Continuous fiber-reinforced thermoplastic resin base material and method for producing same

Abstract

Provided is a continuous fiber-reinforced thermoplastic resin base material in which mechanical properties such as tensile strength and bending strength of the continuous fiber-reinforced thermoplastic resin base material are improved for each type of polyamide resin in a relative manner.　The continuous fiber-reinforced thermoplastic resin base material contains a thermoplastic resin and continuous reinforcing fibers. The continuous reinforcing fibers are oriented in one direction, and the thermoplastic resin is impregnated between fibers of the continuous reinforcing fibers. The thermoplastic resin contains a polyamide resin, and the polyamide resin contains a polycondensation product of at least one type of a monomer selected from the group consisting of lactams and aminocarboxylic acids. The polyamide resin also satisfies condition (a). (a) If the amino group concentration at the terminal is denoted by A μmol / g, and the carboxyl group concentration at the terminal is denoted by C μmol / g, the value of A / (A+C) is greater than 0.50.

Description

Continuous fiber reinforced thermoplastic resin substrate and method for producing the same

[0001] The present invention relates to a continuous fiber-reinforced thermoplastic resin substrate containing a thermoplastic resin and continuous reinforcing fibers, and a method for producing the same.

[0002] Continuous fiber reinforced thermoplastic resin substrates, which are made by impregnating continuous reinforcing fibers with a thermoplastic resin, have excellent specific strength and specific rigidity, a high weight reduction effect, and high heat resistance and chemical resistance, and are therefore expected to be used in a variety of applications.

[0003] Patent Document 1 discloses a fiber-reinforced polyamide resin that has excellent mechanical properties due to a specific volume occupancy and a specific range of fiber dispersion parameters. Patent Document 2 discloses a fiber-reinforced polyamide resin material that has high rigidity, low water absorption, and excellent moldability, by using a polycondensate of a diamine including xylylenediamine and a dicarboxylic acid specified by the number of carbon atoms as the polyamide resin, adjusting the amino group concentration at the terminal of the polyamide resin to a specific range, and treating the surface of carbon fibers with a compound reactive with amino groups.

[0004] International Publication No. 2018 / 061597 International Publication No. 2014 / 050303

[0005] In Patent Document 1, in order to set the fiber dispersion parameter within a specific range, it was necessary to carefully control the manufacturing conditions. In Patent Document 2, xylylenediamine was required as an essential monomer constituting the polyamide resin, and the monomers were narrowly limited. An object of the present invention is to relatively improve the mechanical properties such as tensile strength and flexural strength of continuous fiber reinforced thermoplastic resin substrates for each type of polyamide resin.

[0006] The present invention relates to the following, for example, to [1] to [8]. [1] A continuous fiber-reinforced thermoplastic resin substrate comprising a thermoplastic resin and continuous reinforcing fibers, wherein the continuous reinforcing fibers are oriented in one direction, and the thermoplastic resin is impregnated between the continuous reinforcing fibers, and the thermoplastic resin comprises a polyamide resin, and the polyamide resin comprises a polycondensate of at least one monomer selected from the group consisting of lactams and aminocarboxylic acids, and the polyamide resin satisfies the following condition (a): (a) When the terminal amino group concentration is A μmol / g and the terminal carboxyl group concentration is C μmol / g, the value of the following (Equation 1) is greater than 0.50: A / (A+C) (Equation 1) [2] The continuous fiber-reinforced thermoplastic resin substrate of [1], wherein the polyamide resin comprises at least one selected from the group consisting of polyamide 6 and polyamide 12. [3] The continuous fiber-reinforced thermoplastic resin substrate of [1] or [2], wherein the polyamide resin satisfies the following condition (b): (b) A relative viscosity of less than 4.00 [4] A continuous fiber-reinforced thermoplastic resin substrate according to any one of [1] to [3], wherein the volume content of the continuous reinforcing fibers in the continuous fiber-reinforced thermoplastic resin substrate is 30 to 80 volume %. [5] A continuous fiber-reinforced thermoplastic resin substrate according to any one of [1] to [4], wherein the thickness of the continuous fiber-reinforced thermoplastic resin substrate is 20 to 100 μm. [6] A molded product made of the continuous fiber-reinforced thermoplastic resin substrate according to any one of [1] to [5]. [7] The method for producing a continuous fiber-reinforced thermoplastic resin substrate according to any one of [1] to [6], comprising: Step 1: spreading fiber bundles of a plurality of continuous reinforcing fibers aligned in one direction to obtain a planar spread continuous reinforcing fiber bundle; Step 2: producing a laminate of the spread continuous reinforcing fiber bundles obtained in Step 1 and a thermoplastic resin, and heating the laminate to a temperature equal to or higher than the melting point of the thermoplastic resin while pressurizing in the lamination direction to impregnate the thermoplastic resin between the fibers of the spread continuous reinforcing fiber bundles; and Step 3: cooling the thermoplastic resin to a temperature below the melting point of the thermoplastic resin to produce a continuous fiber-reinforced thermoplastic resin substrate in which the thermoplastic resin exists between the fibers of the spread continuous reinforcing fiber bundles. [8] The method for producing a continuous fiber-reinforced thermoplastic resin substrate according to [7], wherein in Step 1, the continuous reinforcing fibers are spread by passing an air flow in the length direction.

[0007] In the continuous fiber-reinforced thermoplastic resin substrate of the present invention, the mechanical properties such as tensile strength and flexural strength of the continuous fiber-reinforced thermoplastic resin substrate are relatively improved for each type of polyamide resin.

[0008] FIG. 1 is a diagram showing an example of a schematic configuration of a manufacturing apparatus for a continuous fiber reinforced thermoplastic resin substrate.

[0009] In this specification, the content of each component in a substrate refers to the total amount of each component present in the substrate unless otherwise specified, when multiple substances corresponding to each component are present in the substrate. In this specification, the use of "to" to indicate a range of values ​​means that the values ​​before and after the range include the lower and upper limits. In this specification, the term "type of polyamide resin" refers to the basic repeating unit of the polyamide resin, and "each type of polyamide resin" refers to each polyamide resin with the same basic repeating unit. For example, polyamide 6 and polyamide 12 are different types of polyamide, while polyamide 6 with a relative viscosity of 3 and polyamide 6 with a relative viscosity of 4 are the same type of polyamide.

[0010] The present invention relates to a continuous fiber-reinforced thermoplastic resin substrate comprising a thermoplastic resin and continuous reinforcing fibers, wherein the continuous reinforcing fibers are oriented in one direction, the thermoplastic resin is impregnated between the continuous fibers, the thermoplastic resin comprises a polyamide resin, and the polyamide resin comprises a polycondensate of at least one monomer selected from the group consisting of lactams and aminocarboxylic acids, and the polyamide resin satisfies the following condition (a): (a) When the terminal amino group concentration is A μmol / g and the terminal carboxyl group concentration is C μmol / g, the value of the following (Equation 1) A / (A+C) (Equation 1) is greater than 0.50:

[0011] <Thermoplastic Resin> The continuous fiber reinforced thermoplastic resin substrate of the present invention contains a thermoplastic resin. Thermoplastic resin refers to a resin that softens and becomes plastic when heated and solidifies when cooled. Examples of the thermoplastic resin include polyamide resin, polyolefin resin, polyester resin, polyacetal resin, polyphenylene sulfide resin, polycarbonate resin, acrylic resin, acrylonitrile-butadiene-styrene copolymer (ABS), polyamide-imide resin, polysulfone resin, polyphenylsulfone resin, polyetherimide resin, polyethersulfone resin, polyetheretherketone resin, polyetherketoneketone resin, polyimide resin, polyarylate resin, fluororesin, liquid crystal polymer resin, and thermoplastic epoxy resin.

[0012] The thermoplastic resin used in the present invention includes a polyamide resin. The proportion of the polyamide resin in 100% by mass of the thermoplastic resin is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 98% by mass or more. It is particularly preferable that the thermoplastic resin consists solely of the polyamide resin.

[0013] Examples of polyamide resins include polycondensates of monomers such as lactam, aminocarboxylic acid, and combinations of diamine and dicarboxylic acid, but the polyamide resin used in the present invention contains a polycondensate of at least one monomer selected from the group consisting of lactam and aminocarboxylic acid. The proportion of the polycondensate of at least one monomer selected from the group consisting of lactam and aminocarboxylic acid in 100% by mass of polyamide resin is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. It is particularly preferred that the polyamide resin consists solely of a polycondensate of at least one monomer selected from the group consisting of lactam and aminocarboxylic acid.

[0014] Examples of the polycondensate of at least one monomer selected from the group consisting of lactam and aminocarboxylic acid include the polycondensates of lactam, polycondensates of aminocarboxylic acid, and polycondensates that are copolymers containing lactam or aminocarboxylic acid as one of the monomers, which will be described later. Specific examples include, but are not limited to, polyamide 6, polyamide 11, polyamide 12, polyamide 6 / 66, polyamide 6 / 12, and polyamide 6 / 66 / 12.

[0015] Examples of polyamide resins include aliphatic homopolyamide resins, aliphatic copolymer polyamide resins, and aromatic polyamide resins, and among these, aliphatic homopolyamide resins and aliphatic copolymer polyamide resins are preferred, with aliphatic homopolyamide resins being more preferred. The total content of aliphatic homopolyamide resins and aliphatic copolymer polyamide resins in 100% by mass of polyamide resin is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0016] Aliphatic homopolyamide resins are polyamide resins consisting of one type of structural unit derived from an aliphatic monomer and are aliphatic polyamide resins that do not have an aromatic ring. Aliphatic copolyamides are polyamide resins consisting of two or more structural units derived from aliphatic monomers and are aliphatic polyamide resins that do not have an aromatic ring. Aromatic polyamide resins are aromatic polyamide resins that contain at least one aromatic monomer component. Aliphatic also includes alicyclic. Copolyamides are copolymers of two or more monomers selected from the group consisting of a combination of a diamine and a dicarboxylic acid, a lactam, and an aminocarboxylic acid. Here, a combination of a diamine and a dicarboxylic acid is considered to be one type of monomer, with one type of diamine and one type of dicarboxylic acid being the combination.

[0017] The lactam preferably has 4 to 12 carbon atoms. The aminocarboxylic acid preferably has 4 to 12 carbon atoms. The diamine preferably has 2 to 20 carbon atoms, and more preferably has 4 to 12 carbon atoms. The dicarboxylic acid preferably has 2 to 20 carbon atoms, and more preferably has 6 to 12 carbon atoms.

[0018] Examples of lactams include ε-caprolactam, enantholactam, undecane lactam, dodecane lactam, α-pyrrolidone, α-piperidone, etc. Among these, from the viewpoint of polymerization productivity, one selected from the group consisting of ε-caprolactam, undecane lactam, and dodecane lactam is preferred.

[0019] Examples of aminocarboxylic acids include 4-aminobutanoic acid, 5-aminopentanoic acid, 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Among these, from the viewpoint of polymerization productivity, one selected from the group consisting of 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid is preferred.

[0020] When the diamine is an aliphatic diamine, examples of the aliphatic diamine include ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,8-octanediamine, and 2,2,4 / 2,4,4-trimethylhexamethylenediamine. Non-cyclic aliphatic diamines include alicyclic diamines such as 1,3- / 1,4-cyclohexyldiamine, bis(4-aminocyclohexyl)methane, bis(4-aminocyclohexyl)propane, bis(3-methyl-4-aminocyclohexyl)methane, (3-methyl-4-aminocyclohexyl)propane, 1,3- / 1,4-bisaminomethylcyclohexane, 5-amino-2,2,4-trimethyl-1-cyclopentanemethylamine, 5-amino-1,3,3-trimethylcyclohexanemethylamine, bis(aminopropyl)piperazine, bis(aminoethyl)piperazine, and norbornanedimethylenediamine.

[0021] When the dicarboxylic acid is an aliphatic dicarboxylic acid, examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedionic acid, dodecanedionic acid, tridecanedionic acid, tetradecanedionic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and eicosanedioic acid; and alicyclic dicarboxylic acids such as 1,3- / 1,4-cyclohexanedicarboxylic acid, dicyclohexanemethane-4,4'-dicarboxylic acid, and norbornanedicarboxylic acid.

[0022] When the diamine is an aromatic diamine, examples of the aromatic diamine include metaxylylenediamine and paraxylylenediamine, and when the dicarboxylic acid is an aromatic dicarboxylic acid, examples of the aromatic dicarboxylic acid include naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, and phthalic acid.

[0023] Specific examples of aliphatic homopolyamide resins include polybutyrolactam (polyamide 4), polytetramethylene adipamide (polyamide 46), polytetramethylene azelamide (polyamide 49), polytetramethylene sebacamide (polyamide 410), polyvalerolactam (polyamide 5), polycaprolactam (polyamide 6), polyenantholactam (polyamide 7), polyundecane lactam (polyamide 11), polylauryllactam (poly Polyamide 12), Polyhexamethylene adipamide (Polyamide 66), Polytetramethylene adipamide (Polyamide 46), Polytetramethylene sebacamide (Polyamide 410), Polytetramethylene dodecamide (Polyamide 412), Polypentamethylene adipamide (Polyamide 56), Polypentamethylene azelamide (Polyamide 59), Polypentamethylene sebacamide (Polyamide 510), Polypentamethylene dodecamide (Polyamide 512), Poly Polypentamethylene tridecamide (Polyamide 513), Polyhexamethylene azelamide (Polyamide 69), Polyhexamethylene sebacamide (Polyamide 610), Polyhexamethylene dodecamide (Polyamide 612), Polynonameethylene adipamide (Polyamide 96), Polynonameethylene azelamide (Polyamide 99), Polynonameethylene sebacamide (Polyamide 910), Polynonameethylene dodecamide (Polyamide 912), Polydecamethylene adipamide Examples of suitable polyamides include polydodecamethylene azelamide (polyamide 106), polydecamethylene azelamide (polyamide 109), polydecamethylene decamide (polyamide 1010), polydecamethylene dodecamide (polyamide 1012), polydodecamethylene adipamide (polyamide 126), polydodecamethylene azelamide (polyamide 129), polydodecamethylene sebacamide (polyamide 1210), polydodecamethylene dodecamide (polyamide 1212), and polyamide 122.

[0024] Specific examples of aliphatic copolymer polyamide resins include caprolactam / tetramethylenediaminoadipic acid copolymer (polyamide 6 / 46), caprolactam / pentamethylenediaminoadipic acid copolymer (polyamide 6 / 56), hexamethylenediaminoadipic acid / caprolactam (polyamide 56 / 6), pentamethylenediaminoadipic acid / hexamethylenediaminoadipic acid copolymer (polyamide 56 / 66), and pentamethylenediaminoadipic acid. / Pentamethylenediaminosebacic acid copolymer ((Polyamide 56 / 510), Caprolactam / Hexamethylenediaminoadipic acid copolymer (Polyamide 6 / 66), Caprolactam / Hexamethylenediaminoazelaic acid copolymer (Polyamide 6 / 69), Caprolactam / Tetramethylenediaminosebacic acid (Polyamide 6 / 410), Caprolactam / Pentamethylenediaminosebacic acid copolymer (Polyamide 6 / 510), Caprolactam / Hexamethylenediaminosebacic acid copolymer (Polyamide 6 / 510), Caprolactam / Hexamethylenediaminosebacic acid copolymer (Polyamide 6 / 69) Polyamide 6 / 610, Caprolactam / Hexamethylenediaminoundecanedicarboxylic acid copolymer (Polyamide 6 / 611), Caprolactam / Hexamethylenediaminododecanedicarboxylic acid copolymer (Polyamide 6 / 612), Caprolactam / Decamethylenediaminosebacic acid copolymer (Polyamide 6 / 1010), Caprolactam / Aminoundecanoic acid copolymer (Polyamide 6 / 11), Caprolactam / Lauryl Examples of the polyamide 6 / 66 include caprolactam copolymer (polyamide 6 / 12), caprolactam / hexamethylenediaminoadipic acid / lauryllactam copolymer (polyamide 6 / 66 / 12), caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminosebacic acid copolymer (polyamide 6 / 66 / 610), and caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminododecanedicarboxylic acid copolymer (polyamide 6 / 66 / 612).

[0025] Specific examples of aromatic polyamide resins include polynonamethylene terephthalamide (polyamide 9T), polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (polyamide 66 / 6T), polyhexamethylene terephthalamide / polycaproamide copolymer (polyamide 6T / 6), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6I), polyhexamethylene isophthalamide / polycaproamide copolymer (polyamide 6I / 6), polydodecaamide / polyhexamethylene terephthalamide copolymer (polyamide 6I / 6), and polyhexamethylene terephthalamide copolymer (polyamide 6I / 6). polymer (polyamide 12 / 6T), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6T / 6I), polyhexamethylene adipamide / polycaproamide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6 / 6I), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (polyamide 6T / 6I), polyhexamethylene terephthalamide / poly(2-methylpentamethylene terephthalamide) copolymer (polyamide 6T / M5T), polyxylylene adipamide (polyamide MXD6), and mixtures or copolymer resins thereof.

[0026] The polyamide resin may be used alone or in combination of two or more. Among the above polyamide resins, at least one selected from the group consisting of polyamide 6, polyamide 11, polyamide 12, polyamide 56, polyamide 66, polyamide 510, polyamide 610, polyamide 612, polyamide 1010, polyamide 56 / 6, polyamide 56 / 66, polyamide 56 / 510, polyamide 6 / 66, polyamide 6 / 12, polyamide 6 / 66 / 12, polyamide 6T / 6I, polyamide 9T and polyamide MXD6 is preferred, at least one selected from polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 6 / 66 and polyamide 6T / 6I is more preferred, at least one selected from polyamide 6 and polyamide 12 is even more preferred, and polyamide 6 is particularly preferred. In addition, the polyamide resin preferably contains polyamide 6. When the polyamide resin contains polyamide 6, the polyamide 6 content is preferably 50% by mass or more, more preferably 70% by mass, and even more preferably 90% by mass, based on 100% by mass of the polyamide resin.

[0027] Considering the end group concentration and relative viscosity of each, at least one selected from the group consisting of monoamines, diamines, monocarboxylic acids, and dicarboxylic acids can be added to the polyamide resin as an end modifier in appropriate combination. For example, aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine, alicyclic monoamines such as cyclohexylamine and dicyclohexylamine, aromatic monoamines such as aniline, toluidine, diphenylamine, and naphthylamine, aliphatic diamines such as hexamethylenediamine, decamethylenediamine, and dodecamethylenediamine, alicyclic diamines such as cyclohexanediamine, methylcyclohexanediamine, and isophoronediamine, aromatic diamines such as metaphenylenediamine, paraphenylenediamine, metaxylylenediamine, and paraxylylenediamine, and acetic acid, propionic acid, butyric acid, and lactic acid can be added. Examples of suitable monocarboxylic acids include aliphatic monocarboxylic acids such as gallic acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyric acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid; aliphatic dicarboxylic acids such as adipic acid, trimethyladipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, and dodecanedicarboxylic acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; and aromatic dicarboxylic acids such as isophthalic acid and 1,4 / 2,6 / 2,7-naphthalenedicarboxylic acid. These may be used alone or in combination. These may be used in amounts within the range that achieves the effects of the present invention.

[0028] The polyamide resin used in the present invention satisfies the following condition (a): (a) When the terminal amino group concentration is A μmol / g and the terminal carboxyl group concentration is C μmol / g, the value of the following (Equation 1) A / (A+C) (Equation 1) is greater than 0.50.

[0029] The value of the above (Equation 1) is greater than 0.50, preferably 0.60 to 1.00, and more preferably 0.70 to 0.90. The terminal amino group concentration is determined by neutralization titration after dissolving the polyamide resin in a mixed solvent of phenol and methanol. The terminal carboxyl group concentration is determined by neutralization titration after dissolving the polyamide resin in benzyl alcohol. Adjusting the value of the above (Equation 1) to fall within the above range can be achieved by adjusting the molecular weight of the polyamide resin and the use of a terminal modifier. Theoretically, the terminal groups of a typical polyamide resin have a 1:1 ratio of amino groups to carboxyl groups. In the present invention, satisfying the above equation (1) is thought to result in a higher proportion of amino groups than carboxyl groups in the terminal groups of the polyamide resin, which affects the interaction with the continuous reinforcing fibers.

[0030] When the polyamide resin is a mixture containing two or more polyamide resins with different terminal amino group concentrations, the terminal amino group concentration of the polyamide resin in the mixture is generally determined as the terminal amino group concentration of the polyamide resin in the mixture.If the terminal amino group concentration of the polyamide resin in the mixture cannot be measured, the terminal amino group concentration of each polyamide resin in the mixture can be calculated by multiplying the terminal amino group concentration of each polyamide resin in the mixture by their mixing ratio, and the average value calculated by summing the values ​​roughly coincides with the measured value, and therefore the terminal amino group concentration of the polyamide resin can also be used.

[0031] The method for producing a polyamide resin satisfying the formula (1) is not particularly limited, but it can be produced, for example, by the method described in JP-A-2003-171549. Specifically, it can be obtained by adding a diamine compound as the aforementioned terminal modifier when extruding and kneading the composition during polymerization or after the completion of polymerization. For production during melt polymerization, methods such as adding an excess of diamine monomer when charging raw materials and polymerizing it, adding raw material monomers and a diamine compound other than the raw material monomers when charging raw materials, and polymerizing it after polymerizing a polyamide of a predetermined molecular weight, and then adding a diamine compound just before withdrawing the polymer from the polymerization vessel so as to achieve the desired terminal group concentration balance, are used. For production after polymerization, methods such as melt kneading the polymerized polyamide resin and diamine compound so as to achieve the desired terminal group concentration balance are used.

[0032] The polyamide resin used in the present invention preferably satisfies the following condition (b): (b) Relative viscosity of less than 4.00 The relative viscosity is measured in accordance with JIS K-6920 by dissolving 1 g of polyamide resin in 100 ml of 96% concentrated sulfuric acid at 25°C.

[0033] The relative viscosity of the polyamide resin used in the present invention is preferably less than 4.00, more preferably less than 3.50, even more preferably less than 3.00, and even more preferably less than 2.70. The relative viscosity of the polyamide resin is preferably 1.00 or more, more preferably 1.50 or more, more preferably 2.00 or more, even more preferably 2.10 or more, and particularly preferably 2.20 or more. Specifically, the relative viscosity of the polyamide resin is preferably 1.00 or more and less than 4.00, more preferably 1.50 or more and less than 3.50, and even more preferably 2.00 or more and less than 3.00.

[0034] When the polyamide resin contains polyamide 6, the relative viscosity of polyamide 6 is preferably 1.50 or more and less than 4.00, more preferably 2.00 or more and less than 3.50, even more preferably 2.10 or more and less than 3.00, and even more preferably 2.20 or more and less than 2.70. When the polyamide resin contains polyamide 12, the relative viscosity of polyamide 12 is preferably less than 4.00, preferably less than 3.00, more preferably less than 2.70, even more preferably less than 2.60, and even more preferably less than 2.40. Also, it is more preferably 1.00 or more, more preferably 1.20 or more, even more preferably 1.30 or more, and particularly preferably 1.40 or more. Specifically, the relative viscosity of polyamide 12 is preferably 1.00 or more and less than 4.00, preferably 1.00 or more and less than 3.00, more preferably 1.20 or more and less than 2.70, even more preferably 1.30 or more and less than 2.60, and even more preferably 1.40 or more and less than 2.40.

[0035] The relative viscosity can be adjusted to the above range by adjusting the monomer reaction conditions or the use of a terminal modifier. By adjusting the relative viscosity to the above range, it is possible to improve the impregnation of the resin into the fibers and the interaction at the interface between the continuous reinforcing fibers and the thermoplastic resin.

[0036] When a polyamide resin is a mixture containing two or more polyamide resins with different relative viscosities, the relative viscosity of the polyamide resin in the mixture is generally determined as the measured value of the relative viscosity of the polyamide resin. If the relative viscosity of the polyamide resin in the mixture cannot be measured, the average value calculated by multiplying the relative viscosity of each polyamide resin by their mixing ratio will generally coincide with the measured value, and therefore may be used as the relative viscosity of the polyamide resin.

[0037] The number average molecular weight of the polyamide resin is preferably 10,000 to 40,000. When the polyamide resin is polyamide 6, the number average molecular weight is more preferably 11,000 to 20,000. When the polyamide resin is polyamide 12, the number average molecular weight is more preferably 12,000 to 35,000. The number average molecular weight is a value measured by gel permeation chromatography. Adjusting the number average molecular weight to the above range can be achieved by adjusting the monomer reaction conditions or the use of a terminal modifier. By having the number average molecular weight in the above range, the relative viscosity can be adjusted to the above range.

[0038] Examples of polyamide resin production equipment include known polyamide production equipment such as batch-type reaction vessels, single- or multi-vessel continuous reaction vessels, tubular continuous reaction vessels, and kneading reaction extruders such as single-screw kneading extruders and twin-screw kneading extruders. Known polymerization methods, such as melt polymerization, solution polymerization, ring-opening polymerization, condensation polymerization, and solid-state polymerization, can be used, and polymerization can be carried out by repeating operations under normal pressure, reduced pressure, and increased pressure. These polymerization methods can be used alone or in appropriate combination.

[0039] The polyamide resin may contain optional components depending on the purpose, etc., as long as the effects of the present invention are not impaired. Examples of optional components include heat resistance agents, impact resistance materials, dyes, pigments, particulate reinforcements, plasticizers, antioxidants, foaming agents, weather resistance agents, crystal nucleating agents, crystallization accelerators, lubricants, antistatic agents, flame retardants, flame retardant assistants, colorants, and functionality-imparting agents such as spreading agents. The optional components may be contained in an amount of preferably 0.01 to 1 part by mass, more preferably 0.05 to 0.5 parts by mass, per 100 parts by mass of the polyamide resin.

[0040] <Continuous reinforcing fiber> The continuous fiber reinforced thermoplastic resin substrate of the present invention contains continuous reinforcing fiber. In this specification, continuous reinforcing fiber refers to a reinforcing fiber that is substantially uninterrupted in the fiber-reinforced polyamide resin substrate, preferably a reinforcing fiber that is continuous in at least one direction for a length of 100 mm or more. Ideally, all single yarns in the filament are uninterrupted, but if 80% or more of the number of single yarns are uninterrupted, it can be said to be in an "uninterrupted" state. In this specification, "continuous reinforcing fiber oriented in one direction" means a state in which multiple single reinforcing fibers are aligned in the same direction and extend parallel to each other.

[0041] Examples of the form and arrangement of the continuous reinforcing fibers in this specification include those in which a plurality of single reinforcing fibers are aligned in one direction, woven fabrics (cloths), knitted fabrics, braided cords, tows, etc. These are formed by arranging continuous reinforcing fibers in one direction, as this can efficiently improve the mechanical properties in a specific direction.

[0042] The type of continuous reinforcing fiber is not particularly limited, and examples thereof include carbon fiber, metal fiber, organic fiber, and inorganic fiber. Two or more of these may be used.

[0043] Examples of carbon fibers include polyacrylonitrile (PAN)-based carbon fibers made from PAN fibers, pitch-based carbon fibers made from petroleum tar or petroleum pitch, cellulose-based carbon fibers made from viscose rayon or cellulose acetate, vapor-grown carbon fibers made from hydrocarbons, graphitized fibers of these, etc. Among these carbon fibers, PAN-based carbon fibers are preferably used because of their excellent balance between strength and elastic modulus.

[0044] Examples of metal fibers include fibers made of metals such as iron, gold, silver, copper, aluminum, brass, and stainless steel.

[0045] Examples of organic fibers include fibers made of organic materials such as aramid, polybenzoxazole (PBO), polyphenylene sulfide, polyester, polyamide, and polyethylene.

[0046] Examples of inorganic fibers include fibers made from inorganic materials such as glass, basalt, silicon carbide, silicon nitride, boron, alumina, and silicon nitride. Examples of glass fibers include E-glass fiber (for electrical use), C-glass fiber (for corrosion resistance), S-glass fiber, and T-glass fiber (high strength, high elastic modulus). Basalt fiber is a fiber made from the mineral basalt, and is a fiber with extremely high heat resistance. Basalt generally contains 9 to 25 wt% of FeO or FeO2, which are iron compounds, and 1 to 6 wt% of TiO or TiO2, which are titanium compounds. However, it is also possible to increase the amounts of these components in the molten state and fiberize the material.

[0047] Among these, carbon fiber, aramid fiber, glass fiber, boron fiber, alumina fiber, and silicon nitride fiber are preferred from the viewpoints of specific strength and specific elasticity. Furthermore, carbon fiber is more preferred because it can exhibit high mechanical properties of the continuous fiber reinforced thermoplastic resin substrate and improve corrosion resistance, etc. As the carbon fiber, it is preferable to use PAN (polyacrylonitrile)-based carbon fiber, which has particularly high strength. When carbon fiber is used as the reinforcing fiber, the carbon fiber may be surface-treated with a metal. Note that the reinforcing fibers opened from these reinforcing fiber bundles can be used in one type or in combination of two or more types as long as they are oriented in the same direction.

[0048] In a continuous fiber reinforced thermoplastic resin substrate, the reinforcing fibers are usually arranged by arranging one or more reinforcing fiber bundles each consisting of a plurality of single fibers. The total number of reinforcing fiber filaments (number of single fibers) when one or more reinforcing fiber bundles are arranged is preferably 1,000 to 2,000,000. From the viewpoint of productivity, the total number of reinforcing fiber filaments is more preferably 1,000 to 1,000,000, even more preferably 1,000 to 600,000, and particularly preferably 1,000 to 300,000. The upper limit of the total number of reinforcing fiber filaments may be set in consideration of the balance between dispersibility and handleability, as long as productivity, dispersibility, and handleability are maintained favorably.

[0049] One reinforcing fiber bundle is preferably configured by bundling 1,000 to 2,000,000 reinforcing fiber monofilaments each having an average diameter of 5 to 10 μm. As the form of the fiber bundle, a fiber bundle without using a sizing agent such as a sizing agent may be used, or a reinforcing fiber bundle in which the fibers are bundled by a sizing agent such as a sizing agent so as not to become loose may be used. When the fiber bundle with the sizing agent attached is spread to form a thin layer, the form is stabilized even in the spread fiber sheet due to the attachment of the sizing agent.

[0050] As the sizing agent, a composition containing a compound reactive with an amino group is preferred. As the compound reactive with an amino group, either an epoxy compound or a non-epoxy compound can be used. Preferred examples of the non-epoxy compound include functional compounds such as acrylic compounds, silane compounds, titanate compounds, alkylene glycol compounds, carboxylic acid compounds, hydroxide compounds, isocyanate compounds, aldehyde compounds, unsaturated fatty acids, saturated fatty acids, ether compounds, and ester compounds. Specific examples of the sizing agent include polyester, polyurethane, polyether, polyamide, and modified polyolefin. Polyamide resins satisfying Formula 1 have a high proportion of amino groups in their terminal groups, which enhances interaction with the sizing agent and continuous reinforcing fibers, resulting in improved mechanical strength.

[0051] <Continuous fiber reinforced thermoplastic resin substrate> In the continuous fiber reinforced thermoplastic resin substrate of the present invention, the continuous reinforcing fibers are oriented in one direction. The thermoplastic resin is impregnated between the continuous reinforcing fibers. Impregnation includes full impregnation, in which the interface between the fiber and the thermoplastic resin is not visible, i.e., the fiber and the thermoplastic resin are integrated, as well as partial impregnation, in which the thermoplastic resin adheres to part of the continuous reinforcing fibers. In this specification, the substrate refers to a support in the form of a sheet, film, or the like.

[0052] Such a continuous fiber-reinforced thermoplastic resin substrate is preferably produced by the following production method: A method for producing a continuous fiber-reinforced thermoplastic resin substrate, comprising: Step 1: spreading fiber bundles of a plurality of continuous reinforcing fibers aligned in one direction to obtain a planar spread continuous reinforcing fiber bundle; Step 2: producing a laminate of the spread continuous reinforcing fiber bundles obtained in Step 1 and a thermoplastic resin, and pressurizing the laminate in the lamination direction while heating it to a temperature equal to or higher than the melting point of the thermoplastic resin, thereby impregnating the spaces between the fibers of the spread continuous reinforcing fiber bundles with the thermoplastic resin; and Step 3: cooling the thermoplastic resin to a temperature below the melting point of the thermoplastic resin, thereby producing a continuous fiber-reinforced thermoplastic resin substrate in which the thermoplastic resin exists between the fibers of the spread continuous reinforcing fiber bundles. The thermoplastic resin and continuous reinforcing fibers are as described above.

[0053] In step 1, a fiber bundle of a plurality of continuous reinforcing fibers aligned in one direction is opened to obtain a planar opened continuous reinforcing fiber bundle.

[0054] In step 1, the method preferably includes a fluid-spreading step in which a fluid is passed through the fiber bundle in the length direction of the continuous reinforcing fibers to bend the fibers and move them in the width direction to spread them. The fluid is preferably air. After the fluid-spreading step, the method more preferably includes a vertical vibration-imparting step in which a contact member is brought into contact with the conveyed fiber bundle, pushing a portion of the fiber bundle to create a tensioned state, and then separating the contact member from the tensioned fiber bundle to temporarily relax the fiber bundle, and a horizontal vibration-imparting step in which the spread fiber bundle is vibrated back and forth in the width direction. By including these steps, a fluid flowing in one direction is applied to the bent fiber bundle to spread the fiber bundle widely and thinly, and horizontal vibrations are applied to each spread fiber bundle to obtain a planar spread continuous reinforcing fiber bundle with no gaps. The spread continuous reinforcing fiber bundle has a basis weight of 10 to 80 g / m. ２ It is preferable that:

[0055] It is believed that the number of single yarns aligned in the thickness direction of these spread fiber bundles is on average 10 or less. When spread fiber bundles, that is, spread fiber bundles, are used, the number of single yarns aligned in the thickness direction is reduced, so that even with thermoplastic resins that have a higher viscosity than thermosetting resins such as epoxy resins, the impregnation of the thermoplastic resin between the single yarns becomes smoother, and a high-quality continuous fiber-reinforced thermoplastic resin substrate can be obtained with a shorter heating and pressurizing time.

[0056] In step 2, a laminate of the spread continuous reinforcing fiber bundles obtained in step 1 and a thermoplastic resin is produced, and the laminate is pressurized in the lamination direction while being heated to a temperature equal to or higher than the melting point of the thermoplastic resin, thereby impregnating the thermoplastic resin between the fibers of the spread continuous reinforcing fiber bundles.

[0057] Specifically, the side end portions of a planar spread continuous reinforcing fiber bundle are arranged on the outside of the side end portions of a sheet or film-like thermoplastic resin and overlapped to obtain a laminate of the spread continuous reinforcing fiber bundle and the thermoplastic resin. The sheet or film-like thermoplastic resin preferably has an average thickness in the width direction of 10 to 50 μm. The sheet or film-like thermoplastic resin is preferably formed so that the deviation of the thickness in the width direction from the average thickness is within ±10% of the average thickness. The sheet or film-like thermoplastic resin is continuously formed by slitting both ends of the resin sheet or film while forming the resin sheet or film by extrusion molding.

[0058] Planar spread continuous reinforcing fiber bundles are arranged on both sides of a sheet or film-like thermoplastic resin, and a sheet or film-like thermoplastic resin is superimposed on one side of the planar spread continuous reinforcing fiber bundles. In step 2, it is preferable that the planar spread continuous reinforcing fiber bundles formed by orienting the spread fiber bundles in the width direction are shifted in the width direction so that the spread fiber bundles do not overlap each other. It is preferable that both side end portions of the planar spread continuous reinforcing fiber bundles arranged on both sides of the sheet or film-like thermoplastic resin are arranged outside both side end portions of the sheet or film-like thermoplastic resin.

[0059] Furthermore, at least in steps 2 and 3, the planar spread continuous reinforcing fiber bundle is transported with tension applied across its entire width, and it is preferable that the resin-impregnated spread continuous reinforcing fiber bundle and the continuous fiber reinforced thermoplastic resin substrate are also transported with tension applied across their entire width, including the side end portions of the spread continuous reinforcing fiber bundle that is not impregnated with the thermoplastic resin.

[0060] In step 2, the laminate is heated to a temperature equal to or higher than the melting point of the thermoplastic resin and pressurized in the lamination direction, thereby impregnating the spaces between the spread continuous reinforcing fiber bundles with the thermoplastic resin, thereby obtaining a composite sheet of continuous reinforcing fibers and thermoplastic resin. Specifically, in the laminate, it is preferable that the spread fiber bundles are oriented in the width direction and that both end portions of a sheet- or film-like thermoplastic resin impregnate or semi-impregnate the spread fiber bundles arranged at the outermost ends of the planar spread continuous reinforcing fiber bundles. The heating temperature on the planar spread continuous reinforcing fiber bundle side of the laminate is set to a temperature equal to or higher than the melting point of the sheet- or film-like thermoplastic resin, and the laminate is pressurized to melt the thermoplastic resin and impregnate the spaces between the spread continuous reinforcing fiber bundles, thereby obtaining a composite sheet. It is preferable to heat and pressurize the laminate so that the thickness of the composite sheet is thicker than the thickness when the sheet- or film-like thermoplastic resin is melted and completely impregnated into the planar spread continuous reinforcing fiber bundles.

[0061] In step 3, the composite sheet obtained in step 2 is cooled to a temperature below the melting point of the thermoplastic resin to produce a continuous fiber-reinforced thermoplastic resin substrate in which the thermoplastic resin is present between the fibers of the spread continuous reinforcing fiber bundles.

[0062] An example of the method for producing a continuous fiber-reinforced thermoplastic resin substrate of the present invention will be described with reference to Figure 1. In Figure 1, the various symbols represent a continuous fiber-reinforced thermoplastic resin substrate production apparatus 1, a continuous reinforcing fiber bundle F0, continuous reinforcing fibers (continuous reinforcing fibers opened from the continuous reinforcing fiber bundle) F, a thermoplastic resin film R0, a heating roller 2, a cooling roller 3, an endless belt 4, a pull-out roller 5, a bobbin 6, and a continuous fiber-reinforced thermoplastic resin substrate S.

[0063] The continuous fiber-reinforced thermoplastic resin substrate S can be continuously produced using, for example, a continuous fiber-reinforced thermoplastic resin substrate production apparatus 1 shown in Fig. 1. This continuous fiber-reinforced thermoplastic resin substrate production apparatus 1 is an apparatus that continuously produces a continuous fiber-reinforced thermoplastic resin substrate S from a continuous reinforcing fiber bundle F0 and a thermoplastic resin film R0.

[0064] Specifically, the continuous fiber reinforced thermoplastic resin substrate manufacturing apparatus 1 includes multiple pairs (two pairs in FIG. 1 ) of heating rollers 2 arranged vertically, multiple pairs (two pairs in FIG. 1 ) of cooling rollers 3 arranged vertically below the heating rollers 2, a pair of endless belts 4 looped between the heating rollers 2 and the cooling rollers 3, a pair of pull-out rollers 5 located below the endless belts 4, and a winding bobbin 6 located below the pull-out rollers 5.

[0065] Although not shown, a spreading mechanism that spreads the continuous reinforcing fiber bundle F0 into a band shape is provided near the uppermost heating roller 2. This spreading mechanism continuously spreads the continuous reinforcing fiber bundle F0, thereby making it possible to form a large number of continuous reinforcing fibers F while spreading them so that they are oriented and extend in the same direction. The spreading mechanism may be any mechanism that is capable of such processing, and various mechanisms can be used, such as a mechanism that spreads the continuous reinforcing fiber bundle F0 by beating it, a mechanism that spreads the continuous reinforcing fiber bundle F0 by passing a fluid through it, or a mechanism that spreads the continuous reinforcing fiber bundle F0 by applying ultrasound to it, but a mechanism that spreads the continuous reinforcing fiber bundle F0 by passing air as a fluid is preferred.

[0066] 1 , the fiber-spreading mechanism has a mechanism for supplying the spread continuous reinforcing fibers F to one side of the thermoplastic resin film R0, and a mechanism for supplying the spread continuous reinforcing fibers F to the other side of the thermoplastic resin film R0. The former mechanism is provided to introduce the continuous reinforcing fibers F between one side of the thermoplastic resin film R0 and the heating roller 2 in contact with that side, and the latter mechanism is provided to introduce the continuous reinforcing fibers F between the other side of the thermoplastic resin film R0 and the heating roller 2 in contact with that side. However, the fiber-spreading mechanism may also supply the continuous reinforcing fibers F to only one side of the thermoplastic resin film R0.

[0067] The heating rollers 2 are high-temperature rollers heated by an electric heater or a heating medium (e.g., a heated fluid). The two pairs of heating rollers 2 sandwich the thermoplastic resin film R0 and the continuous reinforcing fibers F introduced on both sides thereof via the endless belt 4 while heating, thereby continuously laminating the continuous reinforcing fibers F onto the thermoplastic resin film R0. The continuous reinforcing fibers F are laminated onto the thermoplastic resin film R0 in a state where they are oriented in the same direction (a state where they are pulled together in the vertical direction in Figure 1). The temperature of the heating rollers is equal to or higher than the melting point of the thermoplastic resin used in the thermoplastic resin film R0. The thermoplastic resin film is melted by the heating rollers.

[0068] The cooling roller 3 is a low-temperature roller cooled by a cooling medium or the like (for example, a cooling fluid) and has a temperature lower than the melting point of the thermoplastic resin. The cooling roller 3 cools the thermoplastic resin film R0 having the continuous reinforcing fibers F laminated thereon while sandwiching it from both sides via the endless belt 4, thereby impregnating the molten thermoplastic resin between the fibers of the continuous reinforcing fibers F and then solidifying the thermoplastic resin. This forms a continuous fiber-reinforced thermoplastic resin substrate S in which the thermoplastic resin film R0 (matrix resin) and the reinforcing fibers F are integrated. In the continuous fiber-reinforced thermoplastic resin substrate S, the thermoplastic resin is impregnated between the fibers of the reinforcing fibers F that are oriented in the same direction.

[0069] The pull-out roller 5 is a roller that applies tension to the molded continuous fiber reinforced thermoplastic resin substrate S and pulls it downward.

[0070] The winding bobbin 6 is a core material for winding up the continuous fiber reinforced thermoplastic resin substrate S. The bobbin 6 is driven to rotate by a drive source such as a motor, and sequentially winds up the continuous fiber reinforced thermoplastic resin substrate S drawn out by the drawing roller 5, thereby forming a roll of the continuous fiber reinforced thermoplastic resin substrate S.

[0071] In addition, the continuous fiber reinforced thermoplastic resin substrate S can also be produced by a method in which the thermoplastic resin film R0 and the opened continuous reinforcing fibers are flowed and wound together in the same direction without using the endless belt 4 shown in FIG.

[0072] When continuous reinforcing fibers are laminated on one side of the thermoplastic resin film R0 with the opened continuous reinforcing fibers oriented in the same direction, the reinforcing fibers F shown in Figure 1 are fed from one side instead of both sides, thereby obtaining a continuous fiber-reinforced thermoplastic resin substrate S in which the reinforcing fibers F are laminated on one side of the thermoplastic resin film.

[0073] Although the lower limit of the thickness of the thermoplastic resin film is not particularly limited, it is preferably 5 μm or more, which makes it easier to maintain the shape of the film well during film formation. Furthermore, the thickness of the thermoplastic resin film is preferably 50 μm or less, more preferably 45 μm or less, even more preferably 40 μm or less, and even more preferably 30 μm or less. By setting the thickness of the thermoplastic resin film to 50 μm or less, the continuous fiber reinforced thermoplastic resin substrate in which the thermoplastic resin film is impregnated into a plurality of opened continuous reinforcing fibers can be made thinner.

[0074] The volume content of the continuous reinforcing fibers in the continuous fiber reinforced thermoplastic resin substrate of the present invention is preferably 30 to 80% by volume, more preferably 40 to 70% by volume, and even more preferably 45 to 65% by volume. With such a volume content, the continuous fiber reinforced thermoplastic resin substrate is sufficiently reinforced by the reinforcing fibers and has excellent strength.

[0075] The volume content of the continuous reinforcing fibers can be adjusted within the above range by appropriately controlling not only the type and thickness of the reinforcing fibers, the fiber width in which the reinforcing fibers are oriented, the thickness of the thermoplastic resin film, etc., but also the temperature and pressure applied during the production of the continuous fiber-reinforced thermoplastic resin substrate. The volume content of the reinforcing fibers can be measured by the combustion method, nitric acid decomposition method, sulfuric acid decomposition method, etc., but the volume content of the continuous reinforcing fibers in this specification is the value measured by the combustion method described in the examples.

[0076] The thickness of the continuous fiber reinforced thermoplastic resin substrate of the present invention is preferably 20 to 100 μm, more preferably 30 to 80 μm, and even more preferably 40 to 70 μm. When the thickness of the substrate is within the above range, specifically, by making the thickness of the continuous fiber reinforced thermoplastic resin substrate as thin as possible within the above range, the thermoplastic resin and the reinforcing fibers are fused to each other in most parts before being impregnated, thereby fully demonstrating the strength of the reinforcing fibers. Furthermore, in an embodiment in which multiple fiber reinforced thermoplastic resin substrates are laminated, delamination of the laminate is less likely to occur when stress is applied, and fatigue properties are also excellent. Furthermore, the molding processability when using a continuous fiber reinforced thermoplastic resin substrate is even better. The thickness of the substrate is also affected by the thickness of the thermoplastic resin film, but it can be kept within the above range by appropriately controlling the temperature and pressure applied during the production of the continuous fiber reinforced thermoplastic resin substrate.

[0077] (Applications) The continuous fiber reinforced thermoplastic resin substrate of the present invention may be used as a laminate by stacking multiple continuous fiber reinforced thermoplastic resin substrates in the thickness direction, as in the measurement method of mechanical properties in the examples, or may be chopped into rectangular pieces and used as fiber reinforced resin chopped material. When chopped into rectangular pieces and used as fiber reinforced resin chopped material, it is preferable that the continuous fiber reinforced thermoplastic resin substrate has a short side length of 1 mm to 30 mm and both sides have lengths of 5 mm to 60 mm. It is more preferable that the continuous fiber reinforced thermoplastic resin substrate has a short side length of 2 mm to 20 mm and both sides have lengths of 10 mm to 40 mm. In addition, a laminate may be formed by stacking multiple chopped materials in the thickness direction with the fiber direction of the continuous fibers in any direction.

[0078] Furthermore, by performing press molding, tape winding molding, or the like using the continuous fiber reinforced thermoplastic resin substrate of the present invention, molded articles of any shape that can be produced can be produced. The molded articles can be used for various applications, such as aircraft parts, automobile parts, electrical and electronic parts, building materials, various containers, daily necessities, household goods, and sanitary products. The continuous fiber reinforced thermoplastic resin substrate and molded articles thereof according to an embodiment of the present invention are particularly preferably used for applications requiring stable mechanical properties, such as aircraft engine peripheral parts, aircraft exterior parts, automobile body parts, vehicle frames, automobile engine peripheral parts, automobile underhood parts, automobile gear parts, automobile interior parts, automobile exterior parts, intake and exhaust system parts, engine cooling water system parts, automotive electrical parts, and electrical and electronic parts. Specifically, the continuous fiber reinforced thermoplastic resin substrate according to an embodiment of the present invention and its molded article can be used in a wide range of applications, including aircraft engine peripheral parts such as fan blades, aircraft-related parts such as landing gear pods, winglets, spoilers, edges, rudders, elevators, failings, ribs, and drones, automobile body parts such as various seats, front bodies, underbodies, various pillars, various members, various frames, various beams, various supports, various rails, and various hinges, automobile engine peripheral parts such as engine covers, air intake pipes, timing belt covers, intake manifolds, filler caps, throttle bodies, and cooling fans, cooling fans, radiator tank tops and bases, and cylinder heads. Automotive underhood parts such as door covers, oil pans, brake piping, fuel piping tubes, and exhaust gas system parts; automotive gear parts such as gears, actuators, bearing retainers, bearing cages, chain guides, and chain tensioners; automotive interior parts such as shift lever brackets, steering lock brackets, key cylinders, door inner handles, door handle cowls, interior mirror brackets, air conditioning switches, instrument panels, console boxes, glove boxes, steering wheels, and trim; front fenders, rear fenders, fuel lids, door panels, cylinder head covers, door mirror stays, tailgate panels, license garnishes, roof rails,Automotive exterior parts such as engine mount brackets, rear garnishes, rear spoilers, trunk lids, rocker moldings, moldings, lamp housings, front grilles, mudguards, and side bumpers; intake and exhaust system parts such as air intake manifolds, intercooler inlets, turbochargers, exhaust pipe covers, inner bushings, bearing retainers, engine mounts, engine head covers, resonators, and throttle bodies; engine coolant system parts such as chain covers, thermostat housings, outlet pipes, radiator tanks, oil inators, and delivery pipes; automotive electrical parts such as connectors, wire harness connectors, motor parts, lamp sockets, sensor in-vehicle switches, and combination switches; bicycle parts such as frames, steering systems, and transmission systems; shoe parts such as insoles and midsoles; sporting goods such as tennis rackets, badminton rackets, hockey sticks, padel rackets, pickleball paddles, helmets, and shoulder pads; and electrical and electronic parts such as power generating equipment. machines, electric motors, transformers, current transformers, voltage regulators, rectifiers, resistors, inverters, relays, power contacts, switches, circuit breakers, switches, knife switches, other-pole rods, motor cases, television housings, notebook computer housings and internal parts, CRT display housings and internal parts, printer housings and internal parts, mobile phone, mobile PC, handheld mobile and other mobile device housings and internal parts, IC and LED compatible housings, capacitor bases, fuse holders, various gears, various cases, electrical parts such as cabinets, connectors, SMT compatible connectors, card connectors, jacks, coils, coil bobbins, sensors, LED lamps, sockets, resistors, relays, relay cases, reflectors, small switches, power supply parts, coil bobbins, capacitors, variable capacitor cases, optical pickup chassis, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, Si power modules and SiC power modules, semiconductors, liquid crystal, FDD carriages, FDD chassis,It is preferably used in electronic components such as motor brush holders, transformer components, parabolic antennas, and computer-related components.

[0079] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. The unit of the amount of each component in the table is volume %, and the continuous fiber reinforced thermoplastic resin substrate is 100 volume %. The components used in the examples and comparative examples and the methods for evaluating the physical properties of the molded products are shown below.

[0080] The raw materials used in the examples are as follows: PA6 (A-1): Polyamide 6 (manufactured by UBE Corporation, relative viscosity 2.47) PA6 (A-2): Polyamide 6 (manufactured by UBE Corporation, relative viscosity 2.47) PA6 (A-3): Polyamide 6 (manufactured by UBE Corporation, relative viscosity 4.08) PA12 (A-4): Polyamide 12 (manufactured by UBE Corporation, relative viscosity 2.23) PA12 (A-5): Polyamide 12 (manufactured by UBE Corporation, relative viscosity 2.23) Carbon fiber (B-1): Carbon fiber bundle (manufactured by Toray Industries, Inc.; Torayca (registered trademark) carbon fiber T700SC-60E-1, 2,000 fibers / bundle, single fiber diameter 7 μm) - a bundle of continuous carbon fibers. Values ​​for diameter and the like for the carbon fiber are catalog values. Carbon fiber (B-2): Carbon fiber bundle (manufactured by Mitsubishi Chemical Corporation; Pyrofil (registered trademark) carbon fiber tow TR50S15L GF) is a bundle of continuous carbon fibers.

[0081] Example 1 First, a polyamide resin film was prepared to produce a continuous fiber-reinforced thermoplastic resin substrate. PA6 (A-1) pellets were molded using an extruder equipped with a T-die at a molding temperature of 230 to 270°C to obtain a 20 μm-thick polyamide 6 polyamide resin film. Next, using the manufacturing apparatus shown in Figure 1, air was passed through the fiber bundle to deflect the fibers while moving it widthwise, opening the carbon fiber bundle to obtain a planar spread continuous reinforcing fiber bundle. During this process, vertical and horizontal vibrations were also applied. Next, the polyamide resin film and the planar spread continuous reinforcing fiber bundle were brought into contact and heated with a heating roller while being pressed in the lamination direction to produce a laminate of the polyamide resin film and the planar spread continuous reinforcing fiber bundle. The roll temperature (the temperature of the heating roller 2 shown in Figure 1) was 250 to 260°C, and the feed rate was 10 m / min. The obtained fiber-reinforced resin composite sheet had spread carbon fiber bundles laminated on both sides of a polyamide resin film, with polyamide resin impregnated between the carbon fibers. The fiber-reinforced resin composite sheet was cooled by passing it between cooling rollers having a roll temperature (the temperature of cooling roller 3 shown in FIG. 1 ) of 20 to 30°C at a feed rate of 10 m / min, to obtain a continuous fiber-reinforced thermoplastic resin substrate in which the polyamide resin film and the continuous reinforcing fibers were integrated.

[0082] The thickness of the continuous fiber reinforced thermoplastic resin substrate was 40 μm to 50 μm.

[0083] <Comparative Example 1> In Comparative Example 1, a continuous fiber reinforced thermoplastic resin substrate was obtained in the same manner as in Example 1, except that the type of polyamide resin used as the material was PA6 (A-2).

[0084] Comparative Example 2 In Comparative Example 2, a continuous fiber reinforced thermoplastic resin substrate was obtained in the same manner as in Example 1, except that the type of polyamide resin used as the material was PA6 (A-3).

[0085] Example 2 In Example 2, a continuous fiber-reinforced thermoplastic resin substrate was obtained in the same manner as in Example 1, except that the type of carbon fiber used as the material was carbon fiber (B-2).

[0086] Comparative Example 3 In Comparative Example 3, a continuous fiber reinforced thermoplastic resin substrate was obtained in the same manner as in Example 2, except that the type of polyamide resin used as the material was PA6 (A-2).

[0087] Comparative Example 4 In Comparative Example 4, a continuous fiber reinforced thermoplastic resin substrate was obtained in the same manner as in Example 2, except that the type of polyamide resin used as the material was PA6 (A-3).

[0088] Example 3 In Example 3, a continuous fiber-reinforced thermoplastic resin substrate was obtained in the same manner as in Example 1, except that the type of carbon fiber used as the material was carbon fiber (B-1), the type of polyamide resin was PA12 (A-4), and the roll temperature (the temperature of the heating roller 2 shown in FIG. 1 ) when producing a laminate of a polyamide resin film and a planar spread continuous reinforcing fiber bundle was 200°C.

[0089] <Comparative Example 5> In Comparative Example 5, a continuous fiber reinforced thermoplastic resin substrate was obtained in the same manner as in Example 3, except that the type of polyamide resin used as the material was PA12 (A-5).

[0090] The physical properties of the examples and comparative examples were measured by the following methods: <Relative viscosity> Relative viscosity was measured at 25°C in accordance with JIS K-6920 by dissolving 1 g of polyamide resin in 100 ml of 96% concentrated sulfuric acid.

[0091] <Terminal Amino Group Concentration> A polyamide resin was dissolved in a mixed solution of phenol and methanol, and the concentration was measured by titration with 0.02 mol / L hydrochloric acid.

[0092] <Terminal Carboxyl Group Concentration> The polyamide resin was dissolved in benzyl alcohol and titrated with a 0.05 mol / L sodium hydroxide solution to measure the terminal carboxyl group concentration.

[0093] <Volume Content> The carbon fiber volume content was measured by a combustion method as follows. The obtained continuous fiber reinforced thermoplastic resin substrate was vacuum dried (80°C, 16 hours or more) to prepare a bone-dry test piece for evaluation. The test piece was burned in an electric furnace at a combustion temperature of 400°C for 16 hours or more to completely remove the thermoplastic resin, and the fiber volume content was determined from the weight of the test piece before and after combustion as follows. In this evaluation, the specific gravity of the carbon fiber was 1.80, the specific gravity of the polyamide 6 was 1.14, and the specific gravity of the PA12 was 1.02. Fiber volume fraction (Wf) = test piece weight after combustion / test piece weight before combustion Fiber volume content (Vf) [%] = (Wf / carbon fiber density) / (Wf / carbon fiber specific gravity; + (1 - Wf) / specific gravity of polyamide 6 or polyamide 12) × 100 The volume content of the polyamide resin was calculated by subtracting the volume content of the carbon fiber obtained by the combustion method from 100.

[0094] <90° Tensile Strength of Unidirectional Material> 48 sheets of the obtained continuous fiber reinforced thermoplastic resin substrate were stacked so that the spread carbon fibers were uniaxially oriented with an angle difference of 0°. The stacked continuous fiber reinforced thermoplastic resin substrate was placed in a mold and heated and pressurized at 270°C and 5 MPa for 30 minutes, and then cooled and pressurized at room temperature and 5 MPa. A fiber reinforced resin composite measuring 250 mm x 220 mm x 2 mm (thickness) was removed from the mold and cut to a predetermined size to finally obtain a fiber reinforced resin composite test piece with a uniaxial laminate structure with an angle difference of 0°. The fiber reinforced resin composite test piece was cut to a size of 25 mm (length in the minor axis direction) x 250 mm (length in the major axis direction) x 2 mm (thickness). The tensile strength was measured in accordance with JIS K7165.

[0095] <Near-Isotropic Bending Strength> 48 sheets of the obtained continuous fiber reinforced thermoplastic resin substrate were laminated so that the spread carbon fibers were aligned in four axial directions with an angle difference of 45°. The laminated continuous fiber reinforced thermoplastic resin substrate was placed in a mold and heated and pressurized for 30 minutes at 270°C for polyamide 6 or 250°C and 5 MPa for polyamide 12. Then, the substrate was cooled and pressurized at room temperature and 5 MPa. A fiber reinforced resin composite measuring 250 mm x 220 mm x 2 mm (thickness) was removed from the mold and cut to a predetermined size. Finally, a test piece of a fiber reinforced resin composite with a laminate structure aligned in four axial directions with an angle difference of 45° was obtained. The test piece of the fiber reinforced resin composite was cut to a size of 15 mm (length in the minor axis direction) x 100 mm (length in the major axis direction) x 2 mm (thickness). The bending strength was measured in accordance with the bending test method for carbon fiber reinforced plastics using four-point bending (method B) of JIS K7017.

[0096]

[0097] In the table, A / (A+C) is a value when the terminal amino group concentration of the polyamide resin is A μmol / g and the terminal carboxyl group concentration is C μmol / g.

[0098] Example 1, Comparative Example 1, and Comparative Example 2 are examples in which the same type of polyamide resin and the same carbon fiber were used, but the A / (A+C) values ​​of the polyamide resins were different. From the results shown in Table 1, it can be seen that Example 1, in which the A / (A+C) value of the polyamide resin, as expressed in formula (1), exceeds 0.50, exhibits excellent tensile strength and flexural strength. Comparative Example 1, which uses a polyamide resin in which the A / (A+C) value of formula (1) is 0.50 or less and the relative viscosity is less than 4.00, exhibits inferior flexural strength compared to Example 1. The flexural strength value of Example 1 is 1.10 times that of Comparative Example 1. Comparative Example 2, which uses a polyamide resin in which the A / (A+C) value of formula (1) is 0.50 or less and the relative viscosity is 4.00 or more, exhibits inferior tensile strength and flexural strength compared to Example 1. The tensile strength value of Example 1 is 1.40 times that of Comparative Example 2, and the flexural strength value of Example 1 is 1.11 times that of Comparative Example 2.

[0099] Example 2, Comparative Example 3, and Comparative Example 4 are examples in which the same type of polyamide resin and the same carbon fiber were used, but the A / (A+C) values ​​of the polyamide resins were different. From the results shown in Table 1, it can be seen that Example 2, in which the A / (A+C) value of the polyamide resin, as expressed in formula (1), exceeds 0.50, exhibits excellent tensile strength and flexural strength. Comparative Example 3, which uses a polyamide resin in which the A / (A+C) value of formula (1) is 0.50 or less and the relative viscosity is less than 4.00, exhibits inferior flexural strength compared to Example 2. The flexural strength value of Example 2 is 1.06 times that of Comparative Example 3. Comparative Example 4, which uses a polyamide resin in which the A / (A+C) value of formula (1) is 0.50 or less and the relative viscosity is 4.00 or more, exhibits inferior tensile strength and flexural strength. The tensile strength value of Example 2 is 1.05 times that of Comparative Example 4, and the flexural strength value of Example 2 is 1.10 times that of Comparative Example 4. Therefore, Example 2 is significantly superior to Comparative Example 4 in bending strength.

[0100] Example 3 and Comparative Example 5 are examples in which the same type of polyamide resin and the same carbon fiber were used, but the A / (A+C) values ​​of the polyamide resins were different. From the results shown in Table 1, it can be seen that Example 3, in which A / (A+C) (Equation (1)) is greater than 0.50, had superior tensile strength and flexural strength to Comparative Example 5. Comparative Example 5, in which a polyamide resin with A / (A+C) (Equation (1)) of 0.50 or less and a relative viscosity of less than 4.00 was used, had inferior tensile strength and flexural strength. The tensile strength value of Example 3 was 1.04 times that of Comparative Example 5, and the flexural strength value of Example 3 was 1.07 times that of Comparative Example 5. Therefore, Example 3 has significantly superior flexural strength to Comparative Example 5.

[0101] From the above, it can be seen that even when the same carbon fiber is used, when the value of A / (A+C) of the polyamide resin is within the range of the present invention, the bending strength is excellent. Furthermore, when the relative viscosity of the polyamide resin is within the preferred range of the present invention, the tensile strength is also excellent.

[0102] Molded products using continuous fiber reinforced thermoplastic resin substrates can be used for a variety of purposes, including aircraft parts, automobile parts, electrical and electronic parts, building materials, various containers, daily necessities, household goods, and sanitary products.

[0103] 1: Continuous fiber reinforced thermoplastic resin substrate manufacturing device 2: Heating roller 3: Cooling roller 4: Endless belt 5: Pull-out roller 6: Bobbin F: Continuous reinforcing fiber F0: Continuous reinforcing fiber bundle R0: Thermoplastic resin film S: Continuous fiber reinforced thermoplastic resin substrate

Claims

1. A continuous fiber reinforced thermoplastic resin substrate comprising a thermoplastic resin and continuous reinforcing fibers, wherein the continuous reinforcing fibers are oriented in one direction, the thermoplastic resin is impregnated between the continuous reinforcing fibers, the thermoplastic resin comprises a polyamide resin, and the polyamide resin comprises a polycondensate of at least one monomer selected from the group consisting of lactams and aminocarboxylic acids, and the polyamide resin satisfies the following condition (a): (a) When the terminal amino group concentration is A μmol / g and the terminal carboxyl group concentration is C μmol / g, the value of the following (Equation 1) A / (A+C) (Equation 1) is greater than 0.50:

2. The continuous fiber reinforced thermoplastic resin substrate according to claim 1, wherein the polyamide resin comprises at least one selected from the group consisting of polyamide 6 and polyamide 12.

3. The continuous fiber reinforced thermoplastic resin substrate according to claim 1, wherein the polyamide resin satisfies the following condition (b): (b) a relative viscosity of less than 4.

00.

4. A continuous fiber reinforced thermoplastic resin substrate according to claim 1, wherein the volume content of the continuous reinforcing fibers in the continuous fiber reinforced thermoplastic resin substrate is 30 to 80 volume %.

5. A continuous fiber-reinforced thermoplastic resin substrate according to claim 1, wherein the thickness of the continuous fiber-reinforced thermoplastic resin substrate is 20 to 100 μm.

6. A molded article made from the continuous fiber reinforced plastic resin substrate according to any one of claims 1 to 5.

7. A method for producing a continuous fiber-reinforced thermoplastic resin substrate according to claim 1, comprising: Step 1: spreading fiber bundles of a plurality of continuous reinforcing fibers aligned in one direction to obtain a planar spread continuous reinforcing fiber bundle; Step 2: producing a laminate of the spread continuous reinforcing fiber bundles obtained in Step 1 and a thermoplastic resin, and pressurizing the laminate in the lamination direction while heating it to a temperature equal to or higher than the melting point of the thermoplastic resin, thereby impregnating the thermoplastic resin between the fibers of the spread continuous reinforcing fiber bundles; and Step 3: cooling the thermoplastic resin to a temperature below the melting point of the thermoplastic resin, thereby producing a continuous fiber-reinforced thermoplastic resin substrate in which the thermoplastic resin exists between the fibers of the spread continuous reinforcing fiber bundles.

8. The method for producing a continuous fiber-reinforced thermoplastic resin substrate according to claim 7, wherein in step 1, the continuous reinforcing fibers are opened by passing an air flow in the longitudinal direction of the fibers.

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