Vibration-damping epoxy resin composition, vibration-damping epoxy resin molded article, and method for manufacturing the molded article

Abstract

To provide a vibration-damping epoxy resin composition that allows for the easy formation of molded articles with a good balance of creep resistance and vibration damping properties. [Solution] A vibration-damping epoxy resin composition containing epoxy resin (A), dielectric material (B), conductive material (C), magnetic material (D), alkylene polyamine (E), and extender pigment (F), wherein the pigment volume concentration (PVC) is 25% or more.

Description

[Technical Field]

[0001] The present invention relates to a vibration-damping epoxy resin composition, a vibration-damping epoxy resin molded article, and a method for producing the molded article. [Background technology]

[0002] The underside of ship engines uses a filler material that offers excellent load resistance and heat resistance, aiming to enable accurate and easy installation of equipment. However, this filler material lacks vibration damping properties, raising concerns about damage to engine components due to engine vibrations. Therefore, the application of vibration damping materials to the underside of ship engines is being considered to prevent engine vibrations from being transmitted to engine components.

[0003] On the other hand, vibration damping materials commonly used are those made from flexible rubber-based materials or vibration-damping urethane resin compositions. For example, Patent Document 1 describes a vibration damping material made from a vibration-damping urethane resin composition. Furthermore, Patent Document 2 describes a vibration damping material for ships having a vibration damping layer in which two or more different vibration damping fillers, selected from ferroelectrics, conductors, and magnetics, are mixed in a polymer matrix material. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2016 / 031825 [Patent Document 2] Japanese Patent Publication No. 2019-73046 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] When vibration damping materials are used, especially in the main engines of ships, they are required to have a good balance between excellent creep resistance (small creep rate) and excellent vibration damping (large loss coefficient). On the other hand, conventional vibration damping materials, such as those described in Patent Documents 1 and 2, do not have sufficient creep resistance, and there is room for improvement in terms of the balance between excellent creep resistance and excellent vibration damping.

[0006] The present invention has been made in view of the above-mentioned problems, and aims to provide a vibration-damping epoxy resin composition that can easily form a molded article with a good balance of creep resistance and vibration damping properties. [Means for solving the problem]

[0007] As a result of diligent research to solve the aforementioned problems, the inventors of the present invention have found that the aforementioned problems can be solved according to the following configuration example, and have completed the present invention. An example of the configuration of the present invention is as follows.

[0008] [1] It contains epoxy resin (A), dielectric material (B), conductive material (C), magnetic material (D), alkylene polyamine (E), and extender pigment (F), The pigment volume concentration (PVC) is 25% or higher. Vibration-damping epoxy resin composition. [2] The vibration-damping epoxy resin composition according to [1], wherein the viscosity at 23°C, as measured using a B-type viscometer, is 100,000 mPa·s or less. [3] The vibration-damping epoxy resin composition according to [1] or [2], further comprising a tertiary amine (G).

[0009] [4] A vibration-damping epoxy resin molded article formed from a vibration-damping epoxy resin composition described in any of [1] to [3]. [5] The damping epoxy resin molded body according to [4], wherein the creep change rate, which is the change rate of the thickness before and after applying a load of 4.5 MPa at 80°C for 1,000 hours, is 0.5% or less. [6] The damping epoxy resin molded body according to [4], wherein the creep change rate, which is the change rate of the thickness before and after applying a load of 4.5 MPa at 80°C for 1,000 hours, is 0.2% or less. [7] The damping epoxy resin molded body according to any one of [4] to [6], which is used for the main engine of a ship.

[0010] [8] A method for manufacturing a damping epoxy resin molded body, comprising a step of pouring the damping epoxy resin composition according to any one of [1] to [3] into a construction site to form a molded body.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a damping epoxy resin composition capable of easily forming a molded body that is excellently balanced in creep resistance (small creep change rate) and damping performance (large loss factor). In particular, according to one embodiment of the present invention, it is possible to easily form a molded body having a creep change rate of 0.5% or less, particularly a creep change rate of 0.2% or less, and a loss factor of 2.800% or more. Such a molded body can be said to be excellent in creep resistance, load resistance, heat resistance, and damping performance, and thus can be particularly preferably used as a damping material for the main engine (lower part) of a ship. Further, according to one embodiment of the present invention, it is possible to provide a damping epoxy resin composition that is a composition having a low viscosity (100,000 mPa·s or less) and can easily form a molded body that is excellently balanced in a small creep change rate, a large loss factor, a large dielectric tangent, and a small surface resistance value.

Brief Description of the Drawings

[0012] [Figure 1]FIG. 1 is a schematic diagram showing the arrangement of each member used when measuring the natural frequency and loss coefficient of a molded body.

Embodiments for Carrying Out the Invention

[0013] ≪Vibration Damping Epoxy Resin Composition≫ The vibration damping epoxy resin composition according to the present invention (hereinafter also referred to as "this composition") contains an epoxy resin (A), a dielectric material (B), a conductive material (C), a magnetic material (D), an alkylene polyamine (E), and an extender pigment (F), and is characterized in that the pigment volume concentration (PVC) is 25% or more.

[0014] This composition may be a one-component type composition, but usually, it is a two-component type or more composition including a main agent component containing an epoxy resin (A) and a curing agent component containing an alkylene polyamine (E). Further, if necessary, this composition may be a multi-component type composition including a third component other than the main agent component and the curing agent component. These main agent components, curing agent components, and third components, etc. are usually stored, stored, transported, etc. in separate containers, and are mixed and used immediately before using this composition.

[0015] The viscosity at 23°C measured using a B-type viscometer of this composition is preferably 100,000 mPa·s or less, more preferably 5,000 to 85,000 mPa·s, and even more preferably 10,000 to 40,000 mPa·s. The composition having a viscosity within the above range shows high fluidity and is preferable because it is easy to form a molded body by a method such as pouring. Note that the viscosity refers to the viscosity when this composition is prepared (for example, when the main agent component and the curing agent component are mixed).

[0016] <Epoxy Resin (A)> The epoxy resin (A) is not particularly limited, and conventionally known epoxy resins can be used. Examples of epoxy resin (A) include the non-tar epoxy resins described in Japanese Patent Publication No. 11-343454 and Japanese Patent Publication No. 10-259351. The epoxy resin (A) used in this composition may be one type or two or more types.

[0017] Examples of epoxy resins (A) include polymers and oligomers containing two or more epoxy groups in one molecule, and polymers or oligomers produced by ring-opening reactions of these epoxy groups. Examples of such epoxy resins include glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, glycidylamine type epoxy resins, bisphenol type epoxy resins, novolac type epoxy resins, aliphatic epoxy resins, alicyclic epoxy resins, fatty acid modified epoxy resins, and epoxidized oil-based epoxy resins. Among these, bisphenol-type epoxy resins are preferred due to their excellent mechanical strength (e.g., compressive strength and flexural strength) and high versatility, and bisphenol A-type and bisphenol F-type epoxy resins are even more preferred. In particular, it is preferable to use bisphenol A-type and bisphenol F-type epoxy resins in combination, as this allows for the easy acquisition of epoxy resin compositions with excellent fluidity.

[0018] More specifically, epoxy resin (A) may include bisphenol A type epoxy resin (bisphenol A type diglycidyl ethers); bisphenol AD ​​type epoxy resin; bisphenol F type epoxy resin; phenol novolac type epoxy resin; cresol novolac type epoxy resin; and trishydroxyphenylmethane type epoxy resin. These may also be hydrogenated products (hereinafter also referred to as "hydrogenated"), fatty acid modified products, or brominated products in which at least one hydrogen atom in the resin is replaced by a bromine atom.

[0019] Examples of the bisphenol-type epoxy resin include polymers or oligomers having a bisphenol structure within one molecule and containing two or more epoxy groups, and polymers or oligomers produced by the ring-opening reaction of the epoxy groups. Specific examples of the bisphenol A type epoxy resin include polymers of bisphenol A type diglycidyl ethers such as bisphenol A diglycidyl ether, bisphenol A (poly)propylene oxide diglycidyl ether, bisphenol A (poly)ethylene oxide diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol A (poly)propylene oxide diglycidyl ether, and hydrogenated bisphenol A (poly)ethylene oxide diglycidyl ether.

[0020] The epoxy equivalent of epoxy resin (A) is preferably 150 to 1,000, and more preferably 180 to 500, from the viewpoint of curability and other factors. In this specification, epoxy equivalent refers to the epoxy equivalent of the solid content of epoxy resin (A), and is calculated based on JIS K 7236:2001.

[0021] The weight-average molecular weight of the solid content of epoxy resin (A), as measured by GPC (gel permeation chromatography), is preferably 350 to 20,000.

[0022] The viscosity of epoxy resin (A) at 25°C, as measured with an E-type viscometer (TOKIMEC, FMD type, rotation speed: 60 rpm), is preferably 1,500 to 120,000 mPa·s, and more preferably 3,000 to 30,000 mPa·s.

[0023] The solid content of epoxy resin (A) in this composition is preferably 10 to 60% by mass, more preferably 20 to 50% by mass, based on 100% by mass of the solid content of this composition, in order to easily obtain an epoxy resin composition with excellent filling properties (fluidity) and curability, and to easily form a molded article with excellent load-bearing capacity and creep resistance.

[0024] <Dielectric materials (B)> A dielectric material (B) is a material that does not conduct electric current and becomes polarized when an external electric field is applied to it (a dielectric material). Because this composition contains a dielectric material (B), a conductive material (C), and a magnetic material (D) together with (A), (E), and (F), it is possible to easily form a molded body with a large loss coefficient (loss coefficient at natural frequencies), a large dielectric loss tangent, and excellent vibration damping properties. The dielectric material (B) used in this composition may be one type or two or more types.

[0025] As the dielectric material (B), ferroelectric materials are preferred, and examples include barium titanate, strontium titanate, lithium niobate, lithium tantalate, Rochelle salt (potassium sodium tartrate), BST (barium-strontium-titanium), SBT (strontium-bismuth-tantalum), and PZT (lead-zirconium-titanium).

[0026] The content of dielectric material (B) in this composition is preferably 3 to 50% by mass, more preferably 5 to 30% by mass, based on 100% by mass of the solid content of this composition, in order to easily form a molded body with excellent vibration damping properties.

[0027] <Conductive material (C)> Conductive materials (C) are materials that allow electric current to pass through. The conductive material (C) used in this composition may be one type or two or more types.

[0028] Examples of conductive materials (C) include carbon materials such as graphite, carbon nanotubes (CNTs), carbon fibers, and fullerenes, as well as metal powders (e.g., gold, silver, copper). Among these, carbon materials are preferred because they allow for the easy formation of molded bodies with excellent vibration damping properties.

[0029] The content of the conductive material (C) in this composition is preferably 0.001 to 15% by mass, more preferably 0.005 to 10% by mass, based on 100% by mass of the solid content of this composition, in order to easily form a molded body with low surface resistance and excellent vibration damping properties.

[0030] <Magnetic material (D)> The magnetic material (D) is not particularly limited as long as it is a magnetic material other than the dielectric material (B) and the conductive material (C). The magnetic material (D) used in this composition may be one type or two or more types.

[0031] Examples of magnetic materials (D) include magnetic iron oxides such as magnetite, maghemite, ferrite, and Mn-Zn ferrite; metallic magnetic materials such as cobalt, nickel, iron, electromagnetic soft iron, and carbonyl iron; and alloys and mixtures of the aforementioned metals with other metals, such as iron-silicon-aluminum alloys. Examples of the aforementioned other metals include aluminum, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, strontium, vanadium, neodymium, samarium, and dysprosium.

[0032] The content of magnetic material (D) in this composition is preferably 3 to 30% by mass, more preferably 5 to 20% by mass, based on 100% by mass of the solid content of this composition, in order to easily form a molded body with excellent vibration damping properties.

[0033] The shape of each of the materials (B) to (D) is not particularly limited, but it is preferable that they be in powder form. The average particle size of each of the powdered materials (B) to (D) is not particularly limited, but it is preferably 1000 μm or less, more preferably 800 μm or less, with a lower limit of, for example, 30 μm or more, in order to easily obtain an epoxy resin composition with excellent filling properties (fluidity), and to easily form a molded article with low surface resistance and excellent vibration damping properties. The average particle size is a value measured in accordance with JIS K 5101-14-1:2004.

[0034] The total content of materials (B) to (D) in this composition is preferably 5 to 50% by mass, more preferably 10 to 30% by mass, based on 100% by mass of the solid content of this composition, in order to easily obtain an epoxy resin composition with excellent filling properties (fluidity), and to easily form a molded article with low surface resistance and excellent vibration damping properties.

[0035] <Alkylene polyamine (E)> The alkylene polyamine (E) is not particularly limited as long as it is a polyamine other than a tertiary amine (G) (a polyamine having at least one primary or secondary amino group in one molecule) and has an alkylene group; conventionally known alkylene polyamines can be used. Since this composition contains alkylene polyamine (E) together with (A) to (D) and (F), it is possible to easily form molded articles with excellent creep resistance. The alkylene polyamine (E) used in this composition may be one type or two or more types.

[0036] Examples of alkylene polyamines (E) include compounds represented by the following formulas (1) to (3). H2N-R 1 -NH2···(1) [In equation (1), R 1 It is a divalent hydrocarbon group having 1 to 12 carbon atoms. H2N-(C m H 2m NH) n H ···(2) [In formula (2), m is an integer from 1 to 10. n is an integer from 2 to 10, preferably an integer from 2 to 6.] R 2 2N-(CH2) p -NH2···(3) [In formula (3), R 2 is independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms (however, at least one R 2 is an alkyl group having 1 to 8 carbon atoms.), and p is an integer from 1 to 6.]

[0037] Examples of the compound represented by the formula (1) include methylenediamine, ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, and trimethylhexamethylenediamine.

[0038] Examples of the compound represented by the formula (2) include diethylenetriamine, dipropylenetriamine, triethylenetetramine, tripropylenetetramine, tetraethylenepentamine, tetrapropylenetetramine, pentaethylenehexamine, nonaethylenedecamine, bis(hexamethylene)triamine, and triethylene-bis(trimethylene)hexamine.

[0039] Examples of the compound represented by the formula (3) include dimethylaminoethylamine, diethylaminoethylamine, dibutylaminoethylamine, dimethylaminopropylamine, diethylaminopropylamine, dipropylaminopropylamine, dibutylaminopropylamine, and dimethylaminobutylamine.

[0040] As the alkylene polyamine (E), other compounds other than those represented by formulas (1) to (3) above may be used. Examples of such other compounds include tetra(aminomethyl)methane, tetrakis(2-aminoethylaminomethyl)methane, 1,3-bis(2'-aminoethylamino)propane, and N,N'-bis(3-aminopropyl)ethylenediamine.

[0041] The alkylene polyamine (E) preferably contains the compound represented by formula (2) above, as it allows for easy acquisition of epoxy resin compositions with excellent curability and easy formation of molded articles with excellent load-bearing capacity and creep resistance. It is more preferably contains at least one selected from the group consisting of triethylenetetramine, diethylenetriamine, tetraethylenepentamine, and pentaethylenehexamine.

[0042] The active hydrogen equivalent of alkylene polyamine (E) is preferably 10 to 1,000, more preferably 20 to 400, from the viewpoint that an epoxy resin composition with excellent curability can be easily obtained, and a molded article with excellent load-bearing capacity and creep resistance can be easily formed. The value of the active hydrogen equivalent refers to the amount of active hydrogen per unit of solid content of alkylene polyamine (E).

[0043] The solid content of alkylene polyamine (E) in this composition is preferably 1 to 40% by mass, more preferably 2 to 30% by mass, based on 100% by mass of the solid content of this composition, in order to easily obtain an epoxy resin composition with excellent curability and to easily form a molded article with excellent load-bearing capacity and creep resistance.

[0044] From the standpoint of easily obtaining epoxy resin compositions with excellent curability and easily forming molded articles with excellent load-bearing capacity and creep resistance, it is desirable to use alkylene polyamine (E) in an amount such that the reaction ratio calculated by the following formula (4) is preferably 0.7 to 1.2, more preferably 0.8 to 1.1.

[0045] Reaction ratio = {(Amount of solids of alkylene polyamine (E) / Active hydrogen equivalent of the solids of alkylene polyamine (E)) + (Amount of solids of the raw material reactive with epoxy resin (A) / Functional group equivalent of the solids of the raw material reactive with epoxy resin (A))} / {(Amount of solids of epoxy resin (A) / Epoxy equivalent of the solids of epoxy resin (A)) + (Amount of solids of the raw material reactive with alkylene polyamine (E) / Functional group equivalent of the solids of the raw material reactive with alkylene polyamine (E))} ... (4)

[0046] Here, the "raw material that is reactive with alkylene polyamine (E)" in formula (4) above can be, for example, a silane coupling agent, and the "raw material that is reactive with epoxy resin (A)" can be, for example, a silane coupling agent. As the silane coupling agent, a silane coupling agent having an amino group or an epoxy group as a reactive group can be used, so it is necessary to determine whether the silane coupling agent is reactive with epoxy resin (A) or alkylene polyamine (E) depending on the type of reactive group, and to calculate the reaction ratio. The "functional group equivalent" of each of the above raw materials refers to the mass (g) per mole of functional group obtained by dividing the mass of 1 mole of solid content of these raw materials by the number of moles of functional groups contained in it.

[0047] <Extender pigment (F)> The extender pigment (F) is not particularly limited, and conventionally known extender pigments can be used. The extender pigment (F) used in this composition may be one type or two or more types.

[0048] Examples of extender pigments (F) include silica, talc, mica, potassium feldspar, wollastonite, kaolin, clay, bentonite, titanium dioxide, zinc oxide, calcium carbonate, magnesium carbonate, barium sulfate, and silica sand (quartz sand mainly composed of silicon dioxide (e.g., silica sand described in JIS G 5901:2016 and JIS Z 8901:2006)). Among these, silica, talc, mica, potassium feldspar, wollastonite, kaolin, clay, calcium carbonate, and barium sulfate are preferred, and potassium feldspar and wollastonite are particularly preferred because they have low oil absorption and allow for easy adjustment of the viscosity of the composition.

[0049] The oil absorption capacity of the extender pigment (F) is preferably 40 mL / 100 g or less, more preferably 30 mL / 100 g or less. By using an extender pigment (F) whose oil absorption amount falls within the aforementioned range, even when a large amount of the extender pigment (F) is used, it is possible to easily obtain an epoxy resin composition that is not easily thickened, has low viscosity, and excellent filling properties (fluidity). The oil absorption capacity of the extender pigment (F) can be measured in accordance with JIS K 5101-13-2:2004.

[0050] The average particle size of the extender pigment (F), measured in accordance with JIS K 5101-14-1:2004, is not particularly limited, but is preferably 30 to 1,000 μm, more preferably 50 to 800 μm, from the standpoint that it is possible to easily form molded articles with low surface resistance and excellent load-bearing capacity.

[0051] The content of the extender pigment (F) in this composition is preferably 10 to 60% by mass, more preferably 20 to 50% by mass, based on 100% by mass of the solid content of this composition, in order to easily form a molded article with excellent creep resistance.

[0052] The pigment mass concentration (PWC) in this composition is preferably 20-70%, more preferably 30-60%, from the viewpoint that it is possible to easily form molded articles with excellent creep resistance. The PWC refers to the percentage of the total mass of all pigments, including the dielectric material (B), conductive material (C), magnetic material (D), and extender pigment (F), etc., relative to the mass of the solid content (non-volatile content) in the composition, and is represented by the following formula (5). PWC[%] = Total mass of all pigments in this composition / Mass of solids in this composition × 100 ... (5)

[0053] The pigment volume concentration (PVC) in this composition is 25% or more, preferably 27.5% or more, more preferably 30% or more, preferably 70% or less, and more preferably 65% ​​or less, from the viewpoint that a molded article with excellent creep resistance can be easily formed.

[0054] The PVC refers to the percentage of the total volume concentration of all pigments, including the dielectric material (B), conductive material (C), magnetic material (D), and extender pigment (F), etc., relative to the volume of solids (non-volatile matter) in the composition, and is represented by the following formula (6). PVC[%] = Total volume of all pigments in this composition / Volume of solids in this composition × 100 ... (6)

[0055] In this specification, the solid content of this composition refers to the residual amount obtained by heating according to JIS K 5601-1-2:2008 (heating temperature: 125°C, heating time: 60 minutes). Alternatively, the solid content of this composition can also be calculated by excluding the amount of solvent and dispersion medium in the raw materials used. Furthermore, in this specification, the solid content of each raw material used in this composition (e.g., epoxy resin (A)) refers to the residue in each raw material other than the solvent and dispersion medium.

[0056] The volume of solids in the composition can be calculated from the mass and true density of the solids in the composition. The mass and true density of the solids may be measured values ​​or values ​​calculated from the raw materials used. The volume of the pigment can be calculated from the mass and true density of the pigment used. The mass and true density of the pigment may be measured values ​​or values ​​calculated from the raw materials used. For example, it can also be calculated by separating the pigment from other components from the solid content of the composition and measuring the mass and true density of the separated pigment.

[0057] <Additives> The composition may further contain additives other than those described in (A) to (F) above, as long as it does not impair the objectives of the present invention. Examples of such additives include tertiary amines (G), other pigments other than the extender pigment (F), dispersants, rheology control agents, defoaming agents, curing agents other than the alkylene polyamine (E) and the tertiary amine (G), surface modifiers (leveling agents), silane coupling agents, plasticizers, water, and solvents. These additives may be used individually or in combination of two or more types.

[0058] <Tertiary amine (G)> The use of a tertiary amine (G) together with (A) to (F) in this composition is preferable because it allows for easy acquisition of an epoxy resin composition with excellent curability and easy formation of molded articles with excellent creep resistance. Examples of tertiary amines (G) include triethanolamine (N(C2H5OH)3) and dialkylaminoethanol {[CH3(CH2) n Examples include ]2NC2H5OH, n: number of repetitions}, triethylenediamine{1,4-diazabicyclo[2.2.2]octane}, and 2,4,6-tris(dimethylaminomethyl)phenol{[(CH3)2NCH2]3-C6H5OH}. As the tertiary amine (G), a compound synthesized by a conventionally known method may be used, or a commercially available product may be used. Examples of such commercially available products include Versamin EH30 (manufactured by Henkel White Water Co., Ltd.) and Ancamine K-54 (manufactured by Evonik).

[0059] When this composition contains a tertiary amine (G), the amount of tertiary amine (G) relative to 100% by mass of the solid content of this composition is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, from the viewpoint that an epoxy resin composition with excellent curability can be easily obtained and a molded article with excellent creep resistance can be easily formed.

[0060] [Dispersant] The aforementioned dispersant is not particularly limited, but it is preferable that it is a dispersant that can uniformly disperse the dielectric material (B), conductive material (C), magnetic material (D), extender pigment (F), and other pigments in the composition, and prepare a stable dispersion. Examples of the aforementioned dispersants include various known organic (e.g., aliphatic amines or organic acids) or inorganic dispersants.

[0061] If the composition contains a dispersant, its content is preferably 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, based on 100% by mass of the solid content of the composition.

[0062] [Rheology control agent] The rheology control agent (also called a settling inhibitor or thixotrope) is not particularly limited, but it is preferably a material that can suppress the settling of pigments and the like in the composition and improve its storage stability. As the rheology control agent, conventionally known rheology control agents can be used, such as organic clay waxes including stearate salts, lecithin salts, and alkyl sulfonates of Al, Ca, and Zn; polyethylene wax; amide wax; hydrogenated castor oil wax; mixtures of hydrogenated castor oil wax and amide wax; synthetic fine silica powder; oxidized polyethylene wax; mineral clay viscosity modifiers; urethane association viscosity modifiers; acrylic acid viscosity modifiers; and cellulose viscosity modifiers.

[0063] If the composition contains a rheology control agent, its content is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass, based on 100% by mass of the solid content of the composition.

[0064] [Antifoaming agent] From the viewpoint of obtaining a molded article with excellent load-bearing capacity, it is preferable that the composition and the molded article obtained from it are free of air bubbles. For this reason, it is preferable to incorporate an antifoaming agent into the composition. Examples of such defoaming agents include silicone-based defoaming agents and mineral oil-based defoaming agents, each of which is available in water-based, solvent-based, and solvent-free forms. Among these, solvent-free silicone-based defoamers are preferred in order to suppress shrinkage during the formation of the molded product.

[0065] If the composition contains an antifoaming agent, its content is preferably 0.3 to 5% by mass, and more preferably 0.5 to 3% by mass, based on 100% by mass of the composition.

[0066] <Method for preparing this composition> This composition, or the main component, curing agent component, etc., can be prepared by mixing (kneading) the aforementioned raw materials. During this mixing (kneading), the raw materials may be added and mixed all at once, or they may be added and mixed in multiple stages. During the mixing (kneading) process, conventionally known devices such as mixers, dispersers, and agitators can be used. Examples of such devices include dispersers, mixing / dispersing mills, mortar mixers, rolls, paint shakers, and homogenizers. Furthermore, the mixing (kneading) process may be carried out with heating, cooling, etc., depending on the season, environment, etc.

[0067] If air is incorporated during the preparation of the main component or when mixing the main component with the curing agent component, air bubbles may remain in the resulting molded product, potentially causing cracks and other problems. Therefore, it is preferable to reduce the amount of air incorporated into the composition by performing a degassing process during the preparation of the main component or the composition, or by stirring at a low rotation speed when mixing the main component with the curing agent component.

[0068] <Vibration-damping epoxy resin molded body> The vibration-damping epoxy resin molded article according to the present invention (hereinafter also referred to as "the molded article") is formed from the composition described above.

[0069] This molded body exhibits a well-balanced combination of creep resistance and vibration damping properties. Therefore, this molded product can be suitably used in equipment that generates vibration, such as ships, automobiles, railways, aircraft, buildings, industrial equipment, home appliances, and precision instruments. Among these, it is particularly suitable for use in high-temperature environments, such as around engines, especially marine engines (including main engines and auxiliary engines). This molded body is particularly suitable for use in the lower part of a marine engine, and in the case of a marine engine equipped with a main engine and auxiliary engines, it can be used especially well in the main engine (lower part).

[0070] Because this molded body has excellent vibration damping properties, it can be used particularly suitably as a vibration damping material. The vibration damping material may be a single-layer material or a multi-layer material having two or more layers, but a single-layer material is preferred. In other words, this composition is preferably for forming a single-layer vibration damping material. As for vibration damping materials, when forming multi-layered vibration damping materials, the construction period tends to be longer and the construction method tends to be more complex than when using a single layer. Therefore, if sufficient vibration damping performance can be achieved with a single layer, a single-layer vibration damping material is preferable. According to one embodiment of the present invention, sufficient vibration damping performance can be achieved with a vibration damping material consisting of a single layer of molded body, thus enabling the use of a single-layer vibration damping material and suppressing the lengthening of the construction period and the complexity of the construction method when forming vibration damping materials. Furthermore, the vibration damping material consisting of only a single layer refers to a vibration damping material consisting of only this molded body, and the vibration damping material consisting of multiple layers refers to a vibration damping material in which at least one of the multiple layers is this molded body.

[0071] [Creep change rate] Resin-based materials can undergo plastic deformation when subjected to large loads for extended periods in a high-temperature atmosphere; this phenomenon is called creep. The creep rate, which is the percentage change in thickness of the molded body before and after applying a load of 4.5 MPa at 80°C for 1,000 hours, is preferably 0.5% or less, more preferably 0.4% or less, even more preferably 0.3% or less, and particularly preferably 0.2% or less. A molded article whose creep change rate falls within the aforementioned range can be said to have excellent creep resistance. In this specification, "creep resistance" is determined by the creep change rate. Since the creep change rate is also a physical property related to load-bearing capacity and heat resistance due to its measurement method, a molded article whose creep change rate falls within the aforementioned range and has excellent creep resistance can also be said to have excellent load-bearing capacity and heat resistance. The creep rate can be measured specifically by the method described in the following examples.

[0072] Materials (molded bodies) used in ships must be evaluated in accordance with the classification rules established by classification societies, and vibration damping materials used in the main engines (lower part) of ships are required by design to have a creep change rate of 0.2% or less. According to one embodiment of the present invention, the molded body can have a creep change rate of 0.2% or less, and such a molded body can be suitably used in the main engine (lower part).

[0073] [Loss Factor] The loss coefficient indicates that the larger its value, the more vibration energy can be converted into heat, electrical energy, etc., and thus the better the vibration damping performance. The loss coefficient (loss coefficient at natural frequencies) of this molded body is preferably 2.800% or more, more preferably 3.300% or more, and even more preferably 4.000% or more. Since a larger value of the loss coefficient is preferable, there is no particular upper limit, but for example, it is 10%. A molded body whose loss coefficient falls within the aforementioned range can be said to have excellent vibration damping properties. The loss factor can be measured specifically by the method described in the following examples.

[0074] The surface resistance of this molded body is preferable as small as possible from the viewpoint of conductivity, and is preferably 1 × 10⁻⁶. 12 Less than 1 × 10 11 Less than 1 × 10 10 It is less than. The surface resistance can be measured specifically by the method described in the following examples.

[0075] The dielectric loss tangent of this molded body at 20 to 20,000 Hz is preferably 0.01 or higher, more preferably 0.05 or higher, and even more preferably 0.10 or higher. The dielectric loss tangent represents the degree to which some energy is converted into heat and lost within a material when an alternating electric field is applied to it. When the dielectric loss tangent falls within the specified range, the energy loss is large, and the molded body tends to have excellent vibration damping properties. The dielectric loss tangent can be measured specifically by the method described in the following examples.

[0076] Specifically, this molded body can be formed by, for example, pouring, extrusion, injection molding, or RIM molding of this composition. Alternatively, it can be formed by, for example, applying this composition to the area where the molded body is to be formed (hereinafter also referred to as the "construction area") using a spray, roller, or brush, and allowing it to harden. Among these, this composition has excellent filling properties (fluidity), so it is preferable to pour this composition directly into the application area and allow it to harden to form the molded body. This method is preferable because it allows the molded body to be formed directly in the desired location and also allows the molded body to sufficiently fill even narrow gaps. When forming the molded body by pouring, a mold or the like may be used as necessary to prevent the composition from flowing out from the desired location. [Examples]

[0077] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. In the following description, unless otherwise specified, "parts by mass" will be written as "parts".

[0078] [Example 1] In a container, 39 parts epoxy resin A1, 4.2 parts epoxy resin A2, 16 parts dielectric material B1, 6.6 parts conductive material C2, 8 parts magnetic material D1, 43 parts extender pigment F1, 3 parts extender pigment F2, 0.5 parts dispersant, 0.2 parts rheology control agent, and 0.8 parts defoaming agent were placed and mixed using a high-speed disperser to prepare the main component. In a separate container, 7 parts alkylene polyamine E1 and 2 parts tertiary amine G1 were placed and mixed using a high-speed disperser to prepare the curing agent component. The prepared main component and curing agent component were mixed and degassed to prepare an epoxy resin composition. Next, the degassed epoxy resin composition was poured into molds of the appropriate size for each test, and molded bodies were produced by curing at 23°C for 16 hours.

[0079] [Examples 2-6, Reference Example 1, and Comparative Examples 1-9] An epoxy resin composition was prepared and a molded article was produced in the same manner as in Example 1, except that each component listed in Tables 1 and 2 was used in the numerical values ​​(amount, parts by mass) listed in those tables. Table 3 provides a description of each component listed in Tables 1 and 2.

[0080] [Comparative Example 10] Epoxy resin A1, epoxy resin A2, and magnetic material D1 were added to a container according to the values ​​(amount, parts by mass) listed in Table 2, and mixed using a high-speed disperser to prepare the main component. Epoxy resin composition 1 was prepared by adding 25 parts of alkylene polyamine E1 to the obtained main component and stirring. Next, the degassed epoxy resin composition 1 was poured into molds of the appropriate size for each test, and cured at 23°C for 16 hours to allow it to harden. After the epoxy resin composition 1 cured, epoxy resin composition 2 was similarly prepared using epoxy resin A1, epoxy resin A2, dielectric material B1, and alkylene polyamine E1 in the values ​​(amount, parts by mass) shown in Table 2. Next, the degassed epoxy resin composition 2 was poured onto the cured epoxy resin composition 1 and cured at 23°C for 16 hours. Furthermore, epoxy resin composition 3 was prepared using epoxy resin A1, epoxy resin A2, conductive material C2, and alkylene polyamine E1 in the values ​​(amount, parts by mass) shown in Table 2. Next, the degassed epoxy resin composition 3 was poured onto the cured epoxy resin composition 2, and cured at 23°C for 16 hours to harden, thereby producing a three-layer molded body having layer 1 formed from epoxy resin composition 1, layer 2 formed from epoxy resin composition 2, and layer 3 formed from epoxy resin composition 3, in the order of layer 1 / layer 2 / layer 3.

[0081] <pwc> The pigment mass concentration (PWC) in the prepared epoxy resin composition was calculated based on formula (5) above. The results are shown in Tables 1 and 2.

[0082] <pvc> The pigment volume concentration (PVC) in the prepared epoxy resin composition was calculated based on formula (6) above. The results are shown in Tables 1 and 2.

[0083] <Viscosity> The viscosity of the prepared main component and epoxy resin composition at 23°C was measured using a Type B viscometer (Model: BII viscometer, manufactured by Toki Sangyo Co., Ltd.) with a No. 4 rotor. The results are shown in Tables 1 and 2.

[0084] <Creep change rate> In Examples 1-6, Reference Example 1, and Comparative Examples 1-10, epoxy resin molded bodies were prepared using a 100 × 100 × 12.7 mm mold. The prepared molded bodies were cured in accordance with ASTM D 621. After curing, test specimens approximately 12.7 mm in size per side were cut from the molded bodies. Using a creep tester (Yasuda Seisakusho Co., Ltd., No. 145-B-3), a load of 4.5 MPa was applied in the thickness direction of the test specimens for 1,000 hours under an atmosphere of 80°C, and the thickness of the test specimens before and after the load was measured. The creep change rate was calculated based on the following formula. The results are shown in Tables 1 and 2. When the creep rate is 0.5% or less, it is said that the creep rate is low and the material has excellent creep resistance. Creep rate (%) = {(Initial thickness of the specimen (before testing) - Thickness of the specimen after 1,000 hours) / Initial thickness of the specimen (before testing)} × 100

[0085] <Surface resistance value> In Examples 1-6, Reference Example 1, and Comparative Examples 1-10, epoxy resin molded bodies were prepared using a 100 x 100 x 4 mm mold. Test specimens approximately 60 mm in size per side were cut from the prepared molded bodies. The surface resistance (Ω / □) of the prepared molded bodies was measured using a resistivity meter (Mitsubishi Chemical Corporation, model number: MCP-HT450, measurement range: 9.99 x 10⁻¹). 4 ~9.99 × 10 13 Measurements were taken using an Ω (ohm) under the conditions of 23°C temperature, 50% RH humidity, and 500V applied voltage. The results are shown in Tables 1 and 2. For the molded body produced in Comparative Example 10, the surface resistance values ​​of layer 1 and layer 3, which are the surfaces, were measured. Tables 1 and 2 show that the surface resistance value is 1.0 × 10⁻⁶, which is the measurement limit of the resistivity meter. 12 If it exceeds Ω / □, then ">10 12 " he indicates. A lower measurement value indicates a better result.

[0086] <Dielectric loss tangent> In Examples 1-6, Reference Example 1, and Comparative Examples 1-10, epoxy resin molded bodies were prepared using a 100 x 100 x 4 mm mold. Test specimens approximately 60 mm in size per side were cut from the prepared molded bodies, and the dielectric loss tangent of the prepared molded bodies was measured using an LCR meter (manufactured by Agilent Technologies). Specifically, measuring electrodes were formed on the surface of the fabricated molded body to create a simple parallel plate capacitor. After setting the fabricated parallel plate capacitor in an LCR meter, the dielectric loss tangent of the molded body was measured by applying an AC voltage set to the measurement frequency described in Tables 1 and 2 to the parallel plate capacitor. The results are shown in Tables 1 and 2. Furthermore, the dielectric loss tangents of the epoxy resin molded articles obtained in Examples 1 to 6 were all 0.01 or greater at frequencies of 2,000 Hz, 10,000 Hz, and 20,000 Hz.

[0087] <Natural frequency and loss coefficient> In Examples 1-6, Reference Example 1, and Comparative Examples 1-10, epoxy resin molded bodies were produced using a 60 x 60 x 4 mm mold. The natural frequencies and loss coefficients of the produced molded bodies were calculated as follows. First, as shown in Figure 1, a double clip was used to attach the thread 5, which was suspended from the suspension stand 6, to the central end of the side of the molded body 2, and then the molded body 2 was suspended from the suspension stand 6. An acceleration pickup sensor 3 was attached to the center of one of the surfaces (main surface) of the molded body 2, and the acceleration pickup sensor 3 was connected to an FFT analyzer 4 (Fast Fourier Transform analyzer, manufactured by Ono Sokki Co., Ltd., DS-3000) via wiring 7. Furthermore, the impulse hammer 1 (manufactured by Ono Sokki Co., Ltd., Impulse Hammer GK-3100) was positioned so that it struck the center of the side of the suspended molded body 2 opposite to the side to which the acceleration pickup sensor 3 was attached (a position facing the acceleration pickup sensor 3), and the impulse hammer 1 was connected to the FFT analyzer 4 via wiring 8. Furthermore, the FFT analyzer 4 was connected to the personal computer 9 via wiring.

[0088] After arranging each component as shown in Figure 1, the center of the molded body 2 was struck and vibrated using the impulse hammer 1. The signals received by the impulse hammer 1 and the acceleration pickup sensor 3 were input to the FFT analyzer 4 via wiring 7 and 8, and the transfer function (frequency response function) was calculated. The natural frequency (resonant frequency) was determined from the obtained transfer function, and the loss coefficient at this frequency was determined. Specifically, it was as follows. The natural frequencies and loss coefficients were calculated using dedicated software ("General-Purpose FFT Analysis DS-0320" manufactured by Ono Sokki Co., Ltd.) stored in a personal computer 9 connected to the FTT analyzer 4 via wiring. The results are shown in Tables 1 and 2. A loss factor of 2.800% or higher is considered to indicate a high loss factor and excellent vibration damping properties.

[0089] Furthermore, the same tests as described above were performed on the molded body produced in Comparative Example 10, both when the acceleration pickup sensor 3 was attached to layer 1 and when the acceleration pickup sensor 3 was attached to layer 3. The loss coefficient of the molded body produced in Comparative Example 10 was calculated by determining the loss coefficient when the acceleration pickup sensor 3 was attached to layer 1 and the same test as described above was performed, and the loss coefficient when the acceleration pickup sensor 3 was attached to layer 3 and the same test as described above was performed, and then calculating the average value from these two values.

[0090] [Table 1]

[0091] [Table 2]

[0092] [Table 3] [Explanation of Symbols]

[0093] 1: Impulse Hammer 2: Molded body 3: Accelerometer pickup sensor 4: FFT Analyzer 5: Thread 6: Hanging stand 7 and 8: Wiring 9: Personal Computers< / pvc> < / pwc>

Claims

1. It contains epoxy resin (A), dielectric material (B), conductive material (C), magnetic material (D), alkylene polyamine (E), and extender pigment (F), The pigment volume concentration (PVC) is 25% or higher. Vibration-damping epoxy resin composition.

2. The vibration-damping epoxy resin composition according to claim 1, wherein the viscosity at 23°C, as measured using a B-type viscometer, is 100,000 mPa·s or less.

3. The vibration-damping epoxy resin composition according to claim 1, further comprising a tertiary amine (G).

4. A vibration-damping epoxy resin molded article formed from the vibration-damping epoxy resin composition according to any one of claims 1 to 3.

5. The vibration-damping epoxy resin molded article according to claim 4, wherein the creep change rate, which is the rate of change in thickness before and after applying a load of 4.5 MPa at 80°C for 1,000 hours, is 0.5% or less.

6. The vibration-damping epoxy resin molded article according to claim 4, wherein the creep change rate, which is the rate of change in thickness before and after applying a load of 4.5 MPa at 80°C for 1,000 hours, is 0.2% or less.

7. A vibration-damping epoxy resin molded article according to claim 4, for use in the main engine of a ship.

8. A method for producing a vibration-damping epoxy resin molded article, comprising the step of pouring the vibration-damping epoxy resin composition described in any one of claims 1 to 3 into a construction site to form a molded article.

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