Composite material, molded article, and method for producing molded article

Abstract

To provide a composite material that is excellent in flexibility even when reinforcing fibers such as recycled reinforcing fibers are used and can provide a molded article excellent in mechanical strength, and to provide a molded article. This composite material has continuous thermoplastic resin fibers (1), continuous reinforcing fibers (2) having a thermosetting resin on the surface, and a thermoplastic resin (3) having a lower melting point than the resin constituting the continuous thermoplastic resin fibers (1). The continuous reinforcing fibers (2) contain 2-40 mass% of a thermosetting resin. The content of the thermoplastic resin (3) contained in the composite material is 5-80 mass parts per 100 total mass parts of the continuous thermoplastic resin fibers (1) and the thermoplastic resin (3). At least a part of the continuous thermoplastic resin fibers (1) and at least a part of the continuous reinforcing fibers (2) are bound via the thermoplastic resin (3).

Description

Composite material, molded article, and method for manufacturing the molded article

[0001] The present invention relates to composite materials, molded articles, and methods for making molded articles, and more particularly to composite materials containing continuous thermoplastic resin fibers and continuous reinforcing fibers.

[0002] In recent years, fiber-reinforced resin composite materials, in which thermoplastic resins are reinforced with continuous reinforcing fibers, have been attracting attention. The use of continuous reinforcing fibers is expected to provide high mechanical properties, and the use of thermoplastic resins offers advantages such as ease of secondary processability. However, thermoplastic resin composite materials reinforced with continuous reinforcing fibers have a problem in that the high melt viscosity of the resin makes it difficult to impregnate the continuous reinforcing fiber bundles with the thermoplastic resin. To solve this problem, a blended fiber yarn, a fibrous intermediate material in which continuous thermoplastic resin fibers and continuous reinforcing fibers are blended, has attracted attention (Patent Documents 1 and 2).

[0003] JP 2015-098669 A JP 2014-173196 A

[0004] The above-mentioned blended yarn is a material with excellent flexibility. Meanwhile, in recent years, the use of recycled reinforcing fibers has also been expected from the perspective of effective resource utilization. Here, recycled reinforcing fibers are often recovered by burning molded articles of thermosetting resin reinforced with the reinforcing fibers. However, this combustion often damages the recycled reinforcing fibers. Fiber-reinforced resin materials using damaged reinforcing fibers tend to have poor mechanical strength when formed into molded articles. Furthermore, it is difficult to produce a composite material with excellent flexibility using reinforcing fibers recovered from molded articles of thermosetting resin. The present invention aims to solve these problems and to provide a composite material and molded article that are excellent in flexibility even when using reinforcing fibers such as recycled reinforcing fibers, and that can provide molded articles with excellent mechanical strength.

[0005] In light of the above-mentioned problem, the present inventors conducted research and found that the above-mentioned problem can be solved by using a predetermined ratio of a thermoplastic resin (3) having a lower melting point than the resin constituting the continuous thermoplastic resin fiber when binding continuous thermoplastic resin fibers and continuous reinforcing fibers having a thermosetting resin on their surfaces. Specifically, the above-mentioned problem has been solved by the following means. <1> A composite material comprising continuous thermoplastic resin fibers (1), continuous reinforcing fibers (2) having a thermosetting resin on their surfaces, and a thermoplastic resin (3) having a lower melting point than the resin constituting the continuous thermoplastic resin fibers (1), wherein the continuous reinforcing fibers (2) contain the thermosetting resin in a ratio of 2 to 40 mass%, the content of the thermoplastic resin (3) contained in the composite material is 5 to 80 parts by mass per 100 parts by mass of the total of the continuous thermoplastic resin fibers (1) and the thermoplastic resin (3), and at least a portion of the continuous thermoplastic resin fibers (1) and at least a portion of the continuous reinforcing fibers (2) are bound via the thermoplastic resin (3). <2> The composite material according to <1>, wherein the continuous reinforcing fibers (2) comprise recycled continuous reinforcing fibers. <3> The composite material according to <1> or <2>, wherein the continuous reinforcing fibers (2) comprise recycled continuous carbon fibers. <4> The composite material according to any one of <1> to <3>, wherein the continuous thermoplastic resin fibers (1) and the thermoplastic resin (3) each independently comprise a polyamide resin. <5> The composite material according to any one of <1> to <4>, wherein the resin constituting the continuous thermoplastic resin fibers (1) comprises a xylylenediamine-based polyamide resin containing diamine structural units and dicarboxylic acid structural units, wherein 70 mol % or more of the diamine structural units are derived from xylylenediamine. <6> The composite material according to any one of <1> to <5>, wherein the thermoplastic resin (3) comprises a xylylenediamine-based polyamide resin containing diamine structural units and dicarboxylic acid structural units, wherein 70 mol % or more of the diamine structural units are derived from xylylenediamine. <7> The composite material according to <5> or <6>, wherein 50 mol% or more of the dicarboxylic acid constituent units in the xylylenediamine-based polyamide resin are constituent units derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.<8> The composite material according to any one of <1> to <7>, comprising: a continuous thermoplastic resin fiber layer in which the continuous thermoplastic resin fibers (1) are aligned in one direction; and a continuous reinforcing fiber layer in which the continuous reinforcing fibers (2) are aligned in one direction, with the thermoplastic resin (3) binding the continuous thermoplastic resin fiber layer and the continuous reinforcing fiber layer. <9> The composite material according to <8>, in which the continuous thermoplastic resin fibers (1) and the continuous reinforcing fibers (2) are aligned in the same direction. <10> The composite material according to any one of <1> to <9>, in which the continuous reinforcing fibers (2) are included in an amount of 40 to 90 parts by mass per 100 parts by mass of the continuous thermoplastic resin fibers (1) and the continuous reinforcing fibers (2) combined. <11> The composite material according to any one of <1> to <10>, in a tape form. <12> The composite material according to any one of <1> to <11>, for use in tailored fiber placement processing. <13> The continuous reinforcing fiber (2) is a recycled carbon fiber, The continuous thermoplastic resin fiber (1) and the thermoplastic resin (3) each independently contain a diamine structural unit and a dicarboxylic acid structural unit, and the xylylenediamine-based polyamide resin contains 70 mol% or more of the diamine structural units derived from xylylenediamine, and 50 mol% or more of the dicarboxylic acid structural units in the xylylenediamine-based polyamide resin are derived from α,ω-linear aliphatic dicarboxylic acid structural units having 4 to 20 carbon atoms, and the continuous thermoplastic resin fiber layer has the continuous thermoplastic resin fibers (1) arranged parallel to one another in one direction, and the continuous reinforcing fiber layer has the continuous reinforcing fibers (2) arranged parallel to one another in one direction, and the thermoplastic resin (3) binds the continuous thermoplastic resin fiber layer and the continuous reinforcing fiber layer, and the continuous thermoplastic resin fibers (1) and the continuous reinforcing fibers (2) are arranged parallel to one another in the same direction, and the continuous reinforcing fiber layer contains 40 to 90 parts by mass of the continuous reinforcing fibers (2) relative to a total of 100 parts by mass of the continuous thermoplastic resin fibers (1) and the continuous reinforcing fibers (2), and is tape-shaped, and is characterized by a tailored fiber placement (Tailored Fiber Placement). <14> A molded article formed from the composite material according to any one of <1> to <13>.<15> A method for producing a molded article, comprising stitching the composite material according to any one of <1> to <13> to a substrate and performing tailored fiber placement processing.

[0006] According to the present invention, it is possible to provide a composite material and a molded article that are excellent in flexibility even when using reinforcing fibers such as recycled reinforcing fibers, and that can provide a molded article with excellent mechanical strength.

[0007] Fig. 1 is a cross-sectional schematic diagram showing an example of a composite material of this embodiment. Fig. 2 is a cross-sectional schematic diagram showing another example of a composite material of this embodiment. Fig. 3 is a schematic diagram showing an example of a composite material of this embodiment that has been TFP processed. Fig. 4 is a photograph of embroidery produced by TFP processing in an example.

[0008] Hereinafter, an embodiment of the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the following present embodiment is an example for explaining the present invention, and the present invention is not limited to this embodiment. Note that in this specification, the expression "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit. In this specification, various physical property values ​​and characteristic values ​​are those at 23°C unless otherwise specified.

[0009] In this specification, unless otherwise specified, the weight average molecular weight and number average molecular weight are polystyrene-equivalent values ​​measured by GPC (gel permeation chromatography). In this specification, unless otherwise specified, the weight average molecular weight and number average molecular weight can be measured according to the description in paragraph 0047 of JP 2018-165298 A, the contents of which are incorporated herein. If the measurement methods described in the standards shown in this specification vary depending on the fiscal year, they are based on the standards as of January 1, 2023, unless otherwise specified. In Figures 1 to 3, the scales may not be consistent with reality.

[0010] The composite material of this embodiment is a composite material having continuous thermoplastic resin fibers (1), continuous reinforcing fibers (2) having a thermosetting resin on their surfaces, and a thermoplastic resin (3) having a melting point lower than that of the resin constituting the continuous thermoplastic resin fibers (1), wherein the continuous reinforcing fibers (2) contain 2 to 40 mass% of the thermosetting resin, the content of the thermoplastic resin (3) contained in the composite material is 5 to 80 parts by mass per 100 parts by mass of the continuous thermoplastic resin fibers (1) and the thermoplastic resin (3), and at least a portion of the continuous thermoplastic resin fibers (1) and at least a portion of the continuous reinforcing fibers (2) are bound via the thermoplastic resin (3). This configuration provides a composite material with excellent flexibility and capable of providing molded products with excellent mechanical strength.

[0011] One known method for bonding thermoplastic resins and reinforcing fibers is to heat press them to form prepregs. However, when molding a molded product with many irregularities, a more flexible composite material than prepregs may be required. In this embodiment, a composite material is used that includes continuous thermoplastic resin fibers (1) in which the thermoplastic resin maintains its fibrous shape. Specifically, by binding the continuous thermoplastic resin fibers (1) and continuous reinforcing fibers (2) having a thermosetting resin on their surfaces via a thermoplastic resin (3) (hereinafter sometimes referred to as a "binder resin") having a lower melting point than the resin constituting the continuous thermoplastic resin fibers (1), a composite material with excellent flexibility has been successfully produced. Furthermore, by using a thermoplastic resin with a low melting point as the binder resin, it is possible to sufficiently dissolve the thermoplastic resin during hot molding and prevent it from remaining as a foreign substance in the molded product. Furthermore, recycled reinforcing fibers can be used as the raw material for the composite material of this embodiment, which can be environmentally friendly. In the composite material of this embodiment, the continuous thermoplastic resin fibers (1) are preferably arranged with a regularity. In the composite material of this embodiment, the continuous reinforcing fibers (2) are preferably arranged with regularity. Regular arrangement includes fibers arranged in one direction (opened continuous reinforcing fiber roving), woven fibers, knitted fibers, and the like. It goes without saying that regularity in the present invention includes not only regularity in the geometric sense but also ordinary errors in the technical field of the present invention. Nonwoven fabrics are an example of fibers that are not arranged with regularity.

[0012] FIG. 1 is a schematic diagram showing an example of a composite material of this embodiment, and is a cross-sectional view perpendicular to the longitudinal direction of the continuous reinforcing fiber (2). The composite material 10 shown in FIG. 1 is in the form of a tape. Forming it into a tape facilitates further processing. In FIG. 1, 1 denotes the continuous thermoplastic resin fiber (1), 22 denotes the continuous reinforcing fiber portion of the continuous reinforcing fiber (2), 3 denotes a thermoplastic resin (3) (binder resin) having a lower melting point than the resin constituting the continuous thermoplastic resin fiber (1), and 4 denotes the thermosetting resin present on the surface of the continuous reinforcing fiber 22 of the continuous reinforcing fiber (2). In other words, the continuous reinforcing fiber (2) in this specification refers to a material including the continuous reinforcing fiber itself 22 and the thermosetting resin 4.

[0013] Returning to FIG. 1 , the composite material 10 includes continuous thermoplastic resin fibers (1), continuous reinforcing fibers (2) having a thermosetting resin 4 on their surfaces, and a thermoplastic resin (3) having a melting point lower than that of the resin constituting the continuous thermoplastic resin fibers (1). By using a relatively large amount of thermosetting resin 4 on the surfaces of the continuous reinforcing fibers themselves (22), damage to the reinforcing fibers can be minimized, even when recycled reinforcing fibers are used. The thermosetting resin 4 may cover either a portion or the entire surface of the continuous reinforcing fibers themselves (22). Preferably, the thermosetting resin 4 covers 50% or more of the surface area of ​​the continuous reinforcing fibers themselves (22), and more preferably 80% or more. The thermosetting resin 4 may also cover 100% of the surface area of ​​the continuous reinforcing fibers themselves (22). The thermosetting resin 4 may contain, in addition to the curable resin, resin additives, fillers, reinforcing fiber surface treatment agents, and the like. These will be described in detail below.

[0014] In this embodiment, at least a portion of the continuous thermoplastic resin fibers (1) and at least a portion of the continuous reinforcing fibers (2) are bound together via a thermoplastic resin (3) (binder resin). In Fig. 1, almost all of the continuous reinforcing fibers (2) and almost all of the continuous thermoplastic resin fibers (1) are bonded together via the binder resin 3. In the composite material of this embodiment, the continuous reinforcing fibers (2) and the continuous thermoplastic resin fibers (1) are bound together using the binder resin 3, so that the continuous thermoplastic resin fibers (1) can be maintained in a fibrous state, and flexibility can be achieved for the resulting composite material.

[0015] In this embodiment, the binder resin 3 preferably covers 20% or more, and more preferably 40% or more, of the surface area of ​​the continuous thermoplastic resin fibers 1. The binder resin 3 may cover 100% of the surface area of ​​the continuous thermoplastic resin fibers 1, but even if the binder resin 3 covers 15% or less, the required performance is sufficiently satisfied.

[0016] The shape of the composite material 10 of this embodiment is not particularly limited, but it is preferably tape-shaped. When the composite material of this embodiment is tape-shaped, its thickness is preferably 100 μm or more, more preferably 20 μm or more. By making the thickness equal to or greater than the lower limit, the time required to prepare a preform (molding before heat processing) tends to be shortened. Furthermore, the thickness of the tape-shaped composite material is preferably 500 μm or less, more preferably 400 μm or less. By making the thickness equal to or less than the upper limit, the resin can penetrate deep into the reinforcing fibers, shortening the molding time and tending to improve the mechanical properties of the resulting molded product. When the composite material of this embodiment is tape-shaped, its width is preferably 5 mm or more, more preferably 8 mm or more. By making the thickness equal to or greater than the lower limit, the time required to prepare a preform using TFP or braiding tends to be shortened. Furthermore, the width of the tape-shaped composite material is preferably 25 mm or less, more preferably 20 mm or less. By making the thickness equal to or less than the upper limit, the design of the resulting molded product tends to be improved.

[0017] The composite material of this embodiment preferably includes a continuous thermoplastic resin fiber layer in which continuous thermoplastic resin fibers (1) are arranged in one direction, and a continuous reinforcing fiber layer in which the continuous reinforcing fibers (2) are arranged in one direction, and the thermoplastic resin (3) binds the continuous thermoplastic resin fiber layer and the continuous reinforcing fiber layer. The continuous thermoplastic resin fiber layer in which the continuous thermoplastic resin fibers (1) are arranged in one direction includes, for example, a layered shape in which the continuous thermoplastic resin fiber layers are arranged in a row, as shown in FIG. 1 . Such a layered shape can be formed, for example, by spreading multifilament continuous thermoplastic resin fibers consisting of multiple continuous thermoplastic resin fibers. The continuous reinforcing fiber layer in which the continuous reinforcing fibers (2) are arranged in one direction includes, for example, a layered shape in which the continuous reinforcing fiber layers are arranged in a row, as shown in FIG. 1 . Such a layered shape can be formed, for example, by spreading continuous reinforcing fiber bundles consisting of multiple continuous reinforcing fibers. Recycled reinforcing fibers recovered from UD tape (unidirectional tape) can also be used. In the composite material of this embodiment, the continuous thermoplastic resin fibers (1) and the continuous reinforcing fibers (2) are preferably arranged in parallel in the same direction.

[0018] Fig. 2 shows another example of the composite material of this embodiment, in which the continuous thermoplastic resin fibers (1) and the continuous reinforcing fibers (2) are arranged in parallel in one direction, but the continuous thermoplastic resin fibers (1) and the continuous reinforcing fibers (2) are dispersed and mixed. The symbols are the same as those in Fig. 1.

[0019] In addition to the above, it is also preferable that the composite material of this embodiment has a woven fabric of the continuous thermoplastic resin fibers (1) and a woven fabric of the continuous reinforcing fibers (2) bonded together via a binder resin 3.

[0020] The composite material of this embodiment may be used as is, but is usually preferably used in applications where it will be further processed (secondary processing). The composite material of this embodiment may be heat processed as is, but because it is flexible, it is preferably used as a yarn for Tailored Fiber Placement (TFP) processing, or as a yarn for use in applications involving reeling, such as braiding machines, knitting machines, and looms. Examples of applications involving reeling include braided cords and twisted cords.

[0021] FIG. 3 shows an example of the composite material of this embodiment subjected to TFP processing, with 10 representing the composite material of this embodiment and 11 representing the thread. In the TFP process, the composite material 10 is preferably arranged to conform to the shape of a molded article and stitched with the thread 11. The thread 11 is typically a continuous thermoplastic resin fiber. A preferred example of the thermoplastic resin fiber is a thermoplastic resin fiber corresponding to the continuous thermoplastic resin fiber (1), and another preferred example is a thermoplastic resin fiber formed from the resin that constitutes the binder resin 3. The composite material of this embodiment is preferably used for molded articles having, for example, two or more, preferably three or more folded portions, as shown in FIG. 3. It is particularly preferably used for molded articles having folded portions with a folding angle of 90° or more, as shown in FIG. 3.

[0022] <Continuous thermoplastic resin fiber (1)> Next, the continuous thermoplastic resin fiber (1) will be described. The continuous thermoplastic resin fiber (1) used in this embodiment refers to a thermoplastic resin fiber having a fiber length of more than 6 mm, preferably more than 12 mm, more preferably more than 30 mm, and even more preferably more than 10 cm. There are no particular restrictions on the average fiber length of the continuous thermoplastic resin fiber (1) used in this embodiment, but from the viewpoint of improving molding processability, it is preferably 1 m or more, more preferably 100 m or more, even more preferably 1,000 m or more, and preferably 20,000 m or less, more preferably 1,0000 m or less, and even more preferably 7,000 m or less.

[0023] In the composite material of this embodiment, the total fineness of the continuous thermoplastic resin fibers (1) is preferably 200 to 12,000 dtex, and more preferably 1,000 to 10,000 dtex. By setting it in such a range, the effects of this embodiment can be more effectively exhibited. The total number of fibers of the continuous thermoplastic resin fibers (1) in the composite material of this embodiment is preferably 10 to 10,000 f, more preferably 100 to 5,000 f, and even more preferably 500 to 3,000 f. By setting it in such a range, a composite material with better physical properties and texture can be obtained.

[0024] The continuous thermoplastic resin fiber (1) used in this embodiment is composed mainly of a thermoplastic resin (usually 90% by mass or more, preferably 95% by mass or more, and 100% by mass or less of 100% by mass of the continuous thermoplastic resin fiber (1) is the thermoplastic resin). The continuous thermoplastic resin fiber (1) may also contain known additives, etc. as appropriate. The thermoplastic resin used in the continuous thermoplastic resin fiber (1) can be a wide variety of known thermoplastic resins, and is usually a crystalline resin. Specific examples of the thermoplastic resin used in the continuous thermoplastic resin fiber (1) include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyamide resin, polyethylene terephthalate and polybutylene terephthalate, polyoxymethylene resin, polyether ketone, polyether ether ketone, polyether ketone ketone, polyether ether ketone ketone, polyether sulfone resin, polyether sulfide resin, thermoplastic polyetherimide, thermoplastic polyamideimide, wholly aromatic polyimide, semi-aromatic polyimide, and the like, and polyamide resin is more preferred. The polyamide resin used in this embodiment may be either an aliphatic polyamide resin or an aromatic polyamide resin. Aliphatic polyamide resin refers to a polyamide resin in which aromatic monomer-derived structural units account for less than 20 mol% of the total structural units constituting the polyamide resin. Examples of aliphatic polyamide resins include polyamide 4, polyamide 46, polyamide 6, polyamide 66, polyamide 666, polyamide 610, polyamide 11, polyamide 116, polyamide 12, and polyamide 612. Aromatic polyamide resins contain diamine structural units and dicarboxylic acid structural units, and 20 to 80 mol% (preferably 30 to 80 mol%, more preferably 40 to 70 mol%) of the total structural units of the diamine structural units and dicarboxylic acid structural units contain aromatic rings. The use of such semi-aromatic polyamide resins can enhance the mechanical strength of the resulting molded article.Examples of semi-aromatic polyamide resins include polyamide 6T / 6I, polyamide 66 / 6T, polyamide 9T, polyamide 10T, and xylylenediamine-based polyamide resins described below, with xylylenediamine-based polyamide resins being preferred.

[0025] The xylylenediamine-based polyamide resin in this embodiment is a polyamide resin containing diamine structural units and dicarboxylic acid structural units, with 70 mol % or more of the diamine structural units being derived from xylylenediamine. Preferably, the xylylenediamine-based polyamide resin has 50 mol % or more of the dicarboxylic acid structural units derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The composite material of this embodiment can exhibit the strength and chemical resistance inherent to the xylylenediamine-based polyamide resin.

[0026] The diamine constituent units of the xylylenediamine-based polyamide resin are preferably derived from xylylenediamine (preferably paraxylylenediamine and / or metaxylylenediamine, more preferably metaxylylenediamine) for 75 mol% or more, more preferably 80 mol% or more, even more preferably 85 mol% or more, still more preferably 90 mol% or more, even more preferably 95 mol% or more, and particularly preferably 99 mol% or more. The dicarboxylic acid constituent units of the xylylenediamine-based polyamide resin are preferably derived from α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms for 60 mol% or more, even more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, still more preferably 95 mol% or more, and particularly preferably 99 mol% or more.

[0027] In this embodiment, the molar ratio of metaxylylenediamine to paraxylylenediamine in the xylylenediamine, when the total of metaxylylenediamine and paraxylylenediamine is 100 moles, is preferably metaxylylenediamine / paraxylylenediamine is 00 to 100 / 100 to 0, preferably 10 to 100 / 90 to 0, more preferably 20 to 100 / 80 to 0, even more preferably 50 to 90 / 50 to 10, and still more preferably 60 to 80 / 40 to 20. By including paraxylylenediamine, the melting point of the polyamide resin can be increased.

[0028] Diamines other than metaxylylenediamine and paraxylylenediamine that can be used as raw diamine components for xylylenediamine-based polyamide resins include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine; 1,3-bis( Examples of the diamine include alicyclic diamines such as bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane; and diamines having an aromatic ring such as bis(4-aminophenyl)ether, paraphenylenediamine, and bis(aminomethyl)naphthalene, and these can be used alone or in combination of two or more.

[0029] As described above, the xylylenediamine-based polyamide resin preferably has 50 mol % or more of the dicarboxylic acid constituent units derived from an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The number of carbon atoms in the α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms is preferably 6 or more, and is preferably 18 or less, more preferably 16 or less, even more preferably 14 or less, even more preferably 13 or less, and even more preferably 12 or less. Examples of α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms suitable for use as the raw dicarboxylic acid component of xylylenediamine-based polyamide resins include succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid. These can be used alone or in combination of two or more. Among these, one or more of adipic acid, sebacic acid, and dodecanedioic acid are more preferred, with sebacic acid being even more preferred. A preferred embodiment of the xylylenediamine-based polyamide resin in this embodiment is one in which 50 mol % or more (preferably 70 mol % or more, more preferably 90 mol % or more) of the dicarboxylic acid constituent units are derived from one or more of adipic acid, sebacic acid, and dodecanedioic acid (preferably sebacic acid).

[0030] Examples of dicarboxylic acid components other than the above-mentioned α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms include phthalic acid compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and isomers of naphthalenedicarboxylic acid such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, and these can be used alone or in combination of two or more.

[0031] Although the xylylenediamine-based polyamide resin contains diamine structural units and dicarboxylic acid structural units as its main components, it does not completely exclude other structural units, and may, of course, contain structural units derived from lactams such as ε-caprolactam and laurolactam, and aliphatic aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid. Here, "main component" refers to the structural units constituting the xylylenediamine-based polyamide resin in which the total number of diamine structural units and dicarboxylic acid structural units is the largest among all structural units. In this embodiment, the total of the diamine structural units and dicarboxylic acid structural units in the xylylenediamine-based polyamide resin preferably accounts for 90% by mass or more of all structural units, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more.

[0032] It is also preferable to use the thermoplastic resin (particularly polyamide resin, and further xylylenediamine-based polyamide resin) manufactured using recycled resin or biomass raw material (biomass thermoplastic resin). The use of biomass thermoplastic resin can reduce the environmental impact. For example, bioadipic acid can be used as the biomass raw material for xylylenediamine-based polyamide resin. Mass balance certified (ISCC PLUS) adipic acid can also be used. Mass balance certification means that the amount of renewable raw materials or bio-based raw materials used at each factory or production facility and the amount of products produced or shipped are quantified and guaranteed together with the quality.

[0033] The melting point of the thermoplastic resin (preferably a xylylenediamine-based polyamide resin) contained in the continuous thermoplastic resin fiber (1) is preferably 150°C or higher, more preferably 180°C or higher, even more preferably 200°C or higher, and even more preferably 205°C or higher. The melting point of the thermoplastic resin (preferably a xylylenediamine-based polyamide resin) is preferably 350°C or lower, more preferably 330°C or lower, even more preferably 300°C or lower, even more preferably 280°C or lower, even more preferably 260°C or lower, and even more preferably 250°C or lower. When the continuous thermoplastic resin fiber (1) of this embodiment contains two or more thermoplastic resins, the melting point of the thermoplastic resin constituting the continuous thermoplastic resin fiber (1) is the melting point of the resin with the highest melting point. The melting point is measured as described in the Examples below.

[0034] The thermoplastic resin (preferably a xylylenediamine-based polyamide resin) preferably has a number average molecular weight (Mn) of at least 6,000, more preferably at least 8,000, and even more preferably at least 10,000, and is preferably at most 10,000, more preferably at most 50,000. When the continuous thermoplastic resin fiber (1) used in this embodiment contains two or more types of thermoplastic resins, the number average molecular weight is the number average molecular weight of the mixture.

[0035] The number average molecular weight (Mn) of the thermoplastic resin is measured by gel permeation chromatography (GPC) using a standard polymethyl methacrylate (PMMA) equivalent value. Two columns packed with a styrene polymer are used as the packing material, and hexafluoroisopropanol (HFIP) with a sodium trifluoroacetate concentration of 2 mmol / L is used as the solvent. The resin concentration is 0.02% by mass, the column temperature is 40 ° C, the flow rate is 0.3 mL / min, and the measurement is performed using a refractive index detector (RI). The calibration curve is measured by dissolving six levels of PMMA in HFIP.

[0036] The continuous thermoplastic resin fiber (1) used in this embodiment may contain additives such as antioxidants, stabilizers such as heat stabilizers, hydrolysis resistance improvers, weathering stabilizers, matting agents, UV absorbers, nucleating agents, plasticizers, dispersants, flame retardants, antistatic agents, coloring inhibitors, antigelling agents, colorants, and release agents, within the scope of the objects and effects of the present invention. For details of these, please refer to the descriptions in paragraphs 0130 to 0155 of Japanese Patent No. 4,894,982 and the descriptions in paragraphs 0047 to 0103 of International Publication No. 2021 / 241471, the contents of which are incorporated herein by reference.

[0037] The proportion of the continuous thermoplastic resin fiber (1) in the composite material of this embodiment is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, even more preferably 25% by mass or more, and even more preferably 30% by mass or more, based on 100% by mass of the composite material. By setting the proportion at or above the lower limit, the impregnation time, i.e., the molding time, tends to be further shortened. Furthermore, the proportion of the continuous thermoplastic resin fiber (1) in the composite material of this embodiment is preferably 75% by mass or less, more preferably 70% by mass or less, even more preferably 65% ​​by mass or less, even more preferably 60% by mass or less, and even more preferably 55% by mass or less, based on 100% by mass of the composite material. Setting the proportion at or below the upper limit increases the carbon ratio in the composite material, and tends to further improve the mechanical properties of the resulting molded product. The composite material of this embodiment may contain only one type of continuous thermoplastic resin fiber (1), or may contain two or more types. When two or more types are contained, the total amount preferably falls within the above range.

[0038] <Continuous reinforcing fiber (2) having thermosetting resin on its surface> In the composite material of this embodiment, the continuous reinforcing fiber (2) having a thermosetting resin on its surface contains the continuous reinforcing fiber itself and the thermosetting resin, as described above, and typically the total of the continuous reinforcing fiber itself and the thermosetting resin accounts for 95% by mass (preferably 99% by mass or more and 100% by mass or less) of the total of the continuous reinforcing fiber (2).

[0039] The continuous reinforcing fiber itself in this embodiment refers to a reinforcing fiber having a fiber length of more than 6 mm, preferably more than 12 mm, more preferably more than 30 mm, and even more preferably more than 10 cm. The average fiber length of the continuous reinforcing fiber used in this embodiment is not particularly limited, but from the viewpoint of improving molding processability, it is preferably 1 m or more, more preferably 100 m or more, even more preferably 1,000 m or more, and preferably 20,000 m or less, more preferably 1,0000 m or less, and even more preferably 7,000 m or less.

[0040] Examples of materials for the continuous reinforcing fibers themselves include inorganic fibers such as glass fibers, carbon fibers, metal fibers, boron fibers, basalt fibers, and ceramic fibers; and organic fibers such as aramid fibers, polyoxymethylene fibers, aromatic polyamide fibers, polyparaphenylene benzobisoxazole fibers, and ultra-high molecular weight polyethylene fibers. Among these, inorganic fibers are preferred from the viewpoint of achieving high strength. Because of their light weight, high strength, and high elastic modulus, at least one fiber selected from the group consisting of glass fibers, carbon fibers, and basalt fibers is more preferred, and carbon fibers are even more preferred. Examples of carbon fibers include polyacrylonitrile-based carbon fibers and pitch-based carbon fibers. Carbon fibers derived from plant-derived materials such as lignin and cellulose can also be used.

[0041] The continuous reinforcing fiber (2) used in this embodiment has a thermosetting resin on its surface. Examples of the thermosetting resin include epoxy resin, oxetane resin, phenolic resin, polyurethane resin, melamine resin, maleimide resin, cyanate resin, etc., and epoxy resin is preferred. In this embodiment, the continuous reinforcing fiber (2) having a thermosetting resin on its surface is preferably a recycled continuous reinforcing fiber, and more preferably a recycled continuous carbon fiber. In particular, it is preferred that the continuous reinforcing fiber have a high residual rate of the thermosetting resin.

[0042] In particular, the proportion of the thermosetting resin in the continuous reinforcing fiber (2) is 2% by mass or more, preferably 8% by mass or more, more preferably 10% by mass or more, and may be 12% by mass or more, based on 100% by mass of the continuous reinforcing fiber (2). Furthermore, the proportion of the thermosetting resin in the continuous reinforcing fiber (2) is 40% by mass or less, preferably 38% by mass or less, more preferably 35% by mass or less, and may be 32% by mass or less, based on 100% by mass of the continuous reinforcing fiber (2). By setting the proportion at or above the lower limit, damage to the continuous reinforcing fiber in the resulting molded product can be reduced, and the mechanical strength of the resulting molded product can be further improved. Furthermore, by setting the proportion at or below the upper limit, the resulting composite material can be made more flexible. The continuous reinforcing fiber (2) may use only one type of thermosetting resin, or two or more types. When two or more types are used, it is preferable that the total amount be within the above range.

[0043] The thermosetting resin contained in the continuous reinforcing fibers (2) may be partially carbonized. In particular, when the continuous reinforcing fibers (2) are recycled products, the proportion of carbonized resin tends to be high. The content of thermosetting resin in the reinforcing fibers used in this embodiment refers to the amount of thermosetting resin that remains after carbonization and has not been carbonized.

[0044] The continuous reinforcing fibers (2) used in this embodiment may be further treated with a treatment agent. Treatment with a treatment agent tends to further improve the degree of integration of the resulting composite material. In this embodiment, it is preferable that at least a portion of the treatment agent is present on the surface of the thermosetting resin of the continuous reinforcing fibers (2) having a thermosetting resin on their surfaces. Furthermore, in this embodiment, it is preferable that at least a portion of the treatment agent is present on the surface of the thermosetting resin of the continuous thermoplastic resin fibers (1) and the continuous reinforcing fibers (2) having a thermosetting resin on their surfaces. The treatment agent is a surface treatment agent and / or a sizing agent.

[0045] Specifically, the treating agent that can be used in this embodiment is preferably at least one of an epoxy resin, a urethane resin, a silane coupling agent, a water-insoluble nylon, and a water-soluble nylon, more preferably at least one of an epoxy resin, a urethane resin, a water-insoluble nylon, and a water-soluble nylon, and even more preferably a water-soluble nylon.

[0046] Here, water-insoluble nylon refers to nylon in which 99% or more by mass does not dissolve when 1 g of nylon is added to 100 g of water at 25°C. When using water-insoluble nylon, it is preferable to use a powdered water-insoluble nylon dispersed or suspended in water or an organic solvent. A mixed fiber bundle can be immersed in such a powdered water-insoluble nylon dispersion or suspension and then dried to form a mixed fiber yarn. Examples of water-insoluble nylon include nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, xylylenediamine-based polyamide resins (preferably polyxylylene adipamide and polyxylylene sebacamide), and powders of these copolymers emulsified and dispersed with a nonionic, cationic, anionic surfactant, or a mixture thereof. Commercially available water-insoluble nylons are sold as water-insoluble nylon emulsions, such as Sepolsion PA manufactured by Sumitomo Seika Chemicals and Michem Emulsion manufactured by Michaelman.

[0047] Here, water-soluble nylon refers to a nylon that dissolves at least 99% by mass in water when 1 g of nylon is added to 100 g of water at 25°C. Examples of water-soluble nylon include modified polyamides such as acrylic acid-grafted N-methoxymethylated nylon and N-methoxymethylated nylon to which amide groups have been added. Examples of water-soluble nylon include commercially available products such as AQ-nylon manufactured by Toray and Toresin manufactured by Nagase ChemteX.

[0048] The amount of the treatment agent is preferably 0.001 to 5 mass%, more preferably 0.1 to 4 mass%, and even more preferably 0.5 to 4 mass%, relative to 100 mass% of the amount of the continuous reinforcing fibers themselves contained in the continuous reinforcing fibers (2).

[0049] The content of the continuous reinforcing fiber (2) in the composite material of this embodiment is preferably 40 parts by mass or more, more preferably 45 parts by mass or more, even more preferably 50 parts by mass or more, even more preferably 55 parts by mass or more, and even more preferably 60 parts by mass or more, relative to 100 parts by mass of the total of the continuous thermoplastic resin fiber (1) and the continuous reinforcing fiber (2). By making the content equal to or greater than the lower limit, the thermoplastic resin fiber can be arranged around the entire reinforcing fiber, which tends to further shorten the impregnation time, i.e., the molding time. Furthermore, the content of the continuous reinforcing fiber (2) in the composite material of this embodiment is preferably 90 parts by mass or less, more preferably 85 parts by mass or less, relative to 100 parts by mass of the total of the continuous thermoplastic resin fiber (1) and the continuous reinforcing fiber (2). By making the content equal to or less than the upper limit, the carbon ratio in the composite material tends to be increased, and the mechanical properties of the resulting molded product tend to be further improved. The composite material of this embodiment may contain only one type of continuous reinforcing fiber (2), or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0050] <Thermoplastic resin (3) having a melting point lower than that of the resin constituting the continuous thermoplastic resin fiber (1)> The composite material of this embodiment includes a thermoplastic resin (3) (binder resin) having a melting point lower than that of the resin constituting the continuous thermoplastic resin fiber (1). By using such a binder resin, the thermoplastic resin fiber (1) and the continuous reinforcing fiber (2) can be effectively bound together. The binder resin is composed mainly of a thermoplastic resin having a melting point lower than that of the resin constituting the continuous thermoplastic resin fiber (1) (usually 90% by mass or more, preferably 95% by mass or more, and 100% by mass or less, based on 100% by mass of the binder resin). The binder resin may also contain known additives. A wide variety of known thermoplastic resins can be used as the thermoplastic resin, and a crystalline resin is preferred.

[0051] The difference between the melting point of the resin constituting the continuous thermoplastic resin fiber (1) and the melting point of the binder resin is preferably 1°C or more, more preferably 5°C or more, even more preferably 10°C or more, even more preferably 15°C or more, even more preferably 20°C or more, and even more preferably 30°C or more. By ensuring that the difference is above the lower limit, the thermoplastic resin fiber (1) can more appropriately maintain its fibrous shape, the composite material retains flexibility, and the design can be beautifully reflected when the preform is produced. Furthermore, the difference between the melting point of the resin constituting the continuous thermoplastic resin fiber (1) and the melting point of the binder resin is preferably 100°C or less, more preferably 70°C or less, even more preferably 60°C or less, even more preferably 50°C or less, and even more preferably 49°C or less. By ensuring that the difference is below the upper limit, thermal degradation of the thermoplastic resin fiber (1) can be effectively suppressed. When the composite material of this embodiment contains two or more binder resins, the melting point of the binder resin with the higher melting point is taken as the melting point. The melting point is measured as described in the Examples below.

[0052] Examples of thermoplastic resins used as binder resins include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyamide resins, polyethylene terephthalate and polybutylene terephthalate, polyetherketone resins such as polyoxymethylene resins, polyetherketone, polyetheretherketone, polyetherketoneketone, polyetheretherketoneketone, and polyetheretherketoneketone, and thermoplastic polyimide resins such as polyethersulfone resins, polyethersulfide resins, thermoplastic polyetherimides, thermoplastic polyamideimides, wholly aromatic polyimides, and semi-aromatic polyimides. Polyamide resins are more preferred. The polyamide resin used in this embodiment may be either an aliphatic polyamide resin or an aromatic polyamide resin. Examples of aliphatic polyamide resins and aromatic polyamide resins are the same as those described above for the continuous thermoplastic resin fiber (1), except for the following points.

[0053] The binder resin is preferably a xylylenediamine-based polyamide resin. The xylylenediamine-based polyamide resin in this embodiment is a polyamide resin containing diamine structural units and dicarboxylic acid structural units, with 70 mol % or more of the diamine structural units being derived from xylylenediamine. Preferably, in the xylylenediamine-based polyamide resin, 50 mol % or more of the dicarboxylic acid structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The composite material of this embodiment can exhibit the inherent strength and chemical resistance of the xylylenediamine-based polyamide resin.

[0054] In the binder resin, the molar ratio of metaxylylenediamine to paraxylylenediamine in the xylylenediamine, where the total of metaxylylenediamine and paraxylylenediamine is 100 moles, is preferably metaxylylenediamine / paraxylylenediamine, 0 to 100 / 100 to 0, and more preferably 10 to 100 / 90 to 0. By including metaxylylenediamine, the melting point of the polyamide resin can be lowered. Examples of α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms suitable for use as the raw dicarboxylic acid component of xylylenediamine-based polyamide resins include succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid. These can be used alone or in combination. Among these, at least one of adipic acid, sebacic acid, and dodecanedioic acid is more preferred, with adipic acid and / or sebacic acid being even more preferred. A preferred embodiment of the xylylenediamine-based polyamide resin in the binder resin is one in which 50 mol % or more (preferably at least 70 mol %, more preferably at least 90 mol %) of the dicarboxylic acid constituent units are derived from at least one of adipic acid, sebacic acid, and dodecanedioic acid (preferably adipic acid and / or sebacic acid, more preferably adipic acid).

[0055] The melting point of the thermoplastic resin (preferably a xylylenediamine-based polyamide resin) contained in the binder resin is preferably 120° C. or higher, more preferably 130° C. or higher, even more preferably 150° C. or higher, and even more preferably 180° C. or higher. The melting point of the thermoplastic resin (preferably a xylylenediamine-based polyamide resin) is preferably 300° C. or lower, more preferably 250° C. or lower, even more preferably 220° C. or lower, and even more preferably 200° C. or lower.

[0056] The binder resin used in this embodiment may contain additives such as antioxidants, stabilizers such as heat stabilizers, hydrolysis resistance improvers, weathering stabilizers, matting agents, UV absorbers, nucleating agents, plasticizers, dispersants, flame retardants, antistatic agents, coloring inhibitors, antigelling agents, colorants, and release agents, as long as the objectives and effects of the present invention are not impaired. For details of these, please refer to the descriptions in paragraphs 0130 to 0155 of Japanese Patent No. 4,894,982 and the descriptions in paragraphs 0047 to 0103 of International Publication No. 2021 / 241471, the contents of which are incorporated herein by reference.

[0057] The content of the binder resin in the composite material of this embodiment is 5 parts by mass or more, preferably 10 parts by mass or more, and more preferably 15 parts by mass or more, per 100 parts by mass of the continuous thermoplastic resin fibers (1) and the binder resin combined. By setting the content at or above the lower limit, the continuous thermoplastic resin fibers (1) can be bonded to the continuous reinforcing fibers (2) without any leakage via the binder. Furthermore, the content of the binder resin in the composite material of this embodiment is 80 parts by mass or less, preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 55 parts by mass or less, per 100 parts by mass of the continuous thermoplastic resin fibers (1) and the binder resin combined. Setting the content at or below the upper limit tends to maintain flexibility in the composite material, allowing the design to be more clearly reflected when producing a molded product. The composite material of this embodiment may contain only one type of binder resin, or may contain two or more types. When two or more types are included, the total amount is preferably within the above range.

[0058] In this embodiment, it is preferable that the resin constituting the continuous thermoplastic resin fibers (1) and the binder resin each independently contain a polyamide resin, and it is preferable that each independently contain a xylylenediamine-based polyamide resin.

[0059] <Method for producing a composite material> The composite material of this embodiment can be produced by a known method. For example, a composite material can be produced by binding opened continuous thermoplastic resin fibers (3) and continuous reinforcing fibers (2) having a thermosetting resin on their surfaces (preferably recycled carbon fibers with the thermosetting resin remaining on them) with a binder resin. Heating is preferably performed during binding, and the heating temperature is preferably at least 10°C below the melting point of the binder resin, more preferably at least 5°C below the melting point of the binder resin, even more preferably at least the melting point of the binder resin, and even more preferably at least 5°C above the melting point of the binder resin. It is also preferably at least 5°C below the melting point of the thermoplastic resin constituting the thermoplastic resin fiber (1), more preferably below the melting point of the thermoplastic resin constituting the thermoplastic resin fiber (1), even more preferably at least 5°C below the melting point of the thermoplastic resin constituting the thermoplastic resin fiber (1), and even more preferably at least 10°C below the melting point of the thermoplastic resin constituting the thermoplastic resin fiber (1). By heating at such a temperature, the fibrous shape of the continuous thermoplastic resin fibers (1) is easily maintained, the resulting composite material becomes flexible, and the degree of integration with the continuous reinforcing fibers (2) is further improved.

[0060] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0061] 1. Raw materials <Continuous reinforcing fiber (2)> CF1: Recycled carbon fiber roving, type of curable resin: epoxy resin, proportion of thermosetting resin that did not form a carbonized product after carbonization and remained after carbonization was 10 mass% CF2: Recycled carbon fiber roving, type of curable resin: epoxy resin, proportion of thermosetting resin that did not form a carbonized product after carbonization and remained after carbonization was 30 mass% CF3: Recycled carbon fiber roving, type of curable resin: acrylate resin, proportion of thermosetting resin that did not form a carbonized product after carbonization and remained after carbonization was 10 mass% All of the recycled carbon fibers used had been carbonized at 500°C for 2 hours.

[0062] <Thermoplastic Resins> MPXD10: Polyamide resin synthesized in Synthesis Example 1 MXD6: Polyamide resin synthesized from adipic acid and metaxylylenediamine, manufactured by Mitsubishi Gas Chemical Company, Inc., #6007 MPXD12: Polyamide resin synthesized from metaxylylenediamine, paraxylylenediamine (MP ratio: 7:3) and dodecanedioic acid N66: Polyamide 66, manufactured by Toray Industries, Inc., Amilan CM3001 MXD10: Polyamide resin synthesized in Synthesis Example 3 N12: Polyamide 12, manufactured by Ube Industries, Ltd., UBESTA PET: Polyethylene terephthalate resin, manufactured by Invista, 1101E, intrinsic viscosity 0.80 dL / g

[0063] <Surface treatment agent> Water-soluble nylon: AQ nylon T70 manufactured by Toray Industries, Inc. Epoxy: EM-058 manufactured by Adeka Corporation

[0064] Synthesis Example 1 Synthesis of MPXD10 Sebacic acid (manufactured by CASDA) was placed in a jacketed reactor equipped with a stirrer, a partial condenser, a thermometer, a dropping tank, and a nitrogen gas inlet tube, and the inside was thoroughly purged with nitrogen. After heating and melting at 170°C, a mixed amine (70:30) of metaxylylenediamine and paraxylylenediamine (manufactured by Mitsubishi Gas Chemical Company, Inc., MPXDA) was gradually added dropwise to a molar ratio of 1:1 to sebacic acid while stirring the contents, and the temperature was raised to 240°C. After completion of the dropwise addition, the temperature was raised to 260°C and continued for 20 minutes. Thereafter, the pressure inside the reaction system was continuously reduced to 0.08 MPa, and the reaction was continued. After completion of the reaction, a pressure of 0.2 MPa was applied to the reactor with nitrogen gas, and the polymer was taken out as a strand from a nozzle at the bottom of the polymerization vessel. After water cooling, the polymer was pelletized using a pelletizer.

[0065] Synthesis Example 2: Synthesis Example of MPXD12 A reaction vessel equipped with a stirrer, partial condenser, cooler, thermometer, dropping device, nitrogen inlet tube, and strand die was charged with 13,820 g (60 mol) of dodecanedioic acid and 15.43 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 1 / 1.5), to which 8,173 g (60 mol, manufactured by Mitsubishi Gas Chemical Company, Inc.) of a mixed diamine having a ratio of metaxylylenediamine to paraxylylenediamine of 70:30 was added dropwise with stirring. The resulting condensed water was removed from the system while the internal temperature was continuously raised to 240 ° C. over 2.5 hours. After the dropwise addition was completed, the internal temperature was raised, and when it reached 250 ° C., the pressure inside the reaction vessel was reduced, and the internal temperature was further raised to 255 ° C., and the melt polycondensation reaction was continued for 20 minutes. Thereafter, the system was pressurized with nitrogen, and the polymer was taken out from the strand die and pelletized to obtain polyamide resin MPXD12.

[0066] Synthesis Example 3 Synthesis of MXD10 Sebacic acid (manufactured by CASDA) was placed in a jacketed reactor equipped with a stirrer, a partial condenser, a thermometer, a dropping tank, and a nitrogen gas inlet tube, and the contents were thoroughly purged with nitrogen. After heating and melting at 170°C, metaxylylenediamine (manufactured by Mitsubishi Gas Chemical Company, Inc., MXDA) was gradually added dropwise to the contents to a molar ratio of 1:1 to sebacic acid, while stirring the contents, and the temperature was raised to 240°C. After completion of the dropwise addition, the temperature was raised to 260°C and continued for 20 minutes. Thereafter, the pressure inside the reaction system was continuously reduced to 0.08 MPa, and the reaction was continued. After completion of the reaction, a pressure of 0.2 MPa was applied to the reactor with nitrogen gas, and the polymer was taken out as a strand from a nozzle at the bottom of the polymerization vessel. After water cooling, the polymer was pelletized using a pelletizer.

[0067] <Method for measuring the proportion (mass%) of thermosetting resin in continuous reinforcing fiber (2)> Ten 1-meter continuous reinforcing fibers (2) were cut from the roving, and the mass was measured. The mass was multiplied by 1000 to obtain the fineness (number of grams per 1000 m). The fineness was calculated as the ratio of the fineness to the fineness of virgin carbon fiber (number of grams per 1000 m).

[0068] <Method for producing continuous thermoplastic resin fiber (1) and continuous thermoplastic resin fiber (3) (binder resin)> A thermoplastic resin was melt-extruded using a single-screw extruder having a 30 mmφ screw, extruded in the form of a strand from a 48-hole die, and stretched while being wound around a roll to obtain a continuous thermoplastic resin fiber bundle wound around a roll.

[0069] <Method for measuring melting point of thermoplastic resin> The melting point (Tm) was measured by differential scanning calorimetry (DSC) in accordance with ISO 11357. Using a differential scanning calorimeter, the resin was placed in the measurement pan of the differential scanning calorimeter, heated to a temperature above the melting point at a heating rate of 10 ° C. / min under a nitrogen atmosphere, and then rapidly cooled before measurement. The measurement conditions were a heating rate of 10 ° C. / min, held at 280 ° C. for 5 minutes, and then cooled to 100 ° C. at a heating rate of -5 ° C. / min to determine the melting point (Tm). A "DSC-60" manufactured by Shimadzu Corporation was used as the differential scanning calorimeter.

[0070] 2. Examples 1, 2, 5-9, Comparative Examples 1-3 <Method for Manufacturing Composite Material> From a continuous thermoplastic resin fiber (1) wound with 1 m or more of thermoplastic resin fiber, a continuous reinforcing fiber (2) wound with 1 m or more of reinforcing fiber, and a continuous thermoplastic resin fiber (3) wound with 1 m or more of thermoplastic resin fiber, the continuous thermoplastic resin fiber (1), the continuous reinforcing fiber (2), and the continuous thermoplastic resin fiber (3) were each drawn out, passed through multiple guides, and spread by air blowing. While spreading, the continuous thermoplastic resin fiber (1), the continuous reinforcing fiber (2), and the continuous thermoplastic resin fiber (3) were bundled, passed through multiple guides, and subjected to air blowing to promote homogenization. The bundle was heated to a temperature at which only the continuous thermoplastic resin fiber (3) melted (the melting point of the binder resin constituting the continuous thermoplastic resin fiber (3) + 10°C), to obtain a composite material (hybrid tape, width 9 mm, thickness 0.22 mm). The obtained composite material was evaluated according to "4. Evaluation" described below.

[0071] <Production of molded article> A preform was produced by stitching the composite material in the same direction using the TFP method. The produced preform was placed in a mold heated to the melting point of the continuous thermoplastic resin fiber (1) + 30°C, and press-molded using a 100 ton press. After pressing, water was poured into the mold to cool it to 80°C, and then the mold was opened and removed to obtain a molded article. The temperature of the mold during pressing was the melting point of the continuous thermoplastic resin fiber (1) + 30°C, and the pressure was 100 kgf / cm. ２ (9.8 MPa), pressing time 10 minutes, cooling time 20 minutes. The obtained molded article was evaluated according to "4. Evaluation" described later.

[0072] 3. Example 3 and Example 4 From a continuous thermoplastic resin fiber (1) wound with 1 m or more of thermoplastic resin fiber, a continuous reinforcing fiber (2) wound with 1 m or more of reinforcing fiber, and a continuous thermoplastic resin fiber (3) wound with 1 m or more of thermoplastic resin fiber, the continuous thermoplastic resin fiber (1), the continuous reinforcing fiber (2), and the continuous thermoplastic resin fiber (3) were each drawn out, passed through multiple guides, and air-blown to spread. While spreading, the continuous thermoplastic resin fiber (1), the continuous reinforcing fiber (2), and the continuous thermoplastic resin fiber (3) were bundled, passed through multiple guides, air-blown to promote homogenization, and heated at a temperature at which only the continuous thermoplastic resin fiber (3) melts (the melting point of the binder resin constituting the continuous thermoplastic resin fiber (3) + 10 ° C.), to obtain a hybrid tape (width 9 mm, thickness 0.22 mm). The hybrid tape thus obtained was immersed in an aqueous solution containing a surface treatment agent for 10 seconds, and then dried at 40°C for 60 minutes if the surface treatment agent was water-soluble nylon, or at 60°C for 45 minutes if the surface treatment agent was epoxy, to obtain a composite material. The resulting composite material was evaluated according to "4. Evaluation" described below.

[0073] <Production of molded article> A preform was produced by stitching the composite material in the same direction using the TFP method. The produced preform was placed in a mold heated to the melting point of the continuous thermoplastic resin fiber (1) + 30°C, and press-molded using a 100 ton press. After pressing, water was poured into the mold to cool it to 80°C, and then the mold was opened and removed to obtain a molded article. The temperature of the mold during pressing was the melting point of the continuous thermoplastic resin fiber (1) + 30°C, and the pressure was 100 kgf / cm. ２ (9.8 MPa), pressing time 10 minutes, cooling time 20 minutes. The obtained molded article was evaluated according to "4. Evaluation" described later.

[0074] 4. Evaluation <Degree of Integration> The degree of integration of the composite material was evaluated as follows. The composite material was cut to a length of 10 cm, and one end was fixed with packing tape. Then, a 1 cm portion of the other end was held by hand, and the composite material was brought close to the end fixed with packing tape at a speed of 1 cm / min so that the surface of the composite material was in contact with the end fixed with packing tape. Evaluation was performed by five experts and judged by majority vote. S: When the ends were brought close together, they remained integrated without coming apart even when they came into contact. A: When the ends were brought close together, they partially came apart when they came 8 cm apart. B: When the ends were brought close together, they partially came apart when they came 5 cm apart. C: When the ends were brought close together, they partially came apart when they came 3 cm apart. The integrated Examples 1 to 9 and Comparative Examples 1 and 2 were evaluated as follows.

[0075] <TFP workability (suppleness)> The TFP workability (suppleness) of the composite material was evaluated as follows. The composite material was embroidered into a spiral circular pattern using a TFP device (manufactured by TISM Corporation, product number: TCWM-T01). The embroidery speed was 500 rpm. The evaluation was carried out by five experts and judged by majority vote. A: When embroidering with the TFP device, the embroidery was completed as intended. B: Other than the above A, when embroidering with the TFP device, the embroidery was completed generally as intended, although some parts deviated from the intended path. An example of the above evaluation A is shown in Figure 4 (1), and examples of the above evaluation B are shown in Figures 4 (2) and (3).

[0076] <Rate of fiber loss from composite material> Two bobbins of the same shape and mass were prepared, and the composite material obtained was wound onto one bobbin and then rewound onto the other bobbin. The winding speed was 10 m / min. The evaluation was as follows: A: The mass after winding was 98% or more by mass of the mass before winding; B: The mass after winding was 95% or more by mass and less than 98% by mass of the mass before winding; C: The mass after winding was less than 95% by mass of the mass before winding.

[0077] <Bending strength and bending modulus> The molded articles obtained above were cut to a size suitable for the standard using a Makita sliding circular saw, and measurements were performed in accordance with JIS K7074. The units for bending strength and bending modulus were MPa. Furthermore, measurements were not performed for Comparative Examples 1 to 3, which could not be molded using TFP.

[0078]

[0079]

[0080]

[0081] As is clear from the above results, the composite material of the present invention had an excellent degree of integration and excellent TFP workability. Furthermore, the fiber shedding rate was low. Furthermore, molded articles formed from the composite material of the present invention also had excellent mechanical strength (Examples 1 to 9). In contrast, when the melting point of the resin constituting the continuous thermoplastic resin fiber (1) was the same as or lower than the melting point of the binder resin (thermoplastic resin (3)) (Comparative Examples 1 and 2), the fibers lacked flexibility and TFP was not possible. Furthermore, when the amount of thermosetting resin contained in the continuous reinforcing fiber (2) was high (Comparative Example 3), the fibers were not fibrous and TFP was not possible.

[0082] 1 Continuous thermoplastic resin fiber (1) 22 Continuous reinforcing fiber itself 3 Binder resin 4 Thermosetting resin 10 Composite material 11 Yarn

Claims

1. A composite material having continuous thermoplastic resin fibers (1), continuous reinforcing fibers (2) having a thermosetting resin on the surface thereof, and a thermoplastic resin (3) having a melting point lower than that of the resin constituting the continuous thermoplastic resin fibers (1), wherein the continuous reinforcing fibers (2) contain the thermosetting resin in a ratio of 2 to 40 mass%, the content of the thermoplastic resin (3) contained in the composite material is 5 to 80 parts by mass per 100 parts by mass of the total of the continuous thermoplastic resin fibers (1) and the thermoplastic resin (3), and at least a portion of the continuous thermoplastic resin fibers (1) and at least a portion of the continuous reinforcing fibers (2) are bound via the thermoplastic resin (3).

2. The composite material of claim 1, wherein the continuous reinforcing fibers (2) comprise recycled continuous reinforcing fibers.

3. The composite material according to claim 1 or 2, wherein the continuous reinforcing fibers (2) comprise recycled continuous carbon fibers.

4. The composite material according to any one of claims 1 to 3, wherein the continuous thermoplastic resin fibers (1) and the thermoplastic resin (3) each independently comprise a polyamide resin.

5. The composite material according to any one of claims 1 to 4, wherein the resin constituting the continuous thermoplastic resin fibers (1) contains diamine structural units and dicarboxylic acid structural units, and contains a xylylenediamine-based polyamide resin in which 70 mol % or more of the diamine structural units are derived from xylylenediamine.

6. The composite material according to any one of claims 1 to 5, wherein the thermoplastic resin (3) contains a xylylenediamine-based polyamide resin that contains diamine structural units and dicarboxylic acid structural units, and in which 70 mol % or more of the diamine structural units are derived from xylylenediamine.

7. The composite material according to claim 5 or 6, wherein 50 mol % or more of the dicarboxylic acid constituent units in the xylylenediamine-based polyamide resin are constituent units derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.

8. A composite material according to any one of claims 1 to 7, comprising: a continuous thermoplastic resin fiber layer in which the continuous thermoplastic resin fibers (1) are arranged in parallel in one direction; and a continuous reinforcing fiber layer in which the continuous reinforcing fibers (2) are arranged in parallel in one direction, and the thermoplastic resin (3) binds the continuous thermoplastic resin fiber layer and the continuous reinforcing fiber layer.

9. The composite material according to claim 8, wherein the continuous thermoplastic resin fibers (1) and the continuous reinforcing fibers (2) are arranged in parallel in the same direction.

10. The composite material according to any one of claims 1 to 9, comprising 40 to 90 parts by mass of the continuous reinforcing fiber (2) per 100 parts by mass of the continuous thermoplastic resin fiber (1) and the continuous reinforcing fiber (2) combined.

11. The composite material according to any one of claims 1 to 10, which is in the form of a tape.

12. The composite material according to any one of claims 1 to 11, which is for use in tailored fiber placement processing.

13. The continuous reinforcing fiber (2) is a recycled carbon fiber, the continuous thermoplastic resin fiber (1) and the thermoplastic resin (3) each independently contain a diamine constituent unit and a dicarboxylic acid constituent unit, and the xylylenediamine-based polyamide resin contains 70 mol % or more of the diamine constituent units derived from xylylenediamine, and 50 mol % or more of the dicarboxylic acid constituent units in the xylylenediamine-based polyamide resin are derived from α,ω-linear aliphatic dicarboxylic acid constituent units having 4 to 20 carbon atoms, the continuous thermoplastic resin fiber (1) has a continuous thermoplastic resin fiber layer in which the continuous thermoplastic resin fiber (1) is arranged parallel to one another in one direction, and the continuous reinforcing fiber layer has the continuous reinforcing fiber (2) arranged parallel to one another in one direction, the thermoplastic resin (3) binds the continuous thermoplastic resin fiber layer and the continuous reinforcing fiber layer, and the continuous thermoplastic resin fiber (1) and the continuous reinforcing fiber (2) are arranged parallel to one another in the same direction, The composite material according to any one of claims 1 to 12, comprising 40 to 90 parts by mass of the continuous reinforcing fiber (2) per 100 parts by mass in total of the continuous thermoplastic resin fiber (1) and the continuous reinforcing fiber (2), in a tape form, and for use in tailored fiber placement processing.

14. A molded article formed from the composite material according to any one of claims 1 to 13.

15. A method for producing a molded article, comprising stitching the composite material according to any one of claims 1 to 13 to a substrate and performing a tailored fiber placement process.

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