Curable resin composition and processed article thereof

Abstract

Provided is a capsule-containing curable resin composition capable of maintaining the sealing properties of a screwing part of a screwing member even in a durability test such as a thermal cycle test. A curable resin composition containing the following components (A)-(D): component (A): a capsule containing a polyfunctional epoxy resin and a monofunctional epoxy resin as an inclusion; component (B): a capsule in which a polythiol is encapsulated as an inclusion; component (C): a compound that promotes the curing of the inclusion of component (A) and the inclusion of component (B); and component (D): an inorganic filler.

Description

Technical Field

[0001] The present invention relates to a curable resin composition containing capsules, which maintains airtightness in a durability test. Background Art

[0002] There are known processed parts obtained by applying a curable resin composition containing capsules to the threaded portions of threaded members such as screws, bolts, and nuts and drying them. For such processed parts, in addition to preventing the threaded members from loosening, there is sometimes a need to prevent leakage from the threaded portions. In Japanese Patent Laid-Open No. 5-186751 and Japanese Patent Laid-Open No. 5-186760, attempts have been made to prevent leakage by adding a swelling resin. However, if moisture or oil does not enter the gaps in the threaded portions to a certain extent, the conditions for swelling are not satisfied, the swelling resin does not swell, and it is sometimes impossible to maintain airtightness. Summary of the Invention

[0003] Conventionally, in a curable resin composition containing capsules, it has been difficult to maintain the airtightness of the threaded portions of threaded members during durability tests such as thermal cycle tests.

[0004] The present inventors conducted intensive studies to achieve the above object, and as a result, found a method for a curable resin composition containing capsules that can maintain airtightness in a durability test, thereby completing the present invention.

[0005] The gist of the present invention will be described below. The first embodiment of the present invention is a curable resin composition containing the following components (A) to (D):

[0006] Component (A): Capsules encapsulating a polyfunctional epoxy resin and a monofunctional epoxy resin as the encapsulated substances;

[0007] Component (B): Capsules encapsulating a polythiol as the encapsulated substance;

[0008] Component (C): A compound that promotes the curing of the encapsulated substance of component (A) and the encapsulated substance of component (B); and

[0009] Component (D): An inorganic filler.

[0010] The second embodiment of the present invention is the curable resin composition according to the first embodiment, wherein the mass ratio of the polyfunctional epoxy resin to the monofunctional epoxy resin in the above component (A) is 99:1 to 25:75.

[0011] The third embodiment of the present invention is the curable resin composition according to the first or second embodiment, which further contains a (meth)acrylic polymer having adhesiveness as component (E).

[0012] A fourth embodiment of the present invention is the curable resin composition described in the third embodiment, wherein the (meth)acrylic polymer of the component (E) contains a styrene skeleton.

[0013] A fifth embodiment of the present invention is the curable resin composition described in the third or fourth embodiment, which further contains water as the component (F).

[0014] A sixth embodiment of the present invention is the curable resin composition described in the fifth embodiment, wherein, in the component (F), the component (E) is an emulsion, the components (A), (B), and (D) are dispersed in the component (F), and the component (C) is dissolved or dispersed in the component (E) or the component (F).

[0015] A seventh embodiment of the present invention is the curable resin composition according to any one of the first to sixth embodiments, wherein when a cured product obtained by curing a composition of the inclusion of the component (A), the inclusion of the component (B), the component (C), and the component (D) in an atmosphere of 25°C for 72 hours is measured by thermomechanical analysis (TMA), the coefficient of linear expansion is 170 to 250 ppm / °C in the temperature range of 140 to 150°C.

[0016] An eighth embodiment of the present invention is the curable resin composition according to any one of the first to seventh embodiments, wherein when a cured product obtained by curing a composition of the inclusion of the component (A), the inclusion of the component (B), the component (C), and the component (D) in an atmosphere of 25°C for 72 hours is measured by thermomechanical analysis (TMA), the glass transition temperature is 50°C or lower.

[0017] A ninth embodiment of the present invention is the curable resin composition according to any one of the first to eighth embodiments, wherein the mass ratio of the inclusion of the component (A), the inclusion of the component (B), the component (C), and the component (D) is 100:50 to 100:5 to 20:10 to 30.

[0018] A tenth embodiment of the present invention is a screwed member obtained by applying the curable resin composition according to any one of the first to ninth embodiments to a screwed portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is an example of a jig for confirming airtightness (sealability) used in a pressure test. DETAILED DESCRIPTION OF THE INVENTION

[0020] In this specification, "X to Y" is used to mean "X or more and Y or less", with the values (X and Y) described before and after it being used as the lower limit value and the upper limit value, respectively.

[0021] One embodiment of the present invention is a curable resin composition containing the following components (A) to (D):

[0022] Component (A): A capsule encapsulating a polyfunctional epoxy resin and a monofunctional epoxy resin as the encapsulated substances;

[0023] Component (B): A capsule encapsulating a polythiol as the encapsulated substance;

[0024] Component (C): A compound that promotes the curing of the encapsulated substances of component (A) and the encapsulated substance of component (B); and

[0025] Component (D): An inorganic filler.

[0026] According to the present invention, it is possible to provide a curable resin composition containing capsules, and the composition maintains the sealing property of the screwing portion of the screwing member even in durability tests such as a thermal cycle test.

[0027] Hereinafter, the details of the curable resin composition of the present invention will be described.

[0028] The component (A) that can be used in the present invention is a capsule, which is a capsule encapsulating a polyfunctional epoxy resin and a monofunctional epoxy resin as the encapsulated substances.

[0029] The polyfunctional epoxy resin refers to an epoxy resin (liquid) having two or more epoxy groups in the molecule. Specific examples of the epoxy resin having two epoxy groups in the molecule, that is, a bifunctional epoxy resin, include bisphenol A type epoxy resins and their hydrogenated products, bisphenol F type epoxy resins and their hydrogenated products, bisphenol S type epoxy resins, tetrabromobisphenol A type epoxy resins, bisphenol AD type epoxy resins, and other bisphenol type epoxy resins. The bisphenol type epoxy resins can be used alone or in combination of two or more. In the curable resin composition of the present invention, as the bisphenol type epoxy resin, at least one of bisphenol A type epoxy resin and bisphenol F type resin is preferably used. In addition, the epoxy equivalent (g / eq) of the bisphenol type epoxy resin is preferably 120 to 300.

[0030] As specific examples of bisphenol A type epoxy resins, there can be mentioned jER (registered trademark) series 827, 828, 1001, 1002, 1003, 1003F, 1004, 1004FS, 1004F, 1004AF, 1055, 1005F, 1006FS, 1007, 1007FS, 1008, 1009, etc. manufactured by Mitsubishi Chemical Corporation; EPOTOTO series YD-011, YD-012, YD-013, YD-014, YD-017, YD-019, YD-020N, YD-020H, etc. manufactured by Tohto Kasei Co., Ltd.; EPICLON series 1050, 3050, 4050, 7050, etc. manufactured by DIC Corporation; EP-5100, EP-5400, EP-5700, EP-5900, etc. manufactured by Adeka Corp., but not limited to these. As specific examples of bisphenol F type epoxy resins, there can be mentioned jER (registered trademark) series 806, 807, 4005P, 4007P, 4010P, etc. manufactured by Mitsubishi Chemical Corporation, but not limited to these.

[0031] As for the epoxy resins having 3 or more epoxy groups in the molecule, there is no particular limitation, and examples thereof include novolak type epoxy resins such as phenol novolak type epoxy resins and o-cresol novolak type epoxy resins; glycidyl ether type epoxy resins such as triglycidyl ether of tris(p-hydroxyphenyl)methane and its derivatives, tetraglycidyl ether of tetrakis(p-hydroxyphenyl)ethane and its derivatives, triglycidyl ether of glycerol, tetraglycidyl ether of pentaerythritol, etc.; glycidylamine type epoxy resins such as tetraglycidyl diaminodiphenylmethane, tetraglycidyl metaxylylenediamine, triglycidyl m-aminophenol, etc. As commercially available products of phenol novolak type epoxy resins, there can be mentioned jER (registered trademark) series 152, 154, etc. manufactured by Mitsubishi Chemical Corporation; EPICLON series N-740, N-770, N-775, etc. manufactured by DIC Corporation; PY307, EPN1179, EPN1180, etc. manufactured by Huntsman Advanced Material; YDPN638, YDPN638P, etc. manufactured by Tohto Kasei Co., Ltd., but not limited to these. The epoxy equivalent of the epoxy resin having 3 or more epoxy groups in the molecule is preferably 50 g / eq to 150 g / eq.

[0032] As the monofunctional epoxy resin, a compound having one epoxy group in one molecule is preferably used. Examples thereof include monoglycidyl ether compounds and monoglycidyl ester compounds. As the monoglycidyl ether compounds, examples include methyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, sec-butylphenyl glycidyl ether, 2-methyloctyl glycidyl ether, octadecyl glycidyl ether, phenyl glycidyl ether, tolyl glycidyl ether, octylphenyl glycidyl ether, and the like. As the monoglycidyl ester compounds, examples include glycidyl ester compounds of monocarboxylic acids such as acrylic acid, methacrylic acid, acetic acid, 2-ethylhexanoic acid, and neodecanoic acid. In the present invention, a glycidyl ester is preferably used, and a glycidyl ester having a skeleton with 8 or more carbon atoms is more preferably used. They may be used alone or in combination of two or more. The epoxy equivalent of the compound having one epoxy group in one molecule is preferably 150 to 450 g / eq, more preferably 170 to 350 g / eq.

[0033] Specific examples of the monofunctional epoxy resin include, for example, Epodil (registered trademark) 759 (manufactured by Air Products and Chemicals, Inc., alkyl (C12 - C13) glycidyl ether, epoxy equivalent 275 - 290 g / eq), Cardolite (registered trademark) Lite2513HP (manufactured by Cardolite Corp., alkyl (C15) phenol glycidyl ether, epoxy equivalent 375 - 450 g / eq), GE-10 (manufactured by CVC Thermoset Specialties, Inc., o-cresol glycidyl ether, epoxy equivalent 170 - 195 g / eq), CARDURA E10P (manufactured by Momentive Performance Materials, neodecanoic acid glycidyl ester, epoxy equivalent 240 g / eq), etc., but are not limited thereto. In addition, they may be used alone or in combination of two or more.

[0034] In order to achieve good mixing with other components, the viscosity (25 °C) of the inclusion of component (A) is preferably 1.0 to 500 mPa·s, more preferably 1.0 to 400 mPa·s, and further preferably 1.0 to 350 mPa·s. In the inclusion of component (A), the mass ratio of the polyfunctional epoxy resin to the monofunctional epoxy resin (polyfunctional epoxy resin: monofunctional epoxy resin) is preferably in the range of 99:1 to 25:75, more preferably in the range of 95:5 to 50:50, and most preferably in the range of 90:10 to 70:30.

[0035] In the present invention, the component (A) and the component (B) described below are capsules, and the capsules contain an inclusion. Thereby, direct contact with other components can be avoided, and the storage stability of the capsule-type curable resin composition can be ensured. The capsules in the examples described below are appropriately encapsulated by a method suitable for each raw material.

[0036] As a method for manufacturing a capsule containing an inclusion, known encapsulation methods such as an interfacial polymerization method, an in-situ method, an insoluble precipitation method, a coacervation method, etc. can be used for manufacturing. For example, the method described in Japanese Patent Laid-Open No. 2000-15087 can be used for manufacturing.

[0037] In the present specification, the wall that prevents the inclusion from leaking out of the capsule is called the capsule wall. As the substance (wall material) constituting the capsule wall, conventionally known substances can be used. As the substance (wall material) constituting the capsule wall, for example, gelatin, aldehyde resin, or urea resin can be used. More specifically, urea-formaldehyde resin (such as glyoxal resin), melamine-formaldehyde resin, polyurea resin, polyurethane resin, isobutylene-maleic anhydride copolymer, etc. can be mentioned, but it is not limited to these. The substance (wall material) constituting the capsule wall is preferably urea-formaldehyde resin (such as glyoxal resin) and / or isobutylene-maleic anhydride copolymer. The average particle size of the capsule can reach a desired value by adjusting the stirring speed, stirring time, etc. In the curable resin composition of the present invention, the average particle size of the capsule is preferably 30 μm to 400 μm, more preferably 30 μm to 200 μm. By making the average particle size of the capsule within the above range, the amount of residue generated when the processing bolt is screwed into the base material can be suppressed, and in addition, a strong fixing force can be obtained. Here, the average particle size of the capsule is obtained as described below. That is, a photograph of randomly selected capsules is taken using a scanning electron microscope, and the particle size is measured. This operation is performed on 100 capsules, and the average value thereof is used as the average particle size.

[0038] In one capsule, the mass ratio of the inclusion to the capsule wall (inclusion: capsule wall) is preferably 60:40 to 90:10. By the mass ratio being within the above range, the capsule wall has an appropriate thickness, the capsule itself is stable, and it has effects such as the capsule being sufficiently broken during screwing.

[0039] The component (B) that can be used in the present invention is a capsule, and the inclusion of the capsule of the component (B) is a polythiol. As the polythiol, any compound having two or more mercapto groups in one molecule can be used, preferably a compound having three or more mercapto groups in one molecule, and more preferably a compound having four mercapto groups in one molecule. In addition, only one kind of polythiol can be used, or two or more kinds can be used in combination. As specific examples of the polythiol, aliphatic polythiol compounds, aromatic polythiol compounds, polythiol compounds having a thioether bond, etc. can be mentioned, but it is not limited to these.

[0040] Examples of the aliphatic polythiol compound having two thiol groups include 1,2-ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 1,12-dodecanedithiol, 2,2-dimethyl-1,3-propanedithiol, 3-methyl-1,5-pentanedithiol, 2-methyl-1,8-octanedithiol, 1,4-cyclohexanedithiol, 1,4-bis(mercaptomethyl)cyclohexane, 1,1-cyclohexanedithiol, 1,2-cyclohexanedithiol, bicyclo[2.2.1]hepta-exo-cis-2,3-dithiol, 1,1-bis(mercaptomethyl)cyclohexane, bis(2-mercaptoethyl) ether, ethylene glycol bis(2-mercaptoacetate), and ethylene glycol bis(3-mercaptopropionate). However, the examples are not limited thereto.

[0041] Examples of the aliphatic polythiol compound having three thiol groups include 1,1,1-tris(mercaptomethyl)ethane, 2-ethyl-2-mercaptomethyl-1,3-propanedithiol, 1,2,3-propanetrithiol, trimethylolpropane tris(2-mercaptoacetate), trimethylolpropane tris(3-mercaptopropionate), and tris[(mercaptopropionyloxy)-ethyl] isocyanurate. However, the examples are not limited thereto.

[0042] Examples of the aliphatic polythiol compound having four or more thiol groups include pentaerythritol tetra(2-mercaptoacetate), pentaerythritol tetra(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutyrate), and dipentaerythritol hexa-3-mercaptopropionate. However, the examples are not limited thereto. The aliphatic polythiol compound having four or more thiol groups is preferably pentaerythritol tetra(3-mercaptopropionate).

[0043] Examples of the aromatic polythiol compounds include 1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,2-bis(mercaptomethyl)benzene, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, 1,2-bis(2-mercaptoethyl)benzene, 1,3-bis(2-mercaptoethyl)benzene, 1,4-bis(2-mercaptoethyl)benzene, 1,2-bis(2-mercaptoethyloxy)benzene, 1,3-bis(2-mercaptoethyloxy)benzene, 1,4-bis(2-mercaptoethyloxy)benzene, 1,2,3-trimercaptobenzene, 1,2,4-trimercaptobenzene, 1,3,5-trimercaptobenzene, 1,2,3-tris(mercaptomethyl)benzene, 1,2,4-tris(mercaptomethyl)benzene, 1,3,5-tris(mercaptomethyl)benzene, 1,2,3-tris(2-mercaptoethyl)benzene, 1,2,4-tris(2-mercaptoethyl)benzene, 1,3,5-tris(2-mercaptoethyl)benzene, 1,2,3-tris(2-mercaptoethyloxy)benzene, 1,2,4-tris(2-mercaptoethyloxy)benzene, 1,3,5-tris(2-mercaptoethyloxy)benzene, 1,2,3,4-tetramercaptobenzene, 1,2,3,5-tetramercaptobenzene, 1,2,4,5-tetramercaptobenzene, 1,2,3,4-tetrakis(mercaptomethyl)benzene, 1,2,3,5-tetrakis(mercaptomethyl)benzene, 1,2,4,5-tetrakis(mercaptomethyl)benzene, 1,2,3,4-tetrakis(2-mercaptoethyl)benzene, 1,2,3,5-tetrakis(2-mercaptoethyl)benzene, 1,2,4,5-tetrakis(2-mercaptoethyl)benzene, 1,2,3,4-tetrakis(2-mercaptoethyloxy)benzene, 1,2,3,5-tetrakis(2-mercaptoethyloxy)benzene, 1,2,4,5-tetrakis(2-mercaptoethyloxy)benzene, 2,2'-mercaptobiphenyl, 4,4'-thiobis-benzenethiol, 4,4'-dimercaptobiphenyl, 4,4'-dimercaptobibenzyl, 2,5-toluenedithiol, 3,4-toluenedithiol, 1,4-naphthalenedithiol, 1,5-naphthalenedithiol, 2,6-naphthalenedithiol, 2,7-naphthalenedithiol, 2,4-dimethylbenzene-1,3-dithiol, 4,5-dimethylbenzene-1,3-dithiol, 9,10-anthracenedimethanethiol, 1,3-bis(2-mercaptoethylthio)benzene, 1,4-bis(2-mercaptoethylthio)benzene, 1,2-bis(2-mercaptoethylthiomethyl)benzene, 1,3-bis(2-mercaptoethylthiomethyl)benzene, 1,4-bis(2-mercaptoethylthiomethyl)benzene, 1,2,3-tris(2-mercaptoethylthio)benzene, 1,2,4-tris(2-mercaptoethylthio)benzene, 1,3,5-tris(2-mercaptoethylthio)benzene, 1,2,3,4-tetrakis(2-mercaptoethylthio)benzene, 1,2,3,5-tetrakis(2-mercaptoethylthio)benzene, and 1,2,4,5-tetrakis(2-mercaptoethylthio)benzene, etc., but are not limited thereto.

[0044] Examples of the polythiol compound having a thioether bond include bis(2-mercaptoethyl) sulfide, bis(2-mercaptoethylthio)methane, 1,2-bis(2-mercaptoethylthio)ethane, 1,3-bis(2-mercaptoethylthio)propane, 1,2,3-tris(2-mercaptoethylthio)propane, tetrakis(2-mercaptoethylthiomethyl)methane, 1,2-bis(2-mercaptoethylthio)propanethiol, 2,5-dimercapto-1,4-dithiane, bis(2-mercaptoethyl) disulfide, 3,4-thiophenedithiol, 1,2-bis(2-mercaptoethyl)thio-3-mercaptopropane, and bis-(2-mercaptoethylthio-3-mercaptopropane) sulfide, etc., but are not limited thereto.

[0045] Specific examples of the polythiol having a secondary mercapto group include pentaerythritol tetra(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tri(3-mercaptobutyrate), trimethylolethane tri(3-mercaptobutyrate), trimethylolpropane tri(3-mercaptobutyrate), trimethylolethane tri(3-mercaptobutyrate), etc., but are not limited thereto. As commercial products, there are PEMP manufactured by SC Organic Chemical Co., Ltd., and PE1, BD1, NR1, etc. of the KarenzMT (registered trademark) series manufactured by Showa Denko K.K., etc., but are not limited thereto.

[0046] When measuring the cured product obtained by curing the composition of the inclusion of component (A), the inclusion of component (B), the component (C) described below, and the component (D) described below at 25°C in an atmosphere for 72 hours by thermomechanical analysis (TMA), in order to make the linear expansion coefficient reach a specific range (170 - 250 ppm / °C) in the temperature range of 140 - 150°C, it is preferred that: relative to 100 parts by mass of the inclusion of component (A), the content of the inclusion of component (B) is 50 - 100 parts by mass.

[0047] The component (C) that can be used in the present invention is a compound that promotes the curing of the inclusion of component (A) and the inclusion of component (B). As the component (C), an amine compound or the like is used, and it is preferably liquid at 25°C in an atmosphere. Examples of the amine compound include imidazole, 1,3-bis(4-piperidyl)propane, tris(dimethylaminomethyl)phenol tris(2-ethylhexanoate), 1,6-hexanediamine, 2,4,6-tris(dimethylaminomethyl)phenol, diphenylaminomethane, a substituted alkyl resin amine, a liquid polyamide such as a dimerized unsaturated fatty acid (Versamid (registered trademark) 125) obtained by reacting with an alkylene diamine, a non-volatile solid amine salt obtained by reacting a volatile liquid amine with an acid, an amine addition compound, and a water-insoluble polyamide resin, etc., but are not limited to these. The amine compound can be used alone or in combination of two or more.

[0048] By not being included in the inclusion of component (A) and the inclusion of component (B), the component (C) can further improve the storage stability, and it is preferably present outside the component (A) and the component (B) in the composition. In order to improve the curability, relative to 100 parts by mass in total of the inclusion of component (A) and the inclusion of component (B), the content of the component (C) (when using two or more kinds of component (C), it is the total amount thereof) is preferably 1 to 15 parts by mass. Alternatively, relative to 100 parts by mass of the inclusion of component (A), the content of the component (C) is preferably 5 to 20 parts by mass.

[0049] The component (D) that can be used in the present invention is an inorganic filler. Examples of the inorganic filler include silica powder, fumed silica powder, talc powder, calcium carbonate powder, diatomaceous earth, mica powder, mica powder, glass powder, etc. The component (D) can be used alone or in combination of two or more. From the viewpoint of improving the adhesive strength, the component (D) is preferably a mixture of diatomaceous earth and mica powder. As the shape of the inorganic filler, spherical, plate-like, needle-like, flaky, amorphous, etc. can be cited. The average particle diameter of the component (D) can be measured by a laser diffraction scattering method or the like. The 50% average particle diameter of the component (D) is the particle diameter at which the cumulative value in the particle size distribution obtained by the laser diffraction scattering method is 50%. The 50% average particle diameter of the component (D) is, for example, 0.1 to 150 μm. Each raw material constituting the component (D) preferably has a 50% average particle diameter in the range of 0.1 to 150 μm. In particular, the component (D) is more preferably a combination of a raw material having a 50% average particle diameter of 10 μm or less and a raw material having a 50% average particle diameter of 100 μm or more.

[0050] From the viewpoint of making the cured product exhibit toughness, the content of the component (D) (the total amount when two or more kinds of the component (D) are used) is preferably 1 to 15 parts by mass with respect to 100 parts by mass in total of the inclusion of the component (A) and the inclusion of the component (B), or the content of the component (D) is preferably 10 to 30 parts by mass with respect to 100 parts by mass of the inclusion of the component (A).

[0051] From the viewpoint of improving the airtightness (sealability) of the processing bolt, the mass ratio of the inclusion of the component (A), the inclusion of the component (B), the component (C) and the component (D) ((inclusion of the component (A): inclusion of the component (B): component (C): component (D))) is preferably 100:50 to 100:5 to 20:10 to 30.

[0052] The component (E) that can be used in the present invention is a (meth)acrylic polymer having adhesiveness in an atmosphere at 25°C. It is preferably used in the form of an aqueous solution in which the component (E) is made into an emulsion. An emulsion refers to a form in which polymer particles produced by adding a polymerizable monomer, a surfactant, a polymerization initiator and subjecting them to emulsion polymerization are stably dispersed in water. An emulsion produced in water is particularly referred to as an aqueous emulsion. In the curable composition of the present invention, the component (E) preferably exists in the form of a dispersed substance of the emulsion. As specific examples of the component (E), polymers of various (meth)acrylic monomers, copolymers of styrene monomers and (meth)acrylic monomers, etc. can be cited, but are not limited to these. For the aqueous emulsion, it has the following effects: during the drying process, while water volatilizes, the component (E) aggregates and fuses, causing the capsule to adhere (fix) to a screwed member or the like. Considering the ability to fix the capsule, the (meth)acrylic polymer preferably contains a styrene skeleton derived from a styrene monomer. The component (E) can be used alone or two or more kinds can be mixed and used.

[0053] In the present specification, the term “(meth)acrylic” means acrylic and / or methacrylic.

[0054] As specific examples of the component (E), ACRONAL YS-800ap, YS-756ap, YJ-2716Dap, YJ-2718Dap, YJ-2720Dap, JONCRYL PDX-7430, PDX-7164, 8380, 8383 manufactured by BASF Corporation, Polysol (registered trademark) AP-3160A manufactured by Showa Denko K.K., etc. can be cited, but are not limited to these. They can be used alone or two or more kinds can be mixed and used.

[0055] In an embodiment of the present invention, when the component (E) is added to the curable composition in the form of an aqueous emulsion (dispersoid of the aqueous emulsion), the solid content concentration of the component (E) is preferably 20% by mass to 70% by mass, more preferably 25% by mass to 65% by mass, and further preferably 30% by mass to 60% by mass.

[0056] With respect to 100 parts by mass in total of the components (A) to (D) in the curable resin composition, the content of the component (E) is preferably 1 to 20 parts by mass, more preferably 5 to 15 parts by mass. If the content of the component (E) is 1 part by mass or more, the capsules can be sufficiently adhered, and if it is 20 parts by mass or less, the generation of residues when the curable resin composition is applied to the screwed member and tightened can be suppressed.

[0057] The component (F) that can be used in the present invention is water. The component (F) can be used as a medium (dispersion medium of the emulsion) for dispersing the component (E) in the form of an emulsion (dispersoid of the emulsion). Examples of the component (F) include alkaline electrolyzed water, ion-exchanged water, etc., but are not limited thereto.

[0058] With respect to the whole curable resin composition (100% by mass), the content of the component (F) is preferably 10% by mass to 70% by mass, more preferably 20% by mass to 60% by mass. By adding water to the curable resin composition containing the above components (A) to (D) and, if necessary, the component (E), the respective components can also be brought to appropriate concentrations. In the case where the raw material containing other components contains water, this water from the raw material is treated as the component (F).

[0059] Considering storage stability, when the curable resin composition contains the components (A) to (F), the following state is preferred: in the component (F) (dispersion medium), the component (E) is an emulsion (the component (E) exists in the form of a dispersoid), the components (A), (B), and (D) are dispersed in the component (F), and the component (C) is dissolved or dispersed in the component (E) or the component (F).

[0060] In the curable resin composition of the present invention, in addition to the above respective components, various additives can be added as needed within a range not impairing the effects of the present invention. Examples of the additives include organic fillers (axial force regulators; excluding the component (E)), rust inhibitors (excluding the component (C)), defoamers, pigments (excluding the component (D)), dispersants, surfactants, rheology modifiers, thickeners, etc.

[0061] As an organic filler (axial force regulator; excluding component (E)), examples include polyethylene powder, polypropylene powder, polytetrafluoroethylene powder, nylon powder, etc., but are not limited to these. The organic filler has the effect of regulating the axial force when fastening screwed members, that is, the so-called effect of preventing the screwed part from jamming.

[0062] As a rust inhibitor (excluding component (C)), for example, sodium benzoate, benzotriazole, chromates (e.g., zinc chromate, calcium chromate, strontium chromate, barium chromate, potassium zinc chromate, zinc tetravalent chromate, etc.), phosphates (e.g., zinc phosphate, zinc phosphosilicate, zinc aluminum phosphate, zinc calcium phosphate, calcium phosphate, aluminum pyrophosphate, calcium pyrophosphate, aluminum dihydrogen triphosphate, aluminum metaphosphate, calcium metaphosphate, zinc phosphomolybdate, aluminum phosphomolybdate, etc.), nitrites (e.g., sodium nitrite, calcium nitrite, strontium nitrite, barium nitrite, ammonium nitrite, etc.), phytates (e.g., zinc phytate, sodium phytate, potassium phytate, calcium phytate, etc.), tannates (e.g., sodium tannate, potassium tannate, etc.), polyamine compounds (e.g., N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), propylenediaminetetraacetic acid (PDTA), iminodiacetic acid, nitrilotriacetic acid (NTA), diethylenetriaminepentamethylenephosphonic acid (DTPMP) and their alkali metal salts; intercalation compounds formed by embedding monoalkylamines, polyamines, quaternary ammonium ions, etc. into layered phosphates such as aluminum dihydrogen triphosphate; MIO, lead cyanamide, ammonium metavanadate, ammonium zirconium fluoride, zinc molybdate, aluminum molybdate, barium metaborate, zinc salts of organic nitro compounds, etc.). Specific examples of rust inhibitors include ASCOTRAN series manufactured by ASCOTEC Company, Kileslite series manufactured by Chelest Corp., etc., but are not limited to these.

[0063] As an antifoaming agent, for example, silicone antifoaming agents (silicone surfactants), modified silicone-based antifoaming agents, acetylenic alcohol surfactants, silica-based antifoaming agents, waxes, polyether-modified polydimethylsiloxanes, paraffin-based petroleum, defoaming aliphatic derivatives, etc. are preferred.

[0064] As pigments (excluding component (D)), organic pigments, inorganic pigments, etc. can be cited. As organic pigments, isoindolinone, isoindoline, azomethine, perylene, anthraquinone, dioxazine, phthalocyanine, etc. can be cited, and as inorganic pigments, carbon black, ultramarine blue, Prussian blue, lithopone, etc. can be cited. In addition, these pigments can also be surface-treated to have self-dispersing ability in aqueous media.

[0065] One embodiment of the present invention is to coat the curable resin composition of the present invention on the screwing member of the screwing portion. The curable resin composition of the present invention can be coated (pre-coated) on the screwing portion of screwing members such as screws and bolts, dried, and then used, thereby providing a processed product. In addition, in addition to screws and bolts, for example, threaded joints, sleeves, tapered plugs, elbows and other threaded joints having a screwing portion, the inner circumference of nuts, etc. can be cited, but it is not particularly limited to these. As the material of the above-mentioned screwing member, iron, aluminum, gold, stainless steel, SUS, etc. can be cited. In addition, it can be a material after plating treatment such as zinc chromate treatment is performed on them, or a material after an antirust agent is coated.

[0066] In order to dry the curable resin composition, it is preferably dried in an atmosphere of 25°C to 120°C using a hot air drying furnace or the like. By drying at a temperature of 25°C or higher, the volatilization is slow, and rusting on the screwing member can be suppressed. By drying at a temperature of 120°C or lower, the coating film becomes uniform. In addition, the drying time is preferably 5 minutes to 1 hour, more preferably 5 minutes to 30 minutes.

[0067] Examples

[0068] Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0069] [Raw materials for capsule preparation]

[0070] In order to prepare capsules, the following inclusion substances are prepared, and capsules are prepared by the following method. The capsule names of each capsule, the proportion (mass%) of the inclusion substance, and the components and their proportions (mass%) of the inclusion substance are summarized in Table 1.

[0071] Polyfunctional epoxy resin

[0072] · Bisphenol F type epoxy resin (jER (registered trademark) 806, manufactured by Mitsubishi Chemical Corporation)

[0073] · 4-functional glycidylamine type epoxy (jER (registered trademark) 604, manufactured by Mitsubishi Chemical Corporation)

[0074] Monofunctional epoxy resin

[0075] · Glycidyl neodecanoate (CARDURA E10P, manufactured by Momentive Performance Materials)

[0076] Polythiol

[0077] · Pentaerythritol tetra-3-mercaptopropionate (jER (registered trademark) Cure QX40, manufactured by Mitsubishi Chemical Corporation)

[0078] Acrylate resin

[0079] · Ethylene glycol dimethacrylate (NK ESTER 1G, Shin-Nakamura Chemical Co., Ltd.)

[0080] · Epoxy group-containing acrylic polymer (Marproof G-0150M, NOF Corporation)

[0081] · Ethoxylated bisphenol A dimethacrylate (NK ESTER BPE-80N, Shin-Nakamura Chemical Co., Ltd.)

[0082] · 1,6-Hexanediol dimethacrylate (Light-Ester 1.6HX, manufactured by Kyoeisha Chemical Co., Ltd.)

[0083] Organic peroxide

[0084] · Benzoyl peroxide (Nyper BW, manufactured by NOF Corporation).

[0085] [Preparation of Capsule A, Capsule A'2 and Capsule A'3]

[0086] Add 13.9 g of an isobutene-maleic anhydride copolymer (weight-average molecular weight: 165,000) with a solid content of 100% by mass to 94.5 g of ion-exchanged water, and heat the mixture to 40 °C while stirring. Further, add a 10% by mass aqueous tartaric acid solution, adjust the pH to the range of 3.0 to 4.0, then add 140 g of the inclusion compound described in Table 1, and stir while confirming the particle size. Further, add 183 g of ion-exchanged water, and heat the mixture to 60 °C while stirring. Then, add 57.1 g of a 14.6% by mass aqueous solution of glyoxal resin as the wall material, and carry out polycondensation for 1 hour while stirring. Then, further heat the mixture to 90 °C and carry out a polycondensation reaction for 2 hours while stirring. After cooling to room temperature, add a 28% by mass aqueous ammonia solution to neutralize the solution, thereby ending the reaction and obtaining a slurry of capsules. The slurry is dehydrated using a centrifugal dehydrator and then dried to obtain Capsule A, Capsule A'2 and Capsule A'3. The average particle size of the capsules is 150 μm.

[0087] [Preparation of Capsule A'1]

[0088] To 42.4 g of ion-exchanged water, 15.6 g of an isobutene-maleic anhydride copolymer (weight-average molecular weight: 165,000) with 100% by mass of solid components was added, and the temperature was raised to 40 °C while stirring. Further, a 10% by mass aqueous tartaric acid solution was added dropwise, and after adjusting the pH to 3.5, 140 g of the inclusion compound described in Table 1 was added, and stirring was carried out while confirming the particle size. Next, 268 g of ion-exchanged water and 66.6 g of a 14.6% by mass aqueous solution of glyoxal resin as the wall material were added, the temperature was raised to 60 °C, and polycondensation was carried out for 1 hour while stirring. Then, the temperature was further raised to 90 °C, and polycondensation reaction was carried out for 2 hours while stirring. After cooling to room temperature, a 28% by mass aqueous ammonia solution was added to neutralize the solution, thereby ending the reaction, and a slurry of capsules was obtained. The slurry was dehydrated and dried using a centrifugal dehydrator to obtain Capsule A'. The average particle size of the capsules was 50 μm.

[0089] [Preparation of Capsule B]

[0090] To 27.3 g of ion-exchanged water, 11.5 g of an isobutene-maleic anhydride copolymer (weight-average molecular weight: 165,000) with 100% by mass of solid components was added, and the temperature was raised to 40 °C while stirring in a container. A 10% by mass aqueous tartaric acid solution was added dropwise thereto to adjust the pH to 3.5, 90 g of the inclusion compound described in Table 1 was added, and stirring was carried out. Further, 172 g of ion-exchanged water was added, and stirring was carried out while confirming the particle size. Then, 42.4 g of a 14.6% by mass aqueous solution of glyoxal resin was added, the temperature was raised to 60 °C, and polycondensation was carried out for 1 hour while stirring. After further raising the temperature to 90 °C, polycondensation reaction was carried out for 2 hours while stirring. After cooling to room temperature, a 28% by mass aqueous ammonia solution was added to neutralize the solution, thereby ending the reaction, and a slurry of capsules was obtained. Next, the slurry was dehydrated using a centrifugal dehydrator to obtain Capsule B. The average particle size of the capsules was 55 μm.

[0091] [Preparation of Capsule B']

[0092] To 8500 g of ion-exchanged water, 6000 g of polyvinyl alcohol with a saponification value of 50% or more and a solid content of 100% by mass was added. After adding 7500 g of the inclusion described in Table 1, stirring was carried out while confirming the particle size. An aqueous solution (1762.5 g) obtained by adjusting a mixture of urea and resorcinol premixed at a mass ratio of 1:2 to a concentration of 15% by mass and 630 g of 35% formalin aqueous solution were successively added and stirred and mixed. Finally, neutralization was carried out using 20% by mass dilute sulfuric acid. 600 g of polyvinyl alcohol with a saponification value of 50% or more was added again and stirred. Subsequently, an aqueous solution (2756.25 g) obtained by adjusting a mixture of urea and resorcinol premixed at a mass ratio of 2:7 to 18% by mass and 1260 g of 35% formalin aqueous solution were added and stirred and mixed, thereby obtaining a slurry of capsules. The slurry was dehydrated using a centrifugal dehydrator to obtain capsule B'. The average particle size of this capsule was 30 μm.

[0093] [Table 1]

[0094]

[0095] In order to prepare the curable resin compositions of Examples 1 and 2 and Comparative Examples 1 to 3, the following components were prepared. Hereinafter, the curable resin compositions of Examples and Comparative Examples are also simply referred to as compositions.

[0096] (A) component: Capsules encapsulating polyfunctional epoxy resin and monofunctional epoxy resin as inclusion

[0097] · Capsule A

[0098] (A') component: Capsules other than component (A)

[0099] · Capsule A'1

[0100] · Capsule A'2

[0101] · Capsule A'3

[0102] (B) component: Capsules encapsulating polythiol as inclusion

[0103] · Capsule B

[0104] (B') component: Capsules other than component (B)

[0105] · Capsule B'

[0106] (C) component: A compound that promotes the curing of the inclusion of component (A) and the inclusion of component (B)

[0107] · 2,4,6-Tris(dimethylaminomethyl)phenol (Ankamine (registered trademark) K-54, manufactured by Air Product Japan, Inc.)

[0108] · Tris(dimethylaminomethyl)phenol tris(2-ethylhexanoate) (Ankamine (registered trademark) K-61B, manufactured by AirProduct Japan, Inc.)

[0109] · A solution of 50% by mass of solid components of p-tolyldiethanolamine (reagent) in n-propanol (NPA)

[0110] (D) Component: Filler

[0111] · Silicon dioxide (dried diatomaceous earth) (50% average particle size: 3 μm) (manufactured by SNOW FLOSS Celite Co., Ltd.)

[0112] · Flaky mica powder (50% average particle size: 130 μm) (SB-061R, manufactured by Yamaguchi Mica Co., Ltd.)

[0113] (E) Component: Adhesive (meth)acrylic polymer

[0114] · Non-self-crosslinking (meth)acrylic copolymer aqueous emulsion (solid content: 45% by mass) (Newcoat KSB-1, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0115] · Non-self-crosslinking (meth)acrylic-styrene copolymer aqueous emulsion (solid content: 44% by mass) (Polysol (registered trademark) AP-3160A, manufactured by Showa Denko K.K.)

[0116] (F) Component: Water

[0117] · Ion-exchanged water

[0118] Organic filler (axial force regulator)

[0119] · Chemically pulverized polyethylene fine powder (Flo-Thene UF20S, manufactured by Sumitomo Seika Chemicals Co., Ltd.)

[0120] Rust inhibitor

[0121] · Rust inhibitor without sodium nitrite (ASCOTRAN AL4, manufactured by Ascotec Holding GmbH)

[0122] · Water-soluble rust inhibitor for iron (Kileslite W-16B, manufactured by Chelest Corp.).

[0123] To prepare the composition, weigh the components (C) to (F) and place them in a beaker, and stir for 30 minutes at room temperature. Then, add the component (A) (or component (A')) and the component (B) (or component (B')), and further stir for 30 minutes at room temperature. The detailed preparation amounts are shown in Table 2. All the values in Table 2 are expressed in parts by mass.

[0124] [Table 2]

[0125]

[0126] Produce bolts coated with the composition according to the following processing method. Hereinafter, the bolts processed using the composition are also referred to as processed bolts.

[0127] [Processing method]

[0128] While stirring the composition using a stirrer, add pure water little by little each time, measure the viscosity at 25°C in an atmosphere using a BL-type viscometer at 60 rpm and rotor No. 2, and adjust the viscosity of the composition to 100 mPa·s. Then, prepare bolts that have undergone zinc chromate treatment (hexagonal bolts with a bolt size of M10 (diameter) × 1.5 (pitch) × 20 mm (length)). Hold the hexagonal part of the bolt by hand, or lower the bolt vertically with respect to the liquid level of the processing liquid while it is fixed using a magnet for dip coating, thereby coating 80% to 90% of the threaded part with the processing liquid (dip coating). After a few seconds, slowly remove the bolt from the liquid surface. While keeping the tip of the screw facing down, wipe off the sealant attached to the tip of the screw using a waste cloth, and within 20 minutes, without allowing the tip of the screw to come into contact and keeping it facing down, perform heat drying at 80°C for 20 minutes using a hot air dryer.

[0129] Conduct a pressure resistance test on the processed bolts, and summarize the results in Table 3. In Table 3, the processed bolts using the compositions of Examples 1 and 2 and Comparative Examples 1 to 3 are respectively referred to as Example 1, Example 2, and Comparative Examples 1 to 3.

[0130] [Pressure resistance test]

[0131] To confirm the airtightness (sealability) of the processed bolts, conduct a thermal cycle test with 2 hours in an atmosphere of 140°C and 2 hours in an atmosphere of -40°C as one cycle, and confirm the sealability at the initial (0th cycle), 10th cycle, 20th cycle, and 30th cycle. To confirm the airtightness, use Figure 1 such an aluminum fixture. In Figure 1Insert bolts into hole 1 and thread in 5 machined bolts respectively with a tightening torque of 30 N·m. Install a pipe for supplying pressurized gas into gas inlet hole 2. After dipping the fixture into a container filled with water, supply nitrogen, which is the pressurized gas, to the fixture for evaluation. The pressure of nitrogen is applied in three stages: 0.5 MPa, 1.0 MPa, and 1.5 MPa, and maintained for 2 minutes at each pressure. Check for gas leakage, and then increase the pressure. Visually confirm the pressure at which leakage occurs from the part where the machined bolts are tightened, and count the number of machined bolts among the 5 that do not have gas leakage. This is designated as the "airtightness retention rate (%)". After performing thermal cycle tests for the initial (0th cycle), 10th cycle, 20th cycle, and 30th cycle on different machined bolts, confirm the airtightness retention rate.

[0132] [Table 3]

[0133]

[0134] It can be seen that: compared with Comparative Examples 1 - 3, Examples 1 and 2 maintained airtightness under the pressures of all three conditions from the initial stage to the 30th cycle. In Comparative Examples 1 - 3, there were cases where airtightness was maintained and cases where it was not maintained up to the 30th cycle. It can be speculated that the state of the cured product changed over time.

[0135] Prepare test compositions formed only from the inclusion of component (A), the inclusion of component (B), component (C), and component (D) according to Tables 1 and 2. Summarize the results in Table 4. Similar to Examples 1, 2 and Comparative Examples 1 - 3 in Table 2, in Table 4, the test compositions formed only from the inclusion of component (A), the inclusion of component (B), component (C), and component (D) are also respectively referred to as Examples 1, 2, and Comparative Examples 1 - 3. Perform thermomechanical analysis (TMA) measurements on Examples 1, 2, and Comparative Examples 1 - 3. Summarize the results in Table 4.

[0136] [Thermomechanical analysis (TMA) measurements]

[0137] After preparing the test composition described in Table 4, it was allowed to cure by being placed in an atmosphere at 25°C for 72 hours, and a cylindrical cured product with a diameter of 5 mm was produced and cut into a length of 10 mm. Using a TMA / SS6000 manufactured by Seiko Instruments Inc., the cured product was measured with a load of 9.81 mN in a tensile mode in a temperature range of 25°C to 200°C, at a rate of 5°C / min, and a frequency of 1 Hz. Compared with the temperature at which the coefficient of linear expansion changes, the coefficient of linear expansion at a temperature lower than it was set as α1 (ppm / °C), and the coefficient of linear expansion at a temperature higher than it was set as α2 (ppm / °C). Furthermore, the temperature at the intersection of the tangents of α1 and α2 was taken as the glass transition temperature and denoted as "Tg (°C)". The coefficient of linear expansion in the temperature range of 140 to 150°C in the coefficient of linear expansion (α2) was set as the "coefficient of linear expansion (ppm / °C)". In order to maintain the airtightness, the coefficient of linear expansion is preferably 170 to 250 ppm / °C in the temperature range of 140 to 150°C, and Tg is preferably 0 to 50°C.

[0138] [Table 4]

[0139]

[0140] This application is based on Japanese Patent Application No. 2022-202917 filed on December 20, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0141] Explanation of reference numerals

[0142] 1: Bolt insertion hole

[0143] 2: Gas inlet hole

Claims

1. A curable resin composition comprising components (A) to (D): (A) Component: A capsule encapsulating a polyfunctional epoxy resin and a monofunctional epoxy resin as an inclusion; (B) Component: A capsule encapsulating a polythiol as an inclusion; (C) Component: A compound that promotes the curing of the inclusion of component (A) and the inclusion of component (B); and (D) Component: An inorganic filler.

2. The curable resin composition according to claim 1, wherein, The mass ratio of the polyfunctional epoxy resin to the monofunctional epoxy resin in the component (A) is 99:1 to 25:

75.

3. The curable resin composition according to claim 1, further comprising an adhesive (meth)acrylic polymer as component (E).

4. The curable resin composition according to claim 3, wherein, The (meth)acrylic polymer of the component (E) contains a styrene skeleton.

5. The curable resin composition according to claim 3, further comprising water as component (F).

6. The curable resin composition according to claim 5, wherein, In the component (F), the component (E) is an emulsion, the components (A), (B), and (D) are dispersed in the component (F), and the component (C) is dissolved or dispersed in the component (E) or the component (F).

7. The curable resin composition according to claim 1, wherein, When measuring the cured product obtained by curing the composition of the inclusion of component (A), the inclusion of component (B), the component (C), and the component (D) in a 25°C atmosphere for 72 hours by thermomechanical analysis (TMA), the linear expansion coefficient is 170 ppm / °C to 250 ppm / °C in the temperature range of 140°C to 150°C.

8. The curable resin composition according to claim 1, wherein, When measuring the cured product obtained by curing the composition of the inclusion of component (A), the inclusion of component (B), the component (C), and the component (D) in a 25°C atmosphere for 72 hours by thermomechanical analysis (TMA), the glass transition temperature is 0°C to 50°C.

9. The curable resin composition according to claim 1, wherein, The mass ratio of the inclusion of component (A), the inclusion of component (B), the component (C), and the component (D) is 100:50 to 100:5 to 20:10 to 30.

10. A screwed member obtained by coating the screwed portion with the curable resin composition according to claim 1.

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