Thermosetting resin composition, resin molded body, and resin gear

Abstract

This thermosetting resin composition contains: (A) a bis(2-oxazoline) compound; and (C) an aromatic diamine compound. The contained amount of the aromatic diamine compound is not less than 0.20 mol but less than 0.50 mol with respect to 1 mol of the bis(2-oxazoline) compound.

Description

Thermosetting resin composition, resin molded body, and resin gear

[0001] The present invention relates to a thermosetting resin composition, a resin molded article, and a resin gear.

[0002] Resin molded articles made of a fiber substrate and a matrix resin are used in a variety of fields due to their light weight and excellent mechanical properties. Regarding resin compositions that form the matrix resin, thermosetting resin compositions containing bis(2-oxazoline) compounds are known to be capable of forming crosslinked resins that are excellent in mechanical properties such as toughness and heat resistance (see, for example, Patent Document 1 listed below).

[0003] Japanese Unexamined Patent Publication No. 7-330896

[0004] Resin molded articles are also used for resin gears, etc., but resin gears used in automobile engines, drive units for electric motorcycles, etc. tend to have larger loads on their teeth due to gear compaction, replacement of metal gears, etc. In such applications, resin molded articles are required to have high compressive strength.

[0005] Therefore, an object of the present invention is to provide a thermosetting resin composition capable of forming a resin molded article having excellent compressive strength, and a resin molded article and a resin gear having excellent compressive strength.

[0006] One aspect of the present invention relates to the inventions described in [1] to [7] below.

[0007] [1] A thermosetting resin composition comprising (A) a bis(2-oxazoline) compound and (C) an aromatic diamine compound, wherein the content of the aromatic diamine compound is 0.20 mol or more and less than 0.50 mol per 1 mol of the bis(2-oxazoline) compound. [2] The thermosetting resin composition according to claim 1, further comprising (B) at least one organic compound selected from the group consisting of an organic cyclic compound (excluding carboxylic acid compounds) having at least one polar functional group selected from the group consisting of a hydroxyl group, an amide group, and a carbonyl group, and at least one cyclic structure selected from the group consisting of an alicyclic ring, a heterocyclic ring, and an aromatic ring, and an organic chain compound represented by the following general formula (B8): [In formula (B8), R ８１ represents an alkyl group, and R ８２ represents an alkyl group having a hydroxyl group.] [3] The thermosetting resin composition according to [2], wherein the organic cyclic compound is 2-oxazolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, phthalamide, or N-(2,4,6-trichlorophenyl)maleimide. [4] The thermosetting resin composition according to [2] or [3], wherein the content of the organic compound is 5 to 95 parts by mass when the total mass of the aromatic diamine compound and the organic compound is 100 parts by mass. [5] A resin molded product comprising a cured product of the thermosetting resin composition according to any one of [1] to [4]. [6] A resin molded product comprising a fibrous base material and a cured product of the thermosetting resin composition according to any one of [1] to [4] impregnated into the fibrous base material. [7] A resin gear having teeth made of the resin molded product according to [6].

[0008] According to the present invention, it is possible to provide a thermosetting resin composition capable of forming a resin molded article having excellent compressive strength, as well as a resin molded article and a resin gear having excellent compressive strength.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes in detail an embodiment of the present invention (hereinafter referred to as the "present embodiment"). The present invention is not limited to the following embodiment.

[0010] <Thermosetting Resin Composition> The thermosetting resin composition of this embodiment contains (A) a bis(2-oxazoline) compound (hereinafter sometimes referred to as "component (A)") and (C) an aromatic diamine compound (hereinafter sometimes referred to as "component (C)"), and the content of component (C) is 0.02 mol or more and less than 0.50 mol per 1 mol of component (A). The thermosetting resin composition of this embodiment can be used to form a resin molded product having excellent compressive strength, for example, by impregnating a fiber substrate with the composition and curing it.

[0011] [Component (A)] The bis(2-oxazoline) compound can be any compound having two oxazoline skeletons in one molecule without any particular limitation. The two oxazoline skeletons may be bonded directly or via an organic group. Component (A) may be used alone or in combination of two or more.

[0012] The bis(2-oxazoline) compound may be a compound represented by the following general formula (A). [In formula (A), R １ represents a single bond, an unsubstituted or substituted alkylene group, an unsubstituted or substituted phenylene group, or an unsubstituted or substituted pyridinediyl group; R ２ and R ３ each independently represents a hydrogen atom, an alkyl group, or a phenyl group.

[0013] R １ When has a substituent, examples of the substituent include a methyl group.

[0014] Examples of component (A) include 2,2'-(1,3-phenylene)bis-2-oxazoline (hereinafter sometimes abbreviated as "PBO"), 2,2'-(1,4-phenylene)bis-2-oxazoline, 2,2'-(1,2-ethylene)bis-2-oxazoline, 2,2'-(1,4-butylene)bis-2-oxazoline, and 2,2'-(1,3-phenylene)bis-(5-methyl-2-oxazoline), (S,S)-2,6-bis(4-isopropyl-2-oxazolin-2-yl)pyridine, and (S,S)-2,2'-(dimethylmethylene)bis(4-phenyl-2-oxazoline).

[0015] Component (A) may be PBO because it is inexpensive and readily available.

[0016] The content of component (A) in the thermosetting resin composition may be 25 to 75 mass % based on the total solid content of the thermosetting resin composition. The solid content of the thermosetting resin composition means components other than the solvent (components that form a cured product).

[0017] The thermosetting resin composition of this embodiment may further contain (B) at least one organic compound (hereinafter sometimes referred to as "component (B)") selected from the group consisting of organic cyclic compounds (excluding carboxylic acid compounds) having at least one polar functional group selected from the group consisting of a hydroxyl group, an amide group, and a carbonyl group, and at least one cyclic structure selected from the group consisting of an alicyclic ring, a heterocyclic ring, and an aromatic ring, and an organic chain compound represented by the following general formula (B8). The carboxylic acid compound also includes an acid anhydride compound. The component (B) may be blended alone or in combination of two or more.

[0018] [In formula (B8), R ８１ represents an alkyl group, and R ８２ represents an alkyl group having a hydroxyl group.

[0019] The organic cyclic compound may be a compound represented by the following general formulas (B1) to (B7).

[0020] [In formula (B1), R １１ represents a hydrogen atom or an acetyl group.

[0021] [In formula (B2), R ２１ represents a vinyl group or an alkyl group having a hydroxyl group.

[0022] [In formula (B3), Ar ３１ represents an unsubstituted or substituted aromatic group.

[0023] Ar ３１ The substituent of may be an amide group.

[0024] [In formula (B4), Ar ４１ represents an aromatic group having a halogen atom.

[0025] [In formula (B5), Ar ５１ and Ar ５２ represents an unsubstituted or substituted aromatic group.

[0026] Ar５１ and Ar ５２ The substituent of may be an amino group.

[0027] [In formula (B6), R ６１ represents an alkyl group having a hydroxyl group.

[0028] [In formula (B7), R ７１ and R ７２ represents an alkyl group.

[0029] The organic cyclic compound may be a compound that satisfies one or more of the following conditions: (a) It has two or three or more polar functional groups selected from the group consisting of a hydroxyl group, an amide group, and a carbonyl group, and (b) It has a chloro group.

[0030] The thermosetting resin composition of the present embodiment may contain, as component (B), at least one compound selected from the group consisting of 2-oxazolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, phthalamide, and N-(2,4,6-trichlorophenyl)maleimide.

[0031] The thermosetting resin composition of the present embodiment may contain, as component (B), at least one compound selected from the group consisting of 4,4'-diaminobenzanilide, 1-(2-hydroxyethyl)pyrrolidine-2,5-dione, 5,5-dimethylhydantoin, and N-(2-hydroxyethyl)acetamide.

[0032] From the viewpoint of improving the compressive strength of a resin molded product, the content of the component (B) in the thermosetting resin composition may be 0.03 to 1.0 mol, 0.03 to 0.15 mol, 0.2 to 0.8 mol, or 0.8 to 1.0 mol per 1 mol of the component (A).

[0033] Furthermore, from the viewpoint of improving the compressive strength of the resin molded body, the content of the (B) component may be 5 to 95 parts by mass, 5 to 60 parts by mass, 5 to 30 parts by mass, 30 to 50 parts by mass, or 50 to 60 parts by mass, when the total mass of the (B) component and the (C) component is taken as 100 parts by mass.

[0034] [Component (C)] Examples of aromatic diamine compounds include 4,4'-diaminodiphenylmethane (MDA), 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), methylenebis(2-ethyl-6-methylaniline), and 4,4'-methylenebis(2-ethylaniline).

[0035] The aromatic diamine compound may be an aromatic diamine compound containing a halogen atom such as a chlorine atom or a bromine atom in the molecule.

[0036] The molecular weight of the aromatic diamine compound may be 150 or more or 300 or more from the viewpoint of being less volatile, and may be 350 or less from the viewpoint of the impregnation of the thermosetting resin composition into a fiber substrate or the like and ease of use in a liquid state.

[0037] From the viewpoint of improving the compressive strength of the resin molded product, the content of the component (C) in the thermosetting resin composition is, relative to 1 mole of the component (A), from 0.20 mol to less than 0.50 mol, optionally from 0.20 mol to less than 0.49 mol, optionally from 0.20 mol to less than 0.49 mol, optionally from 0.20 mol to less than 0.48 mol, optionally from 0.25 mol to 0.45 mol, or optionally from 0.25 mol to 0.40 mol.

[0038] When the thermosetting resin composition of the present embodiment contains the component (B), the total amount of the component (B) and the component (C) may be more than 0.20 mol and less than 1.50 mol, more than 0.20 mol and less than 1.49 mol, more than 0.20 mol and less than 1.49 mol, more than 0.20 mol and less than 1.45 mol, or more than 0.25 mol and less than 1.40 mol, per 1 mol of the component (A).

[0039] The thermosetting resin composition of the present embodiment may contain a curing accelerator, if necessary, to accelerate the curing reaction between the bis(2-oxazoline) compound and the components (B) and (C).

[0040] Examples of the curing accelerator include n-octylbromide and p-toluenesulfonic acid esters such as ethyl p-toluenesulfonate.

[0041] The content of the curing accelerator in the thermosetting resin composition may be 0.5 to 1.2 parts by mass, 0.5 to 0.8 parts by mass, or 0.8 to 1.2 parts by mass, relative to 100 parts by mass of the total of the component (A) and the component (C).

[0042] When the thermosetting resin composition contains the component (B), the content of the curing accelerator may be 0.5 to 1.2 parts by mass, 0.5 to 0.8 parts by mass, or 0.8 to 1.2 parts by mass relative to 100 parts by mass of the total of the components (A), (B), and (C).

[0043] The thermosetting resin composition of the present embodiment may contain additives such as a shock absorbing material such as rubber, an organic sliding material such as polyethylene glycol, etc. Examples of the shock absorbing material include silicone rubber, fluororubber, and nitrile rubber.

[0044] <Resin Molded Article> The resin molded article of the present embodiment includes a fibrous base material and a cured product of the thermosetting resin composition of the present embodiment impregnated into the fibrous base material.

[0045] [Fiber substrate] Examples of the fiber substrate include thermoplastic resin fibers such as polyphenylene sulfide, polyamide (aliphatic polyamide, aromatic polyamide), polyethylene, and polypropylene, inorganic fibers such as basalt fiber, alumina fiber, glass fiber, and carbon fiber, and metal fibers such as stainless steel fiber and aluminum fiber. The fiber substrate may contain one type of fiber alone or two or more types of fibers in combination.

[0046] In the resin molded article of this embodiment, the fiber base material may contain aramid fibers from the viewpoint of improving compressive strength, tensile strength, flexural strength, and impact strength.

[0047] The aramid fibers may be either para-aramid fibers (para-type aramid fibers) or meta-aramid fibers (meta-type aramid fibers), or a mixture of both may be used.

[0048] As the para-aramid fiber, fibers having molecular structures represented by the following formulas (1) and (2) can be used.

[0049] As the para-aramid fiber, commercially available products such as "Twaron" and "Technora" (both trade names of Teijin Limited), "Kevlar Pulp" (trade name of Toray DuPont Co., Ltd.), "Taparan" (trade name of Yantai Taiho New Materials Co., Ltd.), and "Heraklon" (trade name of Kolon Industry Co., Ltd.) can be used.

[0050] The meta-aramid fiber may be a fiber having a molecular structure represented by the following formula (3):

[0051] As the meta-aramid fiber, commercially available products such as "Conex" (trade name, manufactured by Teijin Limited), "Nomex" (trade name, manufactured by DuPont Co., Ltd.), "Newstar" (trade name, manufactured by Yantai Taiho New Materials Co., Ltd.), and "Tametal" (trade name, manufactured by Yantai Taiho New Materials Co., Ltd.) can be used.

[0052] The content of the para-aramid fibers in the fiber base material may be 30 to 100% by mass or 40 to 100% by mass based on the total amount of aramid fibers contained in the fiber base material from the viewpoint of improving compressive strength, and may be 80 to 100% by mass from the viewpoint of improving tensile strength.

[0053] The content of the aramid fibers in the fiber substrate may be 50 to 100 mass %, 60 to 100 mass %, or 100 mass %, based on the total mass of the fiber substrate.

[0054] From the viewpoint of availability, the fiber length of the aramid fiber may be 1 to 12 mm, 1 to 2 mm, 3 to 6 mm, or 7 to 12 mm.

[0055] The fiber diameter of the aramid fiber may be 8 to 12 μm from the viewpoints of availability and permeability of the resin into the substrate.

[0056] The fibrous substrate may contain an inorganic sliding material, such as carbon, molybdenum, molybdenum disulfide, potassium hexatitanate, potassium octatitanate, lithium potassium titanate, magnesium potassium titanate, and mica.

[0057] In the resin molded body of this embodiment, from the viewpoint of obtaining a high level of compressive strength, the content of the inorganic sliding material in the resin molded body may be 10 parts by mass or less, or 5 parts by mass or less, per 100 parts by mass of the fiber base material, or the resin molded body may not contain an inorganic sliding material.

[0058] The proportion of the fiber base material in the resin molded body may be 35 to 55% by volume, 35 to 50% by volume, or 50 to 55% by volume, from the viewpoint of ensuring mechanical strength and the resin impregnation rate.

[0059] Furthermore, from the viewpoint of facilitating impregnation of the molten resin into the substrate, the content of the fiber substrate in the resin molded body may be 35 to 50 parts by mass or 40 to 50 parts by mass per 100 parts by mass of the total of the fiber substrate and the cured product of the thermosetting resin composition of this embodiment.

[0060] The resin molded article of the present embodiment can be used as an automobile part, a compressor part, a drone part, a medical machine part, etc. Examples of the parts include a resin gear and a rotor.

[0061] <Method for producing resin molded body> The resin molded body of this embodiment can be produced by impregnating a fiber substrate with the thermosetting resin composition of this embodiment and then curing the thermosetting resin composition by heating.

[0062] In this embodiment, the fiber base material may be formed by a wet method in which paper is made in water.

[0063] The thermosetting resin composition of this embodiment is cured, for example, at 160° C. to 250° C. for 3 to 20 minutes.

[0064] <Resin Gear> The resin gear of the present embodiment has teeth made of the resin molded article of the present embodiment. The teeth may be formed, for example, by using a teeth-shaped mold during the curing step of the thermosetting resin composition of the present embodiment, or by cutting or the like after obtaining a resin molded article of a predetermined shape.

[0065] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0066] The following compounds were prepared as raw materials for preparing the thermosetting resin composition.

[0067] <Component (A)> PBO: 2,2'-(1,3-phenylene)-bis-2-oxazoline (manufactured by Mikuni Pharmaceutical Co., Ltd.)

[0068] <Component (B)> OXZ: 2-oxazolidone (manufactured by Tokyo Chemical Industry Co., Ltd.) HEPL: 1-(2-hydroxyethyl)-2-pyrrolidone (manufactured by Tokyo Chemical Industry Co., Ltd.) PTA: phthalamide (manufactured by Tokyo Chemical Industry Co., Ltd.) T1987: N-(2,4,6-trichlorophenyl)maleimide (manufactured by Tokyo Chemical Industry Co., Ltd.) DABA: 4,4'-diaminobenzanilide (manufactured by Tokyo Chemical Industry Co., Ltd.) 1,2-HEPO: 1-(2-hydroxyethyl)pyrrolidine-2,5-dione (manufactured by Tokyo Chemical Industry Co., Ltd.) DMHD: 5,5-dimethylhydantoin (manufactured by Tokyo Chemical Industry Co., Ltd.) HEAA: N-(2-hydroxyethyl)acetamide (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0069] <Component (C)> MDA: 4,4'-diaminodiphenylmethane (manufactured by Wanka Chemical Japan Co., Ltd.) BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane (manufactured by Wakayama Seika Holdings Co., Ltd.)

[0070] <Curing accelerator> OB: n-octyl bromide (manufactured by Manac Corporation)

[0071] Example A1: PBO as component (A), OXZ as component (B), and MDA as component (C) were mixed in a mass ratio of 69:6:25, and the mixture was heated and dissolved to form a liquid. OB was blended as a curing accelerator in an amount of 0.7 parts by mass per 100 parts by mass of the total amount of components (A), (B), and (C) to obtain a thermosetting resin composition.

[0072] A fiber substrate was prepared by dissociating cut fibers (fiber length 3 mm) of para-aramid fiber (manufactured by Teijin Limited, trade name Technora), cut fibers (fiber length 3 mm) of meta-aramid fiber (manufactured by Teijin Limited, trade name Conex), and para-aramid fiber pulp (manufactured by Toray DuPont Co., Ltd., trade name Kevlar) in water in a mass ratio of 42:53:5 and forming into a paper. This fiber substrate was compressed in the thickness direction in a papermaking mold so that the proportion of the fiber substrate in the resin molded body (hereinafter sometimes referred to as the "fiber substrate volume ratio") was 40 volume %, and a rectangular parallelepiped reinforcing fiber assembly was obtained.

[0073] The rectangular parallelepiped reinforcing fiber assembly obtained above was placed in a molding die and clamped, and the thermosetting resin composition prepared above was then injected and cured at a molding die temperature of 160°C for 5 minutes to form a rectangular parallelepiped plate (resin molded body).

[0074] Example A2 A resin molded article was molded in the same manner as in Example A1, except that HEPL was used instead of OXZ as the component (B) and the mold temperature was set to 180°C.

[0075] Example A3 A resin molded body was molded in the same manner as in Example A1, except that PTA was used instead of OXZ as the component (B), the blending ratio of the components (A), (B), and (C) was set to a mass ratio of 69:1:30, the blending amount of the curing accelerator was set to 0.5 parts by mass per 100 parts by mass of the total amount of the components (A), (B), and (C), and the molding die temperature was set to 190°C.

[0076] Example A4 A resin molded body was molded in the same manner as in Example A1, except that T1987 was used instead of OXZ as the component (B), the amount of curing accelerator was 0.9 parts by mass per 100 parts by mass of the total amount of the components (A), (B), and (C), and the mold temperature was 180°C.

[0077] Example A5 A resin molded body was molded in the same manner as in Example A1, except that DABA was used instead of OXZ as the component (B), the amount of the curing accelerator was 0.5 parts by mass per 100 parts by mass of the total amount of the components (A), (B), and (C), and the mold temperature was 190°C.

[0078] Example A6 A resin molded body was molded in the same manner as in Example A1, except that 1,2-HEPO was used instead of OXZ as the component (B), the amount of curing accelerator was 0.8 parts by mass per 100 parts by mass of the total amount of the components (A), (B), and (C), and the molding die temperature was 190°C.

[0079] Example A7 A resin molded body was molded in the same manner as in Example A1, except that DMHD was used instead of OXZ as the component (B), the amount of curing accelerator was 0.9 parts by mass per 100 parts by mass of the total amount of the components (A), (B), and (C), and the molding die temperature was 190°C.

[0080] Example A8 A resin molded body was molded in the same manner as in Example A1, except that HEAA was used instead of OXZ as the component (B), the amount of curing accelerator was 1.0 part by mass per 100 parts by mass of the total amount of the components (A), (B), and (C), and the mold temperature was 190°C.

[0081] Comparative Example A1 A resin molded body was molded in the same manner as in Example A1, except that the component (B) was not blended, the component (A) and the component (C) were mixed in a blending ratio of 69:31 by mass, the amount of the curing accelerator was 0.9 parts by mass per 100 parts by mass of the total amount of the component (A) and the component (C), and the molding die temperature was 190°C.

[0082] <Compression Test> The resin molded bodies (rectangular plates) obtained in Examples A1 to A8 and Comparative Example A1 were polished on both sides and cut into pieces measuring 13 mm x 13 mm x 25 mm to prepare test pieces for compression tests. Compression tests were performed on these test pieces using an autograph AGS-5000 manufactured by Shimadzu Corporation to measure the compressive strength. This measurement was performed six times, and the maximum value is shown in Table 1.

[0083]

[0084] Example B1: PBO as component (A) and MDA as component (C) were mixed in a mass ratio of 73:27, and the mixture was heated and dissolved to form a liquid. OB as a curing accelerator was blended into the liquid in an amount of 0.9 parts by mass per 100 parts by mass of the total amount of components (A) and (C), to obtain a thermosetting resin composition.

[0085] A fiber substrate was prepared by dissociating cut fibers (fiber length 3 mm) of para-aramid fiber (manufactured by Teijin Limited, trade name Technora), cut fibers (fiber length 3 mm) of meta-aramid fiber (manufactured by Teijin Limited, trade name Conex), and para-aramid fiber pulp (manufactured by Toray DuPont Co., Ltd., trade name Kevlar) in water in a mass ratio of 42:53:5 and forming into a paper. This fiber substrate was compressed in the thickness direction in a papermaking mold so that the proportion of the fiber substrate in the resin molded body (hereinafter sometimes referred to as the "fiber substrate volume ratio") was 40 volume %, and a rectangular parallelepiped reinforcing fiber assembly was obtained.

[0086] The rectangular parallelepiped reinforcing fiber assembly obtained above was placed in a molding die and clamped, and the thermosetting resin composition prepared above was then injected and cured at a molding die temperature of 190°C for 5 minutes to form a rectangular parallelepiped plate (resin molded body).

[0087] Example B2 A resin molded body was molded in the same manner as in Example B1, except that the blending ratio of component (A) to component (C) was set to a mass ratio of 77:23 and the blending amount of the curing accelerator was set to 1.2 parts by mass per 100 parts by mass of the total amount of component (A) and component (C).

[0088] Example B3 A resin molded body was molded in the same manner as in Example B1, except that the blending ratio of component (A) to component (C) was changed to a mass ratio of 79:21 and the molding die temperature was changed to 200°C.

[0089] Example B4 A resin molded body was molded in the same manner as in Example B1, except that the blending ratio of component (A) to component (C) was set to a mass ratio of 81:19, the blending amount of the curing accelerator was set to 1.2 parts by mass per 100 parts by mass of the total amount of component (A) and component (C), and the molding die temperature was changed to 200°C.

[0090] Example B5: PBO as component (A) and BAPP as component (C) were mixed in a mass ratio of 57:43 and heated to dissolve to form a liquid. OB as a curing accelerator was blended into this liquid in a ratio of 2.0 parts by mass per 100 parts by mass of the total amount of components (A) and (C), to obtain a thermosetting resin composition.

[0091] A resin molded article was molded in the same manner as in Example B1, except that the thermosetting resin composition obtained above was used.

[0092] Comparative Example B1 A resin molded article was molded in the same manner as in Example B1, except that the blending ratio of component (A) to component (C) was set to a mass ratio of 69:31.

[0093] (Comparative Example B2) PBO as component (A) and BAPP as component (C) were mixed in a mass ratio of 51:49 and heated to dissolve to form a liquid. OB as a curing accelerator was blended into this liquid in a ratio of 0.5 parts by mass per 100 parts by mass of the total amount of components (A) and (C) to obtain a thermosetting resin composition.

[0094] A resin molded article was molded in the same manner as in Example B1, except that the thermosetting resin composition obtained above was used.

[0095] <Compression Test> The resin molded bodies (rectangular plates) obtained in Examples B1 to B5 and Comparative Examples B1 and B2 were polished on both sides and cut into pieces measuring 13 mm x 13 mm x 25 mm to prepare test pieces for compression tests. Compression tests were performed on these test pieces using an Autograph AGS-5000 manufactured by Shimadzu Corporation to measure the compressive strength. This measurement was performed six times, and the maximum value is shown in Table 2.

[0096]

[0097] As shown in Tables 1 and 2, it was confirmed that the resin molded articles obtained using the thermosetting resin compositions of Examples A1 to A8 and Examples B1 to B5, in which the content of the component (C) was 0.20 mol or more and less than 0.50 mol per 1 mol of the component (A), had superior compressive strength compared to the resin molded articles obtained using the thermosetting resin compositions of Comparative Examples A1 and B1 and B2, in which the content of the component (C) was 0.50 mol or more per 1 mol of the component (A).

Claims

1. A thermosetting resin composition comprising (A) a bis(2-oxazoline) compound and (C) an aromatic diamine compound, wherein the content of the aromatic diamine compound is 0.20 mol or more and less than 0.50 mol per 1 mol of the bis(2-oxazoline) compound.

2. The thermosetting resin composition according to claim 1, further comprising (B) at least one organic compound selected from the group consisting of organic cyclic compounds (excluding carboxylic acid compounds) having at least one polar functional group selected from the group consisting of a hydroxyl group, an amide group, and a carbonyl group, and at least one cyclic structure selected from the group consisting of an alicyclic ring, a heterocyclic ring, and an aromatic ring, and an organic chain compound represented by the following general formula (B8): [In formula (B8), R ８１ represents an alkyl group, R ８２ represents an alkyl group having a hydroxyl group.

3. The thermosetting resin composition according to claim 2, wherein the organic cyclic compound is 2-oxazolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, phthalamide, or N-(2,4,6-trichlorophenyl)maleimide.

4. The thermosetting resin composition according to claim 2, wherein the content of the organic compound is 5 to 95 parts by mass when the total mass of the aromatic diamine compound and the organic compound is 100 parts by mass.

5. A resin molded article comprising a cured product of the thermosetting resin composition according to any one of claims 1 to 4.

6. A resin molded article comprising a fiber substrate and a cured product of the thermosetting resin composition according to any one of claims 1 to 4 impregnated into the fiber substrate.

7. A resin gear having teeth made of the resin molded product according to claim 6.