Compositions, paints, coating films and structures

Abstract

[Problem] To provide a composition having excellent corrosion resistance and durability. [Solution] Provided is a composition containing a curable resin and / or a precursor thereof, inorganic particles, and graphene, wherein the graphene has an average thickness of 0.30 nm to 50 nm.

Description

Compositions and paints

[0001] The present invention relates to a composition and a protective coating using the same.

[0002] In recent years, research into the application of graphene has been actively conducted, and coating technology utilizing the thin-layered sheet structure of graphene has attracted particular attention. The thin-layered sheet structure of graphene can inhibit the permeation of oxygen and water, which are substances that cause metal corrosion. One application that utilizes the properties of graphene is corrosion-resistant paint, and the use of graphene is expected to further improve corrosion resistance.

[0003] Meanwhile, steel materials used in buildings and structures such as steel towers and bridges are required to have improved rust resistance, and paints with high rust prevention properties, such as heavy-duty anticorrosion paints, are being used. Zinc-rich paints containing zinc have been proposed as heavy-duty anticorrosion paints. As a technology for saving the consumption of metal zinc resources in zinc-containing anticorrosion paints, for example, a zinc-carbon alkene corrosion-resistant primer containing an epoxy resin, a solvent, a dispersion medium, zinc powder, an anti-settling agent, and a carbon alkene has been proposed (see, for example, Patent Document 1).

[0004] Furthermore, compositions suitable for corrosion-resistant coatings and metal coatings using nanoplatelets have been proposed, such as a coating composition containing inorganic nanoplatelets modified with an oligomer and forming a mesophase structure in a resin matrix, and an oligomer (see, for example, Patent Document 2), and a composition containing graphene platelets having one nanoscale dimension and 25 or fewer layers, and a carrier medium, which includes one of graphene nanoplates, bilayer graphene nanoplates, few-layer graphene nanoplates, and / or graphite flakes, or a mixture of two or more thereof (see, for example, Patent Document 3).

[0005] Chinese Patent Application Publication No. 105623473 Specification Special Publication No. 2017-512845 Special Publication No. 2021-512995

[0006] However, all of the compositions described in Patent Documents 1 to 3 have the problem that their corrosion resistance is still insufficient. Furthermore, the corrosion resistance tends to decrease over long-term use, and durability is also an issue.

[0007] Therefore, an object of the present invention is to provide a composition that can give a cured product that has excellent corrosion resistance and durability.

[0008] The present invention is mainly a composition containing a curable resin and / or a precursor thereof, inorganic particles, and graphene, wherein the graphene has an average thickness of 0.30 nm or more and 100 nm or less.

[0009] By curing the composition of the present invention, a cured product having excellent corrosion resistance and durability can be obtained. The composition of the present invention can provide a coating material having excellent corrosion resistance and durability in the cured product, a coating film thereof, and a coated structure.

[0010] The composition of the present invention contains a curable resin and / or its precursor, inorganic particles, and graphene having an average thickness of 0.30 nm or more and 100 nm or less. The curable resin and its precursor function as a binder that holds the inorganic particles and graphene in the composition. The inorganic particles function to inhibit the permeation of corrosion-causing substances such as water and oxygen. As described above, graphene has a thin-layer sheet structure and can inhibit the permeation of corrosion-causing substances such as water and oxygen (shielding effect). Furthermore, because graphene is electrically conductive, when combined with inorganic particles, it electrically connects the inorganic particles to form a conductive network, thereby providing a sacrificial corrosion protection effect in which the inorganic particles rust before the steel material. To achieve these effects more efficiently, it is important that graphene maintains a thin layer state and is highly dispersed in the composition. Since such graphene can support and strengthen the function of the inorganic particles, high corrosion resistance can be achieved even with a lower inorganic particle content.

[0011] The average thickness of graphene is an indicator of the maintenance and dispersibility of the thin layer state of graphene in the composition. If the thin layer state cannot be maintained, the graphene will no longer be in a sheet form and will curl up, becoming thick. Furthermore, if the dispersibility is poor, agglomerates will form due to inter-sheet aggregation and in-plane aggregation, resulting in a thicker graphene. In other words, the thinner the average thickness of graphene, the more highly dispersed the graphene will be while maintaining the thin layer state in the composition, and the more excellent the shielding effect and conductive network formation ability will be.

[0012] The average thickness of graphene in the composition of the present invention is 0.30 nm or more and 100 nm or less. An average thickness of 0.30 nm of graphene is the theoretical minimum value of graphene and indicates single-layer graphene. On the other hand, when the average thickness of graphene is 100 nm or less, high dispersibility in the composition, a shielding effect due to the thin-layer sheet structure, and a sacrificial corrosion protection effect due to the formation of a conductive network can be enhanced, and the corrosion resistance and durability of the cured product can be further improved. The average thickness of graphene is 50 nm or less, more preferably 20 nm or less, even more preferably 10 nm or less, and even more preferably 6 nm or less.

[0013] Here, the average thickness of graphene in the present invention is calculated by collecting graphene from the composition, observing it using an atomic force microscope with a magnified field of view of about 1 to 20 μm square so that the graphene can be properly observed, measuring the thickness of each of 10 randomly selected graphene pieces, and calculating the arithmetic mean value of the thickness measurements at five randomly selected points on each graphene. Note that the thickness of each graphene is the arithmetic mean value of the thickness measurements at five randomly selected points on each graphene.

[0014] After forming a cured product such as a coating film, the coating film is peeled off and cut with a spatula to obtain a piece of the cured product, which is then cross-sectioned using ion milling, and the cross-section is subjected to TEM analysis under a magnified observation range of approximately 10 to 100 nm square so that the graphene can be properly observed. The thickness of each graphene is calculated by measuring the thickness of each of 10 randomly selected graphenes and determining the arithmetic mean value of the thickness measurements at five randomly selected points on each graphene.

[0015] <Curable Resin and / or Precursor Thereof> The curable resin in the present invention refers to a resin that cures by volatilization or reaction of a solvent, and examples thereof include epoxy resins, urethane resins, acrylic resins, polyester resins, melamine resins, silicone resins, alkyd resins, and silicate resins. Commercially available curable resins for coating compositions can be suitably used. Two or more of these may be contained. Among these, from the viewpoints of coatability and handleability, epoxy resins, urethane resins, acrylic resins, and silicate resins are preferred. Furthermore, when a surface treatment agent is present on graphene and the graphene, a crosslinkable resin is preferred from the viewpoints of forming a bond with the surface treatment agent, improving coating film strength, and further enhancing durability. Epoxy resins, urethane resins, or silicate resins are more preferred, and epoxy resins or silicate resins are even more preferred.

[0016] Examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, novolac epoxy resins, and modified versions of these, such as acrylic-modified epoxy resins and urethane-modified epoxy resins. Two or more of these may be contained. Among these, bisphenol A epoxy resins, bisphenol F epoxy resins, and novolac epoxy resins are preferred.

[0017] The epoxy equivalent of the epoxy resin is preferably 100 or more and 5,000 or less. If the epoxy equivalent is 100 or more, the strength of the coating film obtained from the composition can be improved. On the other hand, if the epoxy equivalent is 5,000 or less, the composition can be cured efficiently.

[0018] When an epoxy resin is contained as the curable resin, it is preferable to further contain an epoxy resin curing agent. That is, the composition of the present invention may contain an epoxy resin and an epoxy resin curing agent, or the composition of the present invention may contain an epoxy resin as the curable resin and be used in combination with a separately prepared epoxy resin curing agent. The composition of the present invention may also contain an epoxy resin curing agent instead of the curable resin and be used in combination with a separately prepared epoxy resin. Examples of epoxy resin curing agents include polyfunctional amine compounds and polyamidoamine compounds, and commercially available epoxy resin curing agents can be used. Two or more of these may be contained. The active hydrogen equivalent of the epoxy resin curing agent is preferably 30 or more and 5,000 or less. An active hydrogen equivalent of 30 or more can improve the strength of the coating film obtained from the composition. On the other hand, an active hydrogen equivalent of 5,000 or less can efficiently cure the composition.

[0019] Examples of polyfunctional amine compounds include aliphatic polyamines, aromatic polyamines, and alicyclic polyamines. Examples of aliphatic polyamines include alkylenediamines having 2 to 10 carbon atoms, such as ethylenediamine, propylenediamine, and hexamethylenediamine, and polyalkylenepolyamines having 4 to 20 carbon atoms, such as diethylenetriamine and triethylenetetramine. Examples of aromatic polyamines include aromatic polyamines having 6 to 20 carbon atoms, such as phenylenediamine and diphenyletherdiamine. Examples of alicyclic polyamines include N-aminoethylpiperazine, isophoronediamine, methylenebiscyclohexaneamine, norbornenediamine, and 1,2-diaminocyclohexane.

[0020] Examples of polyamidoamine compounds include "LUCKAMIDE" (registered trademark) TD-960, TD-961, TD-977, and TD-984 manufactured by DIC Corporation, and NEWMIDE (trade name) 500, 515, and 522 manufactured by Harima Chemicals Group Co., Ltd.

[0021] As the urethane resin, an ester-based urethane resin, an ether-based urethane resin, or a carbonate-based urethane resin is preferred, and an ester-based urethane resin or a carbonate-based urethane resin is more preferred.

[0022] Examples of urethane resin precursors include polyols and urethane resin curing agents. However, the composition of the present invention may contain only a polyol or a urethane resin curing agent as the curable resin precursor and use it in combination with a separately prepared urethane resin curing agent or polyol. The present invention also includes cases in which only one of a polyol and a urethane resin curing agent is contained as the curable resin and / or its precursor.

[0023] Examples of polyols include polyester polyols, polyether polyols, and polycarbonate polyols. Examples of polyester polyols include condensates of polyols such as alkylene glycols and alkylene diols with carboxylic acids such as glutaric acid and adipic acid. Examples of polyether polyols include polyoxyethylene diols, polyoxyethylene triols, polyoxypropylene diols, and polyoxypropylene triols. Examples of polycarbonate polyols include compounds obtained by dealcoholization or dephenolization of polyols such as alkylene glycols and alkylene diols with dialkyl carbonates, diaryl carbonates, and the like.

[0024] Examples of urethane resin curing agents include polyisocyanates. Examples of polyisocyanates include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and modified products thereof. Examples of aromatic polyisocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and paraphenylene diisocyanate. Examples of aliphatic polyisocyanates include hexamethylene diisocyanate and lysine diisocyanate. Examples of alicyclic polyisocyanates include isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate.

[0025] The acrylic resin preferably contains, as a copolymerization component, acrylic acid, methacrylic acid, or a derivative thereof. Examples of the derivative of acrylic acid or methacrylic acid include esters of acrylic acid or methacrylic acid, acrylamide, methacrylamide, and fluorinated alkyl acrylate. The copolymerization component may further contain a non-acrylic component such as styrene, or an acrylate-functionalized polydimethylsiloxane.

[0026] The silicate resin is preferably, for example, amorphous silica and / or an alkoxysilane compound, such as tetraethoxysilane, tetramethoxysilane, tetraisopropoxysilane, or a derivative thereof.

[0027] <Inorganic particles> Inorganic particles include anti-rust pigments and extender pigments that are generally used in paints.When the composition of the present invention is used as a protective paint, the corrosion resistance of the cured product can be further improved by selecting a material with high sacrificial anticorrosion effect according to the relationship with the object to be protected.For example, when used as a protective paint for steel, by selecting zinc particles as the inorganic material, the sacrificial anticorrosion effect can further improve the corrosion resistance and durability of the cured product.

[0028] The inorganic particles preferably include zinc, iron oxide, mica, talc, bentonite, silicon dioxide, titanium oxide, aluminum oxide, barium sulfate, stainless steel, glass, and aluminum, and may contain two or more of these.

[0029] Examples of the shape of the inorganic particles include spherical, flake, thin plate, fibrous, and irregular shapes.

[0030] Among these, mica, talc, bentonite, flaky titanium oxide, stainless steel flakes, glass flakes, and aluminum flakes have a high shielding effect due to their flat shape, and can further improve the corrosion resistance of the cured product. Furthermore, zinc particles have a high sacrificial anticorrosion effect, and can further improve the corrosion resistance of the cured product. It is preferable to combine zinc particles with talc, bentonite, glass flakes, etc., as this allows the viscosity of the composition and the mechanical properties of the coating film obtained from the composition to be easily adjusted within the desired range.

[0031] The average particle size (Ra) of the inorganic particles is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less, from the viewpoint of suppressing defects such as pinholes and further improving the corrosion resistance of the cured product. On the other hand, from the viewpoint of enhancing the shielding effect and sacrificial anticorrosion effect of the inorganic particles and further improving the corrosion resistance and durability of the cured product, it is preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 2.0 μm or more. The average particle size of the inorganic particles can be easily adjusted to the above range using known particle grinding techniques. Alternatively, commercially available inorganic particles having the desired particle size can be purchased and used.

[0032] The content of inorganic particles in the composition of the present invention is preferably 5 wt% or more and 60 wt% or less, based on the total weight of the solid content of the composition. By containing inorganic particles at 5 wt% or more, the corrosion resistance and durability of the cured product can be further improved. The content of inorganic particles is more preferably 10 wt% or more, and even more preferably 20 wt% or more. On the other hand, from the viewpoint of suppressing defects such as pinholes and cracks and further improving the corrosion resistance and durability of the cured product, the content of inorganic particles is preferably 60 wt% or less, more preferably 50 wt% or less, and even more preferably 40 wt% or less.

[0033] Zinc-rich paints containing a large amount of zinc are generally used to enhance corrosion resistance. However, according to the present invention, the addition of graphene improves corrosion resistance and durability, so that high corrosion resistance and durability can be obtained with a smaller amount of zinc, thereby enabling reduction in the amount of zinc used.

[0034] The content of inorganic particles in the composition of the present invention can be calculated from the raw material composition of the composition, if the raw material composition is known.

[0035] Furthermore, if the raw material composition is not known, it can be determined by the following procedure. First, 100 g of the composition before curing is diluted with 100 g of the composition solvent, and the mixture is centrifuged at 11.00 rpm for 20 minutes to remove the supernatant. Another 100 g of solvent is added, and the mixture is redispersed. The centrifugal separator is then operated at 11.00 rpm for 20 minutes to remove the supernatant. This process is repeated twice to remove the graphene and resin. The resulting solid is separated by filtration, washed five times with solvent, vacuum dried, and weighed to determine the inorganic particle weight (W1). Next, 100 g of the composition before curing is cured and weighed to determine the total solid weight (W2). The content (wt%) of inorganic particles in the composition can be calculated from W1 / W2×100.

[0036] <Graphene> Generally, graphene is a single-atom thick sp ２ Although graphene refers to a sheet of bonded carbon atoms (single-layer graphene), in this specification, the term "graphene" also refers to a thin flake-like structure formed by stacking single-layer graphene. Similarly, the term "graphene oxide" also refers to a thin flake-like structure formed by stacking single-layer graphene.

[0037] In this specification, graphene oxide is referred to as graphene when the O / C ratio, which is the atomic ratio of oxygen atoms to carbon atoms measured by X-ray photoelectron spectroscopy (XPS), exceeds 0.4, and graphene is referred to as graphene when the O / C ratio is 0.4 or less. Also, reduced graphene oxide obtained by reducing graphene oxide and having an O / C ratio of 0.4 or less is referred to as graphene.

[0038] Furthermore, graphene that has been subjected to a surface treatment described below can be used, and in this specification, graphene or graphene oxide that has been subjected to such a surface treatment will also be referred to as "graphene" or "graphene oxide."

[0039] Graphene may be produced by a physical exfoliation method or a chemical exfoliation method. When produced by a chemical exfoliation method, the method for producing graphene oxide is not particularly limited, and known methods such as the Hummers method can be used. Alternatively, commercially available graphene oxide may be purchased.

[0040] The size (Rb) of graphene in the direction parallel to the graphene layer is preferably 0.10 μm or more, more preferably 0.50 μm or more, and even more preferably 1.0 μm or more, from the viewpoint of enhancing the shielding effect due to the thin sheet structure and the sacrificial corrosion protection effect due to the conductive network formation due to high dispersibility in the composition, thereby further improving the corrosion resistance and durability of the cured product, and from the viewpoint of easily adjusting Ra / Rb to the preferred range described below. On the other hand, from the viewpoint of suppressing unintended aggregation, enhancing the sacrificial corrosion protection effect due to the conductive network formation, further improving the corrosion resistance and durability of the cured product, and from the viewpoint of easily adjusting Ra / Rb to the preferred range described below, it is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 20 μm or less. Note that the size of graphene in the direction parallel to the graphene layer can be easily adjusted to the above-mentioned range by micronizing graphene oxide or reduced graphene by the method described below. Alternatively, commercially available graphene oxide or graphene of the desired size may be used.

[0041] To achieve shielding properties and the formation of a conductive network by adding graphene, it is preferable to use thin, highly dispersed graphene as described above, and to have the inorganic particles and graphene appropriately arranged and in contact with each other. In particular, when the content of inorganic particles is low, the distance between the inorganic particles increases, so it is preferable that the graphene be appropriately dispersed and arranged. Therefore, it was found that there is a preferred range for the ratio (Ra / Rb) of the average particle size (Ra) of the inorganic particles to the size (Rb) in the direction parallel to the graphene layer. Ra / Rb is a characteristic that affects the shielding effect and conductive network described above.

[0042] From the viewpoint of improving the connectivity between inorganic particles of graphene and further enhancing corrosion resistance, Ra / Rb is preferably 0.5 or more, more preferably 0.6 or more, and even more preferably 0.7 or more. Similarly, Ra / Rb is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less.

[0043] Here, the average particle size (Ra) of the inorganic particles can be measured by the method described in Measurement Example 4 of the Examples below. Moreover, the size (Rb) of the graphene in the direction parallel to the graphene layer can be measured by the method described in Measurement Example 2 of the Examples below.

[0044] Note that Ra / Rb can be easily adjusted to the above-mentioned range by using graphene and inorganic particles each having Ra and Rb within the preferred ranges described below.

[0045] The oxygen-to-carbon elemental ratio (O / C ratio) of graphene measured by X-ray photoelectron spectroscopy represents the amount of functional groups contained in the graphene and serves as an index of its affinity with solvents and curable resins and / or their precursors. The functional groups contained in graphene enhance its affinity with solvents and curable resins and / or their precursors, making it easier to disperse graphene while maintaining its thin-layer sheet structure, thereby further improving the corrosion resistance of the cured product. Furthermore, the bond between graphene and the curable resins and / or their precursors can further improve durability. For this reason, the O / C ratio of graphene is preferably 0.05 or more, more preferably 0.08 or more. On the other hand, from the viewpoint of further suppressing permeation of water and oxygen and further improving the corrosion resistance and durability of the cured product, the O / C ratio is preferably 0.40 or less, more preferably 0.30 or less.

[0046] The O / C ratio of graphene can be measured by collecting graphene from the composition and subjecting it to X-ray photoelectron spectroscopy (XPS). The C1s main peak due to carbon atoms is assigned to 284.3 eV, and the O1s peak due to oxygen atoms is assigned to a peak around 533 eV. The O / C ratio is calculated from the area ratio of these peaks, and the resulting value is rounded to two decimal places.

[0047] Note that, for example, when a chemical exfoliation method is used, the O / C ratio of graphene can be easily adjusted to the above-mentioned range by adjusting the oxidation degree of the graphene oxide used as a raw material or the reduction degree under the reduction reaction conditions. Alternatively, commercially available graphene oxide or graphene having a desired O / C ratio may be used. Furthermore, the O / C ratio can be easily adjusted to the above-mentioned range by adjusting the amount of the surface treatment agent described below.

[0048] The atomic ratio of nitrogen to carbon (N / C ratio) of graphene measured by X-ray photoelectron spectroscopy serves as an indicator of the amount of nitrogen attached to the surface treatment agent described below when the surface treatment agent contains nitrogen atoms. The attachment of a surface treatment agent containing nitrogen atoms to graphene not only improves dispersibility in the resin, but also alleviates stress generated in the resin, particularly between inorganic particles, and suppresses cracking during drying and curing of the composition. Suppressing cracking can further improve the corrosion resistance and durability of the cured product. For this reason, the N / C ratio of graphene is preferably 0.005 or more, more preferably 0.007 or more, and even more preferably 0.010 or more. Meanwhile, from the viewpoint of suppressing unintended aggregation and further improving the corrosion resistance and durability of the cured product, the N / C ratio of graphene is preferably 0.200 or less, more preferably 0.100 or less, and even more preferably 0.050 or less.

[0049] The N / C ratio of graphene can be measured by extracting graphene from the composition and measuring it by XPS. The C1s main peak due to carbon atoms is assigned to 284.3 eV, and the N1s peak due to nitrogen atoms is assigned to a peak around 402 eV. The N / C ratio is calculated from the area ratio of these peaks, and the resulting value is rounded to three decimal places.

[0050] The N / C ratio of graphene can be easily adjusted to the above-mentioned range, for example, by adjusting the amount of a surface treatment agent to be described later.

[0051] When surface-treated graphene is used as the graphene, the surface treatment agent preferably contains nitrogen atoms. The nitrogen atoms impart a positive charge to the surface treatment agent, allowing it to electrostatically adsorb to the negative charge of graphene. Unlike rigid covalent bonds, electrostatic adsorption is dynamic, providing a stress-relieving effect and further improving the durability of the coating film. Furthermore, the nitrogen atoms are preferably derived from a compound having an amino group, and the cross-linkable resin and the amino group react to form cross-links, thereby further improving the durability of the coating film.

[0052] The nitrogen atom is preferably derived from a primary amine, a secondary amine, a tertiary amine, a quaternary ammonium salt, or a nitrogen-containing cyclic compound. The nitrogen atom may have two or more types of nitrogen atoms derived from different compounds, or one compound may have two or more nitrogen atoms.

[0053] The surface treatment agent may be a low molecular weight or a high molecular weight. From the viewpoint of further improving corrosion resistance, a low molecular weight is preferred, and from the viewpoint of further improving durability, a high molecular weight is preferred. Here, a low molecular weight refers to a compound having a molecular weight of less than 1,000, and a high molecular weight refers to a compound having a molecular weight of 1,000 or more.

[0054] When the surface treatment agent has a low molecular weight, it preferably has an aromatic ring and / or an alkyl group to facilitate attachment of the surface treatment agent to graphene. In this specification, the aromatic ring refers to a cyclic structure that satisfies Hückel's rule and has aromaticity.

[0055] Examples of surface treatment agents having an aromatic ring include 2-halogenated anilines, 3-halogenated anilines, 4-halogenated anilines, benzylamine, phenylethylamine, 1-naphthylamine, 2-naphthylamine, aniline, p-toluidine, m-toluidine, o-toluidine, 1-aminoanthracene, 2-aminoanthracene, 9-aminoanthracene, 1-aminopyrene, N-methylaniline, N-ethylaniline, N-isopropylaniline, 4-ethylaniline, 4-isopropylaniline, N,N-dimethylaniline, 4-nitroaniline, diphenylamine, N-methyldiphenylamine, 2,4,6-trimethylaniline, 4-methoxyaniline, N-methylbenzylamine, N,N-dimethylbenzylamine, N,N-diethylbenzylamine, benzamide, dopamine, phenylalanine, tyrosine, tryptophan, histidine, and salts thereof. Two or more of these may be used.

[0056] Examples of surface treatment agents having an alkyl group include monoamine compounds such as n-butylamine, n-hexylamine, n-octylamine, n-dodecylamine, n-octadecylamine, sec-butylamine, tert-butylamine, isobutylamine, 3-aminopentane, 3-methylbutylamine, 2-heptylamine (2-aminoheptane), 2-aminooctane, 2-ethylhexylamine, and 1,2-dimethyl-n-propylamine; and alkyl compounds having 2 to 10 carbon atoms such as ethylenediamine, propylenediamine, and hexamethylenediamine. Examples include aromatic polyamines having 6 to 20 carbon atoms, such as diamine, 1,6-diaminopyrene, 1,8-diaminopyrene, 1,4-phenylenediamine, 1,3-phenylenediamine, 1,2-phenylenediamine, 1,4-diaminoanthraquinone, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene, p-xylenediamine, m-xylenediamine, and 1,2,4-triaminobenzene, and polyalkylene polyamines having 4 to 20 carbon atoms, such as diethylenetriamine and triethylenetetramine. Two or more of these may be used.

[0057] When the surface treatment agent is a polymer, its weight-average molecular weight is preferably 5,000 or more, and more preferably 10,000 or more, from the viewpoint of facilitating adhesion of the surface treatment agent to graphene and further improving durability. On the other hand, from the viewpoint of suppressing aggregation, the weight-average molecular weight of the surface treatment agent is preferably 500,000 or less, more preferably 200,000 or less, and even more preferably 100,000 or less. Examples of polymer surface treatment agents having a weight-average molecular weight within this range include "Epomin" (registered trademark) and "Polyment" (registered trademark) manufactured by Nippon Shokubai Co., Ltd.

[0058] Furthermore, an epoxy resin curing agent may be used as the surface treatment agent, and the above-mentioned epoxy resin curing agents can be preferably used. For example, many types are commercially available, such as "LUCKAMIDE" (registered trademark) manufactured by DIC Corporation, "jER Cure" (registered trademark) manufactured by Mitsubishi Chemical Corporation, and "NEUMIDE" (trade name) manufactured by Harima Chemical Group Co., Ltd. The use of these curing agents as surface treatment agents is preferred because of their high affinity with thermosetting resins and / or their precursors.

[0059] The chemical structure of the surface treatment agent used in the present invention can be identified by TOF-SIMS.

[0060] The graphene content in the composition of the present invention is preferably 0.01 wt % or more and 0.9 wt % or less based on the total weight of the solid content. The graphene in the composition of the present invention maintains a thin layer and has excellent dispersibility, so that even a small amount added can exhibit its effects. When graphene that is poorly dispersible and no longer a thin layer is used, the amount of graphene required tends to increase. Furthermore, compositions containing aggregated graphene are prone to defects such as pinholes. Therefore, it is preferable to obtain a high effect by adding a smaller amount of graphene.

[0061] By setting the graphene content to 0.01 wt % or more, corrosion resistance and durability can be further improved due to the shielding effect of graphene and the formation of a conductive network. The graphene content is more preferably 0.05 wt % or more, and even more preferably 0.08 wt % or more, based on the total weight of the solid content. On the other hand, by setting the graphene content to 0.9 wt % or less, unintended aggregation can be suppressed, and corrosion resistance and durability can be further improved. The graphene content is more preferably 0.6 wt % or less, and even more preferably 0.4 wt % or less, based on the total weight of the solid content.

[0062] <Others> The composition of the present invention may further contain a solvent and any additives.

[0063] The solvent is preferably one that can dissolve the curable resin and / or its precursor and is volatilizable, and can be appropriately selected depending on the coatability of the composition. Specific examples include mineral oil, xylene, toluene, ethylbenzene, MIBK (methyl isobutyl ketone), MEK (methyl ethyl ketone), acetone, butyl acetate, ethyl acetate, n-butanol, isobutanol, isopropyl alcohol, ethanol, N-methylpyrrolidone, and N,N-dimethylformamide. Two or more of these may be used.

[0064] When an aromatic solvent such as xylene or toluene is used, the content of the aromatic solvent is preferably 1 part by weight or more and 50 parts by weight or less per 100 parts by weight of the solid content of the composition, from the viewpoint of improving the coatability.

[0065] <Production Method> Next, a method for producing the composition of the present invention will be described.

[0066] First, a method for producing graphene will be described using a chemical exfoliation method as an example.

[0067] The chemical exfoliation method preferably includes, in this order, a step of oxidatively exfoliating graphite to obtain graphene oxide (graphite exfoliation step) and a step of reducing graphene (reduction step). If necessary, a step of attaching a surface treatment agent to graphene (surface treatment step) and / or a step of adjusting the size of graphene in a direction parallel to the graphene layer (micronization step) may be included between the graphite exfoliation step and the reduction step. When surface-treated graphene is used, the surface treatment agent may be attached to graphene, or the surface-treated graphene may be obtained by attaching the surface treatment agent to graphene oxide and then performing a reduction treatment. Furthermore, when micronizing graphene, the graphene oxide may be micronized, or the reduced graphene may be micronized. From the viewpoint of uniformity of the reduction reaction, it is preferable to perform the reduction step in a micronized state of graphene oxide, and it is preferable to perform the micronization step before or during the reduction step. Therefore, it is preferable to include the graphite exfoliation step, surface treatment step, micronization step, and reduction step in this order. Furthermore, a drying step for removing moisture may be included as necessary.

[0068] [Graphite Exfoliation Step] First, graphite is oxidatively exfoliated to obtain graphene oxide. The oxidation degree of graphene oxide can be adjusted by changing the amount of oxidizing agent used in the oxidation reaction of graphite. Specifically, the greater the amount of sodium nitrate and potassium permanganate used relative to graphite in the oxidation reaction, the higher the oxidation degree, and the smaller the amount, the lower the oxidation degree. The weight ratio of sodium nitrate to graphite is preferably 0.200 or more and 0.800 or less. The ratio of potassium permanganate to graphite is preferably 1.00 or more and 4.0 or less.

[0069] [Surface Treatment Step] Next, graphene oxide and a surface treatment agent are mixed together to adhere the surface treatment agent to the graphene. Examples of the mixing method include mixing using a mixer or kneader such as an automatic mortar, a triple roll mill, a bead mill, a planetary ball mill, a homogenizer, a homodisper, a homomixer, a planetary mixer, or a twin-screw kneader.

[0070] [Micronization Step] Next, the graphene oxide is micronized. Examples of micronization methods include a method of colliding a pressure-applied dispersion against a single ceramic ball, a method using a liquid-liquid shear wet jet mill in which pressure-applied dispersions are collided with each other to disperse the particles, and a method of applying ultrasonic waves to the dispersion. In the micronization step, the graphene oxide or graphene tends to be micronized as the processing pressure and output increase, and as the processing time increases. The size of the graphene after reduction can be adjusted by the type, processing conditions, and processing time of the micronization treatment in the micronization step. To adjust the size parallel to the graphene layer within the aforementioned range, the solids concentration of the graphene oxide or graphene in the micronization step is preferably 0.01 wt % or more and 2 wt % or less. Furthermore, when performing ultrasonic treatment, the ultrasonic output is preferably 100 W or more and 3000 W or less.

[0071] [Reduction Step] Next, the finely divided graphene oxide is reduced. As a reduction method, chemical reduction is preferred. In the case of chemical reduction, examples of the reducing agent include organic reducing agents and inorganic reducing agents, but inorganic reducing agents are more preferred because of the ease of cleaning after reduction.

[0072] Examples of organic reducing agents include aldehyde reducing agents, hydrazine derivative reducing agents, and alcohol reducing agents. Among them, alcohol reducing agents are particularly suitable because they can reduce relatively gently. Examples of alcohol reducing agents include methanol, ethanol, propanol, isopropyl alcohol, butanol, benzyl alcohol, phenol, ethanolamine, ethylene glycol, propylene glycol, and diethylene glycol.

[0073] Examples of inorganic reducing agents include sodium dithionite, potassium dithionite, phosphorous acid, sodium borohydride, hydrazine, etc. Among them, sodium dithionite and potassium dithionite are preferably used because they can reduce graphene while relatively retaining acidic groups, thereby enabling the production of graphene that is highly dispersible in solvents.

[0074] After the reduction step is completed, the purity of the graphene can be improved by preferably carrying out a washing step of diluting with water and filtering.

[0075] [Drying Step] After the reduction step, the graphene can be diluted with water, frozen, and dried using a dryer such as a freeze dryer or a spray dryer to be powdered.

[0076] Next, an example of a method for producing a composition using graphene powder will be described.

[0077] For example, there are methods of mixing graphene powder with a curable resin and / or its precursor, inorganic particles, and, if necessary, a solvent and any additives, and methods of mixing graphene with a commercially available coating composition containing inorganic particles and a curable resin and / or its precursor. In the former method, the inorganic particles and graphene may be added and mixed simultaneously, or may be added and mixed separately. From the viewpoint of further enhancing the dispersibility of graphene, it is preferable to mix graphene and inorganic particles with a solution in which a curable resin and / or its precursor is dissolved in a solvent.

[0078] Examples of the mixing device include mixers and kneaders such as a bead mill, a homodisper, a homomixer, a planetary mixer, and a sand mill.

[0079] When the composition of the present invention contains a curable resin precursor, the base agent (e.g., polyol) and the curing agent (e.g., urethane resin curing agent) may be stored in separate containers until immediately before use. In this case, the graphene and inorganic particles may be contained together with the base agent or may be contained together with the curing agent. Furthermore, when the composition of the present invention contains an epoxy resin and an epoxy resin curing agent, the epoxy resin and the epoxy resin curing agent may be stored in separate containers until immediately before use. In this case, the graphene and inorganic particles may be contained together with the epoxy resin or may be contained together with the epoxy resin curing agent.

[0080] <Use of the Composition> A second aspect of the present invention is a coating material comprising the composition of the present invention.

[0081] The composition of the present invention can be suitably used in protective coatings, but can also be used in applications that utilize the thermal conductivity, electromagnetic wave shielding properties, and resin strength-enhancing effects of graphene. By adjusting the properties of each material in the composition to the aforementioned ranges, these performances can be improved. Taking thermal conductivity as an example, graphene can connect thermally conductive inorganic particles to form a heat propagation path, thereby improving thermal conductivity.

[0082] Examples of protective coatings include anticorrosion coatings or antirust coatings for preventing decay of wood substrates and corrosion of metal substrates, waterproof coatings for preventing water penetration, chemical-resistant coatings for protecting substrates from deterioration due to contact with chemicals, etc. Among these, the composition and protective coating of the present invention can be suitably used as an antirust coating for preventing corrosion due to rust of metal materials.

[0083] A third aspect of the present invention is a coating film formed by applying the coating material of the present invention.

[0084] By applying a protective coating comprising the composition of the present invention, a coating film with excellent corrosion resistance and durability can be obtained. The composition and coating of the present invention can be suitably used as a coating film formed by applying it to a substrate and drying it. Examples of application methods include applicator application, bar coating, spin coating, roller application, brush coating, and spray coating. The drying method can be appropriately selected depending on the solvent, resin, and application, and examples include natural drying, heat drying, and hot air drying.

[0085] The composition of the present invention may be used by, for example, injecting it into a crack and then drying and / or curing it through a crosslinking reaction. Known methods can be used for the injection and curing.

[0086] A fourth aspect of the present invention is a structure to which the coating material of the present invention is applied.

[0087] By applying the coating material of the present invention, structures with excellent corrosion resistance and durability can be obtained. Here, examples of structures include infrastructure such as bridges, steel bridges, guardrails, and signs, industrial facilities such as plants, pipes, and steel pipes, vehicles such as ships, automobiles, trains, and aircraft, metal casings for electrical equipment, buildings such as buildings and houses, and metal products such as cans. From the viewpoint of requiring higher corrosion resistance, it is preferable to apply the coating material to infrastructure, industrial facilities, and vehicles. It is even more preferable to apply the coating material to structures exposed to highly corrosive environments such as coastal areas.

[0088] The cured product obtained by curing the composition of the present invention has excellent corrosion resistance and durability. As an index of corrosion resistance, it is preferable that the water vapor permeability and oxygen permeability are low. Specifically, the water vapor permeability measured by the method described in Measurement Example 6 of the Examples below is 300 g / m ２ ・24h or less is preferable, 250g / m ２ 24 hours or less is more preferable, 225 g / m ２ 24 hours or less is even more preferable. Because water acts as an oxygen carrier, the lower the water vapor transmission rate, the lower the oxygen transmission rate tends to be.

[0089] As another indicator of corrosion resistance, a low corrosion potential, which indicates the resistance to corrosion, is preferred. Specifically, the corrosion potential measured by the method described in Measurement Example 7 of the Examples below is preferably −0.9 V or less, and more preferably −1.0 V or less.

[0090] As an indicator of durability, a longer time is preferred to reach a score of 3 (the width of the red rust at the notch is 2 mm) when a salt spray resistance test is performed by the method described in Measurement Example 8 of the Examples below. The time to reach a score of 3 in the salt spray resistance test is significantly extended in the presence of the sacrificial corrosion protection effect of zinc. Therefore, when the composition does not contain zinc, the time to reach a score of 3 in the salt spray resistance test is preferably 500 hours or more, more preferably 600 hours or more, and even more preferably 700 hours or more. On the other hand, when the composition contains zinc, the time to reach a score of 3 in the salt spray resistance test is preferably 1,400 hours or more, more preferably 2,000 hours or more, and even more preferably 3,000 hours or more.

[0091] The present invention will be described below using examples. First, the evaluation methods used in each example and comparative example will be described.

[0092] Measurement Example 1: Average Thickness of Graphene The compositions prepared in each of the Examples and Comparative Examples were diluted 10-fold with N-methylpyrrolidone and processed for 30 minutes at 3,000 rpm using a Homodisper 2.5 filter (Primix Corporation) to prepare a diluted solution. The diluted solution was passed through a mesh filter with openings large enough to remove inorganic particles, and the inorganic particles were removed. The obtained filtrate was filtered using filter paper to recover graphene. The recovered graphene was washed five times with 20 mL of N-methylpyrrolidone. The washed graphene was diluted to 0.01 wt % and processed for 60 seconds using a "Filmix" (registered trademark) 30-30 filter (Primix Corporation) at a rotation speed of 40 m / s (shear rate: 20,000 per second) to obtain a diluted graphene solution. The diluted graphene solution was dropped onto a mica substrate and dried, resulting in graphene adhering to the substrate. The graphene on the substrate was observed using an atomic force microscope (Dimension Icon; Bruker) with a magnified field of view of approximately 1 to 10 μm square, and the thickness of each of 10 randomly selected graphenes was measured. The thickness of each graphene was taken as the arithmetic mean of the thickness measurements at five randomly selected points on each graphene. The average thickness of the graphene was calculated by determining the arithmetic mean of the thicknesses of the 10 graphenes.

[0093] Measurement Example 2: Size (Rb) of graphene in the direction parallel to the graphene layers A diluted graphene solution was prepared in the same manner as in Measurement Example 1, and the diluted graphene solution was dropped onto a mica substrate and dried to adhere graphene to the substrate. The graphene on the substrate was observed at a magnification of 30,000 times using an S-5500 electron microscope (manufactured by Hitachi High-Technologies Corporation). For 10 randomly selected graphene particles, the length of the longest part (major axis) and the length of the shortest part (minor axis) in the direction parallel to the graphene layers were measured, and the size in the direction parallel to the graphene layers was calculated by calculating the arithmetic mean of the values ​​obtained by (major axis + minor axis) / 2.

[0094] [Measurement Example 3: O / C Ratio and N / C Ratio by X-ray Photoelectron Spectroscopy] The surface-treated graphene powders prepared in each of the Examples and Comparative Examples were subjected to photoelectron spectrum measurement using an X-ray photoelectron spectrometer Quantera SXM (manufactured by ULVAC-PHI, Inc.). α１，２ The X-ray diameter was 200 μm, and the photoelectron escape angle was 45°. The C1s main peak due to carbon atoms was assigned to 284.3 eV, the O1s peak due to oxygen atoms was assigned to a peak near 533 eV, and the N1s peak due to nitrogen atoms was assigned to a peak near 402 eV. The O / C ratio was calculated from the area ratio of the O1s peak and the C1s peak, and the obtained value was rounded to two decimal places. In addition, the N / C was calculated from the area ratio of the N1s peak and the C1s peak, and the obtained value was rounded to three decimal places. Note that since the O / C ratio and N / C ratio of graphene do not change between the composition and the graphene dispersion, analysis was performed using a graphene dispersion.

[0095] Measurement Example 4: Average Particle Size (Ra) of Inorganic Particles The compositions prepared in each Example and Comparative Example were diluted 100-fold with N-methylpyrrolidone and processed for 30 minutes at 3,000 rpm using a Homodisper 2.5 (Primix Corporation) to prepare a diluted solution. 20 mL of the diluted solution was filtered through filter paper, and the resulting filter cake was washed with 20 mL of N-methylpyrrolidone five times to remove the resin component, yielding a mixture of inorganic particles and graphene. The mixture of inorganic particles and graphene was diluted to 0.01 wt % and processed for 60 seconds using a "Filmix" (registered trademark) 30-30 (Primix Corporation) at a rotation speed of 40 m / s (shear rate: 20,000 per second) to obtain a particle redispersion. The particle redispersion was dropped onto a mica substrate and dried, resulting in the inorganic particles and graphene adhering to the substrate. The inorganic particles on the substrate were observed using an S-5500 electron microscope (Hitachi High-Technologies Corporation) at a magnification of 1,500 to 50,000 times so that the inorganic particles were properly within the field of view, and 20 randomly selected inorganic particles were photographed. However, for flaky or flat-shaped particles such as bentonite and stainless steel flakes, 20 inorganic particles were selected from the particles with the largest surface facing the observation direction and photographed. For spherical particles such as zinc particles, irregular particles, fibrous particles, and flat-shaped particles, the length of the longest part (major axis) and the length of the shortest part (minor axis) in the observed image were measured. The average particle size (Ra) of the inorganic particles was calculated by calculating the arithmetic mean value of the value obtained by (major axis + minor axis) / 2 for each particle measured as described above.

[0096] [Measurement Example 5: Number of Defects] The compositions prepared in each Example and Comparative Example were spray-coated onto an A4 size 50 μm thick PET film, then dried at room temperature, and left to stand for one week to harden, forming a 100 μm thick cured film. The surface of the obtained cured film was observed under an optical microscope at 100x magnification, and 10 randomly selected locations were observed for defects such as cracks and pinholes, and the corrosion resistance was evaluated based on the number of locations where defects were found. The fewer locations where defects were found, the better the corrosion resistance.

[0097] [Measurement Example 6: Water Vapor Transmission Rate] In the same manner as in Measurement Example 5, a 100 μm thick cured film was formed on an A4-sized 50 μm thick PET film. With the cured film surface facing downward, the cured film was peeled off while pulling up the PET film side. The obtained cured film was cut into a 12 cm square, and the area that would come into contact with the chamber packing was protected with aluminum tape. The film was then placed in a MOCON water vapor transmission rate measuring device PERMATRAN-W 3 / 33MG+. The water vapor transmission rate was measured using an isobaric method under conditions of a chamber temperature of 20°C and a relative humidity of 90%. The lower the water vapor transmission rate, the better the corrosion resistance.

[0098] Measurement Example 7: Corrosion Potential The compositions prepared in each Example and Comparative Example were applied using a spray gun to a sandblasted general structural rolled steel plate (material: SS400) measuring 15 cm x 7 cm x 0.25 cm thick, dried at room temperature, and left to stand for one day to form a cured film. The thickness of the cured film was adjusted to 80±10 μm. A commercially available anti-corrosion paint ("Zinky" (registered trademark) 8000HB, manufactured by Nippon Paint Co., Ltd.) was applied using a brush to exposed areas of the substrate where no cured film was formed. After drying, the paint was left to stand for one week to cure, yielding a test plate. The test plate was connected to the working electrode of a Solartron analytical potentiostat Model 1480A, a platinum electrode to the counter electrode, and a silver-silver chloride electrode to the reference electrode. The test plate was immersed in 300 mL of a 3.5 wt % sodium chloride aqueous solution (pH = 7) at room temperature in a 500 mL beaker, and measurement was initiated. The measurement was performed by first stabilizing the sample with an open circuit for an initial 900 seconds, then sweeping the voltage from -0.2 V to +0.5 V at a rate of 0.003 V / s in voltage sweep mode to measure the current value. The absolute values ​​of the obtained current values ​​were plotted, and the voltage at which the current value reached a minimum was taken as the corrosion potential. The lower the corrosion potential (the larger the absolute value), the better the corrosion resistance.

[0099] Measurement Example 8: Salt Spray Resistance Time A test plate was obtained in the same manner as in Measurement Example 7. A linear incision measuring 5 cm in length and 0.5 to 1.0 mm in depth was made in the center of the test plate, and the plate was then placed in a salt spray tester (HAIDA HD-E808-120). After starting the salt spray test using a 5 wt % sodium chloride aqueous solution (pH = 7) heated to 35°C, each sample was scored according to the rust occurrence status as shown below, and the change over time was recorded. Durability was evaluated from the time when a score of 3 was reached. Score 0: Close to the initial state, with no red rust observed. When zinc was used, white rust was observed due to the sacrificial corrosion protection effect, but no red rust was observed. Score 1: Red rust was observed throughout the incision. Score 2: Red rust less than 2 mm in width was observed throughout the incision, and there was one or more locations around the incision where red rust was observed due to swelling of the cured film or pitting corrosion outside the incision. Score 3: Multiple blisters and pitting corrosion are observed around the notch, and the width of the red rust at the notch is 2 mm or more.

[0100] Synthesis Example 1: Preparation of Graphene Oxide Using 1500-mesh natural graphite powder (Shanghai Yifan Graphite Co., Ltd.), 10 g of natural graphite powder was placed in an ice bath. 220 ml of 98% concentrated sulfuric acid, 5 g of sodium nitrate, and 30 g of potassium permanganate were added, and the mixture was mechanically stirred for 1 hour while maintaining the temperature at 20°C or below. The mixture was removed from the ice bath and stirred in a 35°C water bath for 4 hours. 500 ml of ion-exchanged water was then added, and the resulting suspension was stirred at 90°C for an additional 15 minutes. Finally, 600 ml of ion-exchanged water and 50 ml of hydrogen peroxide were added, and the mixture was stirred for 5 minutes to obtain a graphene oxide dispersion. The mixture was filtered while still hot, and the metal ions were washed off with a dilute hydrochloric acid solution. The acid was then washed off with ion-exchanged water. The washing was repeated until the pH reached 7, and the mixture was concentrated by suction filtration to prepare a 45 wt% graphene oxide wet cake. The elemental ratio of oxygen atoms to carbon atoms (O / C ratio) of the prepared graphene oxide measured by X-ray photoelectron spectroscopy was 0.53.

[0101] Example 1 (Preparation of Surface-Treated Graphene) 11.1 g (5 g solids) of 45 wt % graphene oxide wet cake prepared in Synthesis Example 1 was diluted with 988.9 g of ion-exchanged water to a concentration of 0.5 wt %. The diluted solution was treated for 30 minutes at 3,000 rpm using a Homodisper 2.5 (Primix Corporation) to obtain a uniform graphene oxide dispersion. Sodium hydroxide was added to adjust the pH to 8.5, and 2.5 g of dopamine hydrochloride (Tokyo Chemical Industry Co., Ltd.) was added as a surface treatment agent. The resulting mixture was treated for 60 minutes at 3,000 rpm using a Homodisper 2.5 (Primix Corporation). The resulting mixture was then further treated for 180 seconds at a rotation speed of 40 m / s (shear rate: 20,000 per second) using a "Filmix" (registered trademark) 30-30 (Primix Corporation). 25 g of sodium dithionite was added to the graphene oxide dispersion, and the mixture was reduced by stirring for 1 hour at 2,000 rpm using a Homodisper 2.5 (Primix Corporation) in a water bath at 40°C. The mixture was then filtered using a vacuum suction filter, and further washed five times by diluting with water to a concentration of 0.5 wt % and suction filtering. This washing process was repeated five times to obtain a graphene water wet cake. The obtained graphene water wet cake was diluted with water to a concentration of 1 wt % and placed in an eggplant flask. The eggplant flask was cooled and frozen with liquid nitrogen, and the mixture was freeze-dried overnight using an EYELA FDU-1200 freeze dryer to obtain graphene powder. The O / C ratio and N / C ratio of graphene were measured using the method described in Measurement Example 3, and the results are shown in Table 2.

[0102] (Preparation of Composition) 32.45 g of epoxy resin "Epiclon" (registered trademark) 1050 (bisphenol A type epoxy resin, epoxy equivalent 450-500 g / eq) manufactured by DIC Corporation was weighed out, 30 g of xylene and 2.4 g of n-butanol were added, and the mixture was heated to 90°C to dissolve. The mixture was then stirred for 20 minutes at 3,000 rpm using a Homodisper 2.5 (Primix Corporation). 30 g of zinc powder (average particle size 10 μm) manufactured by Hayashi Pure Chemical Industries, Ltd., 5 g of bentonite manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., and 0.1 g of graphene powder obtained by the above-mentioned method (0.1 wt% of the total solid content) were added to the resulting solution, and the mixture was stirred for 30 minutes at 3,000 rpm using a Homodisper 2.5 (Primix Corporation). 46.36 g of NUMIDO 515 (trade name) manufactured by Harima Chemical Group Co., Ltd. (polyamidoamine, active hydrogen equivalent 185, solids content 70 wt%, solids weight 32.45 g) was added as an epoxy resin curing agent, and the mixture was further stirred at 3,000 rpm for 10 minutes using a Homodisper 2.5 (Primix Corporation) to homogenize, thereby preparing a composition. The content of inorganic particles in the resulting composition was 35 wt% based on the total solids content of the composition.

[0103] For the obtained composition, the average thickness of graphene and the size in the direction parallel to the graphene layer were measured by the methods described in Measurement Examples 1 and 2, and the results are shown in Table 2.

[0104] The resulting compositions were evaluated for corrosion resistance and durability by the methods described in Measurement Examples 5 to 8, and the results are shown in Table 3.

[0105] Example 2 Graphene powder was obtained in the same manner as in Example 1, except that in the preparation of surface-treated graphene, the surface treatment agent was changed to 3-chloroaniline manufactured by Tokyo Chemical Industry Co., Ltd. A composition was produced using the obtained graphene powder in the same manner as in Example 1, and evaluated.

[0106] [Example 3] A graphene powder was obtained in the same manner as in Example 1, except that in the preparation of surface-treated graphene, the surface treatment agent was changed to aniline hydrochloride manufactured by ThermoScientific Corp. A composition was produced using the obtained graphene powder in the same manner as in Example 1, and evaluated.

[0107] Example 4 Graphene powder was obtained in the same manner as in Example 1, except that in the preparation of surface-treated graphene, the surface treatment agent was changed to 1-aminopyrene manufactured by Tokyo Chemical Industry Co., Ltd. A composition was produced using the obtained graphene powder in the same manner as in Example 1, and evaluated.

[0108] Example 5 A composition was produced and evaluated in the same manner as in Example 1, except that the amount of graphene powder was changed to 0.03 g (0.03 wt % with respect to the total solid content) in the preparation of the composition.

[0109] Example 6 A composition was produced and evaluated in the same manner as in Example 1, except that the amount of graphene powder was changed to 0.07 g (0.07 wt % with respect to the total solid content) in the preparation of the composition.

[0110] [Example 7] A composition was produced and evaluated in the same manner as in Example 1, except that in preparing the composition, the amount of graphene powder was changed to 0.5 g (0.5 wt % with respect to the total solid content), the amount of "Epiclon" (registered trademark) 1050 was changed to 32.25 g, and the amount of Pneumide 515 (trade name) was changed to 46.07 g.

[0111] [Example 8] A composition was produced in the same manner as in Example 1, except that in preparing the composition, the amount of graphene powder was changed to 0.7 g (0.7 wt % with respect to the total solid content), the amount of "Epiclon" (registered trademark) 1050 was changed to 32.15 g, and the amount of Pneumide 515 (trade name) was changed to 45.93 g, and the composition was evaluated in the same manner as in Example 1.

[0112] [Example 9] A composition was produced in the same manner as in Example 1, except that the amounts of "Epiclon" (registered trademark) 1050 were changed to 17.45 g, zinc powder 60 g, bentonite 5 g, and Pneumide 515 (trade name) were changed to 24.93 g. The content of inorganic particles in the obtained composition was 65 wt% based on the total solid content of the composition. The obtained composition was evaluated in the same manner as in Example 1.

[0113] [Example 10] A composition was prepared in the same manner as in Example 1, except that the amounts of "Epiclon" (registered trademark) 1050 were changed to 22.45 g, zinc powder 50 g, bentonite 5 g, and Pneumide 515 (trade name) were changed to 32.07 g. The content of inorganic particles in the obtained composition was 55 wt% based on the total solid content of the composition. The obtained composition was evaluated in the same manner as in Example 1.

[0114] Example 11 A composition was produced in the same manner as in Example 1, except that the amounts of "Epiclon" (registered trademark) 1050 were changed to 27.4 g, zinc powder 40 g, bentonite 5 g, graphene powder 0.2 g, and Pneumide 515 (trade name) were changed to 39.14 g in the preparation of the composition. The content of inorganic particles in the obtained composition was 45 wt % with respect to the total solid content of the composition. The obtained composition was evaluated in the same manner as in Example 1.

[0115] Example 12 In preparing a composition, 13 g of zinc powder and 2 g of silicon dioxide were mixed with 35 g of isopropyl alcohol, and 0.4 g of graphene powder (0.4 wt % relative to the total solid content) obtained in the same manner as in Example 1 was added. The mixture was stirred for 20 minutes at 3,000 rpm using a Homodisper 2.5 (Primix Corporation) at a liquid temperature of 20°C using a water-cooled jacket. Subsequently, 27.4 g of amorphous silica as a silicate resin and 55 g of tetraethoxysilane (Tokyo Chemical Industry Co., Ltd.) were added, and the mixture was further stirred for 10 minutes at 3,000 rpm using a Homodisper 2.5 (Primix Corporation) to homogenize the mixture, thereby preparing a composition. The content of inorganic particles in the composition was 15 wt % relative to the total solid content of the composition. The resulting composition was evaluated in the same manner as in Example 1.

[0116] [Example 13] A composition was prepared in the same manner as in Example 12, except that the zinc powder, silicon dioxide, graphene powder, amorphous silica, and tetraethoxysilane were changed to 7 g, 1 g, 0.5 g, 45.75 g, and 90 g, respectively. The content of inorganic particles in the composition was 8 wt% relative to the total solid content of the composition. The obtained composition was evaluated in the same manner as in Example 1.

[0117] [Example 14] A composition was prepared in the same manner as in Example 12, except that the amounts of zinc powder, silicon dioxide, graphene powder, amorphous silica, and tetraethoxysilane were changed to 3.5 g, 0.5 g, 0.9 g, 47.5 g, and 100 g, respectively. The content of inorganic particles in the composition was 4 wt% relative to the total solid content of the composition. The obtained composition was evaluated in the same manner as in Example 1.

[0118] Example 15 A composition was produced and evaluated in the same manner as in Example 1, except that in the preparation of surface-treated graphene, the amount of sodium dithionite used was changed to 2.5 g.

[0119] Example 16 A composition was produced and evaluated in the same manner as in Example 1, except that in the preparation of surface-treated graphene, a step of applying ultrasonic waves at an output of 300 W for 10 minutes using an ultrasonic device UP400S (Hielscher) after the treatment with "Filmix" (registered trademark) 30-30 type (Primix Corporation) was added (micro-fine-graining step).

[0120] Example 17 A composition was produced and evaluated in the same manner as in Example 1, except that in the preparation of surface-treated graphene, a step of applying ultrasonic waves at an output of 300 W for 30 minutes using an ultrasonic device UP400S (Hielscher) after the treatment with "Filmix" (registered trademark) 30-30 type (Primix Corporation) was added.

[0121] Example 18 A composition was produced and evaluated in the same manner as in Example 1, except that in the preparation of surface-treated graphene, a step of applying ultrasonic waves at an output of 300 W for 60 minutes using an ultrasonic device UP400S (Hielscher) after the treatment with "Filmix" (registered trademark) 30-30 type (Primix Corporation) was added.

[0122] Example 19 A graphene powder was produced in the same manner as in Example 1, except that in the preparation of surface-treated graphene, the surface treatment agent was changed to 5 g of triethylenetetramine manufactured by Tokyo Chemical Industry Co., Ltd. A composition was produced using the obtained graphene powder in the same manner as in Example 1, and evaluated.

[0123] Example 20 Graphene powder was produced in the same manner as in Example 1, except that in the preparation of surface-treated graphene, the surface treatment agent was changed to 10 g of "Epomin" (registered trademark) SP-18 manufactured by Nippon Shokubai Co., Ltd. A composition was produced using the obtained graphene powder in the same manner as in Example 1, and evaluated.

[0124] Comparative Example 1 A composition was produced and evaluated in the same manner as in Example 1, except that graphene powder was not used in the preparation of the composition.

[0125] Comparative Example 2 A composition was produced and evaluated in the same manner as in Example 9, except that graphene powder was not used in the preparation of the composition.

[0126] Comparative Example 3 A composition was produced and evaluated in the same manner as in Example 10, except that graphene powder was not used in the preparation of the composition.

[0127] Comparative Example 4 A composition was produced and evaluated in the same manner as in Example 11, except that graphene powder was not used in the preparation of the composition.

[0128] Comparative Example 5 A composition was produced and evaluated in the same manner as in Example 12, except that no graphene powder was used and the amount of amorphous silica was changed to 27.8 g in the preparation of the composition.

[0129] Comparative Example 6 A composition was produced and evaluated in the same manner as in Example 13, except that the graphene powder was not used and the amount of amorphous silica was changed to 48.25 g in the preparation of the composition.

[0130] Comparative Example 7 A composition was produced and evaluated in the same manner as in Example 14, except that no graphene powder was used and the amount of amorphous silica was changed to 48.4 g in the preparation of the composition.

[0131] [Comparative Example 8] A composition was produced and evaluated in the same manner as in Example 1, except that in preparing the surface-treated graphene, no surface treatment agent was used and treatment with "FILMIX" (registered trademark) 30-30 type was not performed. [Example 21] Graphene powder was produced in the same manner as in Example 1. In preparing the composition, a composition was produced and evaluated in the same manner as in Example 1, except that stainless steel flakes (average particle size 30 μm) manufactured by Toyo Aluminum K.K. were used instead of zinc powder.

[0132] Example 22 A composition was prepared and evaluated in the same manner as in Example 1, except that aluminum flakes (average particle size: 30 μm) were used instead of zinc powder in preparing the composition.

[0133] Example 23 A composition was prepared and evaluated in the same manner as in Example 1, except that wet-pulverized mica powder (average particle size 22 μm) manufactured by Matsuo Sangyo Co., Ltd. was used instead of zinc powder in the preparation of the composition.

[0134] Example 24 Graphene powder was produced in the same manner as in Example 1, except that in the preparation of surface-treated graphene, the surface treatment agent was changed to 1,4-phenylenediamine manufactured by Tokyo Chemical Industry Co., Ltd.

[0135] (Preparation of Composition) 7.45 g of "Epiclon" 1050 manufactured by DIC Corporation was weighed out as an epoxy resin, and 18 g of xylene and 2 g of n-butanol were added. The mixture was heated to 90°C to dissolve, and then stirred for 20 minutes at 3,000 rpm using a Homodisper 2.5 (Primix Corporation). 82 g of stainless steel flakes (average particle size 30 μm) manufactured by Toyo Aluminum Co., Ltd. and 0.1 g of graphene powder (0.1 wt% based on the total solid weight) were added to the resulting solution, and the mixture was stirred for 30 minutes at 3,000 rpm using a Homodisper 2.5 (Primix Corporation). 10.6 g (solid content 70 wt %, solid weight 7.45 g) of NUMD 515 (trade name) manufactured by Harima Chemicals Group Co., Ltd. was added as an epoxy resin curing agent, 3.0 g of bentonite was added, and the mixture was further stirred at 3,000 rpm for 10 minutes using a Homodisper 2.5 (Primix Corporation) to homogenize, thereby preparing a composition. The resulting composition was evaluated in the same manner as in Example 1.

[0136] Example 25 A composition was prepared and evaluated in the same manner as in Example 24, except that in preparing the composition, the amounts of the epoxy resin, xylene, n-butanol, and epoxy resin curing agent were changed to 16.2 g, 36 g, 23.1 g (solid content 70 wt %, solid weight 16.2 g), and 3.5 g, respectively, and 64 g of aluminum flakes (average particle size 30 μm) were added instead of the stainless steel flakes.

[0137] Example 26 A composition was prepared and evaluated in the same manner as in Example 24, except that in preparing the composition, the added amount of epoxy resin was 15.95 g, the added amount of xylene was 36 g, the added amount of n-butanol was 4 g, the added amount of epoxy resin curing agent was 22.79 g (solid content 70 wt %, solid weight 15.95 g), and 65 g of wet-pulverized mica powder (average particle size 22 μm) manufactured by Matsuo Sangyo Co., Ltd. was added instead of the aluminum flakes.

[0138] Comparative Example 9 A composition was prepared and evaluated in the same manner as in Example 21, except that graphene powder was not used.

[0139] Comparative Example 10 A composition was prepared and evaluated in the same manner as in Example 22, except that graphene powder was not used.

[0140] Comparative Example 11 A composition was prepared and evaluated in the same manner as in Example 23, except that graphene powder was not used.

[0141] Comparative Example 12 A composition was prepared and evaluated in the same manner as in Example 24, except that graphene powder was not used.

[0142] The compositions and evaluation results of each of the Examples and Comparative Examples are shown in Tables 1 to 6.

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

Claims

1. 1. A composition comprising a curable resin and / or a precursor thereof, inorganic particles, and graphene, wherein the graphene has an average thickness of 0.30 nm or more and 100 nm or less, and a ratio (Ra / Rb) of an average particle size (Ra) of the inorganic particles to a size (Rb) of the graphene in a direction parallel to a graphene layer is 0.5 or more and 6 or less.

2. 2. The composition according to claim 1, wherein the graphene has an average thickness of 0.30 nm or more and 50 nm or less.

3. 2. The composition according to claim 1, wherein the graphene has an average thickness of 0.30 nm or more and 6 nm or less.

4. 2. The composition according to claim 1, wherein the graphene has an elemental ratio of oxygen to carbon (O / C ratio) of 0.05 or more and 0.40 or less, and an elemental ratio of nitrogen to carbon (N / C ratio) of 0.005 or more and 0.200 or less, as measured by X-ray photoelectron spectroscopy.

5. The composition according to claim 1, wherein the graphene is contained in an amount of 0.01 wt % or more and 0.9 wt % or less relative to a total weight of solids in the composition.

6. The composition according to claim 1 , comprising inorganic particles in an amount of 5% by weight to 60% by weight based on the total weight of solids in the composition.

7. 2. The composition according to claim 1, wherein the graphene has a size (Rb) of 0.10 μm or more and 100 μm or less in a direction parallel to the graphene layer.

8. The composition according to claim 1 , comprising a compound having an amino group and / or an aromatic ring on a surface of the graphene.

9. 2. The composition according to claim 1, wherein the inorganic particles comprise at least one selected from the group consisting of zinc, iron oxide, mica, talc, bentonite, silicon dioxide, titanium oxide, aluminum oxide, barium sulfate, stainless steel, glass, and aluminum.

10. The composition of claim 9 , wherein the inorganic particles comprise zinc.

11. A paint comprising the composition of claim 1.

12. A coating film formed by applying the coating material according to claim 11.

13. A structure coated with the coating material according to claim 11.