ONE-COMPONENT CURABLE COMPOSITION

Abstract

Included is a one-component curable composition comprising: (A) an epoxy resin; (B) a solid rubber; (C) a latent curing agent; (D) a filler; and (E) a foaming agent, wherein the epoxy resin (A) comprises an unmodified bisphenol-type epoxy resin (A1), the one-component curable composition comprises 10 to 100 parts by mass of the solid rubber (B) per 100 parts by mass of the epoxy resin (A), and the solid rubber (B) comprises a styrene-butadiene-divinylbenzene copolymer (B1).

Description

TECHNICAL FIELD

[0001] The present invention relates to a one-component curable composition, particularly a one-component coating-type curable composition comprising (A) an epoxy resin, (B) a solid rubber, (C) a latent curing agent, (D) a filler, and (E) a foaming agent. BACKGROUND ART

[0002] Thinned sheet metals are used to reduce the weight of automobile bodies. Sheet metal reinforcement materials are used to ensure the tensile rigidity and buckling resistance of such sheets. Sheet metal reinforcement materials typically have a three-layer structure consisting of a glass fabric, an adhesive, and a release paper, and are marketed as standard products with a specific plate-like shape. Such sheet metal reinforcement materials (standard products) are used after being customized to the desired shape. Shape-customized sheet metal reinforcement materials are attached to sheets; however, this process requires human (worker) correction due to deterioration of the adhesiveness, misalignment of the attachment position, and the like caused by the application environment.Therefore, it is difficult to achieve complete automation of sheet reinforcement by using a standard sheet reinforcement material, which inevitably leads to a decline in productivity. Furthermore, the disposal of the release paper described above can lead to increased costs, environmental pollution due to waste generation, and so on. Therefore, there is a demand for a sheet reinforcement material that enables complete automation. As such, sheet reinforcement materials that can be applied automatically have been investigated.

[0003] For example, Patent Document 1 discloses a coating-type sheet reinforcing material composition based on a high-viscosity material obtained by mixing a liquid composition of a thermosetting epoxy resin with an inorganic filler having a certain aspect ratio (L / D).Patent Document 1 discloses that the coating-type sheet reinforcing material composition can be applied under heating, and during the process before curing and baking, cooling solidification of the applied composition not only prevents the scattering, dissolution, and peeling of the composition in a chemical conversion treatment liquid or an electrolytic solution to particularly improve the splash resistance, flexural strength, and rigidity of a sheet in terms of the reinforcing effect, but also prevents distortion of the sheet even after curing (see

[0005] of Patent Document 1). PRIOR ART DOCUMENT

[0004] Patent Document 1: Japanese Patent No. 3547404 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] The coating-type sheet reinforcement material disclosed in Patent Document 1 has excellent properties, and it is required to improve reinforcement performance while reducing deformation and improving water splash resistance while maintaining pump dischargeability. However, in Patent Document 1, the coating-type sheet reinforcement material is obtained by preparing a high-viscosity material, and Patent Document 1 does not provide any teaching regarding improving flexural strength, improving water splash resistance, or maintaining low viscosity and pump dischargeability.

[0006] In view of the above, an object of the present invention is to provide a one-component curable composition which can be applied while maintaining a low viscosity under heating, but is not scattered, dissolved or peeled off particularly in splash water, a chemical conversion treatment liquid or a plating liquid during the process from application to curing and baking, and improves the flexural strength and rigidity of a sheet after curing but does not cause deformation of the sheet. SOLUTIONS TO THE PROBLEMS

[0007] The present inventors have studied intensively to discover that a one-component curable composition that can not only improve reinforcement performance while reducing deformation, but also improve water splash resistance while maintaining pump dischargeability, can be obtained by using a specific solid rubber of styrene-butadiene-divinylbenzene copolymer and a foaming agent. The present inventors also discovered that such a one-component curable composition can be preferentially applied to a sheet and thus can be preferably used as a coating-type sheet reinforcement material, thereby completing the present invention.

[0008] The present description includes the following embodiments. 1. A one-component curable composition comprising: (A) an epoxy resin; (B) a solid rubber; (C) a latent curing agent; (D) a filler; and (E) a foaming agent, where the epoxy resin (A) comprises an unmodified bisphenol-type epoxy resin (A1), the one-component curable composition comprises 10 to 100 parts by mass of the solid rubber (B) per 100 parts by mass of the epoxy resin (A), and the solid rubber (B) comprises a styrene-butadiene-divinylbenzene copolymer (B1). 2. The one-component curable composition according to 1, which has a viscosity of 50 to 300 Pa·s at a temperature of 40°C and a shear rate of 430 sec -1 has. 3. The one-component curable composition according to 1 or 2, wherein the epoxy resin (A) comprises 25 to 90 mass% of the unmodified bisphenol type epoxy resin (A1) based on 100 mass% of the epoxy resin. 4. The one-component curable composition according to any one of 1 to 3, wherein the epoxy resin (A) has 15 to 40 mass% of an aromatic ring based on 100 mass% of the epoxy resin. 5. The one-component curable composition according to any one of 1 to 4, wherein the foaming agent (E) comprises at least one selected from the group consisting of ADCA type chemical foaming agents, OBSH type chemical foaming agents and unexpanded balloons. 6. The one-component curable composition according to any one of 1 to 5, which has a foaming ratio of 10 to 200%. 7. The one-component curable composition according to any one of 1 to 6, wherein the filler (D) comprises a needle-like filler having a length of 0.5 mm or more. 8. The one-component curable composition according to any one of 1 to 7, wherein the solid rubber (B) further comprises a styrene-butadiene copolymer (B2). 9. The one-component curable composition according to any one of 1 to 8, wherein the solid rubber (B) further comprises a nitrile-butadiene copolymer (B3). 10. The one-component curable composition according to any one of 1 to 9, wherein the solid rubber (B1) and / or the solid rubber (B2) have an acid content of 0.2 to 8 mass%. 11. The one-component curable composition according to any one of 1 to 10, wherein the epoxy resin (A) comprises a low-viscosity epoxy resin (A2), and the low-viscosity epoxy resin (A2) has an epoxy equivalent of 250 to 700 and a viscosity of 40 to 5,000 mPa·s at 25°C. 12. The one-component curable composition according to 11, wherein the low-viscosity epoxy resin (A2) comprises a dibasic acid ester type epoxy resin (A2-1). 13. The one-component curable composition according to any one of 1 to 12, wherein the filler (D) comprises an inorganic filler having an aspect ratio (L / D) of 5 or higher. 14. The one-component curable composition according to any one of 1 to 13, which is of the coating type. 15. The one-component curable composition according to any one of 1 to 14, which is used for reinforcing sheets and is pump-dischargeable. EFFECTS OF THE INVENTION

[0009] The one-component curable composition according to one embodiment of the present invention can not only improve reinforcement performance while reducing deformation, but also improve water splash resistance while maintaining pump dischargeability. Furthermore, the one-component curable composition can be preferably applied to a sheet metal and can thus be preferably used as a coating-type sheet metal reinforcement material. DETAILED DESCRIPTION

[0010] One aspect of the present description provides a one-component (or one-liquid) curable composition comprising an epoxy resin (A), a solid rubber (B), a latent curing agent (C), a filler (D) and a foaming agent (E).

[0011] In this one-component curable composition, the epoxy resin (A) comprises an unmodified bisphenol-type epoxy resin (A1), the one-component curable composition comprises 10 to 100 parts by mass of the solid rubber (B) per 100 parts by mass of the epoxy resin (A), and the solid rubber (B) comprises a styrene-butadiene-divinylbenzene copolymer (B1).

[0012] In the present specification, the “epoxy resin (A)” refers to a thermosetting resin which can be cured due to the formation of a crosslinked network by the epoxy groups present therein and is generally referred to as an epoxy resin, and the epoxy resin (A) is not particularly limited as long as the curable composition of the present invention can be obtained.

[0013] The epoxy resin (A) is, for example, a glycidyl ether type epoxy resin, a glycidylamine type epoxy resin or a glycidyl ester type epoxy resin.

[0014] The epoxy resin (A) preferably comprises an unmodified bisphenol-type epoxy resin (A1).

[0015] The unmodified bisphenol-type epoxy resin (A1) is an epoxy resin having a bisphenol skeleton and is not particularly limited as long as it is not particularly modified and the epoxy resin composition of the present invention can be obtained.

[0016] Examples of the unmodified bisphenol-type epoxy resin (A1) include diglycidyl ethers of bisphenol A, bisphenol F, brominated bisphenol A and bisphenol AD.

[0017] The unmodified bisphenol type epoxy resin (A1) has a viscosity at 25°C of preferably 1500 mPa s or more, more preferably 2000 to 25000 mPa s, even more preferably 2500 to 20000 mPa s, even more preferably 3000 to 15000 mPa s.

[0018] The unmodified bisphenol-type epoxy resin (A1) has an epoxy equivalent of preferably 150 to 800 g / eq, more preferably 160 to 500 g / eq, even more preferably 165 to 250 g / eq, and even more preferably 170 to 200 g / eq. The unmodified bisphenol-type epoxy resin (A1) exhibits better processability when the epoxy equivalent is 150 to 800 g / eq.

[0019] A commercially available product can be used as the unmodified bisphenol-type epoxy resin (A1). Examples include "jER (registered trademark) 828," "jER (registered trademark) 1001," and "jER (registered trademark) 807," manufactured by Mitsubishi Chemical Corporation.

[0020] The epoxy resin (A) may contain the unmodified bisphenol-type epoxy resin (A1) in an amount of preferably 25 to 90 mass% or 25 to 60 mass%, more preferably 29 to 80 mass% or 29 to 56 mass%, even more preferably 33 to 65 mass%, even more preferably 33 to 52 mass%, further preferably 35 to 49 mass%, based on 100 mass% of the epoxy resin.

[0021] When the epoxy resin (A) contains 25 to 90 mass% of the unmodified bisphenol-type epoxy resin (A1) based on 100 mass% of the epoxy resin, the Tg, the elastic modulus, and the flexural strength of the curable composition according to an embodiment of the present invention can be improved in a more balanced manner.

[0022] The epoxy resin (A) may comprise a low-viscosity epoxy resin (A2). The "low-viscosity epoxy resin (A2)" refers to an epoxy resin with a viscosity of less than 5,000 mPa s at 25°C, and the low-viscosity epoxy resin (A2) has a viscosity of preferably 40 to 5,000 mPa s, more preferably 45 to 4,000 mPa s, even more preferably 50 to 3,000 mPa s, and even more preferably 60 to 2,500 mPa s.

[0023] When the epoxy resin (A) comprises the low-viscosity epoxy resin (A2), the curable composition according to an embodiment of the present invention can ensure pump dischargeability at relatively low temperatures (40 to 50 °C).

[0024] The low-viscosity epoxy resin (A2) has an epoxy equivalent of preferably 250 to 700, more preferably 280 to 680, even more preferably 300 to 650.

[0025] When the epoxy resin (A) comprises the low-viscosity epoxy resin (A2) having an epoxy equivalent of 250 to 700, the curable composition according to one embodiment of the present invention is flexible and exhibits a large displacement at maximum strength in a flexural test.

[0026] When the epoxy resin (A) comprises the low-viscosity epoxy resin (A2) having an epoxy equivalent of 250 to 700 and a viscosity at 25°C of 40 to 5,000 mPa·s, the curable composition according to one embodiment of the present invention can exert both of the effects described above.

[0027] The low-viscosity epoxy resin (A2) may comprise a dibasic acid ester type epoxy resin (A2-1).

[0028] The “dibasic acid ester type epoxy resin (A2-1)” comprises an epoxy resin based on an ester of a dibasic acid (e.g., a dimer acid which is a long-chain dibasic acid, phthalic acid, or hydrogenated phthalic acid).

[0029] The dibasic acid ester type epoxy resin (A2-1) is not particularly limited as long as it corresponds to the low viscosity epoxy resin (A2) described above and the epoxy resin composition of the present invention can be obtained.

[0030] A commercially available product can be used as the dibasic acid ester type epoxy resin (A2-1). Examples include "jER (registered trademark) 871" (dimer acid glycidyl ester), manufactured by Mitsubishi Chemical Corporation.

[0031] The low-viscosity epoxy resin (A2) may also comprise, for example, a diglycidyl ether of an alkylene oxide adduct of bisphenol A, bisphenol F, bisphenol AD ​​or the like, a bifunctional epoxy resin used as a reactive diluent, and a monofunctional epoxy resin forming part of the epoxy resin.

[0032] The epoxy resin (A) comprises the low-viscosity epoxy resin (A2) in an amount of preferably 20 to 80 mass%, more preferably 30 to 75 mass%, even more preferably 40 to 70 mass%, even more preferably 50 to 65 mass%, based on 100 mass% of the epoxy resin (A).

[0033] When the epoxy resin (A) contains 20 to 80 mass% of the low-viscosity epoxy resin (A2) based on 100 mass% of the epoxy resin (A), the curable composition according to one embodiment of the present invention can ensure pump dischargeability at relatively low temperatures (40 to 50°C).

[0034] It is noted that the low viscosity epoxy resin (A2) does not contain any unmodified bisphenol type epoxy resin (A1).

[0035] The epoxy resin (A) may comprise another epoxy resin (A3) which is neither the unmodified bisphenol type epoxy resin (A1) nor the low viscosity epoxy resin (A2).

[0036] The other epoxy resin (A3) is not particularly limited as long as it is an epoxy resin other than the unmodified bisphenol type epoxy resin (A1) or the low viscosity epoxy resin (A2), and the curable composition of the present invention can be obtained.

[0037] The epoxy resin (A) may contain the other epoxy resin (A3) in an amount of 40 mass% or less, 30 mass%, or 20 mass% or less based on 100 mass% of the epoxy resin.

[0038] Examples of such other epoxy resins (A3) include: rubber-modified epoxy resins [e.g., reaction products obtained by mixing a bisphenol-type epoxy resin (e.g., a diglycidyl ether of bisphenol A, bisphenol F, or bisphenol AD, or a diglycidyl ether of an alkylene oxide adduct of bisphenol A) with a butadiene-acrylonitrile-(meth)acrylic acid copolymer in a mass ratio of 1:5 to 4:1, preferably 1:3 to 3:2, and allowing these materials to react at a temperature of 80 to 180°C]; urethane-modified epoxy resins [e.g.,, reaction products obtained by allowing a polyurethane prepolymer prepared by adding a polyisocyanate to one terminal of a polyalkylene glycol to react with a hydroxy group of an epoxy resin (in a mixing ratio of 10:90 to 50:50); for example, reaction products between a terminal NCO group-containing urethane prepolymer obtained by reacting an excess amount of diisocyanate (e.g., tolylene diisocyanate or diphenylmethane diisocyanate) with a polytetramethylene ether glycol (having a molecular weight of 500 to 5000) and an OH-containing epoxy resin (e.g., a diglycidyl ether of bisphenol A or a diglycidyl ether of an aliphatic polyhydric alcohol)]; Carboxy-terminated butadiene-acrylonitrile copolymer (CTBN)-modified epoxy resins [e.g. reaction products obtained by mixing a bisphenol-type epoxy resin (e.g., a diglycidyl ether of bisphenol A, bisphenol F or bisphenol AD ​​or a diglycidyl ether of an alkylene oxide adduct of bisphenol A) with a carboxyl-terminated butadiene-acrylonitrile copolymer rubber in a mass ratio of 1:5 to 4:1, preferably 1:3 to 3:2, and reacting these materials at a temperature of 80 to 180°C]; and acrylic-modified epoxy resins [e.g., reaction products obtained by reacting carboxyl groups on the surfaces of acrylic rubber particles with an epoxy resin (in a mixing ratio of 10:90 to 50:50)].

[0039] The epoxy resin (A) has an aromatic ring content of preferably 15 to 40 mass%, more preferably 18 to 35 mass%, even more preferably 20 to 32 mass%, even more preferably 25 to 30 mass%, based on 100 mass% of the epoxy resin (A).

[0040] When the aromatic ring content of the epoxy resin (A) is 15 to 40 mass% based on 100 mass% of the epoxy resin (A), the Tg, the elastic modulus and the flexural strength of the curable composition according to an embodiment of the present invention can be improved in a more balanced manner.

[0041] The curable composition according to one embodiment of the present invention may, for example, comprise 25 to 80 parts by mass of the epoxy resin (A) per 100 parts by mass of the curable composition, and preferably comprises 30 to 70 parts by mass, more preferably 35 to 65 parts by mass, even more preferably 40 to 60 parts by mass of the epoxy resin (A).

[0042] When the curable composition according to an embodiment of the present invention contains 25 to 80 parts by mass of the epoxy resin (A) per 100 parts by mass of the curable composition, the curability and flexural strength of the curable composition according to an embodiment of the present invention can be further improved.

[0043] In the present specification, the solid rubber (B) is not particularly limited as long as it is a solid rubbery substance and the curable composition of the present invention can be obtained.

[0044] In this specification, the term "solid" in the sense of "solid rubber" means that the rubber is solid at room temperature (23°C). When a rubber and a liquid component coexist, the term "solid" means that the portion of the rubber excluding the liquid component is solid at room temperature (23°C). Therefore, even if a rubber coexists with a liquid component and is dissolved and / or swollen at room temperature, the rubber corresponds to a solid rubber if the liquid component is removed and the rubber is solid at room temperature (23°C).

[0045] The solid rubber (B) comprises a styrene-butadiene-divinylbenzene copolymer (B1), and the curable composition according to an embodiment of the present invention can exert an advantageous effect of further improving water splash resistance while preventing a decrease in Tg and a reduction in strength (displacement at maximum strength in a flexural test) due to foaming.

[0046] The solid rubber (B) comprises the styrene-butadiene-divinylbenzene copolymer (B1) in an amount of preferably 20 to 80 mass%, more preferably 25 to 75 mass%, even more preferably 30 to 70 mass%, and even more preferably 35 to 65 mass%, based on 100 mass% of the solid rubber (B).

[0047] The solid rubber (B) preferably comprises at least one further polymer selected from styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, ethylene-propylene-diene copolymers, isoprene polymers and butadiene polymers.

[0048] The solid rubber (B) may comprise a styrene-butadiene copolymer (B2), and it may comprise an acrylonitrile-butadiene copolymer (B3).

[0049] When the solid rubber (B) comprises the styrene-butadiene copolymer (B2), a decrease in Tg of a cured product (reinforcing material) of the curable composition according to an embodiment of the present invention is prevented, so that the reinforcing performance can be ensured and a reduction in strength (displacement at maximum strength in a flexural test) due to foaming can be prevented.

[0050] When the solid rubber (B) comprises the acrylonitrile-butadiene copolymer (B3), the amount of displacement of the curable composition according to an embodiment of the present invention at a maximum strength in a flexural test can be further increased.

[0051] The solid rubber (B1) and / or the solid rubber (B2) has an acid content of preferably 0.2 to 8 mass%, more preferably 0.3 to 6 mass%, even more preferably 0.5 to 4 mass%.

[0052] When the solid rubber (B1) and / or the solid rubber (B2) has an acid content of 0.2 to 8 mass%, the storage stability of the curable composition according to an embodiment of the present invention can be further improved.

[0053] The curable composition according to one embodiment of the present invention may, for example, comprise 10 to 100 parts by mass of the solid rubber (B) per 100 parts by mass of the epoxy resin (A), and preferably comprises 20 to 90 parts by mass, more preferably 30 to 80 parts by mass, even more preferably 40 to 70 parts by mass of the solid rubber (B).

[0054] When the curable composition according to an embodiment of the present invention contains 10 to 100 parts by mass of the solid rubber (B) per 100 parts by mass of the epoxy resin (A), the amount of displacement of the curable composition according to an embodiment of the present invention at a maximum strength in a flexural test can be further increased, while the deformation strength of the curable composition is further improved.

[0055] In the present specification, the "latent curing agent (C)", which is a curing agent of the epoxy resin (A), refers to a compound which does not substantially function as a curing agent at room temperature but functions as a curing agent when heated (e.g., to 165°C, preferably 150°C), and the latent curing agent (C) is not particularly limited as long as the curable composition of the present invention can be obtained.

[0056] Specific examples of the latent curing agent include: dicyandiamide; dihydrazide compounds such as adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, dodecanediohydrazide, 1,3-bis(hydrazinocarboethyl)-5-isopropylhydantoin, eicosanedioic acid dihydrazide, hydroquinonediglycolic acid dihydrazide, resorcinoldiglycolic acid dihydrazide, and 4,4'-ethylidenebisphenoldiglycolic acid dihydrazide; 4,4'-diaminodiphenylsulfone; imidazole compounds such as imidazole, 2-n-heptadecylimidazole, and 2-undecylimidazole; melamine; triazine compounds such as 2,4-diamino-6-(2'-methylimidazolyl(1'))-ethyl-o-triazine; benzoguanamine; Dialkylurea compounds, for example N,N-dialkylurea, such as N,N-dimethyl-N'-(3,4-dichlorophenyl)urea, and N,N'-dialkylurea compounds; N,N'-dialkylthiourea compounds;Polyamines such as diaminodiphenylmethane, diaminobiphenyl, diaminophenyl, phenylenediamine, tolylenediamine, dodecanediamine, decanediamine, octanediamine, tetradecanediamine, hexadecanediamine, polyoxypropylenediamine, and hydrazide-based polyamines; and guanidine derivatives such as cyanoguanidine.

[0057] A commercially available latent curing agent can be used. Examples include CG-NA (trade name) manufactured by Air Products Ltd., EH-4030s (trade name) manufactured by ADEKA Corporation, ADH (trade name) manufactured by Otsuka Chemical Co., Ltd., EH3731s (trade name) manufactured by ADEKA Corporation, DYHARD UR200 (trade name) manufactured by AlzChem Group AG, and DDH (trade name) manufactured by Otsuka Chemical Co., Ltd.

[0058] The curable composition according to one embodiment of the present invention may, for example, comprise 1 to 30 parts by mass of the latent curing agent (C) per 100 parts by mass of the epoxy resin, and preferably comprises 2 to 25 parts by mass, more preferably 3 to 20 parts by mass, even more preferably 4 to 15 parts by mass of the latent curing agent (C).

[0059] When the curable composition according to one embodiment of the present invention comprises 1 to 30 parts by mass of the latent curing agent (C) per 100 parts by mass of the epoxy resin, the curable composition has an excellent balance of curability and storage stability.

[0060] In the present specification, the filler (D) is a compound that not only increases the amount of the curable composition according to an embodiment of the present invention but also can impart a certain degree of strength to a cured product formed from the curable composition, and the filler (D) is not particularly limited as long as it can contribute to viscosity adjustment or weight reduction, as the case may be, and the curable composition of the present invention can be obtained.

[0061] Examples of the filler include: carbonates and sulfates of alkaline earth metals such as calcium carbonate (e.g., heavy calcium carbonate, precipitated calcium carbonate and surface-treated calcium carbonate), magnesium carbonate and barium sulfate; mica, graphite, talc, clay, glass flakes (glass beads), vermiculite, kaolinite, wollastonite (acicular calcium metasilicate), silica, diatomaceous earth, gypsum, cement, converter slag, shirasu, zeolite, cellulose powder, rubber powder, xonotlite, potassium titanate, bentonite, aluminum nitride, silicon nitride, zinc white, titanium oxide, aluminum oxide, zinc oxide, iron oxide, magnesium oxide, titanium oxide, magnesium hydroxide, aluminum hydroxide and calcium silicate; Calcium carbonate whiskers (acicular calcium carbonate), ceramic short fibers or whiskers thereof, rock wool short fibers, glass short fibers, potassium titanate short fibers, calcium silicate short fibers, aluminum silicate, carbon short fibers, aramid short fibers, sepiolite mineral fibers and the like;Fibrous fillers, such as various whiskers; hollow fillers, such as glass balloons, silica balloons, resin balloons, and inorganic carbon hollow spheres; organic hollow fillers, for example, plastic balloons made of an organic synthetic resin such as vinylidene chloride or acrylonitrile; and metallic fillers, such as aluminum fillers.

[0062] The filler (D) preferably comprises a needle-shaped filler having a length of 0.4 mm or more, more preferably a needle-shaped filler having a length of 0.4 mm to 40 mm, even more preferably a needle-shaped filler having a length of 5 mm to 30 mm, and even more preferably a needle-shaped filler having a length of 6 mm to 20 mm.

[0063] When the filler (D) comprises a needle-like filler having a length of 0.4 mm or more, the deformation resistance of the curable composition according to an embodiment of the present invention can be further improved.

[0064] The filler (D) preferably comprises an inorganic filler having an aspect ratio (L / D) of 4 or higher, more preferably an inorganic filler having an aspect ratio (L / D) of 4.5 to 20, even more preferably an inorganic filler having an aspect ratio (L / D) of 5 to 15.

[0065] When the filler (D) comprises an inorganic filler having an aspect ratio (L / D) of 4 or higher, the deformation strength of the curable composition according to an embodiment of the present invention can be further improved.

[0066] Examples of inorganic fillers include the fillers mentioned above, excluding organic fillers (e.g., rock wool short fibers, aramid short fibers, hollow fillers such as resin balloons and organic hollow fillers, e.g., plastic balloons made of an organic synthetic resin such as vinylidene chloride or acrylonitrile).

[0067] The curable composition according to one embodiment of the present invention may, for example, comprise 20 to 70 parts by mass of the filler (D) per 100 parts by mass of the curable composition, and preferably comprises 35 to 65 parts by mass, more preferably 30 to 60 parts by mass, even more preferably 35 to 55 parts by mass of the filler (D).

[0068] When the curable composition according to one embodiment of the present invention contains 20 to 70 parts by mass of the filler (D) per 100 parts by mass of the curable composition, the deformation strength of the curable composition can be further improved.

[0069] In the present specification, the "foaming agent (E)" refers to a substance added for the purpose of increasing the volume of a material, for example, a substance added for foaming, and the foaming agent (E) is not particularly limited as long as it is, for example, a substance that generates a gas by decomposition or a substance that becomes a gas itself, and the curable composition according to the present invention can be obtained.

[0070] Since the curable composition according to one embodiment of the present invention contains a foaming agent, the thickness after curing can be increased more efficiently, and the reinforcing performance can be improved. Furthermore, foaming can reduce the elastic modulus of a cured product (i.e., a reinforcing material) obtained by curing the curable composition, and deformation can also be reduced.

[0071] The foaming agent (E) is preferably a foaming agent that foams upon heating, and examples thereof include inorganic foaming agents and organic foaming agents.

[0072] Examples of inorganic foaming agents include ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride and azides.

[0073] Examples of organic foaming agents include n-nitroso compounds, azo compounds (e.g., azodicarbonamide: ADCA), fluorinated alkanes, hydrazine compounds (e.g., 4,4'-oxybis(benzenesulfonylhydrazide): OBSH), semicarbazide compounds, and triazole compounds.

[0074] Examples of the foaming agent (E) further include heat-expandable particles (unexpanded balloons) in which a heat-expandable substance (e.g., isobutane or butane) is encapsulated in microcapsules made of a thermoplastic resin (e.g., polyvinylidene chloride, polyacrylonitrile, or poly(meth)acrylic acid ester).

[0075] The foaming agent (E) preferably comprises at least one foaming agent selected from the group consisting of azo compounds (e.g., ADCA-type chemical foaming agents), hydrazine compounds (e.g., OBSH-type chemical foaming agents) and unexpanded balloons.

[0076] When the foaming agent (E) comprises at least one foaming agent selected from the group consisting of azo compounds (e.g., ADCA-type chemical foaming agents), hydrazine compounds (e.g., OBSH-type chemical foaming agents), and unexpanded balloons, the curable composition according to an embodiment of the present invention can further improve flexural strength and further reduce deformation while achieving a desired foaming ratio.

[0077] The curable composition according to one embodiment of the present invention may, for example, comprise 0.1 to 10 parts by mass of the foaming agent (E) per 100 parts by mass of the curable composition, and preferably comprises 0.2 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, even more preferably 0.4 to 2 parts by mass of the foaming agent (E).

[0078] When the curable composition according to an embodiment of the present invention contains 0.1 to 10 parts by mass of the foaming agent (E) per 100 parts by mass of the curable composition, the curable composition can be foamed more appropriately and ensure better reinforcing performance while further reducing deformation.

[0079] The curable composition according to one embodiment of the present invention may optionally contain other components. Examples of the other components include ordinary curing agents (excluding the latent curing agent described above), diluents, surfactants, and other additives.

[0080] In one embodiment of the present invention, a curing agent is a compound that has no curing effect at normal temperature but exhibits a curing effect at a certain temperature, and is not particularly limited as long as the curable composition of the present invention can be obtained, excluding the latent curing agent described above.

[0081] In one embodiment of the present invention, a diluent is not particularly limited as long as it can impart flowability to the curable composition according to one embodiment of the present invention and the curable composition of the present invention can be obtained.

[0082] Examples of the diluent include hydrocarbon-based solvents such as paraffinic solvents, isoparaffinic solvents, naphthenic solvents, and aromatic solvents.

[0083] In one embodiment of the present invention, examples of the other additives include moisture absorbers (e.g., calcium oxide and molecular sieves), thixotropic agents (e.g., organic bentonite, silica, aluminum stearate, metallic soaps, and castor oil derivatives), stabilizers [e.g., 2,6-di-t-butyl-4-methylphenol, 2,2-methylenebis(4-methyl-6-t-butylphenol), and nickel dibutyldithiocarbamate], curing accelerators (e.g., dibutyltin dilaurate, lead octylate, and bismuth octylate), coupling agents such as silane and titanium, and plasticizers. The other additives are not particularly limited and can be used arbitrarily as long as the curable composition of the present invention can be obtained.

[0084] The curable composition according to one embodiment of the present invention can be prepared by mixing the components described above.

[0085] A mixing apparatus and a mixing method are not particularly limited as long as the curable composition of the present invention can be produced.

[0086] A twin-screw mixer, a planetary mixer, a sigma mixer, a kneader, an attritor, a Glen mill, a roller or a dissolver can be used as a mixing device.

[0087] Mixing can be done using a container in which the components can be mixed, e.g. in a tank, a vessel or the like.

[0088] The curable composition according to one embodiment of the present invention may be of one-component type (or one-liquid type) or two-component type (or two-liquid type) and can be generally used as a one-component type (or two-liquid type) curable composition.

[0089] The curable composition according to one embodiment of the present invention can be applied to a desired location in any thickness and shape by a known method such as bead, slot, spray, swirl or shot coating and can be cured, for example, by heating to a predetermined temperature with a hot air circulating drying oven.

[0090] The curable composition according to one embodiment of the present invention can be used as a one-pack type curable coating type composition.

[0091] In the process described above, the coating can be carried out using a computer-controlled coating machine or a coating robot.

[0092] In one embodiment of the present invention, there may be provided a method of manufacturing an automobile comprising the use of the curable composition according to one embodiment of the present invention.

[0093] The curable composition according to an embodiment of the present invention can be used in an automobile production line to provide a reinforcement layer on an automobile body panel. In other words, an automobile body panel can be provided with a reinforcement layer by applying and heat-curing the curable composition according to an embodiment of the present invention thereto. Furthermore, a reinforced sheet structure having a reinforcement layer formed by applying and curing the curable composition according to an embodiment of the present invention on an automobile body panel, and a method for producing the same, can be provided.

[0094] In addition, a curable composition can be provided which is used for sheet reinforcement and is pump-dischargeable.

[0095] The curable composition according to one embodiment of the present invention has a viscosity of preferably 50 to 300 Pa s, more preferably 65 to 250 Pa s, even more preferably 80 to 200 Pa s, even more preferably 90 to 180 Pa s, at a temperature of 40°C and a shear rate of 430 sec -1 .

[0096] When the viscosity of the curable composition according to an embodiment of the present invention is 50 to 300 Pa·s at a temperature of 40°C and a shear rate of 430 sec -1 the pump dischargeability of the curable composition according to an embodiment of the present invention can be further improved.

[0097] The curable composition according to one embodiment of the present invention has a foaming ratio of preferably 10 to 200%, more preferably 30 to 150%.

[0098] When the foaming ratio of the curable composition according to an embodiment of the present invention is 10 to 200%, the reinforcing performance and the deformation strength of the curable composition according to an embodiment of the present invention can be further improved.

[0099] A cured product of the curable composition according to one embodiment of the present invention has a flexural strength of preferably 18 N or more, more preferably 20 to 60 N, even more preferably 22 to 50 N, even more preferably 24 to 40 N.

[0100] When the flexural strength of a cured product of the curable composition according to an embodiment of the present invention is 18 N or more, the curable composition according to an embodiment of the present invention can have further improved reinforcing performance.

[0101] A cured product of the curable composition according to one embodiment of the present invention has a displacement (deflection) of preferably 4.5 mm or more, more preferably 4.8 to 20 mm, even more preferably 5 to 17 mm, even more preferably 5.5 to 15 mm.

[0102] When the deflection of a cured product of the curable composition according to an embodiment of the present invention is 4.5 mm or more, the curable composition according to an embodiment of the present invention does not crack even upon impact and can further ensure the reinforcing performance.

[0103] A cured product of the curable composition according to one embodiment of the present invention has a warpage of preferably 5 mm or less, more preferably -1 to 4 mm, even more preferably -0.5 to 3.5 mm, even more preferably 0 to 3 mm.

[0104] When the warpage of a cured product of the curable composition according to an embodiment of the present invention is 5 mm or less, the curable composition according to an embodiment of the present invention can further prevent the deformation of a reinforcing plate.

[0105] A cured product of the curable composition according to an embodiment of the present invention has a modulus of elasticity of preferably 1000 to 3000 MPa, more preferably 1100 to 2500 MPa, even more preferably 1200 to 2000 MPa, even more preferably 1300 to 1800 MPa.

[0106] When the elastic modulus of a cured product of the curable composition according to an embodiment of the present invention is 1000 to 3000 MPa, the reinforcing performance of the curable composition according to an embodiment of the present invention can be further improved.

[0107] A cured product of the curable composition according to one embodiment of the present invention has a Tg of preferably 40 to 140°C, more preferably 50 to 120°C, even more preferably 60 to 100°C, even more preferably 70 to 95°C.

[0108] When the Tg of a cured product of the curable composition according to an embodiment of the present invention is 40 to 140°C, the reinforcing performance of the curable composition according to an embodiment of the present invention can be further improved. EXAMPLES

[0109] The present invention will now be described more concretely and in more detail by way of examples and comparative examples; however, the examples described below are merely embodiments of the present invention, and the present invention is by no means limited by the examples described below.

[0110] In the description of the examples, parts by weight and % by weight refer to the parts without taking the solvent into account, unless otherwise stated.

[0111] The components used in these examples are listed below. (A) Epoxy resin (a1-1) Unmodified bisphenol A type epoxy resin (jER828 (trade name), manufactured by Mitsubishi Chemical Corporation) (a1-2) Unmodified bisphenol A type epoxy resin (jER1001 (trade name), manufactured by Mitsubishi Chemical Corporation) (a1-3) Unmodified bisphenol-type epoxy resin (jER807 (trade name), manufactured by Mitsubishi Chemical Corporation) (a2-1) Low-viscosity epoxy resin with an epoxy equivalent of 430 and a viscosity of 600 mPa s at 25°C, dimer acid type diglycidyl ester (jER871 (trade name), manufactured by Mitsubishi Chemical Corporation) (a2-2) Polyoxyalkylene bisphenol A glycidyl ether with an epoxy equivalent of 340 and a viscosity of 2600 mPa s at 25°C (GLYCI-ALE BPP-350 (trade name), manufactured by Sanyo Chemical Industries, Ltd.) (a2-3) Bifunctional epoxy resin used as a reactive diluent with an epoxy equivalent of 296 and a viscosity of 43 mPa s at 25°C (PP-300P (trade name), manufactured by Sanyo Chemical Industries, Ltd.) (a3-1) Elastomer-modified epoxy resin (bisphenol-type epoxy resin modified with an elastomer content of 40%), with an epoxy equivalent of 340 and a viscosity of 190,000 mPa s at 25°C (HYPRO RA840 (trade name), manufactured by CVC Thermoset Specialties, Inc.)) (B) Solid rubber (b1-1) Styrene-butadiene-divinylbenzene copolymer (EMULPRENE 1009 (trade name), manufactured by Industrias Negromex, SA de CV) (b2-1) Styrene-butadiene copolymer (NIPOL 1502 (trade name), manufactured by Zeon Corporation) (b3-1) Acrylonitrile-butadiene copolymer (DN214 (trade name), manufactured by Zeon Corporation) (b3-2) Acrylonitrile-butadiene copolymer (DN219 (trade name), manufactured by Zeon Corporation) (C) Latent hardener (c1) Dicyandiamide (OMICURE DDA 10 (trade name), manufactured by CVC Thermoset Specialties, Inc.) (c2) 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (DYHARD UR-200 (trade name), manufactured by AlzChem Group AG) (D) Filler (d1) Carbon Black (#20 (trade name), manufactured by Asahi Carbon Co., Ltd.) (d2) Glass balloon (GLASS BUBBLE S-38 (trade name), manufactured by 3M Company) (d3) Filler (WHITON B (trade name), manufactured by Bihoku Funka Kogyo Co., Ltd.) (d4) Filler (HAKUENKA CCR (trade name), manufactured by Shiraishi Kogyo Kaisha, Ltd.) (d5) Calcium metasilicate, L / D ratio > or = 5 (NYAD G (trade name), manufactured by NYCO Minerals, Inc.) (E) Foaming agent (e1) Foaming agent (VINYFOR AC#R (trade name), manufactured by Eiwa Chemical Ind. Co., Ltd.) (e2) Foam agent (NEOCELLBORN #1000M (trade name), manufactured by Eiwa Chemical Ind. Co., Ltd.) (e3) Foaming agent (EXPANCEL 920-80 (trade name), manufactured by Japan Fillite Co., Ltd.) (F) Additive (f1) Additive, calcium oxide, QC-X (trade name), manufactured by Inoue Calcium Corporation These components were mixed in the respective amounts (parts by mass) according to Tables 1-3 to prepare one-component curable compositions of Examples 1 to 12 and Comparative Examples 1 to 5.

[0112] For each of the thus-obtained curable compositions (or their cured products), the viscosity, splash resistance, foaming ratio, flexural strength, displacement (bending), warpage, elastic modulus, and Tg were measured and evaluated according to the methods described below. The results are presented in Tables 1-3. Measurement of viscosity

[0113] The viscosity of each curable composition was measured using a pressure viscometer in accordance with JASO323-77. The viscometer cylinder was filled with each curable composition, and the temperature was adjusted to 40°C using a jacket or the like. The temperature was confirmed to be 40°C. A No. 3 capillary (length: 74.1 mm, capillary diameter: 1.85 mm) was used. The measurement was performed at a shear rate of 430 s -1The viscosity range in which each curable composition can be applied is assumed to be 300 Pa s or less, and the viscosity of each curable composition is preferably 50 Pa s to 300 Pa s. Splash resistance

[0114] A test specimen was prepared by applying each curable composition to a 200 mm × 300 mm × 0.8 mm SPCC-SD steel sheet, resulting in a dimension of 150 mm × 200 mm × 1.8 mm. A water jet at a temperature of 50°C was applied to the surface of the test specimen coated with the curable composition at an angle of 45° and a water pressure of 490 kPa. The distance between the nozzle and the test specimen was 700 mm, and the jet was applied for 1 minute. Afterward, the coated surface was visually observed to check for peeling or displacement of the curable composition. The evaluation criteria for splash water resistance were as follows. ⊚: The curable composition was absolutely not detached or displaced. ◯: The curable composition has not been detached or displaced. ◯Δ: The curable composition was easily detached or displaced, but this did not pose a problem. Δ: The curable composition was slightly detached or displaced, but this did not pose a problem in practical application. Δ×: The curable composition was easily peeled off or shifted, which was a problem in practical application. ×: The curable composition has been significantly detached or displaced. Foaming ratio

[0115] A test specimen was prepared by applying each curable composition in bead form to a 3 cm × 7 cm aluminum plate. The specimen was measured according to a water displacement method (see JASO323-77 Specific Gravity Test Method A), and the foaming ratio was calculated from the density (specific gravity) of the curable composition before and after curing. Foaming ratio (%) = (inverse of density after curing−inverse of density before curing) ÷inverse of density before curing × 100

[0116] The curable composition was cured by placing the specimen in a forced circulation oven at 180°C for 25 minutes. From the viewpoint of reinforcement performance and curing deformation of a cured product of each curable composition, the foaming ratio is preferably 10 to 200%, more preferably 30 to 150%. Bending strength and amount of displacement (bending)

[0117] Each curable composition was coated on a 25 mm × 200 mm × 0.8 mm thick SPCC-SD steel sheet, and the coated steel sheet was then placed in a forced-circulation furnace to cure the curable composition at 180°C for 25 minutes, thereby obtaining a test specimen. A three-point bending test of this specimen was performed using a flexural strength tester prescribed in JIS K6911 under the conditions of a fulcrum distance of 100 mm and a loading rate of 1 mm / min. The load (N / 25 mm) at a 1 mm displacement and the amount of displacement at a maximum load were measured to determine the flexural strength and bending. Considering the buckling resistance on an actual vehicle, the load (bending strength) at 1 mm displacement is preferably 18 N or more, and the amount of displacement (bending) at maximum load is preferably 4.5 mm or more. Amount of default

[0118] Each curable composition was coated onto a 25 mm × 200 mm × 0.8 mm thick SPCC-SD steel sheet. The coated steel sheet was then placed in a forced-circulation furnace to cure the curable composition at 180°C for 25 minutes, thereby obtaining a test specimen. A weight of 1 kg·f was applied to one side of this specimen, and the warpage height (mm) on the opposite side was measured. Considering the amount of warpage that does not result in poor appearance on an actual vehicle, the amount of warpage is preferably 5 mm or less. Elastic modulus and Tg

[0119] On a 0.8 mm thick aluminum plate that had been subjected to a release treatment such as TEFLON (registered trademark) coating, each curable composition was coated so that the cured thickness was 1 to 2 mm. The coated specimen was then placed in a forced-circulation oven to cure the curable composition at 180°C for 25 minutes, thereby obtaining a cured product. This cured product was machined to a size of 5 mm wide and 50 mm long, and the elastic modulus and tanδ were measured using a dynamic viscoelastic analysis (DMA) device at a heating rate of 2°C / min in a range of -50 to 150°C. The elastic modulus at 23°C and the temperature exhibiting a peak position of tanδ as Tg were recorded.From the viewpoint of dent resistance on an actual vehicle and the use temperature environment, it is preferable that both a modulus of elasticity of 1000 to 3000 MPa and a Tg of 40°C to 140°C are satisfied. [Table 1] Example 1 2 3 4 5 6 (A) (a1-1) 17 15 17 17 23 13 (a1-2) 4 (a1-3) (a2-1) 13 14 13 13 10 15 (a2-2) 13 14 13 13 10 15 (a2-3) (a3-1) (B) (b1) 5 3 3 7 5 5 (b2-1) (b3-1) 5 3 5 3 5 5 (b3-2) 2 2 (C) (c1) 3 3 3 3 3 3 (c2) 1 1 1 1 1 1 (D) (d1) 2 2 2 2 2 2 (d2) 5 5 5 (d3) 2,5 2,5 7,5 2,5 7,4 7,5 (d4) (d5) 33 33 33 33 33 33 (E) (e1) 0,5 0,5 0,5 0,5 0,6 0,5 (e2) (e3) (F) (f1) In total 100,0 100,0 100,0 100,0 100,0 100,0 Content of aromatic ringenin (A) Mass% 25,9 26,6 25,9 25,9 30,7 22,7 Contents of (A1) Mass% 40 40 40 40 53 30 Salary (B) based on (A) Mass-produced parts 23 13 23 23 23 23 Thickness of the coating mm 1,8 1,8 1,8 1,8 1,8 1,8 viscosity Pa·s 106 100 80 120 140 80 Splash resistance ⊚ ◯Δ ◯ ⊚ ⊚ ⊚ Foaming ratio % 57 60 60 55 60 60 Flexural strength N 24 33 30 28 35 23 Amount of displacement (bending)Amount of distortion mm 6,5 4,8 4,8 5,8 5,8 8,5 mm 0,67 3 0,8 0,7 3,5 0,3 Elastic modulus MPa 1602 1900 1600 1700 2200 1200 Tg °C 77 81 73 82 88 72 [Table 2] Example 7 8 9 10 11 2 (A) (a1-1) 17 17 17 17 10 (a1-2) (a1-3) 17 (a2-1) 13 13 13 13 13 13 (a2-2) 13 13 13 13 13 13 (a2-3) (a3-1) 7 (B) (b1) 5 5 5 5 5 5 (b2-1) (b3-1) 5 5 5 5 5 5 (b3-2) (C) (c1) 3 3 3 3 3 3 (c2) 1 1 1 1 1 1 (D) (d1) 2 2 2 2 2 2 (d2) 5 5 5 5 (d3) 2 1 7,5 7,5 2,5 2,5 (d4) (d5) 33 33 33 33 33 33 (E) (e1) 1 2 0,5 0,5 (e2) 0,5 (e3) 0,5 (F) (f1) In total 100,0 100,0 100,0 100,0 100,0 100,0 Content of aromatic ringenin (A) Mass% 25,9 25,9 25,9 25,9 27,4 18,3 Salary of (A1) Mass% 40% 40% 40% 40% 40% 32% Salary (B) based on (A) Mass-produced parts 23% 23% 23% 23% 23% 23% Thickness of the coating mm 1,8 1,8 1,8 1,8 1,8 1,8 viscosity Pa·s 100 100 100 100 80 140 Splash resistance ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Foaming ratio % 80 120 50 65 55 62 Flexural strength N 28 30 21 22 20 21 Amount of displacement (bending) mm 5,5 4,5 5 5 7,2 7,5 Amount of default mm 0,5 0,5 0,8 0,7 0,5 0,5 Elastic modulus MPa 1200 1000 1450 1500 1200 1150 Tg °C 74 73 73 77 72 70 [Table 3] Comparison example 1 2 3 4 5 (A) (a1-1) 17 17 17 29 (a1-2) (a1-3) (a2-1) 13 13 13 23 (a2-2) 13 13 13 20 (a2-3) 17 (a3-1) (B) (b1) 5 5 5 (b2-1) 4 (b3-1) 5 5 6 5 5 (b3-2) (C) (c1) 3 3 3 3 3 (c2) 1 1 1 1 1 (D) (d1) 2 2 2 2 (d2) 5 5 (d3) 8 8 2,5 7,7 (d4) 8 (d5) 33 33 33 33 33 36 (E) (e1) - 3,5 0,5 0,3 (e2) (e3) (F) (f1) 1 In total 100,0 100,0 100,0 100,0 100,0 Content of aromatic ringenin (A) Mass% 25,9 25,9 25,9 11,3 29,5 Salary of (A1) Mass% -40% 40% 40% 0% -33% Salary (B) based on (A) Mass-produced parts 23% 23% 23% 23% 11% Thickness of the coating mm 1,8 2,5 1,8 1,8 1,8 viscosity Pa·s 35 95 50 40 30 Splash resistance ⊚ ⊚ Δ-x Δ 0,0. Foaming ratio % 0 0 60 60 0 Flexural strength N 17 36 27 11 22 Amount of displacement (bending) mm 7 5 4,2 12 3,2 Amount of default mm 3 14 1 0 5 Elastic modulus MPa 2600 2600 1800 100 2300 Tg °C 75 75 30 10 85

[0120] The curable compositions of Examples 1 to 12 and their cured products can each be used as a pump-dischargeable one-component curable composition for sheet reinforcement, which can not only improve the reinforcement performance while reducing deformation, but also improve the splash resistance while maintaining the pump-dischargeable composition.

[0121] The curable compositions of Comparative Examples 1 to 5 and their cured products are not considered sufficient as one-component curable compositions for coating because they can neither improve the reinforcing performance while reducing deformation nor the splash resistance while maintaining pump-dischargeability. INDUSTRIAL APPLICABILITY

[0122] The one-component curable composition according to one embodiment of the present invention can not only improve reinforcement performance while reducing deformation, but also improve water splash resistance while maintaining pump dischargeability. Furthermore, the one-component curable composition can be preferably applied to a sheet metal and thus can be preferably used as a coating-type sheet metal reinforcement material.

[0123] This patent application claims priority under Article 4 of the Paris Convention based on Japanese Patent Application No. 2022-175739, filed in Japan on November 1, 2022, which is incorporated herein by reference in its entirety. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 3547404

[0004] JP 2022-175739

[0123]

Claims

[1] One-component curable composition comprising: (A) an epoxy resin; (B) a solid rubber; (C) a latent curing agent; (D) a filler; and (E) a foaming agent, where the epoxy resin (A) comprises an unmodified bisphenol-type epoxy resin (A1), the one-component curable composition comprises 10 to 100 parts by mass of the solid rubber (B) per 100 parts by mass of the epoxy resin (A) and the solid rubber (B) comprises a styrene-butadiene-divinylbenzene copolymer (B1). [2] A one-component curable composition according to claim 1, which has a viscosity of 50 to 300 Pa·s at a temperature of 40°C and a shear rate of 430 sec -1 has. [3] The one-component curable composition according to claim 1, wherein the epoxy resin (A) comprises 25 to 90 mass% of the unmodified bisphenol-type epoxy resin (A1) based on 100 mass% of the epoxy resin. [4] The one-component curable composition according to claim 1, wherein the epoxy resin (A) comprises 15 to 40 mass% of an aromatic ring based on 100 mass% of the epoxy resin. [5] The one-component curable composition according to claim 1, wherein the foaming agent (E) comprises at least one selected from the group consisting of ADCA type chemical foaming agents, OBSH type chemical foaming agents and unexpanded balloons. [6] A one-component curable composition according to claim 1, which has a foaming ratio of 10 to 200%. [7] The one-component curable composition according to claim 1, wherein the filler (D) comprises a needle-shaped filler having a length of 0.5 mm or more. [8] A one-component curable composition according to claim 1, wherein the solid rubber (B) further comprises a styrene-butadiene copolymer (B2). [9] A one-component curable composition according to claim 1, wherein the solid rubber (B) further comprises a nitrile-butadiene copolymer (B3). [10] A one-component curable composition according to claim 1, wherein the solid rubber (B1) and / or the solid rubber (B2) have an acid content of 0.2 to 8 mass%. [11] One-component curable composition according to claim 1, wherein the epoxy resin (A) comprises a low-viscosity epoxy resin (A2) and the low-viscosity epoxy resin (A2) has an epoxy equivalent of 250 to 700 and a viscosity of 40 to 5000 mPa·s at 25 °C. [12] The one-component curable composition according to claim 11, wherein the low-viscosity epoxy resin (A2) comprises a dibasic acid ester type epoxy resin (A2-1). [13] The one-component curable composition according to claim 1, wherein the filler (D) comprises an inorganic filler having an aspect ratio (L / D) of 5 or higher. [14] A one-component curable composition according to claim 1, which is of the coating type. [15] A one-component curable composition according to claim 1, which is used for sheet reinforcement and is pump-dischargeable.