Laminate for vibration damping material

Abstract

The purpose of the present invention is to provide a laminate for a damping material, the laminate having excellent resin composition stability and excellent damping properties. The present invention pertains to a laminate for a damping material, the laminate having a resin layer A and a resin layer B, wherein the resin layer A may contain an inorganic filler, the resin layer B contains an inorganic filler, the content of the inorganic filler per 100 parts by mass of the non-volatile content in the resin layer A is 30 parts by mass or less, the content of the inorganic filler per 100 parts by mass of the non-volatile content in the resin layer B is 50-90 parts by mass, the resin layer A and the resin layer B each may contain zinc oxide, the content of zinc oxide per 100 parts by mass of the non-volatile content in the resin layer A is 5 parts by mass or less, the content of zinc oxide per 100 parts by mass of the non-volatile content in the resin layer B is 5 parts by mass or less, and the average film thickness of the laminate is at least 1.5 mm.

Description

Technical Field

[0001] The present invention relates to a laminate for a vibration damping material. More specifically, it relates to a vibration damping coating film used to prevent vibration and noise under the vehicle floor of various structures, particularly in vehicles, and to maintain quietness, and a base material with a vibration damping material formed on the surface thereof.

Background Art

[0002] Vibration damping materials are used to prevent vibration and noise in various structures and maintain quietness. For example, they are used under the vehicle floor of automobiles, and are also widely used in railway vehicles, ships, airplanes, electrical equipment, building structures, construction equipment, etc. Conventionally, as materials used for such vibration damping materials, molded products such as plate-shaped molded bodies and sheet-shaped molded bodies made of materials having vibration absorption performance have been used. As an alternative material to molded products, coating-type vibration damping material formulations (paints) have been developed. For example, various vibration damping coating films formed by spraying or applying by any method to the relevant locations have been proposed. For example, Patent Document 1 describes a vibration damping coating film formed on a base material. The coating film has an average thickness of 1 mm or less and consists of a lower layer on the base material side and an upper layer. The upper layer contains an acrylic resin, zinc oxide, and calcium carbonate, and it is described that the coating film can exhibit excellent vibration damping performance while being a thin film. Also, Patent Document 2 describes a vibration damping coating film formed on a base material. The coating film has a higher hardness on the surface of the coating film on the side opposite to the side in contact with the base material than the hardness of the surface of the coating film on the side in contact with the base material, and the difference in hardness is two or more grades in terms of pencil hardness.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

[0004] The demand for coating-type vibration damping materials that can easily form coatings even on substrates with complex shapes is increasing year by year, and the vibration damping performance required of the vibration-damping coatings formed in this way is also increasing. Furthermore, in order to obtain good coating properties, there is an increasing need for improved stability of the resin composition used. The inventors of the present invention conducted research to obtain a vibration damping material that exhibits excellent stability of the resin composition and excellent vibration damping properties of the formed resin layer. [Means for solving the problem]

[0005] In view of the above-mentioned problems, the inventors conducted studies and found that a laminate for vibration damping material having a resin layer A and a resin layer B, wherein resin layer A may contain an inorganic filler, resin layer B contains an inorganic filler, the inorganic filler content of resin layer A is 30 parts by mass or less per 100 parts by mass of nonvolatile content, and the inorganic filler content of resin layer B is 50 parts by mass or more and 90 parts by mass or less per 100 parts by mass of nonvolatile content, resin layer A and resin layer B may each contain zinc oxide, the zinc oxide content of resin layer A is 5 parts by mass or less per 100 parts by mass of nonvolatile content, and the zinc oxide content of resin layer B is 5 parts by mass or less per 100 parts by mass of nonvolatile content, and the average film thickness of the laminate is 1.5 mm or more, is excellent in the stability of the raw material resin composition and the vibration damping properties of the resulting coating film, thus completing the present invention.

[0006] In other words, the present invention (1) is a laminate for vibration damping material having a resin layer A and a resin layer B, wherein resin layer A may contain an inorganic filler, resin layer B contains an inorganic filler, the inorganic filler content of resin layer A is 30 parts by mass or less per 100 parts by mass of nonvolatile content, and the inorganic filler content of resin layer B is 50 parts by mass or more and 90 parts by mass or less per 100 parts by mass of nonvolatile content, resin layer A and resin layer B may each contain zinc oxide, the zinc oxide content of resin layer A is 5 parts by mass or less per 100 parts by mass of nonvolatile content, and the zinc oxide content of resin layer B is 5 parts by mass or less, and the average film thickness of the laminate is 1.5 mm or more.

[0007] The present invention (2) is a vibration damping laminate of the present invention (1) in which the vibration damping laminate has a resin layer A on a base material and a resin layer B on top of the resin layer A, and the ratio of the average thickness of the resin layer A to the average thickness of the resin layer B of the laminate is 50 / 50 to 10 / 90.

[0008] The present invention (3) is a laminate for vibration damping material according to the present invention (1) or (2), wherein the average thickness of the resin layer A is 0.15 mm or more.

[0009] The present invention (4) is a laminate for vibration damping material according to any of the present inventions (1) to (3), wherein the average thickness of the resin layer A is 3 mm or less.

[0010] The present invention (5) is a laminate for vibration damping material according to any of the present inventions (1) to (4), wherein the average thickness of the resin layer B is 0.7 mm or more.

[0011] The present invention (6) is a laminate for vibration damping material according to any of the present inventions (1) to (5), wherein the average thickness of the resin layer B is 5 mm or less.

[0012] The present invention (7) is a laminate for vibration damping material according to any of the present inventions (1) to (6), wherein the content of inorganic filler in 100 parts by mass of nonvolatile matter of the resin layer A is 10 parts by mass or less, and the content of inorganic filler in 100 parts by mass of nonvolatile matter of the resin layer B is 70 parts by mass or more and 90 parts by mass or less.

[0013] The present invention (8) is a laminate for vibration damping material according to any of the present inventions (1) to (7), wherein the zinc oxide content in 100 parts by mass of nonvolatile matter of the resin layer A is 1 part by mass or less.

[0014] The present invention (9) is a laminate for vibration damping material according to any of the present inventions (1) to (8), wherein the storage modulus of resin layer B at 25°C is 1.0E+07MPa or higher.

[0015] The present invention (10) is a vehicle comprising a laminate of any of the present inventions (1) to (9).

[0016] The present invention (11) is a method for manufacturing a laminate for vibration damping materials, wherein resin composition B is applied to the upper layer of resin layer A derived from resin composition A after or simultaneously with the application of resin composition A, wherein resin composition A may contain an inorganic filler, resin composition B contains an inorganic filler, the inorganic filler content per 100 parts by mass of nonvolatile content of resin composition A is 30 parts by mass or less, and the inorganic filler content per 100 parts by mass of nonvolatile content of resin composition B is 50 parts by mass or more and 90 parts by mass or less, and resin composition A and resin composition B may each contain zinc oxide, the zinc oxide content per 100 parts by mass of nonvolatile content of resin composition A is 5 parts by mass or less, and the zinc oxide content per 100 parts by mass of nonvolatile content of resin composition B is 5 parts by mass or less.

[0017] The present invention (12) is a method for manufacturing a laminate for vibration damping material according to the present invention (11), wherein the storage modulus of the coating film at 25°C after coating with resin composition A to a thickness of 0.3 mm and drying at 140°C for 60 minutes is 1.0E+05 MPa or higher.

[0018] The present invention (13) is a method for manufacturing a laminate for vibration damping material according to the present invention (11) or (12), wherein the storage modulus of the coating film at 25°C after coating with resin composition B to a thickness of 0.6 mm and drying at 140°C for 60 minutes is 1.0E+07 MPa or higher.

[0019] The present invention (14) is a method for manufacturing a laminated body for a vibration damping material according to any one of the present inventions (11) to (13), wherein the storage elastic modulus of the resin composition B is 1.0E+07 MPa or more higher than that of the resin composition A.

[0020] The present invention (15) is a method for manufacturing a laminated body for a vibration damping material according to any one of the present inventions (11) to (14), which includes a step of drying the applied resin composition A and / or the applied resin composition B.

[0021] The present invention is a laminated body for a vibration damping material according to any one of the present inventions (1) to (9), wherein the content of zinc oxide in 100 parts by mass of the non-volatile matter of the resin layer B is 1 part by mass or less.

[0022] The present invention is a laminated body for a vibration damping material having a resin layer A and a resin layer B. The resin layer A may contain an inorganic filler, the resin layer B contains an inorganic filler, the content of the inorganic filler in 100 parts by mass of the non-volatile matter of the resin layer A is 30 parts by mass or less, the content of the inorganic filler in 100 parts by mass of the non-volatile matter of the resin layer B is 50 parts by mass or more and 90 parts by mass or less, and the average film thickness of the laminated body is 1.5 mm or more. Such a laminated body for a vibration damping material is excellent in vibration damping performance.

Advantages of the Invention

[0023] According to the present invention, there is provided a laminated body for a vibration damping material, which is excellent in the stability of the resin composition as a raw material and excellent in the vibration damping performance of the obtained resin layer.

Modes for Carrying Out the Invention

[0024] The vibration-damping laminate of the present disclosure is a vibration-damping laminate having a resin layer A and a resin layer B, wherein resin layer A may contain an inorganic filler, and resin layer B contains an inorganic filler, wherein the inorganic filler content per 100 parts by mass of nonvolatile content of resin layer A is 30 parts by mass or less, and the inorganic filler content per 100 parts by mass of nonvolatile content of resin layer B is 50 parts by mass or more and 90 parts by mass or less, and resin layer A and resin layer B may each contain zinc oxide, wherein the zinc oxide content per 100 parts by mass of nonvolatile content of resin layer A is 5 parts by mass or less, and the zinc oxide content per 100 parts by mass of nonvolatile content of resin layer B is 5 parts by mass or less, and the average film thickness of the laminate is 1.5 mm or more.

[0025] By specifying a low inorganic filler content in resin layer A and a high inorganic filler content in resin layer B, the difference between the storage modulus of resin layer A and resin layer B becomes larger, which is thought to result in a superior vibration damping effect. Furthermore, by specifying the zinc oxide content in resin layers A and B to be within a low range, it is possible to sufficiently prevent gelation by the crosslinking agent from occurring in the resin composition that is the raw material for resin layers A and B before the resin layers are formed, thereby improving the storage stability of the resin composition.

[0026] In the vicinity of the boundary between resin layer A and resin layer B of this disclosure, the components of these two layers may be partially mixed together. In this specification, the term "resin" refers to a broader concept than polymer. A resin may contain one or more polymers, and may further contain materials other than polymers, such as additives, as necessary.

[0027] In the following, resin layer A, resin layer B, the laminate for vibration damping material, resin composition A for forming resin layer A, and resin composition B for forming resin layer B will be described in this order.

[0028] <Resin layer A> The resin layer A of this disclosure is formed using resin composition A. The resin layer A may be formed immediately after applying resin composition A to a substrate, but it is preferable that it is formed by applying resin composition A to a substrate and then performing a drying and / or curing process.

[0029] The zinc oxide content in 100 parts by mass of the nonvolatile content of the resin layer A of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, and may be substantially absent. In this specification, the zinc oxide content includes not only zinc oxide that has not yet been crosslinked, but also zinc oxide that has been crosslinked in the resin layer or resin composition.

[0030] The non-volatile content of the resin layer A in this disclosure may be calculated as the components excluding the volatile components used, or 1 g of resin layer A may be weighed out, dried in a hot air dryer at a temperature of 110°C for 1 hour, and the resulting residue may be used as the non-volatile content. formula: [Non-volatile content in resin layer A (mass%)] = ([Mass of residue] ÷ [1g of resin layer A]) × 100

[0031] The non-volatile content per 100 parts by mass of resin layer A of this disclosure is preferably 80 parts by mass or more, more preferably 90 parts by mass or more, even more preferably 95 parts by mass or more, and particularly preferably 100 parts by mass. The volatile content per 100 parts by mass of resin layer A of this disclosure is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less. Furthermore, it is particularly preferable that resin layer A contains substantially no volatile content. The volatile content of resin layer A in this disclosure may be the value obtained by subtracting the amount of non-volatile content (mass%) in resin layer A calculated from the above formula from the total amount of resin layer A (100% by mass) (see formula below). formula: [Volatile content in resin layer A (mass%)] = 100 - (amount of non-volatile content in resin layer A (mass%))

[0032] The resin layer A of this disclosure may contain crosslinking agents other than zinc oxide. Other crosslinking agents in this disclosure besides zinc oxide include metal oxides other than zinc oxide, (blocked) isocyanate compounds, melamine compounds, epoxy compounds, oxazoline compounds, vinyl ether compounds, and the like. Examples of metal oxides other than zinc oxide in this disclosure include zinc chloride, zinc sulfide, alumina, titanium oxide, magnesium oxide, and zirconium oxide. Examples of epoxy compounds in this disclosure include Adeka Resin EMN-26-60 and EM-101-50 (both trade names, manufactured by ADEKA Corporation). Examples of oxazoline compounds in this disclosure include Epocross WS-500, WS-700, K-2010, 2020, and 2030 (all trade names, manufactured by Nippon Shokubai Co., Ltd.). The content of crosslinking agents other than zinc oxide in 100 parts by mass of the nonvolatile content of resin layer A of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, and may be substantially absent. In this specification, the content of crosslinking agents other than zinc oxide includes not only crosslinking agents that have not yet been crosslinked, but also crosslinking agents that have been crosslinked in the resin layer or resin composition.

[0033] The total content of zinc oxide and other crosslinking agents in 100 parts by mass of the nonvolatile content of resin layer A of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less. It is particularly preferable that the nonvolatile content of resin layer A of this disclosure is substantially free of zinc oxide and other crosslinking agents.

[0034] The resin layer A of this disclosure typically comprises polymer A. The polymer A in this disclosure is not particularly limited, but from the viewpoint of vibration damping properties, it is preferably an acrylic polymer. The acrylic polymers of this disclosure may have any constituent units derived from (meth)acrylic monomers, and may or may not be derived from (meth)acrylic monomers. Examples of (meth)acrylic monomers include alkyl (meth)acrylate monomers and (meth)acrylic acid monomers. Alkyl (meth)acrylate monomers are monomers having a carboxylic acid ester group in which the carboxyl group of (meth)acrylic acid is esterified with an alkyl alcohol, and refer to compounds (monomers) having an acryloyloxy group or a methacryloyloxy group and an alkyl group.

[0035] Examples of the alkyl (meth)acrylate monomers in this disclosure include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, pentyl acrylate, pentyl methacrylate, isoamyl acrylate, isoamyl methacrylate, hexyl acrylate, hexyl methacrylate, cyclohexyl acrylate, cyclohexyl acrylate. Examples include xyl methacrylate, octyl acrylate, octyl methacrylate, isooctyl acrylate, isooctyl methacrylate, nonyl acrylate, nonyl methacrylate, isononyl acrylate, isononyl methacrylate, decyl acrylate, decyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, etc. It is preferable to use one or more of these.

[0036] The content of constituent units derived from alkyl (meth)acrylate monomers in 100 parts by mass of the acrylic polymer of this disclosure is preferably 20 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 60 parts by mass or more, and particularly preferably 65 parts by mass or more. From the viewpoint of polymerization stability, the content is preferably 99.9 parts by mass or less, more preferably 99.8 parts by mass or less, even more preferably 99.6 parts by mass or less, and particularly preferably 99.5 parts by mass or less.

[0037] The acrylic polymer of this disclosure preferably further has constituent units derived from (meth)acrylic acid monomers. The (meth)acrylic acid monomer is a compound (monomer) to which a hydrogen atom in an acryloyloxy group or methacryloyloxy group is bonded, or a compound (monomer) in which the hydrogen atom is replaced by another atom or group of atoms, and is a monomer having a carboxyl group (-COOH group) with a carbonyl group in the group, a carboxylic acid base in which the carboxyl group is a salt, or an acid anhydride group (-C(=O)-OC(=O)- group) of the carboxyl group. By having constituent units derived from (meth)acrylic acid monomers in the acrylic resin, the dispersibility of fillers such as calcium carbonate in the vibration-damping material formulation which is the raw material for the vibration-damping coating film of the present invention is improved, and the function of the resulting coating film is further enhanced. The (meth)acrylic acid monomer is preferably (meth)acrylic acid (salt). (Meth)acrylic acid means acrylic acid and / or methacrylic acid. The salts of the above (meth)acrylic acid monomers are preferably metal salts, ammonium salts, organic amine salts, etc. Suitable metal atoms for forming the metal salts include monovalent metal atoms such as alkali metal atoms such as lithium, sodium, and potassium; divalent metal atoms such as calcium and magnesium; and trivalent metal atoms such as aluminum and iron. Suitable organic amine salts include alkanolamine salts such as ethanolamine salt, diethanolamine salt, and triethanolamine salt, as well as triethylamine salt. The content of structural units derived from (meth)acrylic acid monomers in 100 parts by mass of the acrylic polymer disclosed herein is preferably obtained by copolymerizing 0.1 to 5 parts by mass. In the above monomer component, it is more preferable that the (meth)acrylic acid monomer is 0.3 parts by mass or more, even more preferable that the (meth)acrylic acid monomer is 0.5 parts by mass or more, and particularly preferable that the (meth)acrylic acid monomer is 0.7 parts by mass or more. Furthermore, in the above monomer component, it is preferable that the (meth)acrylic acid monomer is 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferable that the (meth)acrylic acid monomer is 3 parts by mass or less. By keeping it within this range, the monomer component copolymerizes stably.

[0038] The acrylic polymers of this disclosure may further have constituent units derived from alkyl (meth)acrylate monomers and other copolymerizable unsaturated monomers other than (meth)acrylic acid monomers. Other copolymerizable unsaturated monomers include, for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, diallyl phthalate, triallyl cyanurate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, allyl acrylate, allyl methacrylate, etc.; esterified (meth)acrylic acid monomers other than those listed above; acrylamide, methacrylamide, etc.; amidated (meth)acrylic acid monomers other than those listed above; polyfunctional unsaturated monomers such as acrylonitrile and trimethylolpropanediallyl ether; vinyl acetate, etc. It is preferable to use one or more of these.

[0039] The acrylic polymers of this disclosure may include, for example, polymers having structural units derived from unsaturated monomers having aromatic rings. Examples of such unsaturated monomers having aromatic rings include divinylbenzene, styrene, α-methylstyrene, vinyltoluene, ethylvinylbenzene, and the like, with styrene being preferred. This form allows the effects of the present invention to be fully realized while reducing costs. When the acrylic polymer of this disclosure contains structural units derived from an unsaturated monomer having an aromatic ring, it is preferable that the acrylic polymer contains 1 part by mass or more of the structural units derived from the unsaturated monomer having an aromatic ring per 100 parts by mass of the acrylic polymer, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and particularly preferably 25 parts by mass or more. Furthermore, the acrylic polymer of this disclosure preferably contains 80 parts by mass or less of the above-mentioned structural units derived from an unsaturated monomer having an aromatic ring per 100 parts by mass of the acrylic polymer, more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, and particularly preferably 40 parts by mass or less.

[0040] The resin layer A of this disclosure may contain one type of polymer A, or it may contain two or more types. Furthermore, polymer A may consist of two or more polymers, and these polymers may be in a composite form.

[0041] The glass transition temperature of the polymer (more preferably an acrylic polymer) of this disclosure is preferably -30 to 40°C. Using a polymer with such a glass transition temperature allows for effective vibration damping performance in the practical temperature range of the vibration damping material. The glass transition temperature of the above polymer is more preferably -20 to 35°C, and even more preferably -15 to 30°C. The glass transition temperature (Tg) is calculated from the monomer composition used using the following formula (1).

[0042]

number

[0043] In the formula, Tg' is the Tg (absolute temperature) of the polymer. W1', W2', ...W n ′ represents the mass fraction of each monomer relative to the total monomeric components. T1, T2, ...T n This refers to the glass transition temperature (absolute temperature) of the homopolymer (single polymer) composed of each monomer component. Note that if the resin layer A of this disclosure contains two or more polymers, or if at least one of the polymers is obtained by multi-stage polymerization (for example, if it is an emulsion resin particle having a core and a shell), then the above glass transition temperature refers to the Tg (total Tg) calculated from the monomer composition used in all stages.

[0044] For monomers whose glass transition temperature is unknown, such as special monomers and polyfunctional monomers, if the total amount of monomers with unknown glass transition temperatures in the monomer component is 10% by mass or less, the glass transition temperature can be determined using only monomers with known glass transition temperatures. If the total amount of monomers with unknown glass transition temperatures in the monomer component exceeds 10% by mass, the glass transition temperature of the polymer can be determined by differential scanning calorimetry (DSC), differential calorimetry (DTA), thermomechanical analysis (TMA), etc. The glass transition temperature of a polymer can be easily adjusted by adjusting the composition of its monomer components. The composition of the monomer components used as raw materials for the polymer constituting the particles can be determined by considering the glass transition temperature of the polymer constituting the particles. The glass transition temperatures of polymers are, for example, -70°C for 2-ethylhexyl acrylate homopolymer, -56°C for n-butyl acrylate homopolymer, 20°C for n-butyl methacrylate homopolymer, 105°C for methyl methacrylate homopolymer, 83°C for cyclohexyl methacrylate homopolymer, 97°C for isobornyl acrylate homopolymer, 180°C for isobornyl methacrylate homopolymer, 107°C for tert-butyl methacrylate homopolymer, 100°C for styrene homopolymer, 170°C for n-vinylpyrrolidone homopolymer, 95°C for acrylic acid homopolymer, 130°C for methacrylic acid homopolymer, -15°C for 2-hydroxyethyl acrylate homopolymer, and 55°C for 2-hydroxyethyl methacrylate homopolymer.

[0045] When at least one of polymer A in this disclosure consists of two or more polymers and is in a compounded form, the glass transition temperature of one of the polymers is preferably 0 to 60°C, more preferably 10 to 50°C. The glass transition temperature of the other polymer is preferably -30 to 30°C, more preferably -20 to 20°C. The difference between the glass transition temperatures of the two polymers is preferably 5 to 60°C. By providing such a difference in glass transition temperatures, for example, when applied to vibration damping materials, it becomes possible to exhibit higher vibration damping performance over a wide temperature range, and in particular, vibration damping performance in the practical range of 20 to 60°C is further improved. The difference between the glass transition temperatures is more preferably 5 to 50°C, and even more preferably 5 to 40°C. When at least one of the above polymer A (polymer) consists of two or more polymers and is in a compounded form, the mass ratio of the monomer component forming one polymer to the monomer component forming the other polymer is preferably 30 / 70 to 70 / 30. More preferably, the mass ratio is 35 / 65 to 55 / 45.

[0046] The weight-average molecular weight of polymer A in this disclosure is preferably 20,000 or more, more preferably 30,000 or more, and still more preferably 40,000 or more, from the viewpoint of heat resistance, preferably 600,000 or less, more preferably 400,000 or less, and still more preferably 200,000 or less, from the viewpoint of baking properties. The weight-average molecular weight of polymer A in this disclosure can be measured using known methods, but for example, it can be determined by GPC (gel permeation chromatography) measurement under the following measurement conditions. Measuring instrument: HLC-8120GPC (product name, manufactured by Tosoh Corporation) Molecular weight column: TSK-GEL GMHXL-L and TSK-GELG5000HXL (both manufactured by Tosoh Corporation) are used in series. Eluent: Tetrahydrofuran (THF) Calibration standard material: Polystyrene (manufactured by Tosoh Corporation) Measurement method: The substance to be measured is dissolved in THF to a solid content of approximately 0.2% by mass, filtered, and the molecular weight is measured using the resulting sample.

[0047] The content of polymer A in 100 parts by mass of resin layer A of this disclosure is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 60 parts by mass or more. Furthermore, the content of polymer A is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 80 parts by mass or less.

[0048] The resin layer A of this disclosure may contain an inorganic filler. Examples of inorganic fillers in this disclosure include calcium carbonate, mica, wollastonite, and talc. The resin layer A of this disclosure preferably contains at least one of calcium carbonate, mica, wollastonite, and talc as an inorganic filler.

[0049] The inorganic filler of this disclosure preferably has an average particle diameter of 0.1 to 200 μm, more preferably 0.5 to 100 μm, and even more preferably 1 to 50 μm. The average particle diameter of the inorganic filler can be measured by a laser diffraction particle size distribution analyzer and is the 50% weight diameter value from the particle size distribution.

[0050] The inorganic filler content in 100 parts by mass of nonvolatile matter of the resin layer A of this disclosure is preferably 30 parts by mass or less, more preferably 15 parts by mass or less, even more preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and most preferably substantially 0 parts by mass. By setting the content within this range, excellent adhesion to the substrate is achieved, and it is expected that the vibration-damping coating will not peel off from the substrate and the vibration-damping performance will not decrease as a result. The content ratio of inorganic filler to 100 parts by mass of polymer A in the resin layer A of this disclosure is preferably 55 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 15 parts by mass or less, particularly preferably 10 parts by mass or less, and most preferably substantially 0 parts by mass. By specifying that the inorganic filler content in resin layer A of this disclosure is within a low range relative to 100 parts by mass of polymer A, the difference in elastic modulus between resin layer A and resin layer B becomes large, allowing the vibration damping effect to be fully exhibited.

[0051] The resin layer A of this disclosure may further contain other components. Examples of other components include organic fillers (polyethylene, polystyrene, acrylic resin, silicone resin, urethane resin, etc.); fibers (carbon fiber, glass fiber, cellulose nanofiber, metal fiber, etc.); surfactants; dispersants; thickeners; foaming agents; gelling agents; defoaming agents; plasticizers; stabilizers; wetting agents; preservatives; anti-foaming agents; anti-aging agents; antifungal agents; ultraviolet absorbers; antistatic agents; and components derived from these agents. One or more of these can be used.

[0052] The resin layer A of this disclosure preferably has a storage modulus of 1.0E+05 MPa or higher at 25°C, more preferably 1.0E+06 MPa or higher, and even more preferably 1.0E+07 MPa or higher. The storage modulus is preferably 5.0E+08 MPa or lower, and more preferably 5.0E+07 MPa or lower. The storage modulus of the resin layer A is measured by the same method as the method for measuring the storage modulus of resin composition A after heat drying described in the examples.

[0053] The average thickness of the resin layer A in this disclosure is preferably 0.15 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more, even more preferably 0.4 mm or more, even more preferably 0.5 mm or more, even more preferably 0.8 mm or more, and particularly preferably 1.0 mm or more. From the viewpoint of coating suitability, the average thickness of the resin layer A is preferably 3.0 mm or less, more preferably 2.0 mm or less, and even more preferably 1.5 mm or less. The average thickness of the resin layer A in this disclosure can be measured by the conditions described in the examples below. The loss coefficient of the resin layer A of this disclosure at 30°C is preferably 0.1 or higher, more preferably 0.15 or higher, preferably 0.9 or lower, more preferably 0.8 or lower, and even more preferably 0.75 or lower from the viewpoint of coating suitability.

[0054] The most common method for measuring the loss coefficient in this disclosure is the resonance method, which measures near the resonant frequency. Other methods include the full width at half maximum (FWHM) method, the damping rate method, and the mechanical impedance method. In this invention, the loss coefficient of the vibration-damping coating is preferably measured using the resonance method (3dB method) with a cantilever beam. Measurement using the cantilever beam method can be performed, for example, using the vibration-damping material evaluation system manufactured by Spectris Co., Ltd.

[0055] <Resin layer B> The resin layer B of this disclosure is formed using resin composition B. The resin layer B may be formed by applying resin composition A to a substrate or the like, but it is preferable that the resin layer B is formed by applying resin composition A to a substrate or the like and then performing a drying step and / or a curing step. The zinc oxide content in 100 parts by mass of the nonvolatile content of the resin layer B of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, and may be substantially absent. The non-volatile content of resin layer B in this disclosure may be calculated as the components excluding the volatile components used, or 1 g of resin layer B may be weighed out, dried in a hot air dryer at a temperature of 110°C for 1 hour, and the resulting residue may be used as the non-volatile content. formula: [Non-volatile content in resin layer B (mass%)] = ([Mass of residue] ÷ [1g of resin layer B]) × 100

[0056] The non-volatile content per 100 parts by mass of resin layer B of this disclosure is preferably 80 parts by mass or more, more preferably 90 parts by mass or more, even more preferably 95 parts by mass or more, and particularly preferably 100 parts by mass. The volatile content per 100 parts by mass of resin layer B of this disclosure is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less. Furthermore, it is particularly preferable that resin layer B is substantially free of volatile content. The volatile content of resin layer B in this disclosure may be the value obtained by subtracting the amount of non-volatile content (mass%) in resin layer B calculated from the above formula from the total amount of resin layer B (100% by mass) (see formula below). formula: [Volatile content in resin layer B (mass%)] = 100 - (amount of non-volatile content in resin layer B (mass%))

[0057] The resin layer B of this disclosure may contain crosslinking agents other than zinc oxide. Other crosslinking agents in this disclosure besides zinc oxide are as described above in resin layer A of this disclosure. The content of crosslinking agents other than zinc oxide in 100 parts by mass of the nonvolatile content of resin layer B of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, and may be substantially absent. The total content of zinc oxide and other crosslinking agents in 100 parts by mass of the nonvolatile content of resin layer B of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less. It is particularly preferable that the nonvolatile content of resin layer B of this disclosure is substantially free of zinc oxide and other crosslinking agents.

[0058] The resin layer B of this disclosure typically comprises polymer B. The polymer B of this disclosure is not particularly limited, but from the viewpoint of vibration damping properties, it is preferably an acrylic polymer. The acrylic polymers are as described above. The resin layer B of this disclosure may contain one type of polymer B, or it may contain two or more types. Furthermore, polymer B may consist of two or more polymers, and these polymers may be in a composite form. When at least one of polymer B in this disclosure consists of two or more polymers and is in a compounded form, the glass transition temperature of one of the polymers is preferably 0 to 60°C, more preferably 10 to 50°C. The glass transition temperature of the other polymer is preferably -30 to 30°C, more preferably -20 to 20°C. The difference between the glass transition temperatures of the two polymers is preferably 5 to 60°C. By providing such a difference in glass transition temperatures, for example, when applied to vibration damping materials, it becomes possible to exhibit higher vibration damping performance over a wide temperature range, and in particular, vibration damping performance in the practical range of 20 to 60°C is further improved. The difference between the glass transition temperatures is more preferably 5 to 50°C, and even more preferably 5 to 40°C. When at least one of the polymers B (polymers) forming the emulsion resin particles is composed of two or more polymers and is in a composite form, the mass ratio of the monomer component forming one polymer to the monomer component forming the other polymer is preferably 30 / 70 to 70 / 30. More preferably, the mass ratio is 35 / 65 to 55 / 45.

[0059] The weight-average molecular weight of polymer B in this disclosure is preferably 20,000 or more, more preferably 30,000 or more, and still more preferably 40,000 or more, from the viewpoint of heat resistance, preferably 600,000 or less, more preferably 400,000 or less, and still more preferably 200,000 or less, from the viewpoint of baking properties. The weight-average molecular weight of polymer B in this disclosure can be measured using known methods, but for example, it can be determined by GPC (gel permeation chromatography) measurement under the following measurement conditions. Measuring instrument: HLC-8120GPC (product name, manufactured by Tosoh Corporation) Molecular weight column: TSK-GEL GMHXL-L and TSK-GELG5000HXL (both manufactured by Tosoh Corporation) are used in series. Eluent: Tetrahydrofuran (THF) Calibration standard material: Polystyrene (manufactured by Tosoh Corporation) Measurement method: The substance to be measured is dissolved in THF to a solid content of approximately 0.2% by mass, filtered, and the molecular weight is measured using the resulting sample.

[0060] The content of polymer B in 100 parts by mass of resin layer B of this disclosure is preferably 10 parts by mass or more, more preferably 12 parts by mass or more, and still preferably 15 parts by mass or more, and from the viewpoint of vibration damping properties, preferably 60 parts by mass or less, more preferably 50 parts by mass or less, still preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less. The content of polymer B in 100 parts by mass of the nonvolatile content of resin composition B of the present disclosure is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more. The content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, and even more preferably 27 parts by mass or less.

[0061] The resin layer B of this disclosure includes an inorganic filler. The inorganic filler in this disclosure is the same as the inorganic filler in resin layer A described above. In other words, the resin layer B of this disclosure preferably contains at least one of calcium carbonate, mica, wollastonite, and talc as an inorganic filler. The content of inorganic filler in 100 parts by mass of nonvolatile matter of resin layer B of this disclosure is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, even more preferably 60 parts by mass or more, even more preferably 65 parts by mass or more, and particularly preferably 70 parts by mass or more, from the viewpoint of vibration damping properties. The content is preferably 90 parts by mass or less, more preferably 85 parts by mass or less, and even more preferably 80 parts by mass or less, from the viewpoint of coating suitability. The inorganic filler content relative to 100 parts by mass of polymer B in the resin layer B of this disclosure is preferably 150 parts by mass or more, more preferably 200 parts by mass or more, even more preferably 250 parts by mass or more, and particularly preferably 300 parts by mass or more. The inorganic filler content relative to 100 parts by mass of polymer B in the resin layer B of this disclosure is preferably 600 parts by mass or less, and more preferably 500 parts by mass or less.

[0062] The inorganic filler content in 100 parts by mass of nonvolatile matter of resin layer B of this disclosure is more preferably 30 parts by mass or more, even more preferably 35 parts by mass or more, even more preferably 40 parts by mass or more, even more preferably 50 parts by mass or more, and particularly preferably 55 parts by mass or more, than the inorganic filler content in 100 parts by mass of nonvolatile matter of resin layer A. The inorganic filler content in 100 parts by mass of nonvolatile matter of resin layer B of this disclosure is preferably 90 parts by mass or less more than the inorganic filler content in 100 parts by mass of nonvolatile matter of resin layer A, more preferably 80 parts by mass or less more, and even more preferably 70 parts by mass or less more. By increasing the inorganic filler content in resin layer B compared to the inorganic filler content in resin layer A in this way, vibration damping performance can be improved over a wide temperature range within the practical temperature range when combined with the lower layer. The ratio of inorganic filler to 100 parts by mass of polymer B in the resin layer B of this disclosure is more preferably 100 parts by mass or more, even more preferably 200 parts by mass or more, even more preferably 250 parts by mass or more, even more preferably 280 parts by mass or more, and particularly preferably 300 parts by mass or more, than the ratio of inorganic filler to 100 parts by mass of polymer A in the resin layer A. The ratio of inorganic filler to 100 parts by mass of polymer B in the resin layer B of this disclosure is preferably 400 parts by mass or less, and more preferably 300 parts by mass or less, than the ratio of inorganic filler to 100 parts by mass of polymer A in the resin layer A. By increasing the ratio of inorganic filler to 100 parts by mass of polymer B in the resin layer B compared to the ratio of inorganic filler to 100 parts by mass of polymer A in the resin layer A, it is expected that the combination with resin layer B will result in better vibration damping over a wide temperature range within the practical temperature range.

[0063] The resin layer B of this disclosure may further contain other components. Examples of other components include organic fillers (polyethylene, polystyrene, acrylic resin, silicone resin, urethane resin, etc.); fibers (carbon fiber, glass fiber, cellulose nanofiber, metal fiber, etc.); surfactants; dispersants; thickeners; foaming agents; gelling agents; defoaming agents; plasticizers; stabilizers; wetting agents; preservatives; anti-foaming agents; anti-aging agents; antifungal agents; ultraviolet absorbers; antistatic agents; and components derived from these agents. One or more of these can be used.

[0064] The resin layer B of this disclosure preferably has a storage modulus of 1.0E+07MPa or higher at 25°C, more preferably 1.0E+08MPa or higher, even more preferably 1.0E+09MPa or higher, and particularly preferably 2.0E+09MPa or higher. The storage modulus is preferably 1.0E+11MPa or lower, more preferably 1.0E+10MPa or lower, and even more preferably 5.0E+09MPa or lower.

[0065] Furthermore, the storage modulus of resin layer B of this disclosure is preferably 1.0E+07 MPa or higher, more preferably 1.0E+08 MPa or higher, even more preferably 1.0E+09 MPa or higher, and particularly preferably 2.0E+09 MPa or higher than the storage modulus of resin layer A of this disclosure. The storage modulus of resin layer B is preferably 1.0E+11 MPa or lower, more preferably 1.0E+10 MPa or lower, and even more preferably 5.0E+09 MPa or lower than the storage modulus of resin layer A.

[0066] By increasing the storage modulus of resin layer B, the difference in elastic modulus between resin layer A and resin layer B can be increased. Possible ways to increase the storage modulus of resin layer B include increasing the content of inorganic fillers, raising the glass transition temperature of the resin, and introducing a cross-linked structure into the resin. The storage modulus of the resin layer B is measured using the same measurement method as the method for measuring the storage modulus of resin composition B after heat drying described in the examples.

[0067] The average thickness of the resin layer B in this disclosure is preferably 0.7 mm or more, more preferably 1.0 mm or more, even more preferably 1.5 mm or more, and particularly preferably 2.0 mm or more. From the viewpoint of vibration damping, the average thickness of the resin layer B is preferably 5.0 mm or less, more preferably 4.0 mm or less, even more preferably 3.7 mm or less, and particularly preferably 3.0 mm or less. The loss coefficient of the resin layer B at 30°C is preferably 0.05 or higher, more preferably 0.075 or higher, and even more preferably 0.1 or higher. From the viewpoint of coating suitability, the loss coefficient of the resin layer B at 30°C is preferably 0.7 or lower, more preferably 0.6 or lower, and even more preferably 0.5 or lower. The method for measuring the loss factor in this disclosure is as described above.

[0068] <Laminate for vibration damping material> The vibration-damping laminate of this disclosure is a vibration-damping laminate having resin layer A and resin layer B. The vibration-damping laminate of this disclosure may have a resin layer A on a base material and a resin layer B on top of the resin layer A, or it may have a resin layer B on a base material and a resin layer A on top of the resin layer B. However, from the viewpoint of vibration damping performance, it is preferable to have a resin layer A on a base material and a resin layer B on top of the resin layer A. In addition, the vibration-damping laminate of this disclosure may have other resin layers between resin layer A and resin layer B, but from the viewpoint of productivity, it is preferable that resin layer B exists as a layer in contact with resin layer A. The vibration-damping laminate of this disclosure is not particularly limited as long as it includes resin layer A and resin layer B, and may consist of two layers or three or more layers, but two layers are preferred. The average film thickness of the laminate for vibration damping material of this disclosure is preferably 1.5 mm or more, more preferably 2.0 mm or more, and even more preferably 2.5 mm or more, from the viewpoint of vibration damping performance. The average film thickness is preferably 7.0 mm or less, more preferably 5.0 mm or less, and even more preferably 4.0 mm or less, from the viewpoint of coating suitability. In the vibration-damping laminate of the present disclosure, the ratio of the average thickness of resin layer A to the average thickness of resin layer B is preferably 50 / 50 to 10 / 90, more preferably 50 / 50 to 20 / 80, even more preferably 50 / 50 to 30 / 70, and particularly preferably 40 / 60 to 30 / 70.

[0069] While known methods can be used to calculate the average thickness of resin layer A and resin layer B in the vibration-damping laminate of this disclosure, it is also possible to measure them by cutting out five arbitrary cross-sections of the vibration-damping coating and analyzing the images of those cross-sections using a microscope. Alternatively, the average thickness of the substrate, the layer beneath the substrate and the vibration-damping coating (substrate + resin layer A), and the substrate and the vibration-damping coating (substrate + resin layer A + resin layer B) can be measured at five arbitrary locations using calipers, and the average thickness ratio of resin layer A to resin layer B can be calculated by subtracting these values ​​and averaging them. The average film thickness of the vibration-damping laminate described herein can be calculated by summing up the average thicknesses of each resin layer that constitutes the vibration-damping laminate.

[0070] The vibration damping performance of the laminate for vibration damping materials of this disclosure can be evaluated by measuring the loss coefficient of the film. The loss coefficient is usually represented by η and indicates the extent to which vibrations applied to the coating film are attenuated. A higher value for the loss coefficient indicates better vibration damping performance. The loss coefficient can be measured by the method described in the examples below. The loss coefficient at 30°C for the vibration-damping laminate of the present disclosure is preferably 0.15 or higher, more preferably 0.2 or higher, even more preferably 0.25 or higher, and from the viewpoint of coating properties, preferably 0.6 or lower, more preferably 0.55 or lower, and even more preferably 0.525 or lower. The method for measuring the loss factor in this disclosure is as described above. The base material of this disclosure is not particularly limited, but examples include steel, aluminum, plastic materials, etc. Among these, a metal base material is one of the preferred embodiments of the vehicle of the present invention.

[0071] The metal material is not particularly limited, but examples include steel and aluminum. The average thickness of the substrate of this disclosure is preferably 0.1 to 3 mm, more preferably 0.3 to 2 mm, and even more preferably 0.5 to 1.6 mm. The average thickness of the metal substrate in this disclosure is preferably greater than the average thickness of the resin layer B. For example, the average thickness of the resin layer B is preferably 0.1 mm or more thinner than the average thickness of the metal substrate, more preferably 0.3 mm or more thinner, even more preferably 0.5 mm or more thinner, and particularly preferably 0.7 mm or more thinner. The average thickness of the metal substrate can be measured using the same method as described above for the average thickness of the resin layer.

[0072] <Resin composition A> The zinc oxide content in 100 parts by mass of the nonvolatile content of resin composition A of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, and may be substantially absent. The non-volatile content of resin composition A in this disclosure may be calculated as the components excluding the volatile components used, or 1 g of resin composition A may be weighed from the total mass of resin composition A, dried in a hot air dryer at a temperature of 110°C for 1 hour, and the resulting residue may be used as the non-volatile content. formula: [Non-volatile content (mass%) in resin composition A] = ([Mass of residue] ÷ [1g of resin composition A]) × 100

[0073] The non-volatile content per 100 parts by mass of resin composition A of the present disclosure is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, and still preferably 60 parts by mass or more, and from the viewpoint of coating suitability, preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and still preferably 87 parts by mass or less.

[0074] The resin composition A of this disclosure may contain crosslinking agents other than zinc oxide. The crosslinking agents other than zinc oxide in this disclosure are the same as the crosslinking agents other than zinc oxide described above in resin layer A of this disclosure. The content of crosslinking agents other than zinc oxide in 100 parts by mass of the nonvolatile content of resin composition A of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less. The nonvolatile content of resin composition A of this disclosure may not substantially contain any crosslinking agents other than zinc oxide. The total content of zinc oxide and other crosslinking agents in 100 parts by mass of the nonvolatile content of resin composition A of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less. The nonvolatile content of resin composition A may not substantially contain zinc oxide and other crosslinking agents.

[0075] The resin composition A of this disclosure may include polymer A. Polymer A in this disclosure is the same as Polymer A described above in resin layer A of this disclosure.

[0076] The resin composition A of this disclosure may contain one polymer A, or it may contain two or more polymers. Furthermore, polymer A may consist of two or more polymers, and these polymers may be compounded. In the case where polymer A has a core portion and a shell portion as described later, polymer A may consist of two types of polymers, with one of the two polymers forming the core portion and the other forming the shell portion. For example, if polymer A is an acrylic polymer, the (meth)acrylate alkyl ester monomer and other monomers copolymerizable with the (meth)acrylate alkyl ester monomer may be included in either the monomer component forming the core portion of the emulsion, the monomer component forming the shell portion, or used in both. Furthermore, it is preferable that at least one of the polymers (also called polymers) forming the emulsion resin particles is in the form of emulsion resin particles having a core portion and a shell portion. This allows for an increase in the number of interfaces between polymers, thereby enhancing effects such as improved vibration damping.

[0077] When the resin composition A of this disclosure contains emulsion resin particles having a core portion and a shell portion, the core portion and the shell portion may be completely miscible and form a homogeneous structure in which they cannot be distinguished, or they may be a core-shell composite structure or a microdomain structure in which they are not completely miscible and are formed heterogeneously. Among these structures, a core-shell composite structure is preferred in order to fully bring out the properties of the emulsion and produce a stable emulsion. Emulsions with a core-shell composite structure exhibit excellent vibration damping over a wide range within the practical temperature range. In particular, they demonstrate superior vibration damping performance even at high temperatures compared to other forms of vibration damping material formulations, and as a result, they can exhibit vibration damping performance over a wide range from room temperature to high temperatures within the practical temperature range.

[0078] In the above-described core-shell composite structure, it is preferable that the surface of the core portion is covered by the shell portion. In this case, it is preferable that the surface of the core portion is completely covered by the shell portion, but it does not have to be completely covered. For example, it may be covered in a mesh-like manner, or the core portion may be exposed in places. The glass transition temperature of the polymer (preferably an acrylic polymer) of this disclosure is preferably -30 to 40°C. For example, using an acrylic resin having such a glass transition temperature allows for effective vibration damping performance in the practical temperature range of the vibration damping material. The glass transition temperature of the above polymer (preferably an acrylic polymer) is more preferably -20 to 35°C, and even more preferably -15 to 30°C. The glass transition temperature (Tg) is calculated or measured as described above.

[0079] When at least one of the polymers A of this disclosure is in the form of emulsion resin particles having a core portion and a shell portion, the glass transition temperature of the polymer in the core portion is preferably 0 to 60°C, more preferably 10 to 50°C. The glass transition temperature of the polymer in the shell portion is preferably -30 to 30°C, more preferably -20 to 20°C. Furthermore, the difference in glass transition temperatures between the polymer in the core portion and the polymer in the shell portion is preferably 5 to 60°C. By providing such a difference in glass transition temperatures, for example, when applied to vibration damping materials, it becomes possible to exhibit higher vibration damping performance over a wide temperature range, and in particular, vibration damping performance in the practical range of 20 to 60°C is further improved. The difference in glass transition temperatures is more preferably 5 to 50°C, and even more preferably 5 to 40°C. When at least one of the polymers A (polymers) forming the emulsion resin particles is in the form of emulsion resin particles having a core portion and a shell portion, the mass ratio of monomer components forming the core portion to monomer components forming the shell portion (monomer components forming the core portion / monomer components forming the shell portion) is preferably 30 / 70 to 70 / 30. With such a mass ratio, the effects of having a structure with a core portion and a shell portion can be more fully realized. The mass ratio of monomer components forming the core portion to monomer components forming the shell portion is more preferably 35 / 65 to 55 / 45.

[0080] The weight-average molecular weight of polymer A in this disclosure is as described above, as the weight-average molecular weight of polymer A in resin layer A.

[0081] When the resin composition A of this disclosure contains emulsion resin particles, the average particle size of the emulsion resin particles is preferably 80 to 450 nm. By using emulsion resin particles with an average particle diameter within this range, it is possible to achieve sufficient basic performance such as coating appearance and coating properties required for vibration damping materials, while also improving vibration damping performance. The average particle diameter of the emulsion resin particles is more preferably 400 nm or less, and even more preferably 350 nm or less. Furthermore, the average particle diameter is more preferably 100 nm or more. The method for measuring the average particle diameter of emulsion resin particles in this disclosure is measured in accordance with JIS Z 8828, by dynamic light scattering, and is defined as the cumulant average particle diameter. Specifically, it can be measured by the method described in the examples. The emulsion resin particles having the above average particle diameter preferably have a particle size distribution defined by the value obtained by dividing the standard deviation by its average particle diameter (standard deviation / volume average particle diameter × 100) of 40% or less. More preferably, it is 30% or less. By having a particle size distribution of 40% or less, coarse particles are not included, and as a result, the vibration damping material compound can exhibit sufficient heat drying properties.

[0082] The content of polymer A (preferably an acrylic polymer) in 100 parts by mass of resin composition A of this disclosure is preferably 45 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 60 parts by mass or more, from the viewpoint of productivity. From the viewpoint of coating suitability, the content is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 87 parts by mass or less. The content of polymer A in 100 parts by mass of the nonvolatile content of resin composition A of the present disclosure is more preferably 65 parts by mass or more, even more preferably 70 parts by mass or more, even more preferably 75 parts by mass or more, particularly preferably 80 parts by mass or more, even more preferably 95 parts by mass or more, even more preferably 98 parts by mass or more, even more preferably 99 parts by mass or more, and most preferably 100 parts by mass.

[0083] The resin composition A of this disclosure may contain an inorganic filler. Examples of inorganic fillers in this disclosure include those similar to the inorganic filler in resin layer A of this disclosure.

[0084] The inorganic filler of this disclosure preferably has an average particle diameter of 0.1 to 200 μm, more preferably 0.5 to 100 μm, and even more preferably 1 to 50 μm. The average particle diameter of the inorganic filler can be measured by a laser diffraction particle size distribution analyzer and is the 50% weight diameter value from the particle size distribution.

[0085] The inorganic filler content in 100 parts by mass of resin composition A of this disclosure is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, from the viewpoint of vibration damping. The inorganic filler content in 100 parts by mass of the nonvolatile content of resin composition A of this disclosure is preferably 30 parts by mass or less, more preferably 15 parts by mass or less, even more preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and most preferably substantially 0 parts by mass. By setting the content within this range, excellent adhesion to the substrate is achieved, and it is expected that the vibration-damping coating film will not peel off from the substrate and the vibration-damping performance will not decrease as a result. The content ratio of inorganic filler to 100 parts by mass of polymer A in the resin composition A of this disclosure is preferably 55 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 15 parts by mass or less, particularly preferably 10 parts by mass or less, and most preferably substantially 0 parts by mass. In the resin composition A of this disclosure, the content ratio of inorganic filler to 100 parts by mass of polymer A is specified to be within a low range, which increases the difference in elastic modulus between resin layer A and resin layer B, allowing the vibration damping effect to be fully exhibited.

[0086] The resin composition A of this disclosure contains an aqueous solvent, and the polymer A is preferably dispersed or dissolved in the aqueous solvent, and more preferably dispersed in the aqueous solvent. In other words, the resin composition A is more preferably an emulsion. In this specification, dispersed in an aqueous solvent means dispersed without dissolving in the aqueous solvent. The polymer A can be polymerized by known methods such as solution polymerization or suspension polymerization, but in vibration damping material formulations, its form is preferably emulsion resin particles (resin particles present in the emulsion) obtained by emulsion polymerization of monomer components. The aqueous solvent in this disclosure may include organic solvents such as ethylene glycol, butyl cellosolve, butyl carbitol, and butyl carbitol acetate, as long as it contains water, but water is preferred. The amount of solvent added can be appropriately set to properly adjust the solid content concentration of resin composition A of the present invention. The content of the aqueous solvent in 100 parts by mass of resin composition A of this disclosure is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, and even more preferably 40 parts by mass or more, from the viewpoint of coating suitability. The content of the aqueous solvent is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less, from the viewpoint of productivity.

[0087] The resin composition A of this disclosure may further contain other components. Examples of other components include organic fillers (polyethylene, polystyrene, acrylic resin, silicone resin, urethane resin, etc.); fibers (carbon fiber, glass fiber, cellulose nanofiber, metal fiber, etc.); surfactants; dispersants; thickeners; foaming agents; gelling agents; defoaming agents; plasticizers; stabilizers; wetting agents; preservatives; anti-foaming agents; anti-aging agents; antifungal agents; ultraviolet absorbers; antistatic agents; and components derived from these agents. One or more of these can be used.

[0088] The resin composition A of this disclosure preferably has a storage modulus of 1.0E+05MPa or higher at room temperature after coating with a film thickness of 0.3mm and drying at 140°C for 60 minutes, more preferably 1.0E+06MPa or higher, and even more preferably 1.0E+07MPa or higher. The storage modulus is preferably 5.0E+08MPa or lower, and more preferably 5.0E+07MPa or lower. The storage modulus of the resin composition A after heat drying corresponds to the storage modulus of the resin layer A after drying is substantially complete, and serves as an indicator of the vibration damping properties of the resin layer A. The storage modulus of the above resin composition A after heat drying is measured by the method described in the examples.

[0089] The resin composition A of this disclosure preferably has a storage modulus of 1.0E+04 MPa or higher, more preferably 2.0E+04 MPa or higher, and even more preferably 3.0E+04 MPa or higher, after being applied to a film thickness of 0.6 mm and left at room temperature for 60 minutes. The storage modulus is preferably 5.0E+08 MPa or lower, and more preferably 5.0E+07 MPa or lower. The storage modulus of the resin composition A after drying at room temperature is an indicator of its driesability, as the storage modulus increases as the moisture in the resin composition A evaporates. Excellent driesability allows for suitable drying at room temperature, for example. To increase the storage modulus after drying at room temperature, possible methods include reducing the water content in the resin composition, reducing the water-retaining components, and increasing the proportion of inorganic fillers. In this specification, room temperature is intended to mean 25°C.

[0090] The pH of resin composition A of this disclosure is not particularly limited, but is preferably 2 to 10, more preferably 3 to 9.5, and even more preferably 7 to 9. The pH can be adjusted by adding ammonia water, water-soluble amines, alkali hydroxide aqueous solution, etc., to the acrylic resin. The pH of resin composition A of this disclosure can be measured by the method described in the examples below.

[0091] The viscosity of resin composition A of this disclosure is not particularly limited, but is preferably 1 to 10,000 mPa·s, more preferably 10 to 4,000 mPa·s, even more preferably 20 to 3,000 mPa·s, and particularly preferably 40 to 1,000 mPa·s. The viscosity of resin composition A of this disclosure can be measured by the conditions described in the examples below.

[0092] <Resin composition B> The zinc oxide content in 100 parts by mass of the nonvolatile content of resin composition B of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, and may be substantially absent. The non-volatile content of resin composition B in this disclosure may be calculated as the components excluding the volatile components used, or 1 g of resin composition B may be weighed from the total mass of resin composition B, dried in a hot air dryer at a temperature of 110°C for 1 hour, and the resulting residue may be used as the non-volatile content. formula: [Non-volatile content (mass%) in resin composition B] = ([Mass of residue] ÷ [1g of resin composition B]) × 100 The resin composition B of this disclosure may contain crosslinking agents other than zinc oxide. The crosslinking agents other than zinc oxide in this disclosure are the same as the crosslinking agents other than zinc oxide described above in resin layer B of this disclosure. The content of crosslinking agents other than zinc oxide in 100 parts by mass of the nonvolatile content of resin composition B of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less. The nonvolatile content of resin composition B of this disclosure may not substantially contain any crosslinking agents other than zinc oxide. The total content of zinc oxide and other crosslinking agents in 100 parts by mass of the nonvolatile content of resin composition B of this disclosure is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, and may be substantially absent. The non-volatile content per 100 parts by mass of resin composition B of the present disclosure is preferably 60 parts by mass or more, more preferably 70 parts by mass or more, and still preferably 75 parts by mass or more, from the viewpoint of drying properties, preferably 90 parts by mass or less, more preferably 88 parts by mass or less, and still preferably 85 parts by mass or less.

[0093] The resin composition B of this disclosure may include polymer B. The polymer B of this disclosure is not particularly limited, but from the viewpoint of vibration damping properties, it is preferably an acrylic polymer. The acrylic polymers are as described above. The resin composition B of this disclosure may contain one polymer B or two or more polymers. Furthermore, polymer B may consist of two or more polymers, and these polymers may be compounded. In the case where polymer B has a core portion and a shell portion as described later, polymer B may consist of two types of polymers, with one of the two polymers forming the core portion and the other forming the shell portion. For example, alkyl (meth)acrylate monomers and other monomers copolymerizable with alkyl (meth)acrylate monomers may be included in either the monomer component forming the core portion of the emulsion, the monomer component forming the shell portion, or used in both. Furthermore, it is preferable that at least one of the polymers forming the emulsion resin particles is in the form of emulsion resin particles having a core portion and a shell portion. This allows for an increase in the number of interfaces between polymers, thereby enhancing effects such as improved vibration damping. When the resin composition B of this disclosure contains emulsion resin particles having a core portion and a shell portion, the core portion and the shell portion may be completely miscible and form a homogeneous structure in which they cannot be distinguished, or they may be a core-shell composite structure or a microdomain structure in which they are not completely miscible and are formed heterogeneously. Among these structures, a core-shell composite structure is preferred in order to fully bring out the properties of the emulsion and produce a stable emulsion.

[0094] Emulsions with a core-shell composite structure exhibit excellent vibration damping over a wide range within the practical temperature range. In particular, they demonstrate superior vibration damping performance even at high temperatures compared to other forms of vibration damping material formulations, and as a result, they can exhibit vibration damping performance over a wide range from room temperature to high temperatures within the practical temperature range. In the above-described core-shell composite structure, it is preferable that the surface of the core portion is covered by the shell portion. In this case, it is preferable that the surface of the core portion is completely covered by the shell portion, but it does not have to be completely covered. For example, it may be covered in a mesh-like manner, or the core portion may be exposed in places. When at least one of the polymers B of this disclosure is in the form of emulsion resin particles having a core portion and a shell portion, the glass transition temperature of the polymer in the core portion is preferably 0 to 60°C, more preferably 10 to 50°C. The glass transition temperature of the polymer in the shell portion is preferably -30 to 30°C, more preferably -20 to 20°C. Furthermore, the difference in glass transition temperatures between the polymer in the core portion and the polymer in the shell portion is preferably 5 to 60°C. By providing such a difference in glass transition temperatures, for example, when applied to vibration damping materials, it becomes possible to exhibit higher vibration damping performance over a wide temperature range, and in particular, vibration damping performance in the practical range of 20 to 60°C is further improved. The difference in glass transition temperatures is more preferably 5 to 50°C, and even more preferably 5 to 40°C. When at least one of the polymers B (polymers) forming the emulsion resin particles is in the form of emulsion resin particles having a core portion and a shell portion, the mass ratio of monomer components forming the core portion to monomer components forming the shell portion (monomer components forming the core portion / monomer components forming the shell portion) is preferably 30 / 70 to 70 / 30. With such a mass ratio, the effects of having a structure with a core portion and a shell portion can be more fully realized. The mass ratio of monomer components forming the core portion to monomer components forming the shell portion is more preferably 35 / 65 to 55 / 45.

[0095] The weight-average molecular weight of polymer B in this disclosure is as described above, as the weight-average molecular weight of polymer B in resin layer B.

[0096] When the resin composition B of this disclosure contains emulsion resin particles, the average particle size of the emulsion resin particles is preferably 80 to 450 nm. By using emulsion resin particles with an average particle diameter within this range, it is possible to achieve sufficient basic performance such as coating appearance and coating properties required for vibration damping materials, while also improving vibration damping performance. The average particle diameter of the emulsion resin particles is more preferably 400 nm or less, and even more preferably 350 nm or less. Furthermore, the average particle diameter is more preferably 100 nm or more. The method for measuring the average particle diameter of emulsion resin particles in this disclosure is measured in accordance with JIS Z 8828, by dynamic light scattering, and is defined as the cumulant average particle diameter. Specifically, it can be measured by the method described in the examples. The emulsion resin particles having the above average particle diameter preferably have a particle size distribution defined by the value obtained by dividing the standard deviation by its volume average particle diameter (standard deviation / volume average particle diameter × 100) of 40% or less. More preferably, it is 30% or less. By having a particle size distribution of 40% or less, coarse particles are not included, and as a result, the vibration damping material compound can exhibit sufficient heat drying properties.

[0097] The content of polymer B in 100 parts by mass of resin composition B of this disclosure is preferably 10 parts by mass or more, more preferably 12 parts by mass or more, and still preferably 15 parts by mass or more, from the viewpoint of vibration damping properties, preferably 60 parts by mass or less, more preferably 50 parts by mass or less, still preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less, from the viewpoint of coating suitability. The content of polymer B in 100 parts by mass of the nonvolatile content of resin composition B of the present disclosure is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, and from the viewpoint of coating suitability, preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, and even more preferably 27 parts by mass or less.

[0098] The resin composition B of this disclosure includes an inorganic filler. Examples of inorganic fillers in this disclosure include those similar to the inorganic filler in resin layer B of this disclosure. The inorganic filler content in 100 parts by mass of resin composition B of this disclosure is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, even more preferably 57 parts by mass or more, preferably 80 parts by mass or less, more preferably 75 parts by mass or less, and even more preferably 70 parts by mass or less, from the viewpoint of vibration damping. The inorganic filler content in 100 parts by mass of the nonvolatile content of resin composition B of this disclosure is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, even more preferably 60 parts by mass or more, even more preferably 65 parts by mass or more, and particularly preferably 70 parts by mass or more, from the viewpoint of vibration damping properties. The inorganic filler content is preferably 90 parts by mass or less, more preferably 85 parts by mass or less, and even more preferably 80 parts by mass or less, from the viewpoint of coating suitability. The inorganic filler content in the resin composition B of this disclosure is preferably 150 parts by mass or more, more preferably 200 parts by mass or more, even more preferably 250 parts by mass or more, and particularly preferably 300 parts by mass or more. The inorganic filler content in the resin composition B of this disclosure is preferably 400 parts by mass or less, and more preferably 380 parts by mass or less, based on 100 parts by mass of acrylic resin.

[0099] The inorganic filler content in 100 parts by mass of resin composition B of this disclosure is more preferably 30 parts by mass or more, even more preferably 35 parts by mass or more, even more preferably 40 parts by mass or more, even more preferably 50 parts by mass or more, and particularly preferably 55 parts by mass or more, compared to the inorganic filler content in 100 parts by mass of resin composition A.

[0100] The inorganic filler content in 100 parts by mass of resin composition B of this disclosure is preferably 90 parts by mass or less more than the inorganic filler content in 100 parts by mass of resin composition A, more preferably 80 parts by mass or less more, and even more preferably 70 parts by mass or less more. By increasing the inorganic filler content in resin composition B compared to the inorganic filler content in resin composition A in this way, vibration damping performance can be improved over a wide temperature range within the practical temperature range when combined with the lower layer.

[0101] The ratio of inorganic filler to 100 parts by mass of polymer B in resin composition B of this disclosure is more preferably 100 parts by mass or more, even more preferably 200 parts by mass or more, even more preferably 250 parts by mass or more, even more preferably 280 parts by mass or more, and particularly preferably 300 parts by mass or more, than the ratio of inorganic filler to 100 parts by mass of polymer A in resin composition A. The ratio of inorganic filler to 100 parts by mass of polymer B in resin composition B of this disclosure is preferably 400 parts by mass or less, and more preferably 300 parts by mass or less, than the ratio of inorganic filler to 100 parts by mass of polymer A in resin composition A. By increasing the ratio of inorganic filler to 100 parts by mass of polymer B in resin composition B compared to the ratio of inorganic filler to 100 parts by mass of polymer A in resin composition A, it is expected that the combination with resin composition B will result in better vibration damping over a wide temperature range within the practical temperature range.

[0102] The resin composition B of this disclosure contains an aqueous solvent, and the polymer B is preferably dispersed or dissolved in the aqueous solvent, and more preferably dispersed in the aqueous solvent. In other words, it is more preferable that the vibration damping material formulation is an emulsion. In this specification, dispersed in an aqueous solvent means dispersed without dissolving in the aqueous solvent. The polymer B can be polymerized by known methods such as solution polymerization or suspension polymerization, but its form in the vibration damping material formulation is preferably emulsion resin particles (resin particles present in the emulsion) obtained by emulsion polymerization of monomer components. The aqueous solvent in this disclosure may include organic solvents such as ethylene glycol, butyl cellosolve, butyl carbitol, and butyl carbitol acetate, as long as it contains water, but water is preferred. The amount of solvent added can be appropriately set to properly adjust the solid content concentration of resin composition A of the present invention. The water-based solvent content in 100 parts by mass of resin composition B of this disclosure is preferably 10 parts by mass or more, more preferably 13 parts by mass or more, and even more preferably 15 parts by mass or more from the viewpoint of coating suitability, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less from the viewpoint of drying properties. By reducing the water-based solvent content in resin composition B in this way compared to the water-based solvent content in resin composition A, a coating film with high surface hardness can be quickly obtained with less heat (time and temperature) when combined with a lower layer, and high vibration damping properties can be achieved.

[0103] The resin composition B of this disclosure may further contain other components. Examples of other components include organic fillers (polyethylene, polystyrene, acrylic resin, silicone resin, urethane resin, etc.); fibers (carbon fiber, glass fiber, cellulose nanofiber, metal fiber, etc.); surfactants; dispersants; thickeners; foaming agents; gelling agents; defoaming agents; plasticizers; stabilizers; wetting agents; preservatives; anti-foaming agents; anti-aging agents; antifungal agents; ultraviolet absorbers; antistatic agents; and components derived from these agents. One or more of these can be used.

[0104] The resin composition B of this disclosure preferably has a storage modulus at 25°C of 1.0E+07 MPa or higher, more preferably 1.0E+08 MPa or higher, even more preferably 1.0E+09 MPa or higher, and particularly preferably 2.0E+09 MPa or higher, after being applied to a film thickness of 0.6 mm and dried in a 140°C oven for 60 minutes. The storage modulus is preferably 1.0E+11 MPa or lower, more preferably 1.0E+10 MPa or lower, and even more preferably 5.0E+09 MPa or lower. The storage modulus of the resin composition B after heat drying corresponds to the storage modulus of the resin layer B after drying is substantially complete, and serves as an indicator of the vibration damping properties of the resin layer B. The storage modulus of the above resin composition B after heat drying is measured by the method described in the examples.

[0105] The storage modulus of resin composition B after heat drying is preferably 1.0E+07 MPa or higher, more preferably 1.0E+08 MPa or higher, even more preferably 1.0E+09 MPa or higher, and particularly preferably 2.0E+09 MPa or higher than the storage modulus of resin composition A after heat drying. The storage modulus is preferably 1.0E+11 MPa or lower higher, more preferably 1.0E+10 MPa or lower higher, and even more preferably 5.0E+09 MPa or lower higher.

[0106] The resin composition B of this disclosure preferably has a storage modulus at room temperature of 1.8E+08MPa or higher, more preferably 1.9E+08MPa or higher, even more preferably 2.0E+08MPa or higher, preferably 5.0E+09MPa or lower, more preferably 3.0E+09MPa or lower, and even more preferably 2.0E+09MPa or lower after being applied to a film thickness of 0.6mm and left at room temperature for 60 minutes. The storage modulus of the resin composition B after drying at room temperature is an indicator of its driesability, as the storage modulus increases as the moisture in the resin composition B evaporates. Excellent driesability allows for suitable drying at room temperature, for example. To increase the storage modulus after drying at room temperature, possible methods include reducing the water content in the resin composition, reducing the water-retaining components, and increasing the proportion of inorganic fillers. The storage modulus of the above resin composition B after drying at room temperature is measured by the method described in the examples.

[0107] The pH of resin composition B of this disclosure is not particularly limited, but is preferably 2 to 10, more preferably 3 to 9.5, and even more preferably 7 to 9. The pH can be adjusted by adding ammonia water, water-soluble amines, alkali hydroxide aqueous solution, etc., to the acrylic resin. The pH of resin composition B of this disclosure can also be measured by the method described in the examples below. The viscosity of resin composition B of this disclosure is not particularly limited, but is preferably 1 to 10,000 mPa·s, more preferably 10 to 4,000 mPa·s, even more preferably 20 to 3,000 mPa·s, and particularly preferably 40 to 1,000 mPa·s. The viscosity of resin composition B of this disclosure can be measured using known methods, but can also be measured under the conditions described in the examples below.

[0108] <Manufacturing method for laminated materials for vibration damping> The present disclosure is a method for manufacturing a laminate for vibration damping materials, comprising applying resin composition B to the upper layer of resin layer A derived from resin composition A after applying resin composition A or simultaneously with applying resin composition A, wherein resin composition A may contain an inorganic filler, and resin composition B contains an inorganic filler, wherein the content of the inorganic filler per 100 parts by mass of nonvolatile content of resin composition A is 30 parts by mass or less, and the content of the inorganic filler per 100 parts by mass of nonvolatile content of resin composition B is 50 parts by mass or more and 90 parts by mass or less, and resin composition A and resin composition B may each contain zinc oxide, wherein the content of zinc oxide per 100 parts by mass of nonvolatile content of resin composition A is 5 parts by mass or less, and the content of zinc oxide per 100 parts by mass of nonvolatile content of resin composition B is 5 parts by mass or less. The manufacturing method for the vibration-damping laminate of this disclosure is to apply resin composition A to a substrate and then apply resin composition B to the upper layer of resin layer A. The vibration-damping laminate of this disclosure may include, for example, a third step of forming another coating film, insofar as it includes a first step of forming a resin layer A and a second step of forming a resin layer B. The first and second steps may be performed simultaneously. The method for manufacturing a laminate for vibration damping material (vibration-damping coating) according to the second step of the present invention preferably includes a step of drying these coatings in addition to the steps of forming resin layer A and resin layer B. In the method for manufacturing a laminate for vibration damping material (vibration-damping coating) according to the present invention, resin layer A may be formed and dried, then resin layer B may be formed on top of it and dried, or resin layer A and resin layer B may be formed and then these coatings may be dried at once. More preferably, resin layer A and resin layer B are formed and then these coatings are dried at once. That is, it is preferable to perform the step of drying the coatings after performing the steps of forming resin layer A and resin layer B.

[0109] If the manufacturing method for a vibration-damping laminate (vibration-damping coating) includes a step of forming the third and subsequent coatings (the third and subsequent coatings), it is preferable to perform the drying step after the step of forming all the coatings has been completed, so that all the formed coatings can be dried at once. In the method for manufacturing a vibration-damping coating film in the first step of this disclosure, the preferred temperature for drying the coating film is preferably 0°C to 200°C, more preferably 5°C to 150°C, even more preferably 10°C to 100°C, and particularly preferably 15°C to 90°C. In the method for manufacturing a vibration-damping coating in the first step of this disclosure, the preferred time for drying the coating is preferably 10 to 240 minutes. More preferably, it is 20 to 180 minutes, and particularly preferably, it is 30 to 120 minutes. In the method for manufacturing a vibration-damping laminate (vibration-damping coating) according to the second step of the present invention, the preferred temperature and time for drying the coating are the same as those described in the method for manufacturing a vibration-damping laminate (vibration-damping coating) according to the first step of the present invention. Furthermore, in the method for manufacturing a vibration-damping laminate according to the present disclosure, in the method for manufacturing a vibration-damping coating film by performing the steps of forming resin layer A and resin layer B, followed by the step of drying the coating film all at once, the preferred temperature and time for drying the coating film are the same as the temperature and time described in the method for manufacturing a vibration-damping coating film by the first step of the present invention. The application method is not particularly limited, and methods such as using a brush, spatula, air spray, airless spray, mortar gun, or resin gun can be used. The vibration-damping coating of the present invention can also be obtained by processes such as laminating the coating film onto release paper, then bonding a substrate on top of it, and finally peeling off the release paper, or by performing a mold molding process. In these cases, the layer obtained by the first application becomes the upper layer on the surface side. It is preferable that the vibration-damping coating of the present invention is obtained by heating and drying the applied vibration-damping material mixture. The present invention can be suitably used under milder drying conditions compared to those in conventional manufacturing processes. By combining it with resin composition A and resin composition B as described above, it is possible to quickly form a vibration-damping coating film with high surface hardness, i.e., high storage modulus of the upper layer, at temperatures of around 100°C or even lower, compared to conventional drying processes that required around 150°C.

[0110] <Application> The vibration-damping laminate of this disclosure exhibits excellent vibration damping properties and is therefore preferably used in vehicles. Specifically, it can be suitably used by forming a coating film on the surface of materials such as steel plates that constitute various structures such as automobiles, railway vehicles, ships, aircraft, and electrical equipment. This disclosure also applies to the use of the vibration damping material (laminated structure) described herein as a vibration damping material. [Examples]

[0111] The present invention will be described in more detail below with reference to embodiments for carrying out the invention, but the present invention is not limited to these embodiments. Unless otherwise specified, "parts" means "parts by weight" and "%" means "mass%". In the following manufacturing examples, various physical properties were evaluated as follows.

[0112] <Cumulant average particle size> The average particle size of emulsion resin particles was measured using a particle size distribution analyzer (FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.) based on the dynamic light scattering method. <Non-volatile content (NV)> Approximately 1 g of the obtained resin composition was weighed and dried in a hot air dryer at 150°C for 1 hour. The remaining amount after drying was considered non-volatile content, and its ratio to the pre-drying mass was expressed as % (mass%). [Non-volatile content (mass%) in resin compositions] = ([Mass of residue] ÷ [1g of resin composition]) × 100

[0113] <ph> The pH value was measured at 25°C using a pH meter (Horiba F-23). <Viscosity> The measurements were taken using a Type B rotational viscometer (VISCOMETER TUB-10, manufactured by Toki Sangyo Co., Ltd.) under conditions of 25°C and 20 rpm. <Weight average molecular weight> The measurements were performed by GPC (gel permeation chromatography) under the following measurement conditions. Measuring instrument: HLC-8120GPC (product name, manufactured by Tosoh Corporation) Molecular weight column: TSK-GEL GMHXL-L and TSK-GELG5000HXL (both manufactured by Tosoh Corporation) are used in series. Eluent: Tetrahydrofuran (THF) Calibration standard material: Polystyrene (manufactured by Tosoh Corporation) Measurement method: The substance to be measured is dissolved in THF to a solid content of approximately 0.2% by mass, filtered, and the molecular weight is measured using the resulting sample.

[0114] <Glass transition temperature (Tg)> The glass transition temperature (Tg) is calculated from the monomer composition of the polymer component using the following formula (1).

[0115]

number

[0116] In the formula, Tg' is the Tg (absolute temperature) of the polymer. W1', W2', ...Wn' are the mass fractions of each monomer relative to the total monomer components. T1, T2, ...Tn are the glass transition temperatures (absolute temperatures) of the homopolymer (single polymer) composed of each monomer component. When resin composition A of this disclosure contains two or more polymers, or when at least one of the polymers is obtained by multi-stage polymerization (for example, when it is an emulsion resin particle having a core and a shell), the Tg calculated from the monomer composition used in all stages is indicated as "total Tg". The Tg values ​​of each homopolymer used to calculate the glass transition temperature (Tg) of the polymerizable monomer component using the above formula (1) are shown below. Methyl methacrylate (MMA): 105℃ Styrene (St): 100℃ Butyl acrylate (BA): -56℃ 2-Ethylhexyl acrylate (2EHA): -70℃ Acrylic acid (AA): 95℃

[0117] Production example 1 (resin composition A1) 285 parts of deionized water were charged into a polymerization reactor equipped with a stirrer, reflux condenser, thermometer, nitrogen inlet tube, and dropping funnel. The internal temperature was then raised to 75°C while stirring under a nitrogen gas flow. Meanwhile, the dropping funnel was charged with the first stage monomer emulsion, consisting of 170 parts styrene, 130 parts methyl methacrylate, 95 parts butyl acrylate, 95 parts 2-ethylhexyl acrylate, 10 parts acrylic acid, 3.0 parts t-dodecyl mercaptan (a polymerization chain transfer agent), 90 parts of the emulsifier Hythenol 18E (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), which had been prepared as a 20% aqueous solution beforehand, and 97 parts of deionized water. Next, while maintaining the internal temperature of the polymerization reactor at 80°C, 11 parts of the monomer emulsion, 6.6 parts of 3% potassium persulfate aqueous solution and 5.0 parts of 2% sodium bisulfite aqueous solution (polymerization initiators / oxidizing agents) were added to start the initial polymerization. After 20 minutes, while maintaining the reaction system at 80°C, the remaining monomer emulsion was uniformly added dropwise over 120 minutes. Simultaneously, 80 parts of 3% potassium persulfate aqueous solution and 30 parts of 2% sodium bisulfite aqueous solution were uniformly added dropwise over 120 minutes, and the temperature was maintained for 60 minutes after the completion of the addition. Next, a second monomer emulsion consisting of 60 parts styrene, 140 parts methyl methacrylate, 190 parts butyl acrylate, 100 parts 2-ethylhexyl acrylate, 10 parts acrylic acid, 3.0 parts t-dodecyl mercaptan, 75 parts of Hythenol 18E (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) pre-prepared as a 20% aqueous solution, and 100 parts deionized water was charged into the dropping funnel and uniformly added dropwise over 120 minutes. Simultaneously, 80 parts of a 3% potassium persulfate aqueous solution and 30 parts of a 2% sodium bisulfite aqueous solution were uniformly added dropwise over 120 minutes. After the addition was complete, the temperature was maintained for 90 minutes to complete the polymerization. After the resulting reaction solution was cooled to room temperature, 25 parts of 2-dimethylethanolamine were added to obtain a resin composition with a non-volatile content of 54.9%, pH of 7.9, viscosity of 360 mPa·s, a cumulant average particle size of 190 nm, a weight-average molecular weight of 51000, a first stage Tg of 16°C, a second stage Tg of -13°C, and a total Tg of 0°C. The emulsion obtained in Production Example 1 was also used as resin composition A1.

[0118] Production example 2 (resin composition A2) Resin composition A2 was obtained by mixing 100 parts by mass of resin composition A1 with 23 parts of calcium carbonate (NN#200, manufactured by Nitto Funka Kogyo Co., Ltd.) as an inorganic filler.

[0119] Production example 3 (resin composition B1) Resin composition B1 was obtained by mixing 50 parts of resin composition A1, 1.5 parts of zinc oxide, and 72 parts of calcium carbonate (NN#200, manufactured by Nitto Funka Kogyo Co., Ltd.) as an inorganic filler.

[0120] Production examples 4 to 7 (resin composition B2 to resin composition B5) Resin compositions B2 to B5 were prepared in the same manner as in Manufacturing Example 3, except that they were formulated according to the blending ratios listed in Table 1.

[0121] [Table 1]

[0122] *The Epocross used in Manufacturing Example 4 is Epocross WS-500 (manufactured by Nippon Shokubai Co., Ltd., 39% by mass of non-volatile content), which was added in its natural form at a rate of 2 parts by mass.

[0123] Example 1 A 2 mm first layer was formed on a substrate (cold-rolled steel sheet, 250*10*1.0 mm) using resin composition A1 obtained in Manufacturing Example 1, and dried at room temperature (25°C) for 15 hours. Subsequently, a 2 mm second layer was formed on top of this using resin composition B1 obtained above, and dried at room temperature (25°C) for 15 hours, thereby obtaining an evaluation test piece in which a vibration-damping coating film consisting of a first layer / second layer with a thickness ratio of 50 / 50 was formed on the substrate.

[0124] Examples 2-7 An evaluation test piece was obtained in the same manner as in Example 1, with a vibration-damping coating film consisting of a first layer and a second layer, except that the mixing ratio and the thickness of the first and second layers were changed as shown in Tables 2 and 3 below.

[0125] Comparative Example 1 An evaluation test piece was obtained in which a single-layer vibration-damping coating film was formed on a substrate (cold-rolled steel sheet, 250*10*1.0mm) using the vibration-damping material compound 3 obtained in Example 3, and then dried.

[0126] Comparative Example 2 In Example 1, evaluation test pieces were obtained in the same manner as in Example 1, except that the amount of zinc oxide was changed to 6.0 parts and the thickness and ratio of the first and second layers were changed.

[0127] Evaluation method (Coating thickness) The thickness of the dried coating film of each layer described in the Examples and Comparative Examples, as well as the total thickness of the dried coating film (first layer + second layer), were calculated by measuring five arbitrary points with a caliper and determining the average value. The ratio of the average thickness of the lower layer to the average thickness of the upper layer was measured by cutting out five arbitrary cross-sections of the vibration-damping coating and analyzing the resulting microscope images.

[0128] (Vibration damping test) Using the fabricated evaluation test pieces, the loss factor at 30°C was measured using the cantilever beam method (vibration damping material evaluation system, manufactured by Brüel & Kjær (B&K)). The larger the loss coefficient, the better the vibration damping performance.

[0129] (Storage modulus after heat drying) Resin composition A (A1, A2): Using the resin composition corresponding to resin composition A in each example, a 0.3 mm thick coating film was formed on a glass plate. After drying in a 140°C oven for 60 minutes, the film was cut into strips measuring 5.0 mm x 50.0 mm to obtain test pieces for measuring the storage modulus. The obtained test specimens were subjected to a dynamic viscoelasticity analyzer, ARES-G2 (TA Instruments), to measure the storage modulus under tensile mode, frequency of 1 Hz, strain of 0.1%, heating rate of 3°C / min, and conditions from -20°C to 100°C. The storage modulus at 25°C was then evaluated. Resin composition B (B1~B5): Using the resin composition corresponding to resin composition B in each example, a 0.6 mm thick coating film was formed on a glass plate. After drying in a 140°C oven for 60 minutes, the film was cut into strips measuring 2.5 mm x 50.0 mm to obtain test pieces for measuring the storage modulus. The obtained test specimens were subjected to a dynamic viscoelasticity analyzer, ARES-G2 (TA Instruments), to measure the storage modulus in tensile mode, at a frequency of 10.0 Hz, a strain of 0.1%, and a heating rate of 3°C / min, from -20°C to 100°C. The storage modulus at 25°C was then evaluated.

[0130] (Storage modulus after drying at room temperature) Using the resin composition corresponding to resin composition B in each example, a 0.6 mm thick coating film was formed on a glass plate. After drying in a constant temperature chamber at 25°C for 60 minutes, the film was cut into strips measuring 2.5 mm x 50.0 mm to obtain test pieces for measuring the storage modulus. The storage modulus of the obtained test specimens was evaluated by measuring them using a dynamic viscoelasticity analyzer ARES-G2 (manufactured by TA Instruments) under the conditions of tensile mode, frequency of 10.0 Hz, strain of 0.1%, and temperature of 25°C. (Storage stability) The resin compositions corresponding to the resin compositions obtained in each example were subjected to a storage stability test at 50°C for two weeks. The viscosity before and after the test was compared, and the viscosity increase rate calculated from the following formula was used for evaluation. A smaller increase rate indicates higher viscosity stability. [Viscosity increase rate of resin composition] = ([Paint viscosity after 2 weeks at 50°C] ÷ [Initial paint viscosity]) × 100 The evaluation results for various vibration-damping coatings are shown in Tables 2 and 3.

[0131] [Table 2]

[0132] [Table 3] < / ph>

Claims

1. This is a laminate for vibration damping material having a resin layer A on a base material, and a resin layer B on top of resin layer A. Resin layer A contains an acrylic polymer and may contain an inorganic filler, and resin layer B contains an acrylic polymer and an inorganic filler. The inorganic filler is at least one selected from the group consisting of calcium carbonate, mica, wollastonite, and talc. The inorganic filler content in 100 parts by mass of nonvolatile matter of resin layer A is 30 parts by mass or less, and the inorganic filler content in 100 parts by mass of nonvolatile matter of resin layer B is 50 parts by mass or more and 90 parts by mass or less. Resin layer A and resin layer B may each contain zinc oxide. The zinc oxide content in 100 parts by mass of the nonvolatile content of resin layer A is 5 parts by mass or less, and the zinc oxide content in 100 parts by mass of the nonvolatile content of resin layer B is 5 parts by mass or less. The average film thickness of the laminate is 1.5 mm or more, and the average thickness of resin layer A is 0.3 mm or more. A laminate for vibration damping material in which the ratio of the average thickness of resin layer A to the average thickness of resin layer B is 50 / 50 to 10 / 90.

2. The laminate for vibration damping material according to claim 1, wherein the average thickness of the resin layer A is 3 mm or less.

3. The laminate for vibration damping material according to claim 1 or 2, wherein the average thickness of the resin layer B is 0.7 mm or more.

4. The laminate for vibration damping material according to claim 1 or 2, wherein the average thickness of the resin layer B is 5 mm or less.

5. The laminate for vibration damping material according to claim 1 or 2, wherein the content of inorganic filler in 100 parts by mass of nonvolatile matter of resin layer A is 10 parts by mass or less, and the content of inorganic filler in 100 parts by mass of nonvolatile matter of resin layer B is 70 parts by mass or more and 90 parts by mass or less.

6. The vibration-damping laminate according to claim 1 or 2, wherein the zinc oxide content in 100 parts by mass of nonvolatile matter of the resin layer A is 1 part by mass or less.

7. The laminate for vibration damping material according to claim 1 or 2, wherein the storage modulus of resin layer B at 25°C, as measured by the method described below, is 1.0E+07 MPa or more. Method: Resin layer B is cut into strips measuring 2.5 mm in width and 50.0 mm in length to obtain test specimens for measuring the storage modulus. The storage modulus of the obtained test specimens is measured using a dynamic viscoelasticity analyzer ARES-G2 (manufactured by TA Instruments) in tensile mode, at a frequency of 10.0 Hz, with a strain of 0.1%, a heating rate of 3°C / min, and under conditions from -20°C to 100°C. The storage modulus at 25°C is then evaluated.

8. The laminate for vibration damping material according to claim 1 or 2, wherein the structural unit derived from an unsaturated monomer having an aromatic ring in 100 parts by mass of the acrylic polymer of resin layer A is 1 part by mass or more and 80 parts by mass or less.

9. A vehicle comprising the laminate according to claim 1 or 2.

10. A method for manufacturing a laminate for vibration damping materials, comprising applying resin composition B to the upper layer of a resin layer A derived from resin composition A after applying resin composition A or simultaneously with applying resin composition A, wherein resin composition A contains an acrylic polymer and may contain an inorganic filler, resin composition B contains an acrylic polymer and an inorganic filler, the inorganic filler being at least one selected from the group consisting of calcium carbonate, mica, wollastonite, and talc, the inorganic filler content per 100 parts by mass of nonvolatile content of resin composition A is 30 parts by mass or less, the inorganic filler content per 100 parts by mass of nonvolatile content of resin composition B is 50 parts by mass or more and 90 parts by mass or less, resin composition A and resin composition B may each contain zinc oxide, the zinc oxide content per 100 parts by mass of nonvolatile content of resin composition A is 5 parts by mass or less, and the zinc oxide content per 100 parts by mass of nonvolatile content of resin composition B is 5 parts by mass or less.

11. A method for manufacturing a laminate for vibration damping material according to claim 10, wherein the storage modulus of the coating film at 25°C after coating the resin composition A to a thickness of 0.3 mm and drying at 140°C for 60 minutes is 1.0E+05 MPa or more, as measured by the method described below. Method: The above coating film is cut into strips measuring 5.0 mm in width and 50.0 mm in length to obtain test specimens for measuring the storage modulus. The storage modulus of the obtained test specimens is measured using a dynamic viscoelasticity analyzer ARES-G2 (manufactured by TA Instruments) in tensile mode, at a frequency of 1 Hz, with a strain of 0.1%, a heating rate of 3°C / min, and under conditions from -20°C to 100°C, and the storage modulus at 25°C is evaluated.

12. A method for manufacturing a laminate for vibration damping material according to claim 10 or 11, wherein the storage modulus of the coating film at 25°C after coating the resin composition B to a thickness of 0.6 mm and drying at 140°C for 60 minutes is 1.0E+07 MPa or more, as measured by the method described below. Method: The above coating film is cut into strips measuring 2.5 mm in width and 50.0 mm in length to obtain test specimens for measuring the storage modulus. The storage modulus of the obtained test specimens is measured using a dynamic viscoelasticity analyzer ARES-G2 (manufactured by TA Instruments) in tensile mode, at a frequency of 10.0 Hz, a strain of 0.1%, a heating rate of 3°C / min, and under conditions from -20°C to 100°C, and the storage modulus at 25°C is evaluated.

13. The method for manufacturing a laminate for vibration damping material according to claim 10 or 11, wherein the storage modulus at 25°C of the coating film B, after being coated with the resin composition B to a thickness of 0.6 mm and dried at 140°C for 60 minutes, as measured by the method (B) below, is 1.0E+07 MPa or higher than the storage modulus at 25°C of the coating film A, after being coated with the resin composition A to a thickness of 0.3 mm and dried at 140°C for 60 minutes, as measured by the method (A) below. Method (A): The above coating A is cut into strips measuring 5.0 mm in width and 50.0 mm in length to obtain test specimens for measuring the storage modulus. The storage modulus of the obtained test specimens is measured using a dynamic viscoelasticity analyzer ARES-G2 (manufactured by TA Instruments) in tensile mode, with a frequency of 1 Hz, a strain of 0.1%, a heating rate of 3°C / min, and under conditions from -20°C to 100°C, and the storage modulus at 25°C is evaluated. Method (B): The above coating B is cut into strips measuring 2.5 mm in width and 50.0 mm in length to obtain test specimens for measuring the storage modulus. The storage modulus of the obtained test specimens is measured using a dynamic viscoelasticity analyzer ARES-G2 (manufactured by TA Instruments) in tensile mode, with a frequency of 10.0 Hz, a strain of 0.1%, a heating rate of 3°C / min, and under conditions from -20°C to 100°C, and the storage modulus at 25°C is evaluated.

14. A method for manufacturing a vibration-damping laminate according to claim 10 or 11, comprising the step of drying the applied resin composition A and / or the applied resin composition B.

Images