 20 g / m². 2 The upper limit is not particularly limited, but in order to obtain a fiber-reinforced resin with excellent specific strength and specific modulus, the basis weight of the thermoplastic resin is preferably 500 g / m², so that the amount of thermoplastic resin does not become too high relative to the reinforcing fibers. 2 The following applies. Here, the basis weight in the thermoplastic resin region refers to 1 m² of fiber-reinforced resin. 2 This refers to the mass (g) of thermoplastic resin that constitutes the thermoplastic resin region contained within that area.

[0016] The reinforcing fibers included in the fiber-reinforced resin of the present invention can be glass fibers, carbon fibers, metal fibers, aromatic polyamide fibers, polyaramid fibers, alumina fibers, silicon carbide fibers, boron fibers, basalt fibers, and the like. These may be used individually or in combination of two or more types.

[0017] As reinforcing fibers, carbon fiber, which has a low specific gravity, high strength, and high modulus of elasticity, is preferably used. Commercially available carbon fiber products include "Torayca®" T800G-24K, "Torayca®" T800S-24K, "Torayca®" T700G-24K, "Torayca®" T700S-24K, "Torayca®" T300-3K, "Torayca®" T1100G-24K, "Torayca®" M30S-18K, "Torayca®" M40J-12K, and "Torayca®" M60J-6K (all manufactured by Toray Industries, Inc.).

[0018] The thermal conductivity of the reinforcing fibers used in the fiber-reinforced resin of the present invention is preferably 100 W / (m·K) or less. When the thermal conductivity of the reinforcing fibers is 100 W / (m·K) or less, the amount of heat transferred to the epoxy resin cured product in the fiber-reinforced resin is kept low when heat is applied to the fiber-reinforced resin during welding, and thermal decomposition of the epoxy resin is suppressed, which is a preferred embodiment. It is more preferable that the reinforcing fibers having the above thermal conductivity are carbon fibers. The above thermal conductivity is more preferably 50 W / (m·K) or less, and even more preferably 30 W / (m·K) or less. There is no particular lower limit for the thermal conductivity of the reinforcing fibers, but for ordinary carbon fibers, the lower limit is 3 W / (m·K).

[0019] Furthermore, it is preferable that the strand tensile strength of the reinforcing fibers used in the fiber-reinforced resin of the present invention, as measured in accordance with the resin-impregnated strand test method of JIS R7608 (2007), is 5.5 GPa or higher, as this provides a fiber-reinforced resin with excellent bonding strength in addition to tensile strength. It is even more preferable that the strand tensile strength is 5.8 GPa or higher. The bonding strength referred to here is the bonding strength when joined to another member by welding through the thermoplastic resin region of the surface, and refers to the tensile shear bonding strength determined in accordance with ISO 4587:1995 (JIS K6850 (1994)).

[0020] These reinforcing fibers may be surface-treated. Examples of surface treatment include metal deposition treatment, treatment with a coupling agent, treatment with a sizing agent, and adhesion treatment of an additive.

[0021] In particular, as the reinforcing fiber, it is preferable to use one having a surface free energy measured by the Wilhelmy method of 10 mJ / m 2 or more and 50 mJ / m 2 or less. By controlling within this range, the reinforcing fiber exhibits high affinity with the epoxy resin and the thermoplastic resin, and when joined by welding through the thermoplastic resin region on the surface with other members, excellent tensile shear joint strength is exhibited. In addition, aggregation between the reinforcing fibers is suppressed, dispersion of the reinforcing fibers in the molded product becomes good, and the variation coefficient of the tensile shear joint strength becomes small. The surface free energy of the reinforcing fiber is preferably 15 mJ / m 2 or more and 40 mJ / m 2 or less, more preferably 18 mJ / m 2 or more and 35 mJ / m 2 or less. As a method for controlling the surface free energy of the reinforcing fiber, there are a method of oxidizing the surface and controlling by adjusting the amount of oxygen-containing functional groups such as carboxyl groups and hydroxyl groups, and a method of controlling by attaching a single or a plurality of compounds to the surface. When attaching a plurality of compounds to the surface, those with high surface free energy and those with low surface free energy may be mixed and attached. The surface free energy can be calculated by measuring the contact angles of the reinforcing fiber with three kinds of solvents (purified water, ethylene glycol, tricresyl phosphate) respectively and then using Owens' approximate formula to calculate the surface free energy. The procedure is shown below, but the measuring equipment and detailed methods are not necessarily limited to those below.

[0022] Using the DataPhysics DCAT11, first, a single fiber is taken from the reinforcing fiber bundle, cut into eight pieces of 12±2 mm in length, and then attached parallel to a dedicated holder FH12 (a flat plate with an adhesive coating on its surface) with a spacing of 2-3 mm between each fiber. After that, the ends of the single fibers are trimmed and set into the DCAT11 holder. For the measurement, a cell containing each solvent is brought close to the lower end of the eight single fibers at a speed of 0.2 mm / s, and the fibers are immersed up to 5 mm from the tip. Then, the fibers are pulled up at a speed of 0.2 mm / s. This operation is repeated at least four times. The force F acting on the single fiber while immersed in the liquid is measured using an electronic balance. Using this value, the contact angle θ is calculated using the following formula. cosθ = (force F (mN) acting on 8 single fibers) / ((8 (number of single fibers) × circumference of single fiber (m) × surface tension of solvent (mJ / m)) 2 )) The measurements will be performed on single fibers extracted from different locations within three reinforcing fiber bundles. In other words, the average contact angle of a total of 24 single fibers from one reinforcing fiber bundle will be calculated.

[0023] Surface free energy γ of reinforcing fibers f This is the polar component γ of the surface free energy. p f , and the nonpolar component γ of the surface free energy d f It is calculated as the sum of these. The polar component γpf of the surface free energy is obtained by substituting the surface tension components and contact angle of each liquid into Owens' approximation formula shown below (an formula composed of the polar and nonpolar components of the surface tension specific to each solvent, and the contact angle θ), plotting them on X and Y, and then approximating them linearly using the least squares method, and then squaring the slope a. Nonpolar component γ of surface free energy d f The surface free energy γ of the reinforcing fiber is obtained by squaring the intercept b. f This is the sum of the square of the slope a and the square of the y-intercept b. Y = a·X + b X = √((Surface tension of the solvent) polar component (mJ / m) 2 )) / √(Nonpolar component of the surface tension of the solvent (mJ / m 2 ) Y = (1 + COSθ) * (Polar component of the surface tension of the solvent (mJ / m)) 2 )) / 2√(Nonpolar component of the surface tension of the solvent (mJ / m 2 ) Polar component γ of the surface free energy of reinforcing fibers p f =a 2 Nonpolar component γ of the surface free energy of reinforcing fibers d f =b 2 Total surface free energy γ f =a 2 +b 2 .

[0024] The polar and nonpolar components of the surface tension of each solvent are as follows: ·Purified water Surface tension 72.8mJ / m 2 , polar component 51.0mJ / m 2 , non-polar component 21.8 (mJ / m 2 ) Ethylene glycol Surface tension 48.0mJ / m 2 , polar component 19.0mJ / m 2 , non-polar component 29.0 (mJ / m 2 ) Tricresol phosphate Surface tension 40.9mJ / m 2 , polar component 1.7mJ / m 2 , nonpolar component 39.2 (mJ / m 2 ).

[0025] Regarding the form and arrangement of the reinforcing fibers, they can be appropriately selected from options such as fibers arranged in one direction, a laminate of fibers arranged in one direction, or the form of woven fabric, knit, nonwoven fabric, mat, or braid. However, in order to obtain a fiber-reinforced resin that is lightweight and has a higher level of durability, it is preferable that each prepreg has reinforcing fibers in the form of long fibers (fiber bundles) arranged in one direction or continuous fibers such as woven fabric. Furthermore, from the viewpoint of shapeability and shape conformability during molding, it is also preferable that the reinforcing fibers are discontinuous and be in the form of a nonwoven fabric or mat.

[0026] The mass content of reinforcing fibers in the fiber-reinforced resin of the present invention is preferably 30% by mass or more and 90% by mass or less, more preferably 35% by mass or more and 85% by mass or less, and even more preferably 40% by mass or more and 80% by mass or less. When the mass content of reinforcing fibers is 30% by mass or more, the amount of resin does not become too high relative to the fibers, making it easier to obtain a fiber-reinforced resin with excellent specific strength and specific modulus. Furthermore, when the mass content of reinforcing fibers is 90% by mass or less, poor resin impregnation is less likely to occur, and the resulting fiber-reinforced resin tends to have fewer voids.

[0027] The epoxy resin cured product constituting the epoxy resin cured product region of the fiber-reinforced resin of the present invention has an aromatic ring ratio of 50% to 90%. If the aromatic ring ratio is less than 50%, the epoxy resin cured product is prone to thermal decomposition in high-temperature environments, resulting in a significant decrease in mechanical properties such as compressive strength as a fiber-reinforced resin, and a decrease in tensile shear joint strength when welded to other components. If the aromatic ring ratio is 90% or more, the flexibility of the epoxy resin cured product is impaired, leading to a decrease in mechanical properties as a fiber-reinforced resin. A more preferable aromatic ring ratio for the epoxy resin cured product is 55% to 80%.

[0028] In this specification, the aromatic ring ratio of an epoxy resin cured product is the mass ratio of aromatic rings in the chemical structure constituting the epoxy resin cured product, and is calculated by dividing the "total mass of all aromatic rings in the total chemical structure" by the "total mass of all molecules in the total chemical structure." Note that if substituents such as methyl groups are present on the aromatic ring, the mass of the substituents is not included in the mass of the aromatic ring. For example, the structure of benzene is calculated using an aromatic ring mass of 78.1 g / mol, and the structure of toluene is calculated using an aromatic ring mass of 77.1 g / mol.

[0029] The aromatic ring ratio of an epoxy resin cured product can be calculated from the chemical structures of each compound constituting the epoxy resin composition (the state before curing), if those structures are known. If the chemical structures are unknown, the aromatic ring ratio can be calculated by identifying the chemical structure of the epoxy resin cured product using pyrolysis gas chromatography-mass spectrometry. For example, if the epoxy resin cured product is composed of the chemical structures shown in equations (1) and (2) below, with each representing 70% and 30% of the total molecular weight, the aromatic ring ratio of the epoxy resin cured product is: (76.1 × 4 × 0.70 + (126.2 + 76.1 × 2) × 0.3) / (676.9 × 0.7 + 522.6 × 0.3) = 47.1%.

[0030] [ka]

[0031] [ka]

[0032] In the present invention, the cured epoxy resin product is preferably a cured product of an epoxy resin composition containing an epoxy resin having a polycyclic aromatic hydrocarbon skeleton or a biphenyl skeleton, in terms of improving resistance to thermal decomposition at high temperatures.

[0033] Epoxy resins having a polycyclic aromatic hydrocarbon skeleton include epoxy resins having a naphthalene skeleton, epoxy resins having an anthracene skeleton, epoxy resins having a phenanthrene skeleton, epoxy resins having a pyrene skeleton, and epoxy resins having a tetracene skeleton. Examples include naphthylene ether type epoxy resins, naphthalenediol type epoxy resins, methylenedinaphthol type epoxy resins, dinaphthol type epoxy resins, naphthol phenylaralkyl type epoxy resins, naphthol biphenylaralkyl type epoxy resins, and anthracenediol type epoxy resins. Epoxy resins having a biphenyl skeleton include biphenol diglycidyl ether and phenol biphenylaralkyl type epoxy resins.

[0034] Furthermore, in order to improve resistance to thermal decomposition at high temperatures and to exhibit an excellent glass transition temperature, it is preferable that the epoxy resin cured product in the present invention be a cured product of an epoxy resin composition in which the average epoxy equivalent of all epoxy resins is 160 g / eq. or more and 255 g / eq. or less. More preferably, the average epoxy equivalent is 180 g / eq. or more and 255 g / eq. or less. Here, the average epoxy equivalent is calculated as follows, for example, when the epoxy resin contains two components, epoxy resin 1 and epoxy resin 2. In this specification, epoxy equivalent refers to the value obtained by the method described in JIS K7236 (2009). Average epoxy equivalent (g / eq.) = (Parts of epoxy resin 1 × Epoxy equivalent of epoxy resin 1 + Parts of epoxy resin 2 × Epoxy equivalent of epoxy resin 2) / (Parts of epoxy resin 1 + Parts of epoxy resin 2) The same calculation method applies when three or more epoxy resin components are included. If there are N epoxy resin components, from epoxy resin 1 to epoxy resin N, the calculation is performed as follows. Average epoxy equivalent (g / eq.) = (Parts of mass of epoxy resin 1 × Epoxy equivalent of epoxy resin 1 + Parts of mass of epoxy resin 2 × Epoxy equivalent of epoxy resin 2 + ... + Parts of mass of epoxy resin N × Epoxy equivalent of epoxy resin N) / (Parts of mass of epoxy resin 1 + Parts of mass of epoxy resin 2 + ... + Parts of mass of epoxy resin N) In the present invention, the epoxy resin cured product is preferred to be a cured product of an epoxy resin composition containing a polyamine compound having an average active hydrogen equivalent of 55 g / eq. to 100 g / eq., as this improves resistance to thermal decomposition at high temperatures. In this specification, a polyamine compound is a general term for a compound having two or more amino groups, and examples include dicyandiamide, aliphatic amine compound, aromatic amine compound, tetramethylguanidine, thiourea-added amine, and carboxylic acid hydrazide. In this specification, the active hydrogen equivalent of a polyamine compound refers to the active hydrogen equivalent calculated by identifying the chemical structure and its proportion by liquid chromatography-mass spectrometry (LC / MS). Here, the average active hydrogen equivalent is calculated as follows, for example, when the compound contains two components, polyamine compound 1 and polyamine compound 2. Average active hydrogen equivalent (g / eq.) = (Parts by mass of polyamine compound 1 × Active hydrogen equivalent of polyamine compound + Parts by mass of polyamine compound 2 × Active hydrogen equivalent of polyamine compound 2) / (Parts by mass of polyamine compound 1 + Parts by mass of polyamine compound 2) If the mixture contains three or more polyamine compounds, the calculation can be performed in the same manner as for the epoxy resin described above.

[0035] When epoxy resins other than epoxy resins having a polycyclic aromatic hydrocarbon skeleton or a biphenyl skeleton are included, such epoxy resins include, for example, bisphenol-type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, and bisphenol S type epoxy resin; brominated epoxy resins such as tetrabromobisphenol A diglycidyl ether; epoxy resins having a dicyclopentadiene skeleton; novolac-type epoxy resins such as phenol novolac type epoxy resin and cresol novolac type epoxy resin; and N,N,O-triglycerides. Examples include glycidylamine-type epoxy resins such as lysidyl-m-aminophenol, N,N,O-triglycidyl-p-aminophenol, N,N,O-triglycidyl-4-amino-3-methylphenol, N,N,N',N'-tetraglycidyl-4,4'-methylenedianiline, N,N,N',N'-tetraglycidyl-2,2'-diethyl-4,4'-methylenedianiline, N,N,N',N'-tetraglycidyl-m-xylylenediamine, N,N-diglycidylaniline, and N,N-diglycidyl-o-toluidine, as well as resorcinol diglycidyl ether and triglycidyl isocyanurate.

[0036] Using an aromatic amine compound having two or more amino groups as the polyamine compound is preferable because it provides good reactivity and excellent mechanical properties and heat resistance as a cured product. Examples of aromatic amine compounds having two or more amino groups include diaminodiphenylsulfone, diaminobenzanilide, diaminobenzophenone, diaminodiphenylmethane, and their isomers, as well as adducts of aliphatic hydrocarbons and halogen groups.

[0037] The epoxy resin cured product in the fiber-reinforced resin of the present invention is preferably a cured product of an epoxy resin composition in which the thermal mass loss rate when the cured product obtained by heating at 180°C for 120 minutes is held at 300°C for 2 minutes is 1.0% or less. Furthermore, it is preferable that the cured product of the same epoxy resin composition has a glass transition temperature of 180°C to 350°C. By having such properties in the cured product, it is possible to suppress the occurrence of damage during welding when welding the fiber-reinforced resin to other components via the thermoplastic resin layer on the surface of the fiber-reinforced resin. A more preferable thermal mass loss rate when held at 300°C for 2 minutes is 0.7% or less, and even more preferably 0.5% or less. The thermal mass loss rate of the epoxy resin cured product can be determined according to JIS K7120 (1987). The glass transition temperature can be determined according to JIS K7244-7 (2007).

[0038] In the fiber-reinforced resin of the present invention, it is preferable that the average roughness length RSm of the interface between the epoxy resin cured region and the thermoplastic resin region is 100 μm or less, and the average roughness height Rc is 3.5 μm or more. Here, the average roughness length RSm and average roughness height Rc of the interface between the epoxy resin cured region and the thermoplastic resin region are defined as the average roughness length RSm and average roughness height Rc of the cross-sectional curve formed by the interface surface where the two resin regions are in close contact, as defined in JIS B0601 (2001), in a cross section obtained by cutting perpendicular to the planar direction of the fiber-reinforced resin. When the average roughness length RSm of the cross-sectional curve is 100 μm or less, not only chemical and / or physical bonding forces but also mechanical bonding forces called confounding are added, making it difficult for the epoxy resin cured region and the resin region containing the thermoplastic resin to separate, which is preferable. The lower limit of RSm is not particularly limited, but from the viewpoint of avoiding a decrease in mechanical bonding force due to stress concentration, it is preferably 15 μm or more. Furthermore, a cross-sectional curve roughness average height Rc of 3.5 μm or more is preferable because, in addition to the emergence of mechanical bonding forces due to confluence, the reinforcing fibers present on the interface chemically and / or physically bond with the epoxy resin and thermoplastic resin, thereby improving the adhesion between the epoxy resin cured region and the resin region containing the thermoplastic resin. A more preferable range for the cross-sectional curve roughness average height Rc is 10 μm or more, and particularly preferably 20 μm or more, as this allows the reinforcing fibers to more easily contact both resin regions and further improves adhesion. The upper limit of Rc is not particularly limited, but from the viewpoint of avoiding a decrease in mechanical bonding force due to stress concentration, it is preferably 100 μm or less.

[0039] Here, known methods can be used to measure the average roughness height Rc and average roughness length RSm of the cross-sectional curve. For example, methods include measuring from cross-sectional images acquired using X-ray CT, measuring from elemental analysis mapping images obtained by energy-dispersive X-ray spectrometer (EDS), or measuring from cross-sectional observation images obtained by optical microscope, scanning electron microscope (SEM), or transmission electron microscope (TEM). In observation, the epoxy resin and / or thermoplastic resin may be stained to adjust the contrast. In the image obtained by any of the above methods, the average roughness height Rc and average roughness length RSm of the cross-sectional curve are measured in a 500 μm square area.

[0040] An example of a method for measuring the average roughness height Rc and average roughness length RSm of a cross-sectional curve (Method 1 for measuring cross-sectional curve elements) is shown using Figure 1. Using the end 6 on the epoxy resin cured region side of the rectangular observation image 4 as the reference line, perpendicular baselines 7 are drawn at 5 μm intervals from the epoxy resin cured region 3 toward the thermoplastic resin region 2. The point where the perpendicular baseline drawn from the reference line first intersects the thermoplastic resin region 2 is plotted, and the line connecting the plotted points is defined as the cross-sectional curve 8. The obtained cross-sectional curve 8 is subjected to filtering based on JIS B0601 (2001), and the average roughness height Rc and average roughness length RSm of the cross-sectional curve 8 are calculated.

[0041] Furthermore, it is preferable that the fiber-reinforced resin of the present invention contains reinforcing fibers that straddle the interface between the epoxy resin cured region and the thermoplastic resin region and are in contact with both resin regions. The presence of such reinforcing fibers can be confirmed by observing a cross-section obtained by cutting perpendicular to the planar direction. For example, in the cross-sectional observation image 4 shown in Figure 1, multiple reinforcing fibers 1 are present on the interface 5 between the thermoplastic resin region 2 and the epoxy resin cured region 3. The reinforcing fibers 1 on the interface 5 are in contact with both the thermoplastic resin region 2 and the epoxy resin cured region 3. This state in which the thermoplastic resin and epoxy resin are in contact with the reinforcing fibers can be described as the reinforcing fibers "straddle the interface and are in contact with both resin regions."

[0042] The presence of reinforcing fibers that straddle the interface between the epoxy resin cured region and the thermoplastic resin region, and are in contact with both resin regions, improves the strength of the thermoplastic resin region and thus the bonding strength. Furthermore, the chemical and / or physical bonding of the reinforcing fibers that straddle the interface with the heat-cured epoxy resin cured product and thermoplastic resin also improves the adhesion between the heat-cured epoxy resin cured region and the thermoplastic resin region, thereby improving the bonding strength.

[0043] The fiber-reinforced resin of the present invention may contain elastomers or rubber components added to the epoxy resin cured product or thermoplastic resin to improve impact resistance. Furthermore, depending on the application, the epoxy resin cured product or thermoplastic resin may contain other fillers or additives as appropriate, as long as the objectives of the present invention are not impaired. Examples of these include inorganic fillers, flame retardants, conductivity imparters, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping agents, antibacterial agents, insecticides, deodorants, color inhibitors, heat stabilizers, mold release agents, antistatic agents, plasticizers, lubricants, colorants, pigments, dyes, foaming agents, antifoaming agents, coupling agents, and the like.

[0044] One example of a method for producing the fiber-reinforced resin of the present invention involves using a prepreg containing an epoxy resin composition before curing of the epoxy resin and reinforcing fibers, and having a thermoplastic resin region on its surface. The preform, which is laminated with other prepregs as needed, is then subjected to pressure and heat to cure. Examples of methods for applying pressure and heat include press molding, autoclave molding, bagging molding, wrapping tape method, internal pressure molding, and hand lay-up. Other examples of methods for producing the fiber-reinforced resin of the present invention include filament winding, pultrusion, resin injection molding, and resin transfer molding.

[0045] Furthermore, the integrally molded product of the present invention is formed by welding the fiber-reinforced resin of the present invention to another member via the thermoplastic resin region, and because it is welded to another member via the thermoplastic resin region, the adhesive portion between the fiber-reinforced resin portion and the other member has excellent tensile shear joint strength. [Examples]

[0046] The present invention will be described in detail below with reference to examples. However, the scope of the present invention is not limited to these examples. Unless otherwise noted, the unit "parts" in composition ratios refers to parts by mass. Furthermore, unless otherwise noted, all measurements were performed under conditions of 23°C and 50% relative humidity.

[0047] <Materials used in the examples and comparative examples> [Epoxy resin] • Naphthylene ether type epoxy resin ("EPICLON" (registered trademark) HP-6000, manufactured by DIC Corporation, epoxy equivalent: 250 g / eq.) • Biphenyl aralkyl epoxy resin (NC-3000, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 275 g / eq.) • Tetraglycidyldiaminodiphenylmethane ("SumiEpoxy" (registered trademark) ELM434, manufactured by Sumitomo Chemical Co., Ltd., epoxy equivalent: 120 g / eq.) • Bisphenol F type epoxy resin ("EPICLON" (registered trademark) 830, manufactured by DIC Corporation, epoxy equivalent: 172 (g / eq.)) Naphthol phenyl aralkyl type epoxy resin (NC-7000L, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 230 g / eq.).

[0048] [Polyamine compounds] 4,4'-Diaminodiphenylsulfone (Seika Cure S, manufactured by Wakayama Seika Kogyo Co., Ltd., active hydrogen equivalent: 62 g / eq.).

[0049] [Viscosity modifier (thermoplastic resin soluble in epoxy resin)] • Polyethersulfone ("Sumika Excel" (registered trademark) PES5003P, manufactured by Sumitomo Chemical Co., Ltd.).

[0050] [Reinforced fiber] Referring to Japanese Patent Publication No. 2010-255168, carbon fibers 1-4 (before sizing agent application) with different thermal conductivity were obtained by spinning and calcining an acrylonitrile copolymer copolymerized with itaconic acid. A 1% by mass solution was prepared by mixing and dissolving sizing agent compound 1 with acetone, and each compound was applied to the carbon fibers 1-4 by immersion. After heat treatment at 210°C for 90 seconds, the amount of each compound attached was adjusted to 0.5 parts by mass per 100 parts by mass of carbon fiber to which each compound was attached, resulting in a surface free energy of 20 mJ / m². 2 Carbon fibers 1-4 were obtained. The properties of each carbon fiber are as follows. • Carbon fiber 1: Strand tensile strength 5.9 GPa, strand tensile modulus 294 GPa, thermal conductivity 10 W / (m·K) • Carbon fiber 2: Strand tensile strength 5.5 GPa, strand tensile modulus 294 GPa, thermal conductivity 22 W / (m·K) • Carbon fiber 3: Strand tensile strength 4.4 GPa, strand tensile modulus 377 GPa, thermal conductivity 69 W / (m·K) • Carbon fiber 4: Strand tensile strength 4.1 GPa, strand tensile modulus 475 GPa, thermal conductivity 105 W / (m·K) Furthermore, sizing agent compounds 2 to 6 were attached to carbon fiber 1 (before sizing agent application) in the same manner as described above, to obtain carbon fibers with different surface free energies. The sizing compound used for each carbon fiber and the surface free energy after application of the sizing agent are as follows. • Sizing agent compound 1: Polyethylene glycol diglycidyl ether ("Denacol" (registered trademark) EX-841, manufactured by Nagase ChemteX Corporation), surface free energy: 20 mJ / m 2 • Sizing compound 2: Bisphenol A type diglycidyl ether ("jER" (registered trademark) 828, manufactured by Mitsubishi Chemical Corporation), surface free energy: 9 mJ / m2 • Sizing compound 3: Sorbitol polyglycidyl ether ("Denacol" (registered trademark) EX-614B, manufactured by Nagase ChemteX Corporation), surface free energy: 32 mJ / m 2 • Sizing agent compound 4: Bisphenol A propylene oxide 24 molar adduct, surface free energy: 18 mJ / m 2 • Sizing compound 5: Polyallylamine (PAA-01, manufactured by Nippon Shokubai Co., Ltd.), surface free energy: 32 mJ / m 2 • Sizing agent compound 6: Polyethyleneimine (SP-012, manufactured by Nippon Shokubai Co., Ltd.), surface free energy: 33 mJ / m 2 [Thermoplastic resin] • PPS: Polyphenylene sulfide ("Torelina" (registered trademark) A900 (manufactured by Toray Industries, Inc., melting point 278°C, glass transition temperature 92°C) with a basis weight of 120 g / m² 2 film • PEEK: Polyether ether ketone (PEEK 450G (manufactured by Victrex, melting point 343°C, glass transition temperature 143°C), basis weight 120g / m²) 2 film • PEKK: Polyether ketone ("KEPSTAN" 6002 (manufactured by Arkema, melting point 300°C, glass transition temperature 160°C)) with a basis weight of 120 g / m² 2 film • PEI: Polyetherimide ("ULTEM" (registered trademark) 1010, manufactured by SABIC, glass transition temperature 217°C), basis weight 120 g / m² 2 film • Semi-aromatic PA: Made of polyamide 6T (melting point 320°C, glass transition temperature 125°C), with a basis weight of 120 g / m². 2 The film.

[0051] The melting points of thermoplastic resins were measured using a differential scanning calorimeter (DSC) in accordance with JIS K7121 (2012). In cases where multiple melting points were observed for mixtures, the highest melting point was adopted as the melting point of that thermoplastic resin.

[0052] <Evaluation Method> [Characteristics of cured epoxy resin products] The epoxy resin compositions prepared in the reference examples described later were poured into molds, heated in a hot air dryer from 30°C to 180°C at a rate of 1.5°C / min, cured for 120 minutes, and then cooled to 30°C at a rate of 2.5°C / min to produce 2 mm thick plate-shaped epoxy resin cured products.

[0053] A test specimen measuring 12.7 mm in width and 45 mm in length was cut from the resin cured plate prepared by the method described above. The test specimen was dried in a 60°C vacuum oven for 24 hours, and a storage modulus curve was obtained by dynamic viscoelasticity testing in accordance with JIS K7244-7 (2007). The temperature at the intersection of the tangent line in the glassy state and the tangent line in the transition state of this storage modulus curve was defined as the glass transition temperature.

[0054] Furthermore, approximately 10 mg of the plate-shaped resin cured material prepared by the above method was crushed, and the thermal mass loss rate was measured using a thermogravimetric differential thermal analyzer in accordance with JIS K7120 (1987). Air was used as the inlet gas for all measurements. The thermal mass loss rate when heating from room temperature to 300°C and from room temperature to 350°C was evaluated at a heating rate of 50°C / min and a measurement temperature range of 25°C to 400°C, and the mass loss rate when reaching 300°C or 350°C was measured. In isothermal measurements, the temperature was raised from 200°C to 300°C, held at 300°C for 2 minutes, and the thermal mass loss rate was measured.

[0055] [Structural observation of fiber-reinforced resin] An image was taken at 1000x magnification using an optical microscope of an observation cross-section of fiber-reinforced resin cut perpendicular to the planar direction. In the obtained image, if reinforcing fibers were present at the interface between the thermoplastic resin region and the epoxy resin cured region, and these reinforcing fibers were in contact with both the thermoplastic resin region and the epoxy resin cured region, then the state of "reinforcing fibers that straddle the interface and are in contact with both resin regions" was defined. In an arbitrary 500 μm square observation area in the obtained image, the average roughness length RSm and average roughness height Rc, as defined in JIS B0601 (2001), were measured for the cross-sectional curve element obtained by the measurement method 1 of the cross-sectional curve element.

[0056] [Compressive strength of fiber-reinforced resin] Tabs were bonded to the fiber-reinforced resin in accordance with SACMA-SRM 1R-94. Then, rectangular specimens measuring 80 mm in length and 15 mm in width were cut out, with the reinforcing fiber axis aligned with the length of the specimen. The obtained specimens were dried in a 60°C vacuum oven for 24 hours. After that, the compressive strength was measured in accordance with SACMA-SRM 1R-94 using a universal material tester (Instron Japan Co., Ltd., "Instron" (registered trademark) Model 5565 P8564) under the following three measurement conditions. 1) The test specimens were not treated, and the compressive strength was measured under 23°C conditions. (Untreated conditions) 2) After subjecting the test specimen to high-temperature exposure treatment by sandwiching it between hot plates maintained at 300°C for 2 minutes, the compressive strength was measured in a 23°C environment. 3) After immersion in 71°C hot water for 14 days to absorb water, compressive strength measurements were performed in a high-temperature environment of 120°C. Based on the measurement results in 2) above, the following evaluation was performed. The results are shown in Tables 2 to 6. 1.4 GPa or higher: A 1.2 GPa or higher but less than 1.4 GPa: B 1.0 GPa or higher but less than 1.2 GPa: C Less than 1.0 GPa: D (Fail) Furthermore, based on the measurement results in 3) above, the following evaluation was performed. The results are shown in Tables 2 to 6. 1.2GPa or more:A 1.0 GPa or higher but less than 1.2 GPa: B 0.8 GPa or higher but less than 1.0 GPa: C Less than 0.8 GPa: D (Fail) [Tensile shear joint strength of integrated molded products] The desired test specimen was obtained by bonding tabs to the created integrated molded product in accordance with ISO 4587:1995 (JIS K6850 (1994)) and cutting it to a width of 25 mm.

[0057] The obtained test specimens were dried in a vacuum oven for 24 hours, and the tensile shear joint strength was measured at an ambient temperature of 23°C according to ISO 4587:1995 (JIS K6850 (1994)). Based on the measurement results, the following evaluation was performed. The coefficient of variation was calculated by determining the standard deviation and mean from the five measurements of tensile shear joint strength, and then dividing the standard deviation by the mean. The results are shown in Tables 2 to 6. 28MPa or more: A 25 MPa or more and less than 28 MPa: B 20 MPa or more but less than 25 MPa: C Less than 20 MPa: D (Fail).

[0058] <Reference Examples 1-7: Preparation of Epoxy Resin Compositions> The epoxy resin, polyamine compound, and viscosity modifier listed in Table 1 were added to a mixing device, and the mixture was heated and kneaded to dissolve the viscosity modifier. The numbers for these compositions in Table 1 represent parts by mass, with all epoxy resins being 100 parts by mass. Next, the mixture was cooled to a temperature of 100°C or below while continuing to knead, and polyamine compounds and other curing agents appropriately selected from those listed in Table 1 were added and stirred to obtain epoxy resin compositions for Reference Examples 1 to 7.

[0059] [Table 1]

[0060] <Manufacturing of fiber-reinforced resin integrated molded products> [Examples 1-5, Comparative Examples 1, 2: Influence of Aromatic Ring Ratio in Cured Epoxy Resin] The epoxy resin compositions of Reference Examples 1-7 were coated with a resin base of 100 g / m² using a knife coater. 2 A coating was applied to release paper to create an epoxy resin film. A reinforced fiber sheet (basis weight 193g / m²) was made by aligning carbon fiber 1 (coated with sizing agent compound 1) in one direction. 2 While pulling out the ) and moving it in one direction, a thermoplastic resin (PPS) with a basis weight of 120 g / m² is used. 2 A resin sheet was placed on the reinforcing fiber sheet, heated with an IR heater to melt the thermoplastic resin, and adhered to the entire surface of one side of the reinforcing fiber sheet. Then, pressure was applied with a nip roll, whose surface temperature was maintained at 100°C lower than the melting point of the thermoplastic resin, to impregnate the reinforcing fiber sheet with PPS, and it was cooled to obtain an intermediate. Next, the epoxy resin film was placed on the opposite surface of the intermediate that had been impregnated with thermoplastic resin, and the epoxy resin composition was impregnated into the intermediate while heating and pressurizing with a heat roll to obtain a prepreg [I].

[0061] The epoxy resin compositions of Reference Examples 1-7 were coated with a resin base of 50 g / m² using a knife coater. 2 A release paper was coated with this to create an epoxy resin film. This epoxy resin film was then used to create a reinforced fiber sheet (basis weight 193g / m²) in which carbon fibers 1 were aligned in one direction. 2 Using a heat roll with the materials overlapping on both sides, the epoxy resin composition was impregnated into the reinforcing fibers while heating and pressurizing to obtain a prepreg [II].

[0062] The prepregs [I] and [II] prepared as described above were cut to the required size, yielding two sheets of prepreg [I] and four sheets of prepreg [II]. The two outermost layers on each side were prepreg [I], with prepreg [II] sandwiched in between, and a total of six layers were laminated so that all layers had the same reinforcing fiber direction to create a preform. At this time, the two outermost layers on each side of the preform were prepreg [I], and the surface layers on both sides of the preform were made of thermoplastic resin (PPS). That is, the two prepreg [I] sheets sandwiched the four prepreg [II] sheets, and the PPS-impregnated side of prepreg [I] was positioned facing outwards. This preform was set in a press molding die, and while maintaining this shape using jigs and spacers as needed, a pressure of 0.6 MPa was applied with a press machine and heated at 180°C for 120 minutes to obtain fiber-reinforced resin for compressive strength evaluation and cross-sectional observation.

[0063] The prepregs [I] and [II] prepared as described above were cut to the specified size, yielding two pieces of prepreg [I] and six pieces of prepreg [II]. The axial direction of the reinforcing fibers was defined as 0°, and the direction perpendicular to the axis was defined as 90°, so [0° / 90°] 2s A preform was fabricated by laminating the materials as shown (the symbol s indicates mirror symmetry). At this time, the two outermost layers on each side of the preform were prepreg[I], and the surface layers on both sides of the preform were thermoplastic resin (PPS) layers. That is, two prepreg[I] layers sandwiched six prepreg[II] layers, and the PPS-impregnated side of prepreg[I] was positioned facing outwards. This preform was set in a press molding die, and while maintaining this shape using jigs and spacers as needed, a pressure of 0.6 MPa was applied with a press machine, and it was heated at 180°C for 120 minutes to obtain fiber-reinforced resin for evaluation of tensile shear joint strength.

[0064] Furthermore, the obtained fiber-reinforced resin for tensile shear joint strength evaluation was cut into two pieces with a width of 250 mm and a length of 92.5 mm, with the 0° direction as the length direction of the test piece, and dried in a vacuum oven for 24 hours. Then, the two panels cut to a shape of 250 mm width and 92.5 mm length were overlapped with the 0° direction as the length direction to form a 250 mm width × 12.5 mm length panel, and the overlapping surfaces were welded together by applying a pressure of 3 MPa at 300°C and holding for 2 minutes to obtain an integrated molded product for tensile shear joint strength evaluation.

[0065] Table 2 shows the evaluation results of the physical properties of fiber-reinforced resin and integrated molded products.

[0066] [Table 2]

[0067] [Examples 6-8: Influence of Thermal Conductivity of Reinforcement Fibers] Using the epoxy resin composition of Reference Example 1, a fiber-reinforced resin and an integrated molded article were obtained in the same manner as in Example 1, except that the carbon fiber species constituting the reinforcing fiber sheet were changed as shown in Table 3.

[0068] Table 3 shows the evaluation results of the physical properties of the fiber-reinforced resin and the integrated molded product, along with the evaluation results of Example 1.

[0069] [Table 3]

[0070] [Examples 9-12, Comparative Examples 3,4: Influence of Thermoplastic Resin Type] Using the epoxy resin compositions of Reference Examples 1, 6, and 7, the thermoplastic resin type was changed as shown in Table 4, and accordingly, the welding temperature when obtaining the integrally molded product was also changed as shown in Table 4. Otherwise, the fiber-reinforced resin and integrally molded product were obtained in the same manner as in Example 1.

[0071] Table 4 shows the evaluation results of the physical properties of the fiber-reinforced resin and the integrated molded product, along with the evaluation results of Example 1.

[0072] [Table 4]

[0073] [Example 13: Influence of reinforcing fibers spanning the epoxy resin cured region and the thermoplastic resin region] The fiber-reinforced resin of Example 13, in which no reinforcing fibers exist that cross the interface and contact both resin regions, was prepared by the following method: Using the epoxy resin composition of Reference Example 1, a prepreg [II] prepared in the same manner as in Example 1 was cut to a predetermined size, and a total of six layers were laminated so that all had the same reinforcing fiber direction. Then, a PPS with a basis weight of 120 g / m² was applied to both surfaces. 2 A film was attached to create a preform. Subsequently, in the same manner as in Example 1, the material was heated and pressurized in a press machine to obtain fiber-reinforced resin for compressive strength evaluation and cross-sectional observation.

[0074] The prepreg [II] obtained above is cut to a predetermined size, the axial direction of the reinforcing fibers is defined as 0°, and the direction perpendicular to the axis is defined as 90°, and [0° / 90°] 2s After lamination (the symbol s indicates mirror symmetry), PPS with a basis weight of 120 g / m² is applied to both surfaces. 2 A film was attached to create a preform. Subsequently, in the same manner as in Example 1, the material was heated and pressurized in a press machine to obtain fiber-reinforced resin for evaluating tensile shear joint strength, and then welded in the same manner as in Example 1 to obtain an integrated molded product.

[0075] Table 5 shows the evaluation results of the physical properties of the fiber-reinforced resin and the integrated molded product, along with the evaluation results of Example 1. Note that Example 13 is for reference only.

[0076] [Table 5]

[0077] [Examples 14-18: Influence of surface free energy of reinforcing fibers] Using the epoxy resin composition of Reference Example 1, a fiber-reinforced resin and an integrated molded article were obtained in the same manner as in Example 1, except that the carbon fiber species constituting the reinforcing fiber sheet were changed as shown in Table 6.

[0078] Table 6 shows the evaluation results of the physical properties of the fiber-reinforced resin and the integrated molded product, along with the evaluation results of Example 1.

[0079] [Table 6] [Explanation of symbols]

[0080] 1: Reinforced fiber 2: Thermoplastic resin area 3: Area of ​​cured epoxy resin 4: Observation images 5: Interface 6: Reference line 7: Base line 8: Cross section curve

Claims

1. A fiber-reinforced resin having reinforcing fibers and comprising an epoxy resin cured region and a thermoplastic resin region formed on its surface, wherein the reinforcing fibers are present that are in contact with both resin regions across the interface between the thermoplastic resin region and the epoxy resin cured region, and the proportion of aromatic rings in all molecules constituting the epoxy resin cured region is 50% or more and 90% or less.

2. The fiber-reinforced resin according to claim 1, wherein the epoxy resin cured region and the thermoplastic resin region are adjacent to each other in a layered manner.

3. The fiber-reinforced resin according to claim 1 or 2, wherein the thermal conductivity of the reinforcing fibers is 3 W / (m·K) or more and 100 W / (m·K) or less.

4. The fiber-reinforced resin according to claim 3, wherein the thermal conductivity of the reinforcing fibers is 3 W / (m·K) or more and 50 W / (m·K) or less.

5. The aforementioned reinforcing fiber has a surface free energy of 10 mJ / m² as measured by the Wilhelmy method. ２ 50mJ / m or more ２ A fiber-reinforced resin according to any one of claims 1 to 4, using the following reinforcing fibers.

6. The fiber-reinforced resin according to any one of claims 1 to 5, wherein the epoxy resin cured product is a cured product of an epoxy resin composition containing an epoxy resin having a polycyclic aromatic hydrocarbon skeleton or a biphenyl skeleton.

7. The fiber-reinforced resin according to any one of claims 1 to 6, wherein the epoxy resin cured product is a cured product of an epoxy resin composition in which the average epoxy equivalent of all epoxy resins is 160 g / eq. or more and 255 g / eq. or less.

8. The fiber-reinforced resin according to any one of claims 1 to 7, wherein the epoxy resin cured product is a cured product of an epoxy resin composition containing a polyamine compound having an average active hydrogen equivalent of 55 g / eq. to 100 g / eq.

9. The fiber-reinforced resin according to any one of claims 1 to 8, wherein the epoxy resin cured product is a cured product of an epoxy resin composition in which the thermal mass loss rate when the cured product obtained by heating at 180°C for 120 minutes is held at 300°C for 2 minutes is 1.0% or less, and the glass transition temperature is 180°C or higher and 350°C or lower.

10. The fiber-reinforced resin according to any one of claims 1 to 9, wherein the average roughness length RSm of the interface between the epoxy resin cured region and the thermoplastic resin region is 100 μm or less, and the average roughness height Rc is 3.5 μm or more.

11. An integrally molded article comprising a fiber-reinforced resin according to any one of claims 1 to 10, welded to another member via the thermoplastic resin region.

Images