Resin composition, resin cured product, and fiber-reinforced resin

Abstract

The present invention provides a resin composition, a resin cured product, and a fiber-reinforced resin, which can shorten stress relaxation time. To solve the technical problem, the resin composition contains an epoxy compound having two or more epoxy groups in the molecule, an acid anhydride, and a coordination compound in which an organic ligand coordinates with manganese (III). The resin cured product contains a resin having an ester group and a hydroxyl group, and a coordination compound in which an organic ligand coordinates with manganese (III). The fiber-reinforced resin (101) contains a resin (1) having an ester group and a hydroxyl group, a fiber (2) impregnated with at least the above resin, and a coordination compound (3) in which an organic ligand coordinates with manganese (III).

Description

Technical Field

[0001] This invention relates to resin compositions, cured resins, and fiber-reinforced resins. Background Technology

[0002] In recent years, there has been increased interest in resin compositions utilizing dynamic covalent bonds. Dynamic covalent bonds are covalent bonds, but they are covalent bonds that can undergo reversible breakage and re-bonding due to external stimuli such as heat and light. Attempts have been made to introduce this bond into the network structure of resins. In the cured resin product formed by curing the resin composition, the network structure changes due to dynamic covalent bonds. Therefore, when the cured resin product experiences stress such as deformation, it is hoped that this stress can be mitigated to suppress cracking.

[0003] By utilizing such "dynamic" covalent bonds, supramolecular formation and polymer construction that were previously impossible can be achieved. Of particular interest is that, because the involved bonds are covalent, the resulting bonds are much stronger than weak bonds such as hydrogen bonds seen in existing supramolecular molecules and their polymers, making it an important method for constructing new structures. Patent Document 1 describes a technique for resin compositions utilizing dynamic covalent bonds.

[0004] Patent Document 1 relates to a thermosetting resin capable of heat deformation and a thermosetting composite material containing the thermosetting resin. This composition can be obtained by contacting at least one curing agent selected from acid anhydrides with at least one thermosetting resin precursor material in the presence of at least one transesterification catalyst. The thermosetting resin precursor material contains hydroxyl and / or epoxy groups, and optionally, ester groups. The total molar amount of the transesterification catalyst is 5-25% of the total molar amount of hydroxyl and epoxy groups contained in the thermosetting precursor material. Patent Document 1 also relates to a processing method for the above-mentioned material, a manufacturing method for the above-mentioned material, and a method for reusing the above-mentioned material. Patent Document 1 further relates to a thermosetting resin for carrying out the above-mentioned methods and a novel solid form of the composition.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Publication No. 2014-503670 (especially the abstract of the specification) Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] In Patent Document 1, zinc acetylacetonate (section 0094) is described as a suitable transesterification catalyst. However, details will be explained later, but when using zinc acetylacetonate, the bond recombination rate is slow, and therefore the stress relief time (stress relief time) is prolonged when stress is applied.

[0010] The technical problem to be solved by the present invention is to provide a resin composition, a cured resin, and a fiber-reinforced resin that can shorten the stress relief time.

[0011] Technical solutions for solving technical problems

[0012] The resin composition of the present invention contains an epoxy compound having two or more epoxy groups in its molecule, an acid anhydride, and a coordination compound formed by coordinating an organic ligand with manganese(III). Other solutions are described in the specific embodiments.

[0013] According to the present invention, a resin composition, a cured resin, and a fiber-reinforced resin capable of shortening stress relief time are provided. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the fiber-reinforced resin of the present invention.

[0015] Figure 2 It is a graph showing the stress relief time of Examples 1 to 6 and Comparative Examples 1 and 2. Detailed Implementation

[0016] Hereinafter, specific embodiments (referred to as embodiments) will be described with appropriate reference to the accompanying drawings. In the description of one embodiment below, other embodiments applicable to that embodiment will also be described appropriately. The present invention is not limited to the following single embodiment; different embodiments can be combined with each other, or arbitrarily modified within a range that does not significantly impair the effects of the present invention. Furthermore, the same symbols are used for the same parts, and repeated descriptions are omitted. Articles with the same function are given the same name. The illustrations are merely illustrative; for ease of illustration, changes to the actual configuration are sometimes made within a range that does not significantly impair the effects of the present invention.

[0017] First, the relationship between the resin composition, the cured resin, and the fiber-reinforced resin of the present invention will be explained. Hereinafter, unless otherwise specified, when referred to as "resin composition," "cured resin," and "fiber-reinforced resin," they all refer to "the resin composition of the present invention," "the cured resin of the present invention," and "the fiber-reinforced resin of the present invention."

[0018] The resin composition becomes a cured resin product upon curing, as detailed later. A cured resin product containing ester and hydroxyl groups can be obtained through the reaction of the epoxy compound contained in the resin composition with an anhydride. In this case, when the amount of epoxy groups is used as a reference, the epoxy compound and anhydride are used, for example, in amounts where the anhydride is below the stoichiometric ratio. The anhydride typically functions as a curing agent; therefore, this reaction is a curing reaction and is usually carried out by heating. Fiber-reinforced resins are obtained by reinforcing the cured resin product with fibers; the description of cured resin products, except those containing fibers, also applies.

[0019] Details of the cured resin and the fiber-reinforced resin will be explained later. Both have ester groups and hydroxyl groups, and undergo transesterification reactions as shown in Formula (1) below, for example, when deformed due to applied stress. The structural formula shown in Formula (1) is an example of a structure obtained through transesterification, and R, R′, and R″ represent arbitrary chemical structures. On both the left and right sides, the structures of the first term and the second term can exist in the same molecule or in different molecules.

[0020]

[0021] The reaction of formula (1) is typically carried out in the presence of the coordination compound of the present invention, which acts as a catalyst, for example by external stimulation such as heating, resulting in ester bond recombination. Such recombined covalent bonds are referred to as dynamic covalent bonds. By using the materials shown below as the ester bonds, hydroxyl groups, and coordination compounds of the present invention, respectively, and by appropriately adjusting the amounts, the transesterification reaction can proceed rapidly even in cured resin products, thus shortening the stress relief time.

[0022] The stress relief time of this invention is defined as the time it takes for the residual stress in a test piece to decrease to 30% of the applied stress, based on the initial stress applied to a test piece made of a resin-cured material containing resin and coordination compounds. Stress relief occurs due to the reorganization of ester bonds (reaction of formula (1)) caused by the applied stress, thereby reducing the stress (i.e., affinity). The stress relief time is used as an indicator to evaluate the stress relief effect. Specific methods for measuring the stress relief time are described later in the examples.

[0023] The resin composition of the present invention contains an epoxy compound having two or more epoxy groups in its molecule, an acid anhydride, and a coordination compound formed by coordination of an organic ligand with manganese(III). Among these, the epoxy groups in the epoxy compound react with the acid anhydride, for example, by heating, thereby generating ester groups and hydroxyl groups in the cured resin. The resin composition preferably has fluidity, specifically, for example, being a liquid, and the epoxy compound, acid anhydride, and coordination compound are miscible and become homogeneous. The resin composition may also contain a solvent if desired.

[0024] Examples of epoxy compounds include, for example, bisphenol A type resins, phenolic varnish resins, alicyclic resins, and glycidylamine resins. Specifically, examples include, at least one of, but not limited to, bisphenol A diglycidyl ether phenol, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, resorcinol diglycidyl ether, hexahydrobisphenol A diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, diglycidyl phthalate, diglycidyl dimeric acid, triglycidyl isocyanurate, tetraglycidyl diaminodiphenylmethane, tetraglycidyl m-xylenediamine, cresol phenolic varnish polyglycidyl ether, tetrabromobisphenol A diglycidyl ether, and bisphenol hexafluoroacetone diglycidyl ether.

[0025] Among these, the epoxy compound is preferably bisphenol A diglycidyl ether or phenolic varnish resin.

[0026] Examples of acid anhydrides include, but are not limited to, at least one of the following: phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3-dodecenylsuccinic anhydride, octenylsuccinic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, dodecylsuccinic anhydride, chloric anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bis(triphenylene trioxide), methylcyclohexene tetracarboxylic anhydride, trimellitic anhydride, polyazelaic anhydride, or derivatives thereof.

[0027] Among these, the anhydride preferably includes at least one of phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, or derivatives thereof.

[0028] When the resin composition is cured, as described above, when the amount of epoxy groups is used as a reference, it is preferable, for example, to use the epoxy compound and the acid anhydride in an amount where the acid anhydride is below the stoichiometric ratio. By setting it in this way, in the reaction between the epoxy groups and the acid anhydride, because the amount of acid anhydride is insufficient, the epoxy groups can react with moisture in the air, for example, to generate hydroxyl groups.

[0029] The content of acid anhydride in the resin composition is, for example, 30 mol% or more, preferably 40 mol% or more, relative to the epoxy group, with an upper limit of, for example, 70 mol%, preferably 60 mol%. By making the amount of acid anhydride as described above, hydroxyl groups can be generated after polymerization, thus enabling efficient reconstruction of the polymer structure using dynamic covalent bonds. In particular, by making it 30 mol% or more, sufficient curing can be achieved. Furthermore, by making it 70 mol% or less, the amount of hydroxyl groups generated can be increased, facilitating transesterification.

[0030] The coordination compounds of the present invention are generally compounds that catalyze the transesterification reaction shown in formula (1) above, and as described above, are, for example, organometallic coordination compounds formed by the coordination of an organic ligand with manganese (III). The organic ligand is a carbon-containing ligand that binds to manganese (III) in a manner that surrounds manganese (III). Compared with other catalysts that promote transesterification reactions, the coordination compounds of the present invention have high solubility for epoxides and acid anhydrides, and thus high catalytic activity.

[0031] For example, the inventors of this invention conducted research and found that when using coordination compounds that are identical except for the use of manganese (II) instead of manganese (III), the solubility and catalytic activity are lower compared to the coordination compounds of this invention containing manganese (III). This is likely because the inclusion of manganese (III), a trivalent metal, increases the number of organic ligands that contribute to solubility, thereby improving solubility. Furthermore, manganese (III) exhibits catalytic activity by coordinating with the oxygen atom of the ester group, and the use of manganese (III) with its strong coordinating ability can enhance catalytic activity. Therefore, it can be considered that these effects cannot be achieved when using coordination compounds containing divalent metals or coordination compounds containing trivalent metals other than manganese (III), and the effect of shortening the stress relief time cannot be obtained. Therefore, the coordination compound of this invention, when added in the same amount as other catalysts, can be added in large quantities compared to other catalysts, thereby increasing the reaction rate of transesterification, and thus shortening the stress relief time by accelerating stress relief.

[0032] The coordination compound of the present invention is preferably uniformly dispersed in at least one, preferably both, of the epoxy compound or acid anhydride contained in the resin composition. Specifically, examples include at least one of manganese acetylacetonate (III), manganese naphthenate (III), manganese isopropoxide (III), manganese acetate (III), manganese di(2-ethylhexanoate) (III), manganese naphthalenedicarboxylate (III), etc., but are not limited to these.

[0033] Among these, considering their versatility and ease of availability, the coordination compound preferably contains at least one of manganese acetylacetonate (III), manganese acetate (III), or manganese naphthalene(III).

[0034] The content of the coordination compound in this invention is not particularly limited, but is preferably 5 mol% or more relative to the epoxy group, more preferably 10 mol% or more, more preferably 15 mol% or more, and as an upper limit thereto, for example, 30 mol%, more preferably 25 mol%. By setting it to 5 mol% or more, the catalytic effect achieved by the coordination compound can be increased. In particular, by setting it to 10 mol% or more, the amount of coordination compound can be increased, further shortening the stress relief time. Furthermore, by setting it to 15 mol% or more, the amount of coordination compound can be particularly increased, making the stress relief time particularly short. Additionally, by setting it to 30 mol% or less, it can be sufficiently dissolved in at least one of the epoxy compound or acid anhydride contained in the resin composition, and a homogeneous resin composition can be easily obtained.

[0035] In addition to the aforementioned epoxy compounds, acid anhydrides, and coordination compounds, the resin composition may contain additives such as curing accelerators, flame retardants, antioxidants, light stabilizers, dispersants, lubricants, plasticizers, antistatic agents, pigments, and dyes, as needed. Furthermore, the resin composition may also contain inorganic fillers. Examples of inorganic fillers include powders of fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, aluminum nitride, boron nitride, beryllium oxide, zircon, forsterite, steatite, spinel, andalusite, titanium dioxide, etc., as well as beads and glass fibers formed from these materials into spherical shapes. Moreover, there are no limitations on the shape of the inorganic filler; spherical or flake-like shapes can be used.

[0036] The resin cured product of the present invention can be obtained, for example, by curing a resin composition, containing, for example, a resin having ester and hydroxyl groups generated by the reaction of epoxy groups with acid anhydrides. The ester and hydroxyl groups may also be present before the reaction of the epoxy groups with acid anhydrides. Furthermore, since the resin cured product contains, for example, coordination compounds contained in the resin composition, coordination compounds formed by the coordination of organic ligands with manganese(III) are also present. The coordination compounds are generally dispersed in the resin cured product.

[0037] The stress relief time when applied to a test piece formed from a resin-cured material (i.e., a test piece containing resin and coordination compounds) is, for example, 11 minutes or less. Preferably, the stress relief time is 9 minutes or less. By setting it to 9 minutes or less, the stress relief time can be significantly shortened compared to conventional resin-cured materials.

[0038] The cured resin can be used in various coatings, molding resins for transformers, molding sealants, and motor coils. When used as a coating for moving objects such as cars and trams, it can repair damage through moderate heating. Heating causes an ester exchange reaction in the damaged area, allowing temporarily broken joints to reconnect and thus repairing the damage. It can also be used in coatings for building materials.

[0039] Cracks can occur in the molding resin material used in transformers due to deformation caused by the difference in expansion coefficients between the resin and other components during molding. However, reducing the crosslinking density of the resin to improve crack resistance results in decreased heat resistance. Using additives such as rubber particles and fillers increases resin viscosity, making it easier for voids to form during injection molding, which can then become the starting point for cracks, and also reduces electrical insulation. However, these technical problems can be overcome using the cured resin of this invention. Furthermore, small cracks that develop after use can be repaired by heating.

[0040] In molded sealing materials, there is a technical problem of crack resistance due to the difference in expansion coefficients between the resin and other components such as metals. Methods to improve the crack resistance of resins used in molded sealing materials include reducing the crosslinking density of the resin and using additives such as rubber particles and fillers to reduce the toughness value. However, these methods cannot suppress cracking caused by deformation during the use of the product after molding. Therefore, the cured resin of the present invention alleviates the stress caused by bond reorganization during transesterification due to the heat generated during product use, reduces deformation between the product and other components after molding, and suppresses cracking.

[0041] Furthermore, there is a technical problem with electric motor coils cracking due to electromagnetic vibrations, etc. However, when using the resin cured product of the present invention, the heat generated during the use of the electric motor causes bond recombination, thus mitigating the deformation, i.e., stress, that causes cracking.

[0042] For these products, by applying the resin cured product of the present invention, stress can be mitigated at a high speed compared with existing resin cured products that utilize this reaction, thus improving crack resistance and repairability.

[0043] Figure 1 This is a schematic diagram of the fiber-reinforcing resin 101 of the present invention. The fiber-reinforcing resin 101 comprises a resin 1 having ester groups and hydroxyl groups, a fiber 2 at least impregnated with the resin 1, and a coordination compound 3 formed by coordinating an organic ligand with manganese (III). The meaning of resin 1 is the same as that of resin described in the resin cured product of the present invention, and the coordination compound 3 is dispersed in the resin 1. Therefore, the fiber 2 is impregnated with resin 1 in which the coordination compound 3 is dispersed.

[0044] As fiber 2, examples include inorganic fibers and organic fibers. Inorganic fibers include glass fiber, asbestos fiber, carbon fiber, silica fiber, silica-alumina fiber, alumina fiber, zirconium oxide fiber, potassium titanate fiber, Tyranno fiber, silicon carbide fiber, and metal fiber. Organic fibers include high-strength polyethylene fiber, polyacetal fiber, aliphatic or aromatic polyamide fiber, polyacrylate fiber, fluorine fiber, boron fiber, polyacrylonitrile fiber, aromatic polyamide fiber, and PBO (poly(p-phenylenebenzodioxazole)) fiber. These fibers can be used alone or in combination of two or more.

[0045] Among these, fiber 2 preferably comprises at least one of aramid fiber, glass fiber, or organic fiber (such as carbon fiber). By including at least one of these, the mechanical strength of fiber-reinforced resin 10 can be improved. Carbon fibers can be classified according to their raw materials into carbon fibers derived from synthetic polymers (polyacrylonitrile-based, polyvinyl alcohol-based, rayon-based carbon fibers, etc.) and carbon fibers derived from minerals (pitch-based carbon fibers, etc.). Among these, from the viewpoint of mechanical strength, carbon fibers derived from synthetic polymers are preferred.

[0046] Fiber 2 can be used in the form of continuous fiber, long fiber, short fiber, chopped fiber, etc., and in the form of unidirectional material, plain weave fabric, non-woven fabric, etc. In addition, it is sometimes added directly to resin 1, but in this embodiment, it is not limited to these fiber shapes and fiber states.

[0047] Fiber-reinforced resin 101 exhibits a reversible transesterification reaction in resin 1. As a result, stress generated during curing and use can be mitigated, suppressing cracking and peeling. Furthermore, by applying external stimuli such as raising the temperature, the transesterification reaction of fiber-reinforced resin 101 can be initiated, enabling secondary processing, reprocessing, and repair. For example, by using a hot press, the fiber-reinforced resin 101 can be heated and pressed simultaneously, thereby molding it into a mold shape. In addition, compared with existing technologies, fiber-reinforced resin 101 exhibits a higher stress mitigation rate, thus enabling the molding of shapes that are currently impossible to form, and allowing for high-speed molding.

[0048] In addition to vehicle parts, fiber-reinforced resin 101 can also be used in components and bodies used in various fields such as railway vehicles, ships, aircraft, prefabricated bathrooms, septic tanks, printed circuit boards, amusement facilities, and skis.

[0049] Example

[0050] The present invention will be described in more detail below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0051] <Example 1>

[0052] Prepare the following materials.

[0053] Epoxy compounds with two or more epoxy groups in their molecules:

[0054] Bisphenol A diglycidyl ether (jER828 epoxy resin manufactured by Mitsubishi Chemical Corporation).

[0055] Acid anhydride:

[0056] Methyl-3,6-methylene-1,2,3,6-tetrahydrophthalic anhydride (a derivative of tetrahydrophthalic anhydride, MHAC-P curing agent manufactured by Showa Denko Materials (formerly Hitachi Chemical Industries) Co., Ltd.).

[0057] Coordination compounds formed by the coordination of organic ligands with manganese(III):

[0058] Manganese acetylacetone (III) (manufactured by Tokyo Chemical Co., Ltd.)

[0059] Curing accelerator:

[0060] Imidazole-based epoxy resin curing agent (2E4MZ-CN manufactured by Shikoku Kasei Corporation).

[0061] To 100 parts by weight of the epoxy compound, 47 parts by weight of acid anhydride (50 mol% relative to epoxy groups), 19 parts by weight of coordination compound (10 mol% relative to epoxy groups), and 0.3 parts by weight of curing accelerator were added. The mixture was stirred and mixed in atmospheric air to obtain a resin composition. In the resin composition, the epoxy compound, acid anhydride, and coordination compound are miscible, and the resin composition is a viscous liquid. The obtained resin composition was cured by heating at 100°C for 1 hour and then at 200°C for 1 hour to obtain a cured resin product.

[0062] The stress relief time of the prepared resin-cured product was evaluated using a tensile stress relief test with a thermomechanical analysis apparatus. Test specimens with a length of 10 mm, a width of 5 mm, and a thickness of 0.5 mm were prepared using the obtained resin-cured product. The test specimens were stretched at 220°C using the thermomechanical analysis apparatus to achieve an elongation of 5%. The stress at 5% elongation (initial stress) was set as 100%, and the time it took for the stress to decrease to 30% was used as the stress relief time. The measured stress relief time was 9 minutes.

[0063] <Example 2>

[0064] The amount of coordination compound was changed to 27 parts by mass (15 mol% relative to the epoxy group), and otherwise the same procedure was followed as in Example 1. The stress relief time was measured to be 7 minutes.

[0065] <Example 3>

[0066] The amount of coordination compound was changed to 38 parts by mass (20 mol% relative to the epoxy group), and otherwise the same procedure was followed as in Example 1. The stress relief time was measured to be 5 minutes.

[0067] <Example 4>

[0068] The amount of coordination compound was changed to 46 parts by mass (25 mol% relative to the epoxy group), and otherwise the same procedure was followed as in Example 1. The stress relief time was measured to be 6 minutes.

[0069] <Example 5>

[0070] The amount of coordination compound was changed to 57 parts by mass (30 mol% relative to the epoxy group), and otherwise the same procedure was followed as in Example 1. The stress relief time was measured to be 6 minutes.

[0071] <Example 6>

[0072] The amount of coordination compound was changed to 14 parts by mass (7.5 mol% relative to the epoxy group), and the same procedure was followed as in Example 1. The stress relief time was measured to be 11 minutes.

[0073] <Comparative Example 1>

[0074] The amount and type of coordination compound were changed to 14 parts by mass of zinc acetylacetonate (II) (manufactured by Tokyo Chemical Co., Ltd.) (wherein the amount relative to the epoxy group was the same as in Example 1). Otherwise, the procedure was the same as in Example 1, and the stress relief time was measured to be 13 minutes.

[0075] <Comparative Example 2>

[0076] The amount and type of coordination compound were changed to 28 parts by mass of zinc acetylacetonate (II) (manufactured by Tokyo Chemical Co., Ltd.) (wherein the amount relative to the epoxy group was the same as in Example 3). Otherwise, the procedure was the same as in Example 3, and the stress relief time was measured to be 10 minutes.

[0077] <Comparative Example 3>

[0078] The amount and type of coordination compound were changed to 35 parts by mass of zinc acetylacetonate (II) (manufactured by Tokyo Chemical Co., Ltd.) (wherein the amount relative to the epoxy group was the same as in Example 4), and the resin composition was prepared in the same manner as in Example 4. During preparation, the coordination compound did not dissolve or disperse in the resin composition. In addition, even when heated in the same manner as in Example 4, the prepared resin composition did not cure, and a cured resin product could not be obtained, so the stress relief time could not be determined.

[0079] <Inspection>

[0080] Table 1 shows the stress relief times for Examples 1-6 and Comparative Examples 1 and 2. Additionally, Figure 2 This is a graph showing the stress relief time of Examples 1-6 and Comparative Examples 1 and 2. Additionally, for reference, Comparative Example 3, where the stress relief time could not be determined, is also shown. Figure 2 In the diagram, solid lines represent the stress relief times of Examples 1 to 6, and dashed lines represent the stress relief times of Comparative Examples 1 and 2.

[0081] [Table 1]

[0082]

[0083] like Figure 2 As shown, in Examples 1 to 6 using the coordination compound (ester exchange catalyst) of the present invention, the stress relief time was generally shortened compared to Comparative Examples 1 and 2 using conventional catalysts. For example, by making the content of the coordination compound 5 mol% to 30 mol% relative to the epoxy group, the coordination compound can be dissolved in the resin composition, and the stress relief time can be shortened. In addition, when comparing Example 1 with Comparative Example 1, which uses a different type of coordination compound but the same amount of 10 mol%, the stress relief time was shortened from 13 minutes to 9 minutes by using the coordination compound of the present invention, a reduction of about 30%. In addition, when comparing Example 3 with Comparative Example 2, which uses a different type of coordination compound but the same amount of 20 mol%, the stress relief time was halved from 10 minutes to 5 minutes by using the coordination compound of the present invention.

[0084] In Comparative Example 3, since zinc acetylacetonate(II) is insoluble, it can be assumed that the upper limit of the amount used when using zinc acetylacetonate(II) is about 20 mol%. The smaller the amount used, the longer the stress relief time. Therefore, it is speculated that the shortest stress relief time when using zinc acetylacetonate(II) is about 10 minutes.

[0085] On the other hand, by making the content of the coordination compound of the present invention 10 mol% to 30 mol% relative to the epoxy group, the stress relief time can be reduced to 9 minutes or less (Example 1), which is shorter than the shortest stress relief time of about 10 minutes when using conventional catalysts. In particular, by making the content of the coordination compound 15 mol% to 30 mol% relative to the epoxy group, the stress relief time can be reduced to 5 to 7 minutes, which is particularly short.

[0086] As can be seen from the above, by using coordination compounds formed by coordinating organic ligands with manganese(III), the stress relief time can be shortened, and in particular, by adjusting the amount, the stress relief time can be reduced by up to half compared with the prior art. Therefore, according to the present invention, a resin composition, a cured resin, and a fiber-reinforced resin capable of shortening the stress relief time are provided.

[0087] Symbol Explanation

[0088] 1: Resin; 2: Fiber; 3: Coordination compound; 101: Fiber-reinforced resin.

Claims

1. A resin composition, characterized in that, contain: Epoxy compounds with two or more epoxy groups in their molecules; Acid anhydrides; and Coordination compounds formed by the coordination of organic ligands with manganese(III), The coordination compound comprises at least one of manganese acetylacetonate (III), manganese acetate (III), or manganese naphthalene(III). The content of the coordination compound relative to the epoxy group is more than 5 mol% and less than 30 mol%. The content of the anhydride relative to the epoxy group is more than 30 mol% and less than 70 mol%.

2. The resin composition according to claim 1, characterized in that: The content of the coordination compound relative to the epoxy group is more than 10 mol% and less than 30 mol%.

3. The resin composition according to claim 2, characterized in that: The content of the coordination compound relative to the epoxy group is more than 15 mol% and less than 30 mol%.

4. The resin composition according to claim 1 or 2, characterized in that: The epoxy compound is bisphenol A diglycidyl ether or phenolic varnish resin.

5. The resin composition according to claim 1, characterized in that: The acid anhydride comprises at least one of phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, or derivatives thereof.

6. A cured resin product, characterized in that, contain: A resin having ester and hydroxyl groups is obtained by reacting the epoxy compound contained in the resin composition according to any one of claims 1 to 5 with an acid anhydride; and Coordination compounds formed by the coordination of organic ligands with manganese(III), The coordination compound comprises at least one of manganese acetylacetonate (III), manganese acetate (III), or manganese naphthalene(III). The content of the coordination compound is between 5 mol% and 30 mol% relative to the epoxy groups present in the epoxy compound. The content of the anhydride is 30 mol% to 70 mol% relative to the epoxy groups present in the epoxy compound.

7. The resin cured product as described in claim 6, characterized in that: The stress relief time is defined as the time it takes for the residual stress in the test piece to decrease to 30% of the applied stress, based on the stress applied to the test piece containing the resin and the coordination compound. The stress relief time is less than 11 minutes.

8. The resin cured product as described in claim 7, characterized in that: The stress relief time is less than 9 minutes.

9. A fiber-reinforced resin, characterized in that, Include: A resin having ester and hydroxyl groups is obtained by reacting the epoxy compound contained in the resin composition according to any one of claims 1 to 5 with an acid anhydride. Fibers impregnated with at least the resin; and Coordination compounds formed by the coordination of organic ligands with manganese(III), The coordination compound comprises at least one of manganese acetylacetonate (III), manganese acetate (III), or manganese naphthalene(III). The content of the coordination compound is between 5 mol% and 30 mol% relative to the epoxy groups present in the epoxy compound. The content of the anhydride is 30 mol% to 70 mol% relative to the epoxy groups present in the epoxy compound.

10. The fiber-reinforced resin as described in claim 9, characterized in that: The fiber comprises at least one of aramid fiber, glass fiber, or carbon fiber.

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