Resin composition, prepreg, method for producing the same, and molded article

Abstract

An object of the present invention is to provide a resin composition that has excellent impregnability into fibers, enables favorable continuous production of a prepreg, and enables production of a prepreg that enables favorable production of a molded article.SOLUTION: A three dimensional crosslinked structure in which a compound (A) having two or more acetoacetic acid ester groups, aldehyde groups, or triketone structures alone or in combination in a molecule and an amine compound (B) having two or more primary amino groups in a molecule are bonded to each other, and a ketimine compound (D) in which at least one primary amino group of the amine compound (B) and a ketone group of the ketone compound (C) are condensation-bonded, wherein among the primary amino groups of the amine compound (B) constituting the ketimine compound (D), a proportion of the primary amino groups bonded to the ketone compound (C) is 1kPa% or more, the ketone compound (C) having a steam pressure at 20 °C of 0. 50mol or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a prepreg containing the resin composition, a method for producing the same, and a molded article obtained by molding the prepreg. [Background technology]

[0002] Composite reinforced materials are formed by combining a base resin with reinforcing materials such as carbon fiber, glass fiber, metal fiber, high-strength organic fiber, inorganic filler, metal filler, carbon nanotube, and cellulose nanofiber. Because they are strong and lighter than metals such as iron, they are beginning to be used in some automobiles, aircraft, and wind turbine blades as materials that make a significant contribution to improving energy efficiency.

[0003] In addition to thermosetting and thermoplastic resins, resins with dynamic covalent bonds (Vitrimers) formed by bond exchange have recently attracted increasing attention as base resins. These dynamic covalent bonds are capable of reversibly dissociating and recombining under the action of heat (temperature), light, catalysts, etc. By introducing dynamic covalent bonds into resins, the strong polymer structure formed by the covalent bonds can be reversibly reorganized. Therefore, the introduction of dynamic covalent bonds is expected to improve mechanical properties, control functionality, impart self-healing properties, and enable recyclability.

[0004] For example, Patent Document 1 discloses a composition containing Vitrimer that has been developed to have excellent mechanical properties, an appropriate glass transition temperature, and the ability to flow at high temperatures while remaining insoluble. Furthermore, Patent Document 2 discloses a composite reinforcement material containing Vitrimer having an increased glass transition temperature. Patent Document 3 discloses a composite reinforcing material that contains a resin composition containing Vitrimer and reinforcing fibers, and in which the resin and reinforcing fibers can be recovered and recycled separately. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2017 / 0327625 [Patent Document 2] International Publication No. 2020 / 051506 [Patent Document 3] International Publication No. 2024 / 043285 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when Vitrimer is used to produce prepreg, an intermediate base material for composite reinforcing materials, the curing reaction of Vitrimer is so fast that it hardens rapidly, making it difficult to impregnate fibers with Vitrimer. It is also not possible to produce prepreg continuously over long periods of time. Even if prepreg can be produced, it hardens easily, making it difficult to produce molded articles.

[0007] In view of the state of the prior art, the problem that the present invention aims to solve is to provide a resin composition that is excellent in impregnation into fibers, allows good continuous production of prepregs, and makes it possible to obtain prepregs that can be used to produce good molded articles; a prepreg containing the resin composition, a method for producing the same, and a molded article obtained by molding the prepreg. [Means for solving the problem]

[0008] That is, the present invention is as follows. [1] a monomer unit (a) derived from a compound (A) having two or more acetoacetate groups, aldehyde groups, or triketone structures, either singly or in combination, in the molecule; and a monomer unit (b) derived from an amine compound (B) having two or more primary amino groups in the molecule, the monomer unit (b) having a condensation bond between a part of the primary amino groups and a ketone group of a ketone compound (C) having a vapor pressure of 0.1 kPa or more at 20°C, a three-dimensional crosslinked structure in which an acetoacetate group, an aldehyde group, and / or a ketone group of a triketone structure of the compound (A) is condensed with a primary amino group of the amine compound (B); Resin and a ketimine compound (D) formed by condensation bonding at least one primary amino group of an amine compound (B) having two or more primary amino groups in the molecule with a ketone group of a ketone compound (C) having a vapor pressure of 0.1 kPa or more at 20°C; Including, When the total of the primary amino groups of the amine compound (B) constituting the monomer unit (b) of the resin and the primary amino groups of the amine compound (B) constituting the ketimine compound (D) is taken as 100 mol %, the proportion of the primary amino groups condensed with the ketone groups of the ketone compound (C) is 50 mol % or more. A resin composition comprising: [2] A prepreg comprising the resin composition according to [1] and reinforcing fibers. [3] The prepreg according to [2], which contains 1% by mass or more of a compound having a ketone group. [4] A method for producing the prepreg according to [2] or [3], a capping step of capping at least one primary amino group of a part of the amine compound (B) by subjecting the amine compound (B) to a condensation reaction with the ketone compound (C) to form a ketimine bond between at least one primary amino group of a part of the amine compound (B) and a ketone group of the ketone compound (C); a synthesis step of dissolving the compound (A) and the amine compound (B) that has been subjected to the capping step in a ketone-based solvent, mixing and stirring the mixture to synthesize a resin, thereby obtaining a resin solution; an impregnation step in which the resin liquid obtained in the synthesis step is placed in a resin bath, and reinforcing fibers are immersed in the resin liquid in the resin bath to impregnate the reinforcing fibers with the resin liquid; A method for producing a prepreg, comprising: [5] A molded article obtained by molding the prepreg according to [2] or [3]. [6] The molded article according to [5], which is a high-pressure tank, a construction material, a sporting goods, an automobile part, an aircraft part, a railway part, or a robot part. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a resin composition capable of obtaining a prepreg that has excellent fiber impregnation properties, allows good continuous production of prepregs, and allows good production of molded articles; a prepreg containing the resin composition, a method for producing the same; and a molded article obtained by molding the prepreg. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content.

[0011] <Resin composition> The resin composition of the present embodiment comprises a resin having a three-dimensional crosslinked structure in which the acetoacetate groups, aldehyde groups, and / or ketone groups of the compound (A) are condensed with the primary amino groups of the amine compound (B), and the acetoacetate groups, aldehyde groups, and / or triketone structures of the compound (A) are condensed with the primary amino groups of the amine compound (B). The resin composition of the present embodiment also contains a ketimine compound (D) formed by condensation bonding of at least one primary amino group of an amine compound (B) having two or more primary amino groups in the molecule with a ketone group of a ketone compound (C) having a vapor pressure of 0.1 kPa or more at 20°C.

[0012] <<resin>> [Monomer unit (a)] The resin of this embodiment contains a monomer unit (a) derived from a compound (A) having, in the molecule, two or more acetoacetic ester groups, aldehyde groups or triketone structures, either singly or in combination.

[0013] (Compound (A)) Compound (A) is not particularly limited as long as it has two or more acetoacetate groups, aldehyde groups, or triketone structures, either alone or in combination, in the molecule, and may be a compound having two or more acetoacetate groups in the molecule, a compound having two or more aldehyde groups in the molecule, a compound having two or more triketone structures in the molecule, a compound having one or more acetoacetate groups and one or more aldehyde groups in the molecule, a compound having one or more acetoacetate groups and one or more triketone structures in the molecule, a compound having one or more aldehyde groups and one or more triketone structures in the molecule, a compound having one or more acetoacetate groups, one or more aldehyde groups, and one or more triketone structures in the molecule, etc. Among these, a compound having two or more acetoacetate groups in the molecule, a compound having two or more aldehyde groups in the molecule, or a compound having two or more triketone structures in the molecule is preferred. The compound (A) may be used alone or in combination of two or more kinds.

[0014] -Compounds containing two or more acetoacetate groups in the molecule- The compound having two or more acetoacetate groups in the molecule may be an acetoacetate compound having two acetoacetate groups in the molecule (bisacetoacetate compound), or an acetoacetate compound having three or more acetoacetate groups in the molecule.

[0015] Bisacetoacetate compounds are esters of polyols such as diols and triols with two acetylacetates. The bisacetoacetate compound is not particularly limited, but examples thereof include alkanediol bisacetoacetates such as ethylene glycol-1,2-bisacetoacetate, propanediol-1,3-bisacetoacetate, propanediol-1,2-bisacetoacetate, butanediol-1,4-bisacetoacetate, hexanediol-1,6-bisacetoacetate, and decanediol-1,10-bisacetoacetate; oxyalkylenediol bisacetoacetates such as diethylene glycol bisacetoacetate, triethylene glycol bisacetoacetate, polyethylene glycol bisacetoacetate, and polypropylene glycol bisacetoacetate; and 1,4-cyclohexanedimethanol bisacetoacetate.

[0016] Among these, oxyalkylenediol bisacetoacetate such as polypropylene glycol bisacetoacetate is particularly preferred from the viewpoint of high mechanical properties and good self-repairing properties. The above bisacetoacetic acid ester compounds may be used alone or in combination of two or more.

[0017] An acetoacetate compound having three or more acetoacetate groups in the molecule is an ester of a polyol such as a triol with three or more acetoacetic acids. The acetoacetate compound having three or more acetoacetate groups in the molecule is not particularly limited, but examples thereof include polyacetoacetates such as trisacetoacetate and tetrakisacetoacetate. Examples of trisacetoacetate include, but are not limited to, trimethylolpropane trisacetoacetate, 1,2,3-propanetriol trisacetoacetate, 1,2,4-butanetriol trisacetoacetate, and 1,2,6-hexanetriol trisacetoacetate. Other polyacetoacetates are not particularly limited, and examples thereof include pentaerythritol tetrakisacetoacetate, as well as those obtainable by the method described in JP-A-2017-533088.

[0018] Among these, trisacetoacetate-1,2,3-propanetriol is particularly preferred from the viewpoint of high mechanical properties and good self-repairing properties. The acetoacetic acid ester compounds having three or more acetoacetic acid ester groups in the molecule may be used alone or in combination of two or more.

[0019] -Compounds with two or more aldehyde groups in the molecule- The compound having two or more aldehyde groups in the molecule (aldehyde compound) is not particularly limited, but examples thereof include terephthalaldehyde, isophthalaldehyde, 2,5-diformylfuran, 3,4-diformylthiophene, 2,4-diformylimidazole, 3,4-dicarboxaldehydepyrrole, etc. Among these, terephthalaldehyde is preferred from the viewpoint of obtaining high mechanical properties. The aldehyde compound having two or more aldehyde groups in the molecule may be used alone or in combination of two or more.

[0020] -Compounds with two or more triketone structures in the molecule- The compound having two or more triketone structures in the molecule (triketone compound) is not particularly limited, but a compound obtained by a condensation reaction between a cyclic diketone and a dicarboxylic acid is preferred. Specific examples of the cyclic diketone include dimedone. Examples of the dicarboxylic acid include adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. Among these, adipic acid is preferred from the viewpoint of obtaining high mechanical properties. The triketone compound having two or more triketone structures in the molecule may be used alone or in combination of two or more. The three ketone groups (carbonyl groups) in the triketone structure do not include the carbonyl groups in the acetoacetate group and the aldehyde group.

[0021] The total amount of acetoacetate groups, aldehyde groups, and triketone structures in the monomer unit (a) is preferably 70 to 120 mol%, more preferably 80 to 110 mol%, and even more preferably 90 to 100 mol%, relative to the amount of primary amino groups in the monomer unit (b). When the total amount of acetoacetate groups, aldehyde groups, and triketone structures is within the above range, the density of the three-dimensional crosslinked structure formed by the condensation reaction between the acetoacetate groups, aldehyde groups, and ketone groups of the triketone structure of the compound (A) and the primary amino groups of the amine compound (B) is appropriately controlled, tending to achieve high mechanical properties and good flowability due to bond exchange. Furthermore, within the above range, when the resin composition is composited with fibers, the good flowability allows for flawless composite formation of the fibers and resin. In particular, when the monomer units derived from a compound having three or more acetoacetic ester groups in the molecule are contained within the above range, the resin composition tends to be less prone to molding defects and to have less dimensional change in shape. Furthermore, in the case of the above composition, the rate at which the viscosity decreases in a certain temperature range is slowed, so when the prepreg is cut to an appropriate size in a certain temperature range, the resin and fibers are less likely to separate, making cutting easy.

[0022] [Monomer unit (b)] The resin of this embodiment contains a monomer unit (b) derived from an amine compound (B) having two or more primary amino groups in the molecule. The amine compound (B) having two or more primary amino groups in the molecule is a compound having two or more -NH2 groups in the molecule. The amine compound (B) may be used alone or in combination of two or more kinds.

[0023] (Amine Compound (B)) The amine compound (B) may be a diamine, triamine or polyamine, an aromatic amine, an aliphatic amine or a compound having both an aliphatic amino group and an aromatic amino group.

[0024] Examples of aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1,4-diamino-2-methoxybenzene, 2,5-diamino-p-xylene, 1,3-diamino-4-chlorobenzene, 3,5-diaminobenzoic acid, 1,4-diamino-2,5-dichlorobenzene, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-2,2'-dimethylbibenzyl, 4,4'-diaminodiphenylmethane, 3, 3'-Diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 2,2'-diaminostilbene, 4,4'-diaminostilbene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene benzene, 1,4-bis(4-aminophenoxy)benzene, 3,5-bis(4-aminophenoxy)benzoic acid, 4,4'-bis(4-aminophenoxy)bibenzyl, 2,2-bis[(4-aminophenoxy)methyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, 1,1-bis(4-aminophenyl)cyclohexyl San, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, 9,9-bis(4-aminophenyl)fluorene, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenylamine, 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrene, 1,6-diaminopyrene, 1,8-diaminopyrene, 2,7-diaminofluorene, 1,3-bis(4-aminophenyl)tetramethyldisiloxane, benzidine, 2,2'-dimethylbenzidine, 1,2-bis(4-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,5-bis(4-aminophenyl)pentane, 1,6-bis(4-aminophenyl)hexane, 1,7-bis(4-aminophenyl)heptane, 1,8-bis(4-aminophenyl)octane, 1,9-bis(4-aminophenyl)nonane, 1,1 0-Bis(4-aminophenyl)decane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 1,7-bis(4-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, di(4-aminophenyl)propane-1,3-diene di(4-aminophenyl)butane-1,4-dioate, di(4-aminophenyl)pentane-1,5-dioate, di(4-aminophenyl)hexane-1,6-dioate, di(4-aminophenyl)heptane-1,7-dioate, di(4-aminophenyl)octane-1,8-dioate, di(4-aminophenyl)nonane-1,9-dioate, di(4-aminophenyl)decane-1,10-dioate, 1,3-bis[4-(4-aminophenoxy)phenoxy]propane, 1,4- Examples include bis[4-(4-aminophenoxy)phenoxy]butane, 1,5-bis[4-(4-aminophenoxy)phenoxy]pentane, 1,6-bis[4-(4-aminophenoxy)phenoxy]hexane, 1,7-bis[4-(4-aminophenoxy)phenoxy]heptane, 1,8-bis[4-(4-aminophenoxy)phenoxy]octane, 1,9-bis[4-(4-aminophenoxy)phenoxy]nonane, and 1,10-bis[4-(4-aminophenoxy)phenoxy]decane.

[0025] Examples of aromatic-aliphatic diamines include 3-aminobenzylamine, 4-aminobenzylamine, 3-amino-N-methylbenzylamine, 4-amino-N-methylbenzylamine, 3-aminophenethylamine, 4-aminophenethylamine, 3-amino-N-methylphenethylamine, 4-amino-N-methylphenethylamine, 3-(3-aminopropyl)aniline, 4-(3-aminopropyl)aniline, 3-(3-methylaminopropyl)aniline, 4-(3-methylaminopropyl)aniline, 3-(4- ... aminobutyl)aniline, 4-(4-aminobutyl)aniline, 3-(4-methylaminobutyl)aniline, 4-(4-methylaminobutyl)aniline, 3-(5-aminopentyl)aniline, 4-(5-aminopentyl)aniline, 3-(5-methylaminopentyl)aniline, 4-(5-methylaminopentyl)aniline, 2-(6-aminonaphthyl)methylamine, 3-(6-aminonaphthyl)methylamine, 2-(6-aminonaphthyl)ethylamine, 3-(6-aminonaphthyl)ethylamine, and the like.

[0026] Examples of heterocyclic diamines include 2,6-diaminopyridine, 2,4-diaminopyridine, 2,4-diamino-1,3,5-triazine, 2,7-diaminodibenzofuran, 3,6-diaminocarbazole, 2,4-diamino-6-isopropyl-1,3,5-triazine, and 2,5-bis(4-aminophenyl)-1,3,4-oxadiazole.

[0027] Examples of aliphatic diamines include 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,3-diamino-2,2-dimethylpropane, 1,6-diamino-2,5-dimethylhexane, 1,7-diamino-2,5-dimethylheptane, 1,7-diamino-4,4-dimethylheptane, 1,7-diamino-3-methylheptane, 1,9-diamino-5-methylheptane, 1,12-diaminododecane, 1,18-diaminooctadecane, and 1,2-bis(3-aminopropoxy)ethane.

[0028] Examples of the alicyclic diamine include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylamine, and isophoronediamine.

[0029] Among these aliphatic diamines, those in which the amino group is located at the end of the molecular chain are preferred from the viewpoint of improving reactivity.

[0030] Among these, 1,6-diaminohexane is particularly preferred from the viewpoint of high mechanical properties and good fluidity. The diamine compounds may be used alone or in combination of two or more.

[0031] Specific examples of aromatic triamines include 1,3,5-triaminobenzene, tris(3-aminophenyl)amine, tris(4-aminophenyl)amine, tris(3-aminophenyl)benzene, tris(4-aminophenyl)benzene, 1,3,5-tris(3-aminophenoxy)benzene, 1,3,5-tris(4-aminophenoxy)benzene [TAPOB], 1,3,5-tris(aminophenyl)benzene [TAPB], and 1,3,5-tris(4-aminophenoxy)triazine.

[0032] It is also possible to use an aromatic triamine having a predetermined asymmetric structure represented by the following general formula (1). [ka] (In the formula, -Z- is -O-, -CO-, -S-, -SO2-, -CH2-, -C(CH3)2-, -C(CF3)2- or a single bond. Ra and Rb each independently represent a hydrogen atom, a halogen atom, a hydroxyl group or a hydrocarbon group. m is an integer of 0 to 3, and n is an integer of 0 to 4.)

[0033] Specific examples of aromatic triamines having a predetermined asymmetric structure represented by the above general formula (1) include 2,3',4-triaminobiphenyl, 2,4,4'-triaminobiphenyl, 3,3',4-triaminobiphenyl, 3,3',5-triaminobiphenyl, 3,4,4'-triaminobiphenyl, 3,4',5-triaminobiphenyl, 2,3',4-triaminodiphenyl ether, 2,4,4'-triaminodiphenyl ether, 3,3',4-triaminodiphenyl ether, 3,3',5-triaminodiphenyl ether, 3,4,4'-triaminodiphenyl ether, Triaminodiphenyl ether, 3,4',5-triaminodiphenyl ether, 2,3',4-triaminobenzophenone, 2,4,4'-triaminobenzophenone, 3,3',4-triaminobenzophenone, 3,3',5-triaminobenzophenone, 3,4,4'-triaminobenzophenone, 3,4',5-triaminobenzophenone, 2,3',4-triaminodiphenyl sulfide, 2,4,4'-triaminodiphenyl sulfide, 3,3',4-triaminodiphenyl sulfide, 3,3',5-triaminodiphenyl sulfide amide, 3,4,4'-triaminodiphenyl sulfide, 3,4',5-triaminodiphenyl sulfide, 2,3',4-triaminodiphenyl sulfone, 2,4,4'-triaminodiphenyl sulfone, 3,3',4-triaminodiphenyl sulfone, 3,3',5-triaminodiphenyl sulfone, 3,4,4'-triaminodiphenyl sulfone, 3,4',5-triaminodiphenyl sulfone, 2,3',4-triaminodiphenyl methane, 2,4,4'-triaminodiphenyl methane, 3,3',4-triaminodiphenyl methane ethane, 3,3',5-triaminodiphenylmethane, 3,4,4'-triaminodiphenylmethane, 3,4',5-triaminodiphenylmethane, 2-(2,4-diaminophenyl)-2-(3-aminophenyl)propane, 2-(2,4-diaminophenyl)-2-(4-aminophenyl)propane, 2-(3,4-diaminophenyl)-2-(3-aminophenyl)propane, 2-(3,5-diaminophenyl)-2-(3-aminophenyl)propane, 2-(3,4-diaminophenyl)-2-(4-aminophenyl)propane, 2-(3,2-(3,5-diaminophenyl)-2-(4-aminophenyl)propane, 2-(2,4-diaminophenyl)-2-(3-aminophenyl)hexafluoropropane, 2-(2,4-diaminophenyl)-2-(4-aminophenyl)hexafluoropropane, 2-(3,4-diaminophenyl)-2-(3-aminophenyl)hexafluoropropane, 2-(3,5-diaminophenyl)-2-(3-aminophenyl)hexafluoropropane, 2-(3,4-diaminophenyl)-2-(4-aminophenyl)hexafluoropropane, 2-(3,5-diaminophenyl)-2-(4-aminophenyl)hexafluoropropane, and the like can be mentioned.

[0034] Among the above aromatic triamines, those having a symmetrical molecular structure are preferred.

[0035] The aliphatic triamine is not particularly limited, but examples thereof include 1,2,3-triaminopropane, 1,3,5-triaminocyclohexane, and tris(2-aminoethyl)amine.

[0036] Specific examples of triamine compounds having both an aliphatic amino group and an aromatic amino group include 5-(2-aminoethyl)benzene-1,3-diamine and 2-((4-aminophenoxy)methyl)propane-1,3-diamine.

[0037] Commercially available amine compounds having three or more primary amino groups in the molecule can also be used, such as JEFFAMINE T-403, JEFFAMINE T-3000, and JEFFAMINE T-5000 manufactured by Huntsman, Polyment NK-350 manufactured by Nippon Shokubai Co., Ltd., and Hexatran 110 manufactured by Ascend. Furthermore, examples of amine compounds having three or more primary amino groups in the molecule include amino group-modified polysiloxanes, such as X-22-3939A manufactured by Shin-Etsu Silicones Co., Ltd.

[0038] The amine compound having three or more primary amino groups in the molecule preferably does not contain a secondary amino group or a tertiary amino group in the molecule.

[0039] Among these, Hexatran 110 manufactured by Ascend is particularly preferred from the viewpoint of high mechanical properties and good flowability. The amine compound having three or more primary amino groups in the molecule may be used alone or in combination of two or more.

[0040] The resin of this embodiment contains the monomer unit (b) derived from the amine compound (B) as an essential constituent unit, but may also contain a monomer unit derived from a monoamine within the scope of the object of the invention. Examples of monoamines include n-butylamine and benzylamine.

[0041] The monomer unit (b) of the resin of this embodiment has a condensation bond (ketimine bond) between some of the primary amino groups derived from the compound (B) and the ketone group of the ketone compound (C) which is a capping agent. In this way, some of the primary amino groups in the monomer unit (b) form condensation bonds (ketimine bonds) with the ketone compound (C), i.e., some of the primary amino groups in the monomer unit (b) are capped with the ketone compound (C), which slows down the resin curing reaction (extending the time it takes for the resin to harden). This allows the resin to be sufficiently impregnated into the fibers during the prepreg production described below, allowing the resin liquid in the resin bath to be used for a longer period of time without replacement, thereby enabling good continuous production of prepregs. Furthermore, the resulting prepregs maintain their tackiness for a long period of time, resulting in good adhesion between prepregs and allowing good production of molded articles using the prepregs.

[0042] (Ketone Compound (C)) The ketone compound (C) has a vapor pressure of 0.1 kPa or more at 20°C. Therefore, the ketone compound (C) volatilizes during the manufacturing process of the molded body and does not remain in the molded body, preventing molding defects. Furthermore, since the ketone compound (C) does not remain, the amino groups in the resin do not recombine and become capped, which has the advantage of not impairing properties such as reorganization due to bond exchange and fluidity. The ketone compound (C) is not particularly limited as long as it has a vapor pressure of 0.1 kPa or more at 20° C., and examples thereof include monoketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone, and dibutyl ketone. It should be noted that this ketone compound (C) does not include the ketone compounds included in the category of the above compound (A).

[0043] The amount of primary amino groups in the monomer unit (b) is preferably 80 to 140 mol %, more preferably 90 to 120 mol %, and even more preferably 100 to 110 mol %, based on the total amount of acetoacetate groups, aldehyde groups, and triketone structures in the monomer unit (a). When the amount of primary amino groups in the monomer unit (b) is within the above range, reorganization of the resin due to bond exchange is likely to occur, and the density of the three-dimensional crosslinked structure formed by the condensation reaction of the acetoacetate groups, aldehyde groups, and ketone groups of the triketone structure of the compound (A) with the primary amino groups of the amine compound (B) is appropriately adjusted, which tends to result in high mechanical properties and good flowability.

[0044] In the resin of this embodiment, when compound (A) has an acetoacetate group in the molecule, the acetoacetate group of compound (A) and the primary amino group of amine compound (B) undergo a condensation reaction to form a vinylogous urethane bond, thereby three-dimensionally crosslinking the resin. Vinylogous urethane bonds are dynamic covalent bonds that can reversibly dissociate and recombine in response to external stimuli such as heat (temperature), light, or a catalyst. Among resins with dynamic covalent bonds, those with vinylogous urethane bonds are preferred because they shorten the time it takes to decompose the resin while maintaining the mechanical strength (e.g., flexural strength) of the molded product (fiber-reinforced composite). Furthermore, because the recycling reaction proceeds without a catalyst, they are preferred because they eliminate the need for the effort of uniformly dispersing a catalyst when compounding fibers and resin, and the risk of catalyst bleeding out over time.

[0045] As shown below, reactions of vinylogous urethane include the formation of vinylogous urethane bonds, as well as amination and hydrolysis. Reversible dissociation and recombination are possible through the formation of vinylogous urethane bonds, the amination and hydrolysis reactions. In the following reaction formula, R1 to R3 each independently represent any chemical structure. [ka]

[0046] The three-dimensional cross-linked structure (polymer network structure) formed by vinylogous urethane bonds is a strong structure, and therefore the resin of this embodiment has good mechanical properties, heat resistance properties, and chemical resistance properties. Furthermore, the polymer network structure can be restored to a monomer or a chain-like low-molecular-weight derivative by hydrolysis of vinylogous urethane or an amine exchange reaction with a monofunctional primary amine. Therefore, by using a resin composition containing the resin of this embodiment, a molded product (fiber-reinforced composite material) that can be chemically recycled can be obtained.

[0047] A catalyst may be added to the resin of this embodiment as needed for the purpose of accelerating the above-mentioned transamine reaction, reducing the resin viscosity, and increasing the self-repairing property. Examples of the catalyst include sulfuric acid, paratoluenesulfonic acid, paratoluenesulfonic acid monohydrate, ethylphosphinic acid, phenylphosphinic acid, ethylphosphonic acid, phenylphosphonic acid, zinc(II) chloride, zinc(II) acetate, iron(II) chloride, iron(III) chloride, diethylamine, diisopropylamine, triethylamine, tributylamine, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo[4.3.0]non-5-yne, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, ammonium chloride, ammonium acetate, and ammonium carbamate. The amount of catalyst added is preferably 0.1 to 6 mass % relative to the total amount of resin, more preferably 0.1 to 5 mass %, and even more preferably 0.1 to 3 mass %. When the amount of catalyst added is within the above range, the transamine reaction is appropriately controlled, and high mechanical properties and good self-repairing properties tend to be obtained.

[0048] In the resin of this embodiment, when compound (A) has an aldehyde group in the molecule, the aldehyde group of compound (A) and the primary amino group of amine compound (B) undergo a condensation reaction to form an imine bond, thereby achieving three-dimensional crosslinking. The imine bond is a dynamic covalent bond, similar to the vinylogous urethane bond. Resins having imine bonds tend to have a short decomposition time. Furthermore, since the recycling reaction proceeds without a catalyst, it is preferable because there is no need to worry about the effort of uniformly dispersing a catalyst when compounding fibers and resins, or about the catalyst bleeding out over time.

[0049] An example of a reversible reaction of an imine bond is the imine-amine exchange reaction shown below: In the reaction formula below, R4 to R6 each independently represent any chemical structure. [ka] By dissociating the bonds through an imine-amine exchange reaction with a monofunctional primary amine, the polymer network structure can be returned to a monomer or a chain-like low-molecular-weight derivative. Therefore, molded bodies (fiber-reinforced composites) containing resins with imine bonds as dynamic covalent bonds can be chemically recycled.

[0050] A catalyst may be added to the resin of this embodiment as needed for the purpose of accelerating the imine-amine exchange reaction, reducing the resin viscosity, and increasing the self-repairing property. Examples of the catalyst include sulfuric acid, paratoluenesulfonic acid, paratoluenesulfonic acid monohydrate, ethylphosphinic acid, phenylphosphinic acid, ethylphosphonic acid, phenylphosphonic acid, zinc(II) chloride, zinc(II) acetate, iron(II) chloride, iron(III) chloride, diethylamine, diisopropylamine, triethylamine, tributylamine, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo[4.3.0]non-5-yne, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, ammonium chloride, ammonium acetate, and ammonium carbamate. The amount of catalyst added is preferably 0.1 to 6 mass % relative to the total amount of resin, more preferably 0.1 to 5 mass %, and even more preferably 0.1 to 3 mass %. When the amount of catalyst added is within the above range, the imine-amine exchange reaction is appropriately adjusted, and high mechanical properties and good self-repairing properties tend to be obtained.

[0051] In the resin of this embodiment, when compound (A) has a triketone structure in the molecule, one of the three ketone groups in the triketone structure of compound (A) undergoes a condensation reaction with the primary amino group of amine compound (B) to form a diketoenamine bond, thereby achieving three-dimensional crosslinking. The diketoenamine bond is a dynamic covalent bond, similar to the vinylogous urethane bond. Resins having a diketoenamine bond tend to have a short decomposition time. Furthermore, since the recycling reaction proceeds without a catalyst, it is preferable because there is no need to worry about the effort of uniformly dispersing a catalyst when compounding fibers and resins, or about catalyst bleeding over time.

[0052] An example of a reversible reaction of a diketoenamine bond is the diketoenamine-amine exchange reaction shown below: In the reaction formula below, R7 to R9 each independently represent an arbitrary chemical structure. [ka] By dissociating the bond through a diketoenamine-amine exchange reaction with a monofunctional primary amine, the polymer network structure can be returned to a monomer or a chain-like low-molecular-weight derivative. Therefore, molded bodies (fiber-reinforced composites) containing resins with diketoenamine bonds as dynamic covalent bonds can be chemically recycled.

[0053] A catalyst may be added to the resin of this embodiment as needed for the purpose of accelerating the diketoenamine-amine exchange reaction, reducing the resin viscosity, and increasing the self-repairing property. Examples of the catalyst include sulfuric acid, paratoluenesulfonic acid, paratoluenesulfonic acid monohydrate, ethylphosphinic acid, phenylphosphinic acid, ethylphosphonic acid, phenylphosphonic acid, zinc(II) chloride, zinc(II) acetate, iron(II) chloride, iron(III) chloride, diethylamine, diisopropylamine, triethylamine, tributylamine, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo[4.3.0]non-5-yne, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, ammonium chloride, ammonium acetate, and ammonium carbamate. The amount of catalyst added is preferably 0.1 to 6 mass % relative to the total amount of resin, more preferably 0.1 to 5 mass %, and even more preferably 0.1 to 3 mass %. When the amount of catalyst added is within the above range, the imine-amine exchange reaction is appropriately controlled, and high mechanical properties and good self-repairing properties tend to be obtained.

[0054] From the viewpoint of recyclability, the resin content in the resin composition is preferably 40% by mass or more, more preferably 60% by mass or more, even more preferably 80% by mass or more, still more preferably 95% by mass or more, particularly preferably 97% by mass or more, and most preferably 99% by mass or more, with the resin composition (total solids content if the resin composition is in varnish form) being 100% by mass.

[0055] <<Resin manufacturing method>> The method for producing a resin of this embodiment includes a capping step in which an amine compound (B) and a ketone compound (C) are subjected to a condensation reaction to form a ketimine bond between at least one primary amino group of a part of the amine compound (B) and a ketone group of the ketone compound (C), thereby capping at least one primary amino group of a part of the amine compound (B); and a synthesis step in which the amine compound (B) that has undergone the capping step, the compound (A), and optionally other monomers within the scope of the object of the invention are each dissolved in an organic solvent, mixed, and stirred to synthesize a resin.

[0056] (Capping process) The capping step is a step in which amine compound (B) is subjected to a condensation reaction with ketone compound (C) to form a ketimine bond between at least one primary amino group of a part of amine compound (B) and a ketone group of ketone compound (C) (at least one primary amino group of a part of amine compound (B) is capped), thereby preventing the primary amino group that has formed the ketimine bond from immediately reacting with compound (A) and other monomers that are optionally blended in the subsequent synthesis step. In this way, by forming a ketimine bond in at least one primary amino group of a portion of the amine compound (B) (capping the primary amino group), the capped primary amino group does not react immediately even when the compound is mixed with compound (A) and any other optional monomers and stirred, thereby delaying the resin curing reaction (extending the time until the resin hardens). This allows the resin to be sufficiently impregnated into the fibers during the production of the prepreg described below, allowing the resin liquid in the resin bath to be used for a long period of time without replacement, thereby enabling successful continuous production of prepregs. Furthermore, the resulting prepregs maintain their tackiness for a long period of time, resulting in good adhesion between prepregs and enabling successful production of molded articles using the prepregs. The phrase "capping at least one primary amino group of a part of the amine compound (B)" means capping at least one primary amino group of a part of the amine compound (B). Therefore, for example, when an amine compound (B) (diamine) having two primary amino groups is subjected to a capping step, a mixture of a diamine in which neither of the two primary amino groups is capped and a diamine in which one or two primary amino groups are capped is obtained.

[0057] The amount of ketone groups in the ketone compound (C) relative to the amount of primary amino groups in the amine compound (B) is preferably 55 to 95 mol%, more preferably 60 to 90 mol%, and even more preferably 70 to 90 mol%, from the viewpoint of adjusting the capping ratio described below to 50 mol% or more.

[0058] (synthesis process) In the synthesis step, the amine compound (B) that has been subjected to the capping step (i.e., a mixture of an amine compound in which none of the primary amino groups is capped and an amine compound in which at least one primary amino group is capped), the compound (A), and optionally other monomers within the scope of the object of the invention are dissolved in an organic solvent, mixed, and stirred to synthesize a resin. Examples of the organic solvent include alcohol solvents such as methanol and ethanol, and ketone solvents such as acetone. The synthesis temperature may be room temperature (20 to 25° C.), but the temperature may be raised to hasten the completion of the reaction, in which case the temperature is preferably within the range of the boiling point of the solvent used minus 10° C.

[0059] <<Ketimine Compound (D)>> The ketimine compound (D) contained in the resin composition of this embodiment is an amine compound (B) in which at least one primary amino group is capped with a ketone compound (C), which is synthesized in the capping step of the resin production method of this embodiment, i.e., a ketimine compound in which at least one primary amino group of the amine compound (B) is bonded to a ketone group of the ketone compound (C).

[0060] In the resin composition of this embodiment, when the total of the primary amino groups of the amine compound (B) constituting the monomer unit (b) of the resin and the primary amino groups of the amine compound (B) constituting the ketimine compound (D) is taken as 100 mol %, the proportion of primary amino groups condensed with the ketone group of the ketone compound (C), i.e., the proportion of primary amino groups capped with the ketone compound (C) (capping proportion), is 50 mol % or more, preferably 60 to 90 mol %, and more preferably 70 to 90 mol %. A capping proportion within this range can delay the resin curing reaction (extend the time it takes for the resin to solidify). This allows the resin to be sufficiently impregnated into the fibers during the prepreg production described below, allowing the resin solution in the resin bath to be used for a long period of time without replacement, thereby enabling successful continuous production of prepregs. Furthermore, the resulting prepregs maintain tackiness for a long period of time, resulting in good adhesion between prepregs and enabling successful production of molded articles using the prepregs. The capping ratio can be adjusted by adjusting the molar ratio of the amount of ketone groups in the ketone compound (C) to the amount of primary amino groups in the amine compound (B) in the capping step of the above-mentioned resin production method, or by adjusting the reaction time. The capping ratio in the monomer state (after the capping step and before the synthesis step) is calculated based on the ratio of the amine compound (B) that has undergone the capping step in the resin production method, i.e., a mixture of an amine compound in which none of the primary amino groups is capped and an amine compound (ketimine compound (D)) in which at least one primary amino group is capped. 1 It can be determined as the percentage of capping by molecular structure analysis using H-NMR. In addition, the capping ratio in the resin composition and prepreg state can be evaluated by carrying out infrared spectroscopy (IR) measurement and calculating based on the capping ratio in the monomer state. Specifically, both the resin composition and the prepreg state can be measured by the method described later in the section "Capping ratio in prepreg" in the Examples, and the capping ratio can be calculated by the method described later in the Examples section. -1 Capping can be confirmed by the peak intensity derived from the nearby ketimine bond. The capping ratio determined in the state of the resin composition and the capping ratio determined in the state of the prepreg can be considered to be equivalent.

[0061] Since the above-mentioned capping is an equilibrium reaction in which the capping is removed by hydrolysis, the curing rate can be increased, for example, by leaving the composition standing for several hours in a humidity-controlled thermostatic bath. The hydrolysis reaction can be accelerated by a catalyst. Specifically, the catalyst is preferably a proton-donating catalyst, and an acid catalyst or a carbonyl compound capable of donating a proton with a pKa of 18 or less is preferred. Specific examples of acid catalysts include Brønsted acids, sulfuric acid, nitric acid, hydrochloric acid, sulfonic acid, phosphoric acid, carboxylic acid, and Lewis acids. Examples of carbonyl compounds capable of donating a proton with a pKa of 18 or less include compounds having an acetoacetate group, an aldehyde group, or a triketone structure. These carbonyl compounds are particularly preferred because they function as catalysts and are ultimately incorporated into the resin skeleton, thereby suppressing the occurrence of voids and other defects that can result in molding defects compared to acid catalysts. In particular, in order for a proton-donating carbonyl compound with a pKa of 18 or less to function as a catalyst, the amount added is preferably 20 to 80 parts by mass, and more preferably 30 to 70 parts by mass, relative to 100 parts by mass of the resin. If the amount is 20 parts by mass or more, the compound tends to function well as a catalyst, and if the amount is 80 parts by mass or less, the mechanical strength of the resulting crosslinked resin is improved.

[0062] <<Other Ingredients>> (thermoplastic resin) The resin composition of the present embodiment may contain, as other components, thermoplastic resins other than the above-mentioned resins. Examples of the thermoplastic resin include phenoxy resins, acrylic resins, methacrylic resins, polyvinyl acetal resins, thermoplastic polyimide resins, polyamide resins, polyamideimide resins, polyphenylene oxide resins, polyethersulfone resins, polyester resins, polyethylene resins, polystyrene resins, polysulfone resins, polybutadiene resins, ABS resins, and coumarone resins. The thermoplastic resins may be used singly or in combination of two or more types having different weight average molecular weights, or in combination of one or more types and their prepolymers. Among these, it is preferable to use one or more resins selected from the group consisting of polyimide resins, polyamide resins, phenoxy resins, and coumarone resins.

[0063] The phenoxy resin is not particularly limited, and examples thereof include phenoxy resins having a bisphenol skeleton such as phenoxy resins having a bisphenol A skeleton, phenoxy resins having a bisphenol F skeleton, phenoxy resins having a bisphenol S skeleton, phenoxy resins having a bisphenol M (4,4'-(1,3-phenylenediisopridiene)bisphenol) skeleton, phenoxy resins having a bisphenol P (4,4'-(1,4)-phenylenediisopridiene)bisphenol) skeleton, and phenoxy resins having a bisphenol Z (4,4'-cyclohexydienebisphenol) skeleton, phenoxy resins having a novolac skeleton, phenoxy resins having an anthracene skeleton, phenoxy resins having a fluorene skeleton, phenoxy resins having a dicyclopentadiene skeleton, phenoxy resins having a norbornene skeleton, phenoxy resins having a naphthalene skeleton, phenoxy resins having a biphenyl skeleton, and phenoxy resins having an adamantane skeleton. The phenoxy resin may have a structure having multiple types of the above skeletons, or may have different ratios of the skeletons. Furthermore, multiple types of phenoxy resins with different skeletons may be used, or multiple types of phenoxy resins with different weight-average molecular weights may be used, or prepolymers of these may be used in combination.

[0064] The lower limit of the weight-average molecular weight (Mw) of the phenoxy resin is, for example, 10,000 or more, preferably 15,000 or more, and more preferably 20,000 or more. When the lower limit of the weight-average molecular weight (Mw) is within the above range, compatibility with other resins and solubility in solvents can be improved. On the other hand, the upper limit of the weight-average molecular weight (Mw) of the phenoxy resin is, for example, 60,000 or less, preferably 55,000 or less, and more preferably 50,000 or less.

[0065] From the viewpoint of recyclability, the content of the above thermoplastic resin in the resin composition of this embodiment is preferably 5 to 50 mass%, more preferably 10 to 40 mass%, and even more preferably 15 to 30 mass%, with the resin composition (total solids content if the resin composition is in varnish form) being 100 mass%.

[0066] (Inorganic filler) The resin composition may contain an inorganic filler. Examples of the inorganic filler include silicates such as talc, calcined clay, uncalcined clay, mica, and glass; oxides such as titanium oxide, alumina, boehmite, silica, and fused silica; carbonates such as calcium carbonate, magnesium carbonate, and hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate, and calcium sulfite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; nitrides such as aluminum nitride, boron nitride, silicon nitride, and carbon nitride; and titanates such as strontium titanate and barium titanate. Among these, talc, alumina, glass, silica, mica, aluminum hydroxide, and magnesium hydroxide are preferred, and silica is particularly preferred. As the inorganic filler, one of these may be used alone, or two or more may be used in combination.

[0067] The lower limit of the average particle diameter of the inorganic filler is not particularly limited, but may be, for example, 0.01 μm or more, or 0.05 μm or more. When the lower limit of the average particle diameter is within the above range, the viscosity of the varnish-like resin composition described below can be prevented from increasing, improving workability during prepreg production. Furthermore, the upper limit of the average particle diameter of the inorganic filler is not particularly limited, but is preferably, for example, 5.0 μm or less, more preferably 2.0 μm or less, and even more preferably 1.0 μm or less. When the upper limit of the average particle diameter is within the above range, phenomena such as sedimentation of the inorganic filler in the varnish-like resin composition described below can be prevented, and a uniform resin composition can be obtained. In this embodiment, the average particle diameter of the inorganic filler can be determined by measuring the particle size distribution of the particles on a volume basis using, for example, a laser diffraction particle size distribution analyzer (LA-500, manufactured by HORIBA Corporation), and taking the median diameter (D50) as the average particle diameter.

[0068] The inorganic filler is not particularly limited, but may be an inorganic filler having a monodisperse average particle size, or an inorganic filler having a polydisperse average particle size. Furthermore, one or more types of inorganic fillers having monodisperse and / or polydisperse average particle sizes may be used in combination.

[0069] The lower limit of the inorganic filler content is not particularly limited, but is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, based on 100% by mass of the resin composition (total solids content when the resin composition is in varnish form). When the lower limit of the content is within the above range, the resin composition can have particularly low thermal expansion and low water absorption. On the other hand, the upper limit of the inorganic filler content is not particularly limited, but may be, for example, 85% by mass or less, 80% by mass or less, or 75% by mass or less, based on 100% by mass of the resin composition. This improves handling during prepreg production.

[0070] (coupling agent) The resin composition of this embodiment may contain a coupling agent. The coupling agent may be added directly during preparation of the resin composition, or may be added to the inorganic filler in advance. The use of a coupling agent can improve the wettability of the interface between the inorganic filler and each resin. Therefore, it is preferable to use a coupling agent, especially when an inorganic filler is contained, as it can improve the heat resistance of the resin composition.

[0071] Examples of the coupling agent include silane coupling agents such as epoxy silane coupling agents, cationic silane coupling agents, and amino silane coupling agents, titanate coupling agents, and silicone oil coupling agents. One type of coupling agent may be used alone, or two or more types may be used in combination. In this embodiment, the coupling agent may contain a silane coupling agent, which can increase the wettability at the interface between the inorganic filler and each resin.

[0072] As the silane coupling agent, various types can be used, and examples thereof include epoxy silane, amino silane, alkyl silane, ureido silane, mercapto silane, and vinyl silane. Specific examples include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-phenylγ-aminopropyltriethoxysilane, N-phenylγ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, N-6-(aminohexyl)3-aminopropyltrimethoxysilane, N-(3-(trimethoxysilylpropyl)-1,3-benzenedimethanane, γ-glycidoxypropyltriethoxysilane, Examples of suitable silanes include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane (also known as 3-mercaptopropyltrimethoxysilane), methyltrimethoxysilane, γ-ureidopropyltriethoxysilane, and vinyltriethoxysilane. These silanes may be used singly or in combination. Of these, epoxysilanes, mercaptosilanes, and aminosilanes are preferred, and primary aminosilanes or anilinosilanes are more preferred as aminosilanes.

[0073] The content of the coupling agent can be appropriately adjusted based on the specific surface area of ​​the inorganic filler. The lower limit of the content of such a coupling agent may be, for example, 0.01% by mass or more, preferably 0.05% by mass or more, based on 100% by mass of the resin composition (total solids content when the resin composition is in varnish form). When the content of the coupling agent is equal to or more than the lower limit, the inorganic filler can be sufficiently coated, and the heat resistance of the resin composition can be improved. On the other hand, the upper limit of the content of the coupling agent may be, for example, 3% by mass or less, preferably 1.5% by mass or less, based on 100% by mass of the resin composition. When the content of the coupling agent is equal to or less than the upper limit, the coupling agent can be prevented from affecting the reaction and can prevent a decrease in the bending strength, etc. of the resin composition.

[0074] (additives) The resin composition of the present embodiment may contain additives other than the above components, such as colorants including one or more selected from the group consisting of dyes such as green, red, blue, yellow, and black, pigments such as black pigments, and coloring agents, stress reducing agents, antifoaming agents, leveling agents, ultraviolet absorbers, foaming agents, antioxidants, flame retardants, ion scavengers, rubber components, light stabilizers, dispersants, lubricants, plasticizers, and antistatic agents, provided that the object of the present invention is not impaired. These may be used alone or in combination of two or more. The content of the additive in the resin composition of this embodiment is preferably 0.1 to 25% by mass, more preferably 0.2 to 20% by mass, and even more preferably 0.5 to 15% by mass, based on 100% by mass of the resin composition (total solids content when the resin composition is in varnish form). Furthermore, the content of the additive in the molded product of this embodiment is preferably 0.1 to 5% by mass, more preferably 0.2 to 4.5% by mass, and even more preferably 0.3 to 4.0% by mass, based on 100% by mass of the molded product. When the content of the additive is within the above range, when the reinforcing fibers are separated and recovered from the molded product, less additive remains (adheres) on the surfaces of the recovered reinforcing fibers. This prevents the fibers from adhering to each other and forming bundles, making it easier to reuse the recovered reinforcing fibers. The content of the additives can be confirmed not only from the charge ratio but also by extracting the additives from the obtained molded body using a solvent or the like, or by decomposing the molded body using a decomposition solution in which a low molecular weight amine or alcohol is dissolved, extracting the additives, and quantifying them using an analytical device such as liquid chromatography.

[0075] Examples of the pigment include inorganic pigments such as kaolin, synthetic iron oxide red, cadmium yellow, nickel titanium yellow, strontium yellow, hydrous chromium oxide, chromium oxide, cobalt aluminate, and synthetic ultramarine blue; polycyclic pigments such as phthalocyanine; and azo pigments.

[0076] Examples of the dye include isoindolinone, isoindoline, quinophthalone, xanthene, diketopyrrolopyrrole, perylene, perinone, anthraquinone, indigoid, oxazine, quinacridone, benzimidazolone, violanthrone, phthalocyanine, and azomethine.

[0077] The rubber component may include, for example, one or more selected from the group consisting of butadiene rubber, acrylic rubber, and silicone rubber. The rubber component may be contained in the form of particles, such as core-shell rubber particles, cross-linked acrylonitrile butadiene rubber particles, cross-linked styrene butadiene rubber particles, acrylic rubber particles, and silicone particles.

[0078] In the present embodiment, when the resin composition is in the form of a varnish, the resin composition may contain a solvent. Examples of the solvent include organic solvents such as methanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethyl acetate, cyclohexane, heptane, cyclohexane, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve-based solvents, carbitol-based solvents, anisole, and N-methylpyrrolidone. These may be used alone or in combination of two or more.

[0079] When the resin composition is in the form of a varnish, the solid content of the resin composition may be, for example, 30 to 80 mass %, more preferably 40 to 70 mass %. When the solid content of the resin composition is in the above range, a resin composition with excellent workability and film-forming properties can be obtained.

[0080] <Method of manufacturing resin composition> The resin composition of this embodiment can be produced by mixing and stirring the resin of this embodiment and, if necessary, the other components and additives described above. In the case of a varnish-like resin composition, the above-mentioned components can be dissolved, mixed, and stirred in a solvent using various mixers such as those used in ultrasonic dispersion, high-pressure collision dispersion, high-speed rotation dispersion, bead mill dispersion, high-speed shear dispersion, and rotation-revolution dispersion.

[0081] <Prepreg> The prepreg of this embodiment includes the resin composition of this embodiment described above and reinforcing fibers. The prepreg of this embodiment may be configured to include a reinforcing fiber substrate in the resin composition of this embodiment described above. The prepreg of this embodiment contains a resin composition including the resin of this embodiment in which some of the primary amino groups have been capped, which can delay the curing reaction of the resin (extending the time it takes for the resin to harden). This maintains the tackiness of the prepreg for a long period of time, resulting in good adhesion between prepregs and enabling the prepreg to be used to produce a good molded article. Furthermore, the prepreg of this embodiment contains a resin composition including the resin of this embodiment having the above-mentioned three-dimensional crosslinked structure, which allows the production of a molded article (fiber-reinforced composite material) that has sufficient mechanical properties, heat resistance, and chemical resistance and is chemically recyclable. Prepreg is an intermediate material made by impregnating fibers with resin and leaving them in a semi-hardened state.

[0082] The shape and size of the prepreg of this embodiment are not particularly limited and may be determined appropriately depending on the shape and size of the desired molded body (fiber-reinforced composite material), and may be, for example, in the form of a tape (tow prepreg, yarn prepreg, strand prepreg, etc.) or a sheet.

[0083] The prepreg of this embodiment preferably contains a compound having a ketone group. The condensation reaction (imidization reaction) between the primary amino group of the amine compound (B) constituting the monomer unit (b) of the resin and the ketone group of the ketone compound (C) is an equilibrium reaction. Therefore, when a compound having a ketone group is contained in the prepreg, the condensation bond (imide bond) is more easily maintained. In other words, the primary amino group is less likely to be capped, and the resin curing reaction can be more effectively delayed (the time until the resin hardens) can be extended. This allows the tackiness of the prepreg to be maintained for a longer period of time, improving adhesion between prepregs and enabling the prepreg to be used to produce molded articles more efficiently. The compound having a ketone group is not particularly limited, and may be a ketone-based solvent used in the synthesis step of the above-mentioned method for producing a resin. As described above, the condensation reaction (imidization reaction) between the primary amino group of the amine compound (B) constituting the monomer unit (b) of the resin and the ketone group of the ketone compound (C) is an equilibrium reaction. Therefore, it is preferable to use the ketone compound (C) condensed to the primary amino group of the resin in the prepreg as the ketone-based solvent in the synthesis step.

[0084] The content of the compound having a ketone group in the prepreg is preferably 1% by mass or more, more preferably 1 to 5% by mass, and even more preferably 1 to 2% by mass, from the viewpoint of enabling better production of molded articles. The content of the ketone group-containing compound in the prepreg is the content when the prepreg is molded. The content of the ketone group-containing compound in the prepreg can be adjusted by adjusting the temperature and time for drying the prepreg so that it falls within the above range when the prepreg is molded. Furthermore, since the ketone group-containing compound may volatilize during storage of the prepreg, causing the content of the ketone group-containing compound to decrease, it is preferable to use the prepreg for producing a molded article within 8 hours of its preparation. When the prepreg is stored in a refrigerator or in a sealed film under vacuum or nitrogen, the possibility of the cap coming off is significantly reduced, allowing it to be used for 30 days or more.

[0085] [Reinforced fiber] The reinforcing fibers of this embodiment may be continuous or discontinuous. When the reinforcing fibers of this embodiment are continuous, the shape and arrangement of the fibers are not limited, and examples thereof include fiber structures such as long fibers aligned in one direction, a single tow, a woven fabric, a knitted fabric, and a braided cord. Examples of reinforcing fibers include carbon fiber, glass fiber, aramid fiber, boron fiber, PBO fiber, high-strength polyethylene fiber, alumina fiber, and silicon carbide fiber. From the viewpoints of mechanical properties, thermal properties, and versatility, glass fiber, carbon fiber, and aramid fiber are preferred, and from the viewpoint of productivity, carbon fiber and glass fiber are preferred. The reinforcing fibers may be used alone or in combination of two or more.

[0086] The reinforcing fibers used in this embodiment preferably have a fiber length of 10 mm or more, more preferably 50 mm or more. If the fiber length is 10 mm or more, when the resin in the molded body is decomposed using a decomposition solution (solvent), only the fibers can be easily recovered from the decomposition solution. However, if the fiber length is less than 10 mm, it is necessary to use fine filter paper, etc., which reduces the recovery rate. Furthermore, if the fiber length is less than 10 mm, the recovered fibers will contain monomers produced by the decomposition of the solvent and resin, which poses a problem when it comes to reuse. The upper limit of the fiber length of the reinforcing fibers is not particularly limited, but it is preferably longer than the length of the longest side of the molded article. The length, diameter, etc. of the fibers can be evaluated not only from the raw material fibers but also by observing the fibers recovered after decomposing the molded body using an electron microscope, etc., and the single fiber fineness can also be confirmed from the length, diameter, etc. of the fibers evaluated in this way.

[0087] (carbon fiber) Carbon fiber is a fiber made by carbonizing acrylic fiber or pitch (a by-product of petroleum, coal, coal tar, etc.) at high temperatures. In particular, acrylic carbon fibers having high tensile strength are preferably used.

[0088] Such acrylic carbon fibers can be produced, for example, by the following process. A spinning dope containing polyacrylonitrile obtained from a monomer mainly composed of acrylonitrile is spun by a wet spinning method, a dry-wet spinning method, a dry spinning method, or a melt spinning method. The coagulated fiber after spinning is subjected to a spinning process to obtain a precursor, which is then subjected to processes such as flame retardation and carbonization to obtain a carbon fiber.

[0089] The carbon fiber may be in the form of twisted yarn, untwisted yarn, or non-twisted yarn, but in the case of twisted yarn, the filaments constituting the carbon fiber are not oriented parallel to one another, which can cause a decrease in the mechanical properties of the resulting carbon fiber reinforced composite material. Therefore, untwisted yarn or non-twisted yarn is preferably used, as it provides a good balance between the formability and strength properties of the carbon fiber reinforced composite material.

[0090] In order to improve the adhesion of the carbon fiber to the matrix resin, it is preferable that the carbon fiber is usually subjected to an oxidation treatment to introduce an oxygen-containing functional group. As the oxidation treatment method, gas phase oxidation, liquid phase oxidation, and liquid phase electrolytic oxidation are used, but liquid phase electrolytic oxidation is preferably used from the viewpoints of high productivity and enabling uniform treatment.

[0091] In this embodiment, the electrolyte used in the liquid-phase electrolytic oxidation may be an acidic electrolyte or an alkaline electrolyte. From the viewpoint of adhesion, it is more preferable to apply a sizing agent after liquid-phase electrolytic oxidation in an alkaline electrolyte.

[0092] Examples of acidic electrolytes include inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, boric acid, and carbonic acid, organic acids such as acetic acid, butyric acid, oxalic acid, acrylic acid, and maleic acid, and salts such as ammonium sulfate and ammonium hydrogen sulfate. Of these, sulfuric acid and nitric acid, which exhibit strong acidity, are preferably used.

[0093] Specific examples of alkaline electrolytes include aqueous solutions of hydroxides such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, and barium hydroxide, aqueous solutions of carbonates such as sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, barium carbonate, and ammonium carbonate, aqueous solutions of bicarbonates such as sodium bicarbonate, potassium bicarbonate, magnesium bicarbonate, calcium bicarbonate, barium bicarbonate, and ammonium bicarbonate, aqueous solutions of ammonia, tetraalkylammonium hydroxide, and hydrazine, etc. Among these, aqueous solutions of ammonium carbonate and ammonium bicarbonate, or aqueous solutions of tetraalkylammonium hydroxide, which exhibit strong alkalinity, are preferred from the viewpoint of not containing alkali metals that inhibit curing of the matrix resin.

[0094] In this embodiment, the total amount of electricity used in the electrolysis is preferably 3 to 300 coulombs per 1 g of carbon fiber. By setting the total amount of electricity used in the electrolysis to 3 coulombs / g or more, sufficient functional groups can be imparted to the carbon fiber surface, resulting in excellent interfacial adhesion between the matrix resin and the carbon fiber. On the other hand, by setting the total amount of electricity used in the electrolysis to 300 coulombs / g or less, the expansion of defects on the surface of single carbon fiber can be suppressed, and a decrease in the strength of the carbon fiber can be reduced.

[0095] Commercially available carbon fibers include "TORAYCA (registered trademark)" T800G-24K, "TORAYCA (registered trademark)" T300-3K, "TORAYCA (registered trademark)" T700G-12K, and "TORAYCA (registered trademark)" T1100G-24K (all manufactured by Toray Industries, Inc.).

[0096] The carbon fibers used in this embodiment preferably have a single fiber fineness of 0.2 to 2.0 dtex, more preferably 0.4 to 1.8 dtex. If the single fiber fineness is less than 0.2 dtex, the carbon fibers may not be sufficiently impregnated with the resin composition, resulting in reduced fatigue resistance. If the single fiber fineness is more than 2.0 dtex, the fiber surface area per unit volume of the molded article decreases, reducing the effects of the sizing agent and functional groups on the fiber surface, as described below, and making recycling more time-consuming.

[0097] The carbon fiber used in this embodiment preferably has a filament count in the range of 2,500 to 50,000 in one fiber bundle. If the filament count is less than 2,500, the fiber arrangement tends to be meandering, which can easily cause a decrease in strength. If the filament count is more than 50,000, it may be difficult to impregnate the fiber with the resin composition during prepreg production or molding. The filament count is more preferably in the range of 2,800 to 40,000.

[0098] The carbon fiber of this embodiment is preferably a sizing-coated carbon fiber. By using a sizing-coated carbon fiber, the carbon fiber has excellent handleability and excellent interfacial adhesion between the carbon fiber and the matrix resin, making it suitable for use in carbon fiber reinforced composite materials. In addition, the effect of the sizing agent is that it acts as a catalyst when recycling carbon fiber reinforced composite materials, thereby promoting recycling.

[0099] In this embodiment, the sizing agent preferably contains at least one sizing agent having an amino group. This is because the amino groups of the sizing agent are present on the fiber surface when the sizing agent is applied, which increases the rate of bond exchange between the resin and the fiber, making it easier for the resin to peel from the fiber surface and shortening the recycling time. Furthermore, the presence of the amino groups of the sizing agent on the fiber surface promotes interaction at the interface between the fiber and the resin when they are composited, resulting in high adhesive strength and tending to increase the strength of the composite material. Specifically, the sizing agent preferably contains a silane coupling agent having an amino group, and a curing agent that contains an amino group and is an epoxy resin compound, polyurethane resin compound, or polyamide resin compound.

[0100] In the present embodiment, the sizing agent preferably contains one or more compounds selected from the group consisting of a silane coupling agent, an epoxy resin compound, a polyurethane resin compound, and a polyamide resin compound. Examples of silane coupling agents contained in the sizing agent include aminosilanes such as propyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane; mercaptosilanes such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane; epoxysilanes such as 3-glycidoxypropylmethyldimethoxysilane; vinylsilanes, and maleic acids, and these may be used alone or in combination. The epoxy resin compound may be, for example, an aliphatic epoxy compound, an aromatic epoxy compound, or the like, and these may be used alone or in combination. Examples of polyurethane resin compounds include polyether polyurethane resins, polyester polyurethane resins, and polyurethane elastomers, which may be used alone or in combination. Examples of polyamide resin compounds include nylon 6, nylon 66, nylon 11, nylon 12, and nylon 610, which may be used alone or in combination.

[0101] Methods for determining whether a reinforcing fiber contains (is coated with) a sizing agent having an amino group, i.e., whether amino groups are present on the fiber surface, include, for example, a method of directly observing the fiber surface before compounding, or a method of observing the surface of the remaining fiber after decomposing the resin portion of the molded body. Examples of observation methods include observation by X-ray photoelectron spectroscopy (XPS) and observation by time-of-flight secondary ion mass spectrometry (TOF-SIMS), with XPS being particularly preferred. Specifically, measurement can be performed by the method described in the Examples below.

[0102] In this embodiment, the amount of sizing agent applied is preferably 0.1 parts by mass or more, more preferably 0.1 to 3.0 parts by mass, and even more preferably 0.2 to 3.0 parts by mass, per 100 parts by mass of carbon fiber. When the amount of sizing agent applied is within this range, high shear toughness can be achieved. The amount of sizing agent applied is measured by taking 2±0.5 g of sizing-coated carbon fiber and heat-treating it in a nitrogen atmosphere at 450°C for 15 minutes, and dividing the mass change before and after the heat treatment by the mass before the heat treatment, which is measured as a mass %.

[0103] (glass fiber) Glass fiber is made by melting and drawing glass into fibers.

[0104] The glass fiber used in this embodiment preferably has a single fiber fineness of 1.0 to 10 dtex, more preferably 1.5 to 8.0 dtex. If the single fiber fineness is less than 1.0 dtex, the glass fiber may not be sufficiently impregnated with the resin composition, resulting in reduced fatigue resistance. If the single fiber fineness is more than 10 dtex, the fiber surface area per unit volume of the molded article decreases, reducing the effects of the sizing agent and functional groups on the fiber surface, as described below, and making recycling more time-consuming.

[0105] The glass fiber used in this embodiment preferably has a filament count in the range of 2,500 to 50,000 in one fiber bundle. If the filament count is less than 2,500, the fiber arrangement tends to be meandering, which can easily cause a decrease in strength. If the filament count is more than 50,000, it may be difficult to impregnate the fiber with the resin composition during prepreg production or molding. The filament count is more preferably in the range of 2,800 to 40,000.

[0106] (sizing agent) When glass fibers are selected as the reinforcing fibers, a sizing agent (a bundling agent) may be used. In this embodiment, the sizing agent preferably contains one or more selected from the group consisting of a silane coupling agent, an epoxy resin compound, a polyurethane resin compound, and a polyamide resin compound, similar to the carbon fiber. In this embodiment, the sizing agent preferably contains at least one sizing agent having an amino group. This is because the amino groups of the sizing agent are present on the fiber surface when the sizing agent is applied, which increases the rate of bond exchange between the resin and the fiber, making it easier for the resin to peel from the fiber surface and shortening the recycling time. Furthermore, the presence of the amino groups of the sizing agent on the fiber surface promotes interaction at the interface between the fiber and the resin when they are combined, resulting in high adhesive strength and a tendency for the composite material to have high strength. Specifically, the sizing agent preferably contains a silane coupling agent having an amino group, and a curing agent that contains an amino group and is an epoxy resin compound, polyurethane resin compound, or polyamide resin compound.

[0107] The sizing agent preferably contains one or more selected from the group consisting of a silane coupling agent, a lubricant, and a binder, and preferably contains at least a binder or a silane coupling agent. The sizing agent may be composed of a silane coupling agent and a binder, or may be composed of a silane coupling agent, a lubricant, and a binder. The sizing agent creates a strong bond between the glass fiber and the resin coating around it, making it possible to obtain a prepreg with a low void ratio. The sizing agent may be added externally to the material being used, or may be included internally in the material being used, for example, lubricants may be included in the commercial product of the thermoplastic resin being used.

[0108] (Silane coupling agent) The silane coupling agent contributes to improving the interfacial adhesive strength of the glass fiber, and also has the effect of facilitating recycling by acting as a catalyst when recycling molded articles. Examples of silane coupling agents include, but are not limited to, aminosilanes such as propyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane; mercaptosilanes such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane; epoxysilanes such as 3-glycidoxypropylmethyldimethoxysilane; vinylsilanes, maleic acids, etc. When polyamide is used as the thermoplastic resin, it is preferable to select one that easily bonds with the carboxyl group or amino group that is the terminal group of the polyamide resin, and aminosilanes are preferred. Furthermore, among the above silane coupling agents, those having an amino group are particularly preferred for recyclability, because the presence of an amino group on the fiber surface increases the rate of bond exchange between the resin and the fiber, making it easier for the resin to peel off from the fiber surface and shortening the recycling time.

[0109] (lubricant) The lubricant contributes to improving the opening property of the glass fibers. As the lubricant, any ordinary liquid or solid lubricating material can be used depending on the purpose, as long as it does not interfere with the silane coupling agent and the binder. Examples of the lubricant include, but are not limited to, animal, vegetable, or mineral waxes such as carnauba wax and lanolin wax; surfactants such as fatty acid amides, fatty acid esters, fatty acid ethers, aromatic esters, and aromatic ethers; and the like.

[0110] (binding agent) The binder contributes to improving the bundling property of the glass fibers and improving the interfacial adhesive strength. As the binder, polymers according to the purpose and thermoplastic resins other than the thermoplastic resin as the main material of the molded body can be used. Examples of polymers that can be used as binders include, but are not limited to, homopolymers of acrylic acid, copolymers of acrylic acid with other copolymerizable monomers, and salts of these with primary, secondary, and tertiary amines. Polyurethane resins synthesized from isocyanates such as m-xylylene diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), and isophorone diisocyanate, and polyester or polyether diols are also suitable. The homopolymer of acrylic acid preferably has a weight average molecular weight of 1,000 to 90,000, more preferably 1,000 to 25,000. The copolymerizable monomer constituting the copolymer of acrylic acid and other copolymerizable monomers is not limited to the following, but examples thereof include, among monomers having a hydroxyl group and / or a carboxyl group, one or more selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, vinylacetic acid, crotonic acid, isocrotonic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid (excluding the case where only acrylic acid is used). It is preferable to have one or more ester-based monomers as the copolymerizable monomer. Salts of acrylic acid homopolymers and copolymers with primary, secondary, and tertiary amines include, but are not limited to, triethylamine salts, triethanolamine salts, glycine salts, etc. The degree of neutralization is preferably 20 to 90%, more preferably 40 to 60%, from the viewpoints of improving the stability of a mixed solution with other concomitant chemicals (such as a silane coupling agent) and reducing the amine odor. The weight average molecular weight of the acrylic acid polymer that forms the salt is not particularly limited, but is preferably in the range of 3,000 to 50,000. From the viewpoint of improving the bundling ability of the glass fibers, it is preferably 3,000 or more, and from the viewpoint of improving the properties of a molded article, it is preferably 50,000 or less. When polyamide is used as the thermoplastic resin, it is preferable to use a resin as the binder that has good wettability or a surface tension similar to that of the polyamide resin. Specifically, for example, an emulsion of a polyurethane resin, an emulsion of a polyamide resin, or a modified product thereof can be selected.

[0111] Thermoplastic resins used as binders include, but are not limited to, polyolefin resins, polyamide resins, polyurethane resins, polyacetal resins, polycarbonate resins, polyester resins, polyether ketone, polyether ether ketone, polyether sulfone, polyphenylene sulfide, thermoplastic polyetherimide, thermoplastic fluorine-based resins, and modified thermoplastic resins obtained by modifying these resins. If the thermoplastic resin used as the binder is the same type of thermoplastic resin and / or modified thermoplastic resin as the resin that coats the periphery of the reinforcing fibers, the adhesion between the glass fibers and the thermoplastic resin is improved after the molded article is formed, which is preferable.

[0112] Furthermore, a modified thermoplastic resin is preferred as the thermoplastic resin used as a binder from the viewpoints of further improving the adhesion between the reinforcing fibers and the thermoplastic resin coating them, and reducing the proportion of the emulsifier component or eliminating the need for an emulsifier when the sizing agent is attached to the glass fibers as an aqueous dispersion. Here, the modified thermoplastic resin means a thermoplastic resin obtained by copolymerizing a different monomer component other than a monomer component capable of forming the main chain of the thermoplastic resin, in order to change the properties of the thermoplastic resin, thereby modifying the hydrophilicity, crystallinity, thermodynamic properties, etc. The modified thermoplastic resin used as the binder is not limited to the following, but examples thereof include modified polyolefin resins, modified polyamide resins, modified polyester resins, and the like.

[0113] The modified polyolefin resin used as a binder is a copolymer of an olefin monomer such as ethylene or propylene with a monomer copolymerizable with the olefin monomer, such as an unsaturated carboxylic acid and / or its ester, or a homopolymer of a monomer copolymerizable with the olefin monomer, such as an unsaturated carboxylic acid and / or its ester, and can be produced by a known method. It may be a random copolymer in which an olefin monomer is copolymerized with an unsaturated carboxylic acid and / or its ester, or a graft copolymer in which an unsaturated carboxylic acid is grafted onto an olefin. Examples of olefin monomers include, but are not limited to, ethylene, propylene, 1-butene, etc. These may be used alone or in combination of two or more. Examples of monomers copolymerizable with olefin-based monomers include unsaturated carboxylic acids such as acrylic acid, maleic acid, maleic anhydride, methacrylic acid, vinylacetic acid, crotonic acid, isocrotonic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid, and esters of these unsaturated carboxylic acids (methyl esters, ethyl esters, and the like). These may be used alone or in combination of two or more. When the modified polyolefin resin is a copolymer of an olefin monomer and a monomer copolymerizable with the olefin monomer, the monomer ratio is preferably 60 to 95 mass% of the olefin monomer and 5 to 40 mass% of the monomer copolymerizable with the olefin monomer, and more preferably 70 to 85 mass% of the olefin monomer and 15 to 30 mass% of the monomer copolymerizable with the olefin monomer, with the total mass of the copolymer being 100 mass%. If the olefin monomer is 60 mass% or more, the affinity with the matrix is ​​good, and if the mass% of the olefin monomer is 95 mass% or less, the water dispersibility of the modified polyolefin resin is good and it is easy to apply it uniformly to the reinforcing fibers.

[0114] In the modified polyolefin resin used as a binder, modified groups such as carboxyl groups introduced by copolymerization may be neutralized with a basic compound. Examples of basic compounds include, but are not limited to, alkalis such as sodium hydroxide and potassium hydroxide; ammonia; and amines such as monoethanolamine and diethanolamine. The weight-average molecular weight of the modified polyolefin resin used as a binder is not particularly limited, but is preferably 5,000 to 200,000, and more preferably 50,000 to 150,000. From the viewpoint of improving the bundling ability of glass fibers, a molecular weight of 5,000 or more is preferred, and from the viewpoint of emulsion stability when the resin is made water-dispersible, a molecular weight of 200,000 or less is preferred.

[0115] The modified polyamide resin used as a binder is a modified polyamide compound having a hydrophilic group such as a polyalkylene oxide chain or a tertiary amine component introduced into the molecular chain, and can be produced by a known method. When a polyalkylene oxide chain is introduced into the molecular chain, for example, it is produced by copolymerizing a polyethylene glycol, a polypropylene glycol, or the like, which is partially or completely modified with a diamine or a dicarboxylic acid.When a tertiary amine component is introduced, it is produced by copolymerizing, for example, aminoethylpiperazine, bisaminopropylpiperazine, α-dimethylamino ε-caprolactam, or the like.

[0116] The modified polyester resin used as a binder is a copolymer of polycarboxylic acid or its anhydride with polyol, and has hydrophilic groups in the molecular skeleton including the terminals, and can be produced by known methods. Examples of hydrophilic groups include polyalkylene oxide groups, sulfonate salts, carboxyl groups, and neutralized salts thereof. Examples of polycarboxylic acids or anhydrides thereof include aromatic dicarboxylic acids, sulfonate-containing aromatic dicarboxylic acids, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, trifunctional or higher functional polycarboxylic acids, and the like. Examples of aromatic dicarboxylic acids include, but are not limited to, phthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and phthalic anhydride. Examples of sulfonate-containing aromatic dicarboxylic acids include, but are not limited to, sulfoterephthalate, 5-sulfoisophthalate, and 5-sulfoorthophthalate. Examples of the aliphatic dicarboxylic acid or alicyclic dicarboxylic acid include, but are not limited to, fumaric acid, maleic acid, itaconic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, 1,4-cyclohexanedicarboxylic acid, succinic anhydride, and maleic anhydride. Examples of tri- or higher functional polycarboxylic acids include, but are not limited to, trimellitic acid, pyromellitic acid, trimellitic anhydride, and pyromellitic anhydride. Among these, from the viewpoint of improving the heat resistance of the modified polyester resin, it is preferable that 40 to 99 mol% of the total polycarboxylic acid components be aromatic dicarboxylic acids, and from the viewpoint of emulsion stability when the modified polyester resin is made into an aqueous dispersion, it is preferable that 1 to 10 mol% of the total polycarboxylic acid components be sulfonate-containing aromatic dicarboxylic acids.

[0117] Examples of polyols constituting the modified polyester resin include diols and tri- or higher functional polyols. Examples of diols include, but are not limited to, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, polybutylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, polytetramethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A or an alkylene oxide adduct thereof, etc. Examples of tri- or higher functional polyols include trimethylolpropane, glycerin, pentaerythritol, etc.

[0118] The copolymerization ratio of the polycarboxylic acid or its anhydride and the polyol that constitutes the modified polyester resin is preferably 40 to 60 mass% of the polycarboxylic acid or its anhydride and 40 to 60 mass% of the polyol, and more preferably 45 to 55 mass% of the polycarboxylic acid or its anhydride and 45 to 55 mass% of the polyol, where the total mass of the copolymerization components is 100 mass%. The weight average molecular weight of the modified polyester resin is preferably 3,000 to 100,000, and more preferably 10,000 to 30,000. From the viewpoint of improving the bundling ability of the glass fibers, it is preferably 3,000 or more, and from the viewpoint of emulsion stability when it is made water-dispersible, it is preferably 100,000 or less.

[0119] The polymer or thermoplastic resin used as the binder may be used alone or in combination of two or more kinds. With the total amount of binder being 100% by mass, it is preferable to use at least 50% by mass, and more preferably at least 60% by mass, of one or more polymers selected from homopolymers of acrylic acid, copolymers of acrylic acid and other copolymerizable monomers, and salts of these with primary, secondary, and tertiary amines.

[0120] When the sizing agent is composed of a silane coupling agent and a binder, the sizing agent is applied and attached in an amount of preferably 0.1 to 3 mass%, more preferably 0.2 to 2 mass%, and even more preferably 0.2 to 1 mass% as the total mass of the silane coupling agent and binder relative to 100 mass% of the glass fibers. From the viewpoint of controlling the bundling ability of the glass fibers and improving the interfacial adhesive strength, the amount of the sizing agent attached is preferably 0.1 mass% or more as the total mass of the silane coupling agent and binder relative to 100 mass% of the glass fibers, and from the viewpoint of yarn handleability, it is preferably 3 mass% or less. Furthermore, when the sizing agent is composed of a silane coupling agent, a lubricant, and a binder, the sizing agent is applied and attached in an amount of preferably 0.1 to 3 mass%, more preferably 0.2 to 2 mass%, and even more preferably 0.2 to 1 mass% as the total mass of the silane coupling agent, lubricant, and binder relative to 100 mass% of the glass fibers. From the viewpoint of controlling the bundling ability of the glass fibers and improving the interfacial adhesive strength, the amount of the sizing agent attached is preferably 0.1 mass% or more as the total mass of the silane coupling agent, lubricant, and binder relative to 100 mass% of the glass fibers, and from the viewpoint of yarn handleability, it is preferably 3 mass% or less.

[0121] (Composition of sizing agent for glass fiber) The amount of the silane coupling agent in the sizing agent for glass fibers is preferably 0.1 to 2 mass %, more preferably 0.1 to 1 mass %, and even more preferably 0.2 to 0.5 mass %, from the viewpoints of improving the bundling ability of the glass fibers, improving the interfacial adhesive strength, and improving the mechanical strength of the molded body. The amount of lubricant in the sizing agent for glass fibers is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, from the viewpoint of providing sufficient lubrication, and is preferably 1% by mass or less, more preferably 0.5% by mass or less, from the viewpoint of improving the interfacial adhesive strength and the mechanical strength of the molded product. The amount of binder in the sizing agent for glass fibers is preferably 1 to 25% by mass, more preferably 3 to 15% by mass, and even more preferably 3 to 10% by mass, from the viewpoints of controlling the bundling of the glass fibers, improving the interfacial adhesive strength, and improving the mechanical strength of the molded body.

[0122] When glass fibers are used as the reinforcing fibers and the sizing agent is composed of a silane coupling agent, a lubricant, and a binder, the sizing agent for the glass fibers preferably contains 0.1 to 2 mass% of the silane coupling agent, 0.01 to 1 mass% of the lubricant, and 1 to 25 mass% of the binder, respectively, and it is preferable to dilute these components with water to adjust the total mass to 100 mass%.

[0123] (Use of sizing agent for glass fiber) The sizing agent for glass fibers may be prepared in any form, such as an aqueous solution, a colloidal dispersion, or an emulsion using an emulsifier, depending on the mode of use. From the viewpoint of improving the dispersion stability and heat resistance of the sizing agent, however, it is preferably prepared in the form of an aqueous solution. The glass fibers as the reinforcing fibers constituting the molded body of this embodiment can be continuously obtained by applying the above-mentioned sizing agent to glass fibers using a known method such as a roller-type applicator in a known glass fiber manufacturing process, and then drying the produced glass fibers.

[0124] When other reinforcing fibers are used, the type and amount of sizing agent that can be used for glass fibers and carbon fibers may be appropriately selected depending on the characteristics of the reinforcing fibers, and it is preferable to use the type and amount of sizing agent that conforms to the sizing agent used for carbon fibers.

[0125] When glass fiber is used, the content of the resin composition in the prepreg of this embodiment is preferably 15 to 80% by mass, more preferably 20 to 35% by mass, and even more preferably 20 to 30% by mass, from the viewpoint of mechanical strength. From the same viewpoint, the content of reinforcing fiber in the prepreg of this embodiment is preferably 20 to 85% by mass, more preferably 65 to 80% by mass, and even more preferably 70 to 80% by mass. In particular, when carbon fiber is used as the reinforcing fiber, from the same viewpoint, the content of carbon fiber in the prepreg of this embodiment is preferably 20 to 50% by mass, more preferably 20 to 40% by mass, and even more preferably 20 to 30% by mass. From the same viewpoint, the content of glass fiber in the prepreg of this embodiment is preferably 50 to 80% by mass, more preferably 60 to 80% by mass, and even more preferably 70 to 80% by mass.

[0126] <Prepreg manufacturing method>

[0127] The method for producing a prepreg of this embodiment includes the following steps: a capping step in which an amine compound (B) and a ketone compound (C) are subjected to a condensation reaction to form a ketimine bond between at least one primary amino group of a portion of the amine compound (B) and a ketone group of the ketone compound (C), thereby capping at least one primary amino group of a portion of the amine compound (B); a synthesis step in which compound (A), the amine compound (B) that has been subjected to the capping step, and optionally other monomers within the scope of the object of the invention are dissolved in a ketone solvent, mixed, and stirred to synthesize a resin and obtain a resin liquid; and an impregnation step in which the resin liquid obtained in the synthesis step is placed in a resin bath and reinforcing fibers are immersed in the resin liquid in the resin bath to impregnate the reinforcing fibers with the resin liquid.

[0128] (Capping process) The capping step is a step in which amine compound (B) is subjected to a condensation reaction with ketone compound (C) to form a ketimine bond between at least one primary amino group of a part of amine compound (B) and a ketone group of ketone compound (C), thereby preventing the primary amino group that has formed the ketimine bond from immediately reacting with compound (A) and other monomers that are optionally blended in the subsequent synthesis step, and may be the same as the capping step in the above-mentioned resin production method. In this way, by forming a ketimine bond in at least one primary amino group of a portion of the amine compound (B) (capping the primary amino group), the capped primary amino group does not react immediately when the compound is mixed with compound (A) and any other optional monomers and stirred, thereby delaying the resin curing reaction (extending the time it takes for the resin to harden). This allows the resin to be sufficiently impregnated into the reinforcing fibers in the subsequent impregnation step, allowing the resin solution in the resin bath to be used for a long period of time without replacement, thereby enabling successful continuous production of prepregs. Furthermore, the resulting prepregs maintain their tackiness for a long period of time, resulting in good adhesion between prepregs and enabling successful production of molded articles using the prepregs.

[0129] (synthesis process) The synthesis step is a step in which compound (A), an amine compound (B) that has undergone a capping step (a mixture of an amine compound in which none of the primary amino groups is capped and a ketimine compound (D) that is an amine compound in which at least one primary amino group is capped), and optionally other monomers within the scope of the object of the invention are dissolved in a ketone-based solvent, mixed, and stirred to synthesize a resin and obtain a resin liquid. The ketone-based solvent is a compound having a ketone group that is preferably contained in the above-mentioned prepreg, and is not particularly limited. However, since the condensation reaction (imidization reaction) between the primary amino group of the amine compound (B) and the ketone group of the ketone compound (C) in the capping step is an equilibrium reaction as described above, it is preferable to use the ketone compound (C) as the ketone-based solvent as well. The synthesis temperature may be room temperature (20 to 25°C). In the subsequent impregnation step, from the viewpoint of more thoroughly impregnating the reinforcing fibers with the resin liquid (resin) and allowing the resin liquid in the resin bath to be used for a longer period of time without replacement, it is preferable to transfer the resin liquid to the resin bath (transition to the impregnation step) within a range of 10 to 60 minutes from the start of mixing and stirring the monomers in the synthesis step.

[0130] (Impregnation process) The impregnation step is a step in which the reinforcing fibers are immersed in a resin liquid in a resin bath to impregnate the reinforcing fibers with the resin liquid (resin). Impregnation using a resin bath can reduce the removal of capping by the ketone compound (C) during the impregnation step compared to other impregnation methods such as coating or spraying, and allows prepregs to be produced continuously over a longer period of time. The time for which the reinforcing fibers are immersed in the resin bath is not particularly limited, and may be set appropriately within a range that allows the resin to be sufficiently impregnated into the reinforcing fibers.

[0131] <Molded body> The molded article of this embodiment is a molded article (fiber reinforced composite material) obtained by molding the prepreg of this embodiment described above. The molded article of the present embodiment contains a resin composition containing the resin of the present embodiment having the above-described three-dimensional crosslinked structure, and therefore has sufficient mechanical properties, heat resistance, and chemical resistance, while allowing chemical recycling of the resin and reinforcing fibers. Therefore, the molded article of the present embodiment can be used in a wide variety of applications, including high-pressure tanks (hydrogen tanks, gas tanks, etc.), building materials (repair sheets for construction and civil engineering, structural materials, etc.), sporting goods (golf clubs, face plates, snowboards, surfboards, protectors, tennis rackets, fishing rods, helmets, etc.), as well as various automobile parts (doors, bonnets, tailgates, side fenders, side panels, fenders, energy absorbing members, trunk lids, hard tops, side mirror covers, spoilers, diffusers, ski carriers, engine cylinder covers, engine hoods, chassis, air spoilers, propeller shafts, oil The material can be suitably used for automobile parts (pans, seat pans, pumps, cylinder head covers, gearboxes, battery cases, coil covers, non-contact charging covers, housings for electronic components, etc.), aircraft parts (interiors, inner and outer panels of wings in wing trucks, roofs, floors, etc., aero parts such as side skirts attached to automobiles and motorcycles, window frames, luggage racks, seats, floor panels, wings, propellers, fuselages, etc.), railway parts (outer panels for vehicles such as noses, roofs, side panels, doors, bogie covers, side skirts, luggage racks, seats, etc.), robot parts (robot arms, battery boxes, etc.), etc.

[0132] The method for producing the molded body of the present embodiment is not particularly limited, and the molded body may be obtained by, for example, winding the prepreg of the present embodiment around a liner (mold) using a filament winding method (dry method), a sheet winding method (dry method), or the like, curing the resin in a heating furnace or a heat press, or the like, and then removing the liner (mold). The method for winding the liner is not particularly limited, and any known method can be used, such as hoop winding, low-angle helical winding, or high-angle helical winding. When curing the resin using a heating furnace, the temperature and time may be set as appropriate, for example, 120 to 250°C for 1 to 6 hours. When curing the resin by hot compression pressing using a heat press or the like, the temperature, pressure, and time may also be set as appropriate, for example, 120 to 250°C, 1 to 5 MPa, and 1 to 6 hours. [Example]

[0133] The present invention will be described in more detail below with reference to examples. However, it goes without saying that the present invention is not limited to these examples and can be practiced in various modified forms within the scope of the present invention.

[0134] The measurement methods used in the examples and comparative examples are as follows.

[0135] [Capping ratio in monomer state] For ketimine compounds (partially capped amine compounds), under the following measurement conditions 1 H-NMR measurement was carried out, and the percentage of capping in the monomer state was calculated. 1 H-NMR measurement conditions: Measurement equipment: JEOL "ESCA500 equipment" Observation kernel: 1 H Solvent: deuterated chloroform Reference substance: TMS (0.0ppm) Observation frequency: 500MHz( 1 H) Pulse width: 45° Wait time: 5 seconds Accumulation count: 16 times After that, IR measurement was performed on the ketimine compound (partially capped amine compound) whose capping ratio was now known, and the peak at 1650 cm derived from the capped amino group was detected. -1 The peak absorbance A (NH bending vibration) near 3000 cm is due to the uncapping amino group. -1The relationship between the IR absorbance and the capping ratio was calculated from the ratio (A / B) of the absorbance to the peak absorbance B (NH stretching vibration) in the vicinity. Capping ratio in the monomer state X (mol%) = (A / B) × 100 [Capping ratio in prepreg] The prepreg was subjected to IR measurement using an infrared spectrophotometer ("Fourier transform infrared spectrophotometer FT / IR-4100" manufactured by JASCO Corporation). After subtracting the spectrum of the IR measurement results of the prepreg after molding from the obtained spectrum, the 1650 cm spectrum derived from the capped amino group was obtained. -1 The peak absorbance A' (NH bending vibration) near 3000 cm is due to the non-capped amino group. -1 The capping ratio in the prepreg was calculated from the following formula using the ratio (A' / B') of the peak absorbance B' (NH stretching vibration) in the vicinity of the capping ratio. Capping ratio in prepreg Y (mol%) = (A' / B') × (X (mol%)) ÷ (A / B) The capping ratio in the resin composition can be considered to be equivalent to the capping ratio determined in the prepreg state.

[0136] (Content of compounds having ketone groups in prepreg) The produced prepreg (after drying in a vacuum dryer at 80°C for 30 minutes) was heated from 30°C to 200°C at a rate of 20°C / min using a thermogravimetric analyzer (PerkinElmer "TG-DTA2500"), and the heat weight loss rate (mass%) at 200°C measured at this time was taken as the solvent content (mass%) in the prepreg.

[0137] (Resin impregnation into fibers) The obtained molded body (carbon fiber reinforced composite material) was cut out, and the cut cross section was observed at a magnification of 500 times using an optical microscope (Keyence Corporation "VHX-500") Five cross sections were observed, and the impregnation was evaluated according to the following evaluation criteria. Evaluation criteria: A (excellent): No voids with a diameter of 1 μm or more. B (Good): There are 1 to 3 voids with a diameter of 1 μm or more C (acceptable): 3 to less than 10 voids with a diameter of 1 μm or more D (poor): There are 10 or more voids with a diameter of 1 μm or more.

[0138] (Continuous operation time) A resin liquid with the same composition as the resin liquid in the resin bath was prepared and stirred at room temperature. The time until the stirrer stopped rotating was measured and used as the time during which prepregs could be continuously produced (continuous operation time).

[0139] (Prepreg tack retention time) Immediately after the prepreg was produced (immediately after the carbon fiber was impregnated with the resin liquid, without drying), a test piece measuring 5 cm in length and 5 cm in width was cut from the prepreg, and a portion of the test piece (approximately 1 / 4 of the entire surface) was attached to the remaining prepreg. After 1 hour, the test piece was peeled off, and the same portion of the test piece was reattached to a different portion of the remaining prepreg. This procedure was repeated, and the time from immediately after the prepreg was produced until the test piece could no longer be peeled off was taken as the tack retention time, and was evaluated according to the following criteria. Evaluation criteria: A (Excellent): Tackiness retention time was 10 hours or more. B (Good): Tackiness retention time was 6 hours or more and less than 10 hours. C (Acceptable): Tackiness retention time was 4 hours or more and less than 6 hours. D (poor): Tackiness retention time was less than 4 hours.

[0140] (Curing time during molding) The prepared prepreg (after drying in a vacuum dryer at 80°C for 30 minutes) was wrapped around a metal plate, hot-pressed at 230°C and 5 MPa for 25 minutes, and then cooled for 10 minutes to obtain a plate-shaped molded product (carbon fiber reinforced composite material). The time from immediately after molding until the prepreg layers no longer peeled off was measured, which was taken as the cure time during molding, and evaluated according to the following criteria. Evaluation criteria: A (excellent): The hardening time during molding was 4 hours or less. B (Good): The hardening time during molding was more than 4 hours and not more than 6 hours. C (poor): The setting time during molding was more than 6 hours, or molding was poor or impossible.

[0141] The materials used in the examples and comparative examples are as follows.

[0142] [Compound (A)] Ethylene glycol-1,2-bisacetoacetate (EGAA) Ethylene glycol (diol type, Fujifilm Wako Pure Chemical Industries, Ltd., 18.6 g, 0.3 mol) and tert-butyl acetoacetate (Tokyo Chemical Industry Co., Ltd., 100 g, 0.632 mol) were placed in a 300 mL four-neck flask and stirred with a stirring blade under Ar flow. The temperature was then raised to 130 °C in an oil bath, and the pressure in the system was gradually reduced to 68 hPa. After heating and reducing pressure for 4 hours, the external temperature was increased to 130 °C and the pressure was reduced to 3 hPa to distill off the unreacted tert-butyl acetoacetate. After heating and reducing pressure for 2 hours, the flask was allowed to cool to room temperature, and the resin ethylene glycol acetoacetate diester (EGAA) was recovered from the flask (recovery amount: 66.3 g, 96% yield). Trimethylolpropane trisacetoacetate (TMPAA) Trimethylolpropane (69.5 g) and tert-butyl acetoacetate (368.5 g) were placed in a 300 mL four-neck flask and stirred with a stirring blade under Ar flow. The temperature was then raised to 130 °C in an oil bath, and the system was gradually depressurized to 68 hPa. After heating and depressurization for 4 hours, the system was heated to 130 °C and depressurized to 3 hPa to distill off unreacted tert-butyl acetoacetate. After heating and depressurization for 2 hours, the system was allowed to cool to room temperature, and trimethylolpropane triacetoacetate (TMPAA) was recovered from the flask (recovery yield: 193.9 g, 97%). Terephthalaldehyde (TPA): manufactured by Tokyo Chemical Industry Co., Ltd. Triketone (TK) compounds Dimedone (74 g, 0.75 mol), adipic acid (37 g, 0.25 mol), and N,N-dimethyl-4-aminopyridine (DMAP) (92 g, 0.75 mol) were dissolved in methylene chloride (250 mL), and a solution of N,N'-dicyclohexylcarbodiimide (DCC) (124 g, 0.6 mol) dissolved in methylene chloride (600 mL) was added and the reaction was carried out at room temperature for 4 hours. The precipitated white solid was removed by filtration, and a 3% (w / w) aqueous hydrochloric acid solution was added to separate the layers, and the organic layer was recovered. The solvent in the resulting organic layer was removed, yielding a pale yellow solid. Recrystallization was carried out using a mixed solvent of ethyl acetate and hexane to obtain a white solid (87.9 g, 90% yield).

[0143] [Amine compound (B)] 4,4-Methylenebiscyclohexylamine (MBCA): Fujifilm Wako Pure Chemical Industries, Ltd. Trimethylhexamethylenediamine (2,2,4-, 2,4,4-mixture) (TMHMDA): manufactured by Tokyo Chemical Industry Co., Ltd. Tris(2-aminoethyl)amine (TREN): manufactured by Tokyo Chemical Industry Co., Ltd.

[0144] [Capping agents and solvents] (Ketone Compound (C)) Methyl ethyl ketone (MEK): manufactured by Tokyo Chemical Industry Co., Ltd., boiling point 80°C, vapor pressure 11 kPa (@20°C) Methyl isobutyl ketone (MIBK): manufactured by Tokyo Chemical Industry Co., Ltd., boiling point 116°C, vapor pressure 2.1 kPa (at 20°C) Methyl propyl ketone (MIPK): manufactured by Tokyo Chemical Industry Co., Ltd., boiling point 101°C, vapor pressure 1.6 kPa (at 20°C) Dibutyl ketone (DIBK): manufactured by Tokyo Chemical Industry Co., Ltd., boiling point 163°C, vapor pressure 0.2 kPa (at 20°C) (Other capping agents) Acetophenone (AcPh): manufactured by Tokyo Chemical Industry Co., Ltd.

[0145] [Reinforced fiber] Carbon fiber cloth (ASA-80I manufactured by Sakai Ovex Co., Ltd.)

[0146] [Example 1] (Amine compound capping) 4,4-Methylenebiscyclohexylamine (MBCA) (15 g) was added to methyl ethyl ketone (MEK) (19.3 mL) and the reaction was carried out at 100 °C for over 4 hours while removing water from the system using a Dean-Stark apparatus. The temperature was then raised to 120 °C, and the remaining MEK was distilled off. The mixture was then dried in vacuo to obtain the ketimine compound (MBCA partially capped with MEK). (Resin synthesis) The ketimine compound (4.2 g) obtained above was dissolved in MEK (6.5 mL). Then, ethylene glycol acetoacetic acid diester (EGAA) (0.7 g) and trimethylolpropane tris-acetoacetate (TMPAA) (2.7 g) were added, and the mixture was stirred at room temperature for 3 hours or more to carry out a condensation reaction, synthesizing a resin. The resulting resin composition was dried in a vacuum dryer at 80°C for 2 hours and at 160°C for 4 hours. (Prepreg production) The ketimine compound (4.2 g) obtained above was dissolved in MEK (11.6 mL). Then, EGAA (0.7 g) and TMPAA (2.7 g) were added, and the mixture was stirred uniformly at room temperature for 10 minutes. The resin solution was then transferred to a metal resin bath. Next, within 5 minutes of transferring the resin solution, a carbon fiber cloth cut into a size of 70 cm long x 4 cm wide was passed through the resin solution in the resin bath at a speed of approximately 1 cm / sec. This allowed the carbon fiber to be impregnated with the resin solution (resin), yielding a prepreg. The prepreg was then dried in a vacuum dryer at 80°C for 30 minutes. (Production of Molded Body) The dried prepreg was wrapped around a metal plate and then hot pressed at 230° C. and 5 MPa for 30 minutes to obtain a plate-shaped molded product (carbon fiber reinforced composite material). The measurement results are shown in Table 1.

[0147] [Example 2] (Amine compound capping) MBCA (15 g) was added to methyl isobutyl ketone (MIBK) (22.4 mL) and the reaction was carried out at 110 °C for more than 2 hours while removing water from the system using a Dean-Stark apparatus. The temperature was then raised to 120 °C, and the remaining MIBK was distilled off. The mixture was then dried in vacuo to obtain a ketimine compound (MBCA partially capped with MIBK). (Resin synthesis) The ketimine compound (4.1 g) obtained above was dissolved in MIBK (6.5 mL). EGAA (0.7 g) and TMPAA (2.7 g) were then added, and the mixture was stirred at room temperature for 3 hours or more to cause a condensation reaction, synthesizing a resin. The resulting resin composition was dried in a vacuum dryer at 80°C for 2 hours and then at 160°C for 4 hours. (Prepreg production) The ketimine compound (4.1 g) obtained above was dissolved in MIBK (11.6 mL). Then, EGAA (0.7 g) and TMPAA (2.7 g) were added, and the mixture was stirred uniformly at room temperature for 10 minutes. The resin solution was then transferred to a metal resin bath. Next, within 5 minutes of transferring the resin solution, a carbon fiber cloth cut to a size of 70 cm long x 4 cm wide was passed through the resin solution in the resin bath at a speed of approximately 1 cm / sec. This allowed the carbon fiber to be impregnated with the resin solution (resin), yielding a prepreg. The prepreg was then dried in a vacuum dryer at 80°C for 30 minutes. (Production of Molded Body) The dried prepreg was wrapped around a metal plate and then hot pressed at 230° C. and 5 MPa for 30 minutes to obtain a plate-shaped molded product (carbon fiber reinforced composite material). The measurement results are shown in Table 1.

[0148] [Example 3] (Amine compound capping) MBCA (15 g) was added to MIBK (26.7 mL) and the reaction was carried out at 110 °C for more than 2 hours while removing water from the system using a Dean-Stark apparatus. The temperature was then raised to 120 °C, and the remaining MIBK was distilled off. The mixture was then dried in vacuo to obtain a ketimine compound (MBCA partially capped with MIBK). (Resin synthesis) The ketimine compound (4.8 g) obtained above was dissolved in MIBK (6.5 mL). EGAA (0.7 g) and TMPAA (2.7 g) were then added, and the mixture was stirred at room temperature for 3 hours or more to cause a condensation reaction, synthesizing a resin. The resulting resin composition was dried in a vacuum dryer at 80°C for 2 hours and then at 160°C for 4 hours. (Prepreg production) The ketimine compound (4.8 g) obtained above was dissolved in MIBK (11.6 mL). Then, EGAA (0.7 g) and TMPAA (2.7 g) were added, and the mixture was stirred uniformly at room temperature for 10 minutes. The resin solution was then transferred to a metal resin bath. Next, within 5 minutes of transferring the resin solution, a carbon fiber cloth cut into a size of 70 cm long x 4 cm wide was passed through the resin solution in the resin bath at a speed of approximately 1 cm / sec. This allowed the carbon fiber to be impregnated with the resin solution (resin), yielding a prepreg. The prepreg was then dried in a vacuum dryer at 80°C for 30 minutes. (Production of Molded Body) The dried prepreg was wrapped around a metal plate and then hot pressed at 230° C. and 5 MPa for 30 minutes to obtain a plate-shaped molded product (carbon fiber reinforced composite material). The measurement results are shown in Table 1.

[0149] [Example 4] A resin, a prepreg, and a molded article were obtained in the same manner as in Example 3, except that the capping of the amine compound was changed as follows. (Amine compound capping) MBCA (15 g) was dissolved in toluene (29 mL). MIBK (26.7 mL) was added, and the reaction was carried out at 110 °C for over 4 hours while removing water from the system using a Dean-Stark apparatus. The temperature was then raised to 120 °C, and the remaining MIBK and toluene were distilled off. The residue was then dried in vacuo to obtain the ketimine compound (MBCA partially capped with MIBK). The measurement results are shown in Table 1.

[0150] [Example 5] (Amine compound capping) MBCA (15 g) was added to methyl propyl ketone (MIPK) (23 mL) and the reaction was carried out at 100 °C for over 4 hours while removing water from the system using a Dean-Stark apparatus. The temperature was then raised to 120 °C, and the remaining MIPK was distilled off. The mixture was then dried in vacuo to obtain the ketimine compound (MBCA partially capped with MIPK). (Resin synthesis) The ketimine compound (4.8 g) obtained above was dissolved in MIPK (6.5 mL). EGAA (0.7 g) and TMPAA (2.7 g) were then added, and the mixture was stirred at room temperature for 3 hours or more to cause a condensation reaction, synthesizing a resin. The resulting resin composition was dried in a vacuum dryer at 80°C for 2 hours and then at 160°C for 4 hours. (Prepreg production) The ketimine compound (4.8 g) obtained above was dissolved in MIPK (11.6 mL). Then, EGAA (0.7 g) and TMPAA (2.7 g) were added, and the mixture was stirred uniformly at room temperature for 10 minutes. The resin solution was then transferred to a metal resin bath. Next, within 5 minutes of transferring the resin solution, a carbon fiber cloth cut to a size of 70 cm long x 4 cm wide was passed through the resin solution in the resin bath at a speed of approximately 1 cm / sec. This allowed the carbon fiber to be impregnated with the resin solution (resin), yielding a prepreg. The prepreg was then dried in a vacuum dryer at 80°C for 30 minutes. (Production of Molded Body) The dried prepreg was wrapped around a metal plate and then hot pressed at 230° C. and 5 MPa for 30 minutes to obtain a plate-shaped molded product (carbon fiber reinforced composite material). The measurement results are shown in Table 1.

[0151] [Example 6] (Amine compound capping) MBCA (15 g) was added to dibutyl ketone (DIBK) (37.2 mL) and the reaction was carried out at 110 °C for over 4 hours while removing water from the system using a Dean-Stark apparatus. The temperature was then raised to 170 °C, and the remaining DIBK was distilled off. The mixture was then dried in vacuo to obtain the ketimine compound (MBCA partially capped with DIBK). (Resin synthesis) The ketimine compound (4.8 g) obtained above was dissolved in DIBK (6.5 mL). EGAA (0.7 g) and TMPAA (2.7 g) were then added, and the mixture was stirred at room temperature for 3 hours or more to cause a condensation reaction, synthesizing a resin. The resulting resin composition was dried in a vacuum dryer at 80°C for 2 hours and then at 160°C for 4 hours. (Prepreg production) The ketimine compound (4.8 g) obtained above was dissolved in DIBK (11.6 mL). Then, EGAA (0.7 g) and TMPAA (2.7 g) were added, and the mixture was stirred uniformly at room temperature for 10 minutes. The resin solution was then transferred to a metal resin bath. Next, within 5 minutes of transferring the resin solution, a carbon fiber cloth cut into a size of 70 cm long x 4 cm wide was passed through the resin solution in the resin bath at a speed of approximately 1 cm / sec. This allowed the carbon fiber to be impregnated with the resin solution (resin), yielding a prepreg. The prepreg was then dried in a vacuum dryer at 80°C for 30 minutes. (Production of Molded Body) The dried prepreg was wrapped around a metal plate and then hot pressed at 230° C. and 5 MPa for 30 minutes to obtain a plate-shaped molded product (carbon fiber reinforced composite material). The measurement results are shown in Table 1.

[0152] [Example 7] In the preparation of the prepreg, a resin, a prepreg, and a molded article were obtained in the same manner as in Example 3, except that the drying time was changed to 2 hours. The measurement results are shown in Table 1.

[0153] [Example 8] (Amine compound capping) MBCA (7.0 g) and trimethylhexamethylenediamine (TMHMDA) (5.3 g) were added to MIBK (24.9 mL) and reacted at 110 °C for over 4 hours while removing water from the system using a Dean-Stark apparatus. The temperature was then raised to 120 °C, and the remaining MIBK was distilled off. The mixture was then dried in vacuo to obtain a mixture of ketimine compounds (a mixture of MBCA and TMHMDA capped with MIBK). (Resin synthesis) The mixture of ketimine compounds (3.1 g) obtained above was dissolved in MIBK (6.5 mL). Terephthalaldehyde (TPA) (9.9 g) was then added and stirred at room temperature for 3 hours or more to cause a condensation reaction, synthesizing a resin. The resulting resin composition was dried in a vacuum dryer at 80°C for 2 hours and at 160°C for 4 hours. (Prepreg production) The mixture of ketimine compounds (3.1 g) obtained above was dissolved in MIBK (11.6 mL). Then, TPA (9.9 g) was added, and the mixture was stirred uniformly at room temperature for 10 minutes. The resin solution was then transferred to a metal resin bath. Next, within 5 minutes of transferring the resin solution, a carbon fiber cloth cut into a size of 70 cm long x 4 cm wide was passed through the resin solution in the resin bath at a speed of approximately 1 cm / sec. This allowed the carbon fiber to be impregnated with the resin solution (resin), yielding a prepreg. The prepreg was then dried in a vacuum dryer at 80°C for 30 minutes. (Production of Molded Body) The dried prepreg was wrapped around a metal plate and then hot pressed at 230° C. and 5 MPa for 30 minutes to obtain a plate-shaped molded product (carbon fiber reinforced composite material). The measurement results are shown in Table 1.

[0154] [Example 9] (Amine compound capping) Tris(2-aminoethyl)amine (TREN) (10.4 g) was added to MIBK (26.7 mL) and the reaction was carried out at 110 °C for over 4 hours while removing water from the system using a Dean-Stark apparatus. The temperature was then raised to 120 °C, and the remaining MIBK was distilled off. The mixture was then dried in vacuo to obtain the ketimine compound (TREN partially capped with MIBK). (Resin synthesis) The ketimine compound (2.2 g) obtained above was dissolved in MIBK (6.5 mL). Triketone (TK) (3.9 g) was then added and stirred at room temperature for 3 hours or more to cause a condensation reaction, synthesizing a resin. The resulting resin composition was dried in a vacuum dryer at 80°C for 2 hours and at 160°C for 4 hours. (Prepreg production) The ketimine compound (2.2 g) obtained above was dissolved in MIBK (11.6 mL). Then, TK (3.9 g) was added, and the mixture was stirred uniformly at room temperature for 10 minutes. The resin solution was then transferred to a metal resin bath. Next, within 5 minutes of transferring the resin solution, a carbon fiber cloth cut into a size of 70 cm long x 4 cm wide was passed through the resin solution in the resin bath at a speed of approximately 1 cm / sec. This allowed the carbon fiber to be impregnated with the resin solution (resin), yielding a prepreg. The prepreg was then dried in a vacuum dryer at 80°C for 30 minutes. (Production of Molded Body) The dried prepreg was wrapped around a metal plate and then hot pressed at 230° C. and 5 MPa for 30 minutes to obtain a plate-shaped molded product (carbon fiber reinforced composite material). The measurement results are shown in Table 1.

[0155] [Comparative Example 1] (Resin synthesis) MBCA (2.7 g) was dissolved in MIBK (6.5 mL). EGAA (0.7 g) and TMPAA (2.7 g) were then added, and the mixture was stirred at room temperature for at least 3 hours to induce a condensation reaction, synthesizing a resin. The resulting resin composition was dried in a vacuum dryer at 80°C for 2 hours and then at 160°C for 4 hours. (Prepreg production) MBCA (2.7 g) was dissolved in MIBK (11.6 mL). EGAA (0.7 g) and TMPAA (2.7 g) were then added and stirred uniformly at room temperature for 10 minutes. The resin solution was then transferred to a metal resin bath. Within 5 minutes of transferring the resin solution, a carbon fiber cloth cut to a size of 70 cm long x 4 cm wide was passed through the resin solution in the resin bath at a speed of approximately 1 cm / sec. This allowed the carbon fiber to be impregnated with the resin solution (resin), yielding a prepreg. The prepreg was then dried in a vacuum dryer at 80°C for 30 minutes. (Production of Molded Body) The dried prepreg was wrapped around a metal plate and then hot pressed at 230° C. and 5 MPa for 30 minutes to obtain a plate-shaped molded product (carbon fiber reinforced composite material). The measurement results are shown in Table 1.

[0156] Comparative Example 2 (Amine compound capping) MBCA (15 g) was added to MIBK (17.5 mL) and the reaction was carried out at 110 °C for more than 2 hours while removing water from the system using a Dean-Stark apparatus. The temperature was then raised to 120 °C, and the remaining MIBK was distilled off. The mixture was then dried in vacuo to obtain the ketimine compound (MBCA partially capped with MIBK). (Resin synthesis) The ketimine compound (3.9 g) obtained above was dissolved in MIBK (6.5 mL). EGAA (0.7 g) and TMPAA (2.7 g) were then added, and the mixture was stirred at room temperature for at least 3 hours to carry out a condensation reaction, synthesizing a resin. The resulting resin composition was dried in a vacuum dryer at 80°C for 2 hours and then at 160°C for 4 hours. (Prepreg production) The ketimine compound (3.9 g) obtained above was dissolved in MIBK (11.6 mL). Then, EGAA (0.7 g) and TMPAA (2.7 g) were added, and the mixture was stirred uniformly at room temperature for 10 minutes. The resin solution was then transferred to a metal resin bath. Next, within 5 minutes of transferring the resin solution, a carbon fiber cloth cut to a size of 70 cm long x 4 cm wide was passed through the resin solution in the resin bath at a speed of approximately 1 cm / sec. This allowed the carbon fiber to be impregnated with the resin solution (resin), yielding a prepreg. The prepreg was then dried in a vacuum dryer at 80°C for 30 minutes. (Production of Molded Body) The dried prepreg was wrapped around a metal plate and then hot pressed at 230° C. and 5 MPa for 30 minutes to obtain a plate-shaped molded product (carbon fiber reinforced composite material). The measurement results are shown in Table 1.

[0157] Comparative Example 3 (Amine compound capping) MBCA (7 g) and TMHMDA (5.3 g) were dissolved in toluene (29 mL). AcPh (acetophenone) (22.9 mL) was added to the solution, and the reaction was carried out at 110 °C for over 4 hours while removing water from the system using a Dean-Stark apparatus. The temperature was then raised to 200 °C, and the remaining AcPh and toluene were distilled off. The mixture was then dried in vacuo to obtain a mixture of ketimine compounds (a mixture of MBCA and TMHMDA capped with AcPh). (Resin synthesis) The mixture of ketimine compounds (3.4 g) obtained above was dissolved in MIBK (6.5 mL). Then, TPA (1.3 g) was added and the mixture was stirred at room temperature for 3 hours or more to cause a condensation reaction, synthesizing a resin. The resulting resin composition was dried in a vacuum dryer at 80°C for 2 hours and at 180°C for 4 hours. (Prepreg production) The mixture of ketimine compounds (3.4 g) obtained above was dissolved in MIBK (11.6 mL). Then, TPA (1.3 g) was added, and the mixture was stirred uniformly at room temperature for 10 minutes. The resin solution was then transferred to a metal resin bath. Next, within 5 minutes of transferring the resin solution, a carbon fiber cloth cut into a size of 70 cm long x 4 cm wide was passed through the resin solution in the resin bath at a speed of approximately 1 cm / sec. This allowed the carbon fiber to be impregnated with the resin solution (resin), yielding a prepreg. The prepreg was then dried in a vacuum dryer at 80°C for 30 minutes. (Production of Molded Body) The dried prepreg was wrapped around a metal plate and then hot pressed at 230° C. and 5 MPa for 30 minutes to obtain a plate-shaped molded product (carbon fiber reinforced composite material). The measurement results are shown in Table 1.

[0158] [Table 1] [Industrial Applicability]

[0159] The resin composition of this embodiment has excellent fiber impregnation properties, allows for good continuous production of prepregs, and provides prepregs with excellent moldability, making it industrially applicable. Furthermore, molded articles obtained by molding the prepregs have sufficient mechanical properties, heat resistance, and chemical resistance, and the resin and reinforcing fibers can be chemically recycled. Therefore, the resin composition of this embodiment can be suitably used for high-pressure tanks, building materials, sporting goods, automobile parts, aircraft parts, railway parts, robot parts, and the like.

Claims

1. a monomer unit (a) derived from a compound (A) having two or more acetoacetate groups, aldehyde groups, or triketone structures, either singly or in combination, in the molecule; and a monomer unit (b) derived from an amine compound (B) having two or more primary amino groups in the molecule, the monomer unit (b) having a condensation bond between a part of the primary amino groups and a ketone group of a ketone compound (C) having a vapor pressure of 0.1 kPa or more at 20°C, a three-dimensional crosslinked structure in which an acetoacetate group, an aldehyde group, and / or a ketone group of a triketone structure of the compound (A) is condensed with a primary amino group of the amine compound (B); Resin and a ketimine compound (D) obtained by condensation bonding at least one primary amino group of an amine compound (B) having two or more primary amino groups in the molecule with a ketone group of a ketone compound (C) having a vapor pressure of 0.1 kPa or more at 20°C; Including, When the total of the primary amino groups of the amine compound (B) constituting the monomer unit (b) of the resin and the primary amino groups of the amine compound (B) constituting the ketimine compound (D) is taken as 100 mol %, the proportion of the primary amino groups condensed with the ketone groups of the ketone compound (C) is 50 mol % or more. A resin composition comprising:

2. A prepreg comprising the resin composition according to claim 1 and reinforcing fibers.

3. The prepreg according to claim 2 , comprising 1% by mass or more of a compound having a ketone group.

4. A method for producing the prepreg according to claim 2 or 3, a capping step of capping at least one primary amino group of a part of the amine compound (B) by subjecting the amine compound (B) to a condensation reaction with the ketone compound (C) to form a ketimine bond between at least one primary amino group of a part of the amine compound (B) and a ketone group of the ketone compound (C); a synthesis step of dissolving the compound (A) and the amine compound (B) that has been subjected to the capping step in a ketone-based solvent, mixing and stirring the mixture to synthesize a resin, thereby obtaining a resin liquid; an impregnation step in which the resin liquid obtained in the synthesis step is placed in a resin bath, and reinforcing fibers are immersed in the resin liquid in the resin bath to impregnate the reinforcing fibers with the resin liquid; A method for producing a prepreg, comprising:

5. A molded article obtained by molding the prepreg according to claim 2 or 3.

6. The molded article according to claim 5, which is a high-pressure tank, a construction material, a sporting goods, an automobile part, an aircraft part, a railway part, or a robot part.