Composition for vibration-damping material, vibration-damping material and member

Abstract

Provided is a composition for a vibration-damping material capable of yielding a vibration-damping material having a wide temperature range in which the tanδ value is 0.5 or more. Provided is a vibration-damping material obtained by curing this composition for a vibration-damping material, and provided is a member containing this vibration-damping material. This composition for a vibration-damping material specifically contains 0.05-9.5 mass% of a polyfunctional polymerizable compound (A) represented by general formula (a1) and 90.5-99.95 mass% of a polymerizable monomer (B). [In general formula (a1), R1 to R3 each independently represent a hydrogen atom, a C1-6 alkyl group, a C2-6 alkenyl group, a C6-12 aryl group, or a C7-13 aralkyl group, and R4 represents a (meth)acryloyl group, a vinyl phenyl group, or a C2-6 alkenyl group. n represents an integer of 1 to 6.]

Description

Vibration-damping composition, vibration-damping material and component

[0001] The present invention relates to a composition for a vibration damper, a vibration damper, and a member including the vibration damper.

[0002] In the fields of building materials such as housing, transportation such as automobiles, ships, and aircraft, and machinery, electrical, and electronics, various vibration-damping materials are used inside or on the surface of structures to suppress or prevent vibration and vibration-associated noise. Known examples of such vibration-damping materials include a molded product of a thermoplastic polymer composition containing a conjugated diene polymer (A), a thermoplastic resin (B), and a crystalline propylene-based elastomer (C), with predetermined amounts of each of the components (A), (B), and (C) (see Patent Document 1). However, conventional vibration-damping materials have a problem in that they tend to exhibit vibration-damping properties over a narrow temperature range. Meanwhile, a known vibration-damping material exhibits good vibration-damping effects with little temperature dependency even in low-frequency ranges of a few Hz or less, such as seismic motion, and is composed of a rubber composition containing (A) epoxidized liquid butadiene rubber, (B) a plasticizer, and (C) a curing agent (see Patent Document 2).

[0003] JP 2020-152811 A JP 2000-063638 A

[0004] However, the vibration-damping material described in Patent Document 2 has a tan δ value of less than half of the maximum value at 50° C., and there is a risk that it will not be able to maintain excellent vibration-damping properties in high-temperature ranges. In order to maintain vibration-damping properties over a wide temperature range, one criterion is that the temperature range over which the tan δ value is 0.5 or more is wide.

[0005] Therefore, the present invention aims to provide a composition for a vibration-damping material that can provide a vibration-damping material having a wide temperature range and a tanδ value of 0.5 or more, to provide a vibration-damping material obtained by curing the composition for a vibration-damping material, and to provide a member that includes the vibration-damping material.

[0006] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by the vibration damping composition etc. described in this specification. The present invention includes the following embodiments [1] to

[13] .

[0007] [1] A composition for vibration damping materials, comprising: 0.05 to 9.5 mass% of a polyfunctional polymerizable compound (A) represented by the following general formula (a1); and 90.5 to 99.95 mass% of a polymerizable monomer (B): [In general formula (a1), R １ ~R ３ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms; R ４ represents a (meth)acryloyl group, a vinylphenyl group, or an alkenyl group having 2 to 6 carbon atoms. n represents an integer of 1 to 6.] [2] R in the general formula (I) １ and R ２ is a hydrogen atom, and R ３ is a hydrogen atom or a methyl group, n is an integer of 1 to 4, and R ４ is a (meth)acryloyl group or a vinylphenyl group. [3] The composition for vibration damping material according to the above [1] or [2], wherein the component (B) contains a monofunctional polymerizable monomer (B1). [4] The composition for vibration damping material according to the above [3], wherein the component (B1) has a (meth)acryloyl group. [5] The composition for vibration damping material according to the above [3], wherein the component (B1) contains at least one selected from the group consisting of alkyl or cycloalkyl (meth)acrylates (B1-1) and hydroxyalkyl (meth)acrylates (B1-2). [6] The composition for vibration damping material according to any one of the above [1] to [5], wherein the component (B) contains a polyfunctional polymerizable monomer (B2). [7] The composition for vibration damping material according to the above [6], wherein the component (B2) contains a poly(meth)acrylate. [8] The composition for vibration damping material according to the above item [7], wherein the poly(meth)acrylate comprises at least one selected from the group consisting of urethane poly(meth)acrylate and epoxy poly(meth)acrylate. [9] The composition for vibration damping material according to any one of the above items [6] to [8], wherein the content of the component (B2) relative to the total amount of the component (B) is 20 mass% or less.

[10] The composition for vibration damping material according to any one of the above items [1] to [9], wherein the component (A) is a polyfunctional polymerizable compound represented by the following general formula (a2): [In general formula (a2), R ５represents a hydrogen atom or a methyl group.]

[11] The composition for a vibration damper according to any one of the above [1] to

[10] , further comprising 0.1 to 3 mass % of a polymerization initiator (C).

[12] A vibration damper obtained by curing the composition for a vibration damper according to any one of the above [1] to

[11] .

[13] A member comprising the vibration damper according to the above

[12] .

[0008] According to the present invention, it is possible to provide a composition for a vibration-damping material that can provide a vibration-damping material having a wide temperature range and a tanδ value of 0.5 or more, to provide a vibration-damping material obtained by curing the composition for a vibration-damping material, and to provide a member including the vibration-damping material.

[0009] 1 is a graph showing the loss tangent (tan δ) measured in Examples 1 to 3 and Comparative Example 1.

[0010] The following describes an embodiment of the present invention. However, the embodiment described below is merely an example for embodying the technical concept of the present invention, and the present invention is not limited to the following description. Although preferred embodiments are shown in this specification, a combination of two or more of the individual preferred embodiments is also a preferred embodiment. When several numerical ranges exist for a given item, the lower and upper limits can be selectively combined to create a preferred embodiment. Note that, in this specification, a numerical range such as "XX to YY" means "XX or more and YY or less." In this specification, the term "(meth)acryloyl group" includes both acryloyl and methacryloyl groups. The term "(meth)acrylate" includes both acrylate and methacrylate. In this specification, the following components used in the production of a vibration-damping composition may be at least partially reacted or unreacted in the composition. Furthermore, at least partially reacted components and unreacted components may be present in the composition.

[0011] [Vibration Damping Material Composition] The vibration damping material composition of this embodiment is a vibration damping material composition containing 0.05 to 9.5 mass % of a polyfunctional polymerizable compound (A) represented by the following general formula (a1) [hereinafter, may be simply referred to as "polyfunctional polymerizable compound (A)" or "component (A)"], and 90.5 to 99.95 mass % of a polymerizable monomer (B) [hereinafter, may be simply referred to as "component (B)"]. [In general formula (a1), R １ ~R ３ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms; R ４ represents a (meth)acryloyl group, a vinylphenyl group, or an alkenyl group having 2 to 6 carbon atoms, and n represents an integer of 1 to 6.

[0012] The vibration-damping composition of this embodiment, in particular, contains the predetermined amount of the multifunctional polymerizable compound (A), thereby providing a vibration-damping material having a tan δ value of 0.5 or greater over a wide temperature range. This is presumably due to the fact that the multifunctional polymerizable compound (A) having a predetermined molecular length has a crosslinkable structure, resulting in a high crosslink density. However, even if this presumption is incorrect, this does not affect the scope of the present invention. Because the vibration-damping composition of this embodiment is liquid at 25°C, it can also be referred to as a "liquid vibration-damping composition." In this specification, "liquid" refers to having fluidity, specifically a viscosity value of 10,000 mPa·s or less when measured with a cone-plate type viscometer, preferably 7,000 mPa·s or less, more preferably 5,000 mPa·s or less. Below, each component contained in the vibration-damping composition of the present invention will be described in detail.

[0013] (Polyfunctional Polymerizable Compound (A)) The component (A) is a polyfunctional polymerizable compound and is represented by the general formula (a1). Here, the term "polyfunctional polymerizable" means that the compound represented by the general formula (a1) has a polymerizable functional group R ４ and a polymerizable functional group having the following structure: This is because R １ ~R３ Even if the polymerizability is reduced depending on the type of n or the value of n, the compound is referred to as a polyfunctional polymerizable compound in the present invention.

[0014] In general formula (a1), R １ ~R ３ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms. １ ~R ３ From the viewpoint of vibration damping properties over a wide temperature range, the alkyl group having 1 to 6 carbon atoms that each independently represents is preferably an alkyl group having 1 to 3 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an n-propyl group, and an n-hexyl group. １ ~R ３ From the viewpoint of vibration damping properties over a wide temperature range, the alkenyl groups having 2 to 6 carbon atoms that are each independently represented are preferably alkenyl groups having 2 to 4 carbon atoms, more preferably alkenyl groups having 2 or 3 carbon atoms. Examples of the alkenyl groups include vinyl groups, allyl groups, 1-propenyl groups, 1-butenyl groups, 1-pentenyl groups, 3-pentenyl groups, 5-pentenyl groups, 1-hexenyl groups, 3-hexenyl groups, and 6-hexenyl groups. １ ~R ３ The aryl group having 6 to 12 carbon atoms that each independently represents is preferably an aryl group having 6 to 10 carbon atoms from the viewpoint of vibration damping properties over a wide temperature range. Examples of the aryl group include a phenyl group, a naphthyl group, and a biphenylyl group. １ ~R ３ From the viewpoint of vibration damping properties over a wide temperature range, the aralkyl group having 7 to 13 carbon atoms represented by each independently is preferably an aralkyl group having 7 to 9 carbon atoms. Examples of the aralkyl group include a benzyl group and a phenethyl group.

[0015] Among the above, from the viewpoint of vibration damping performance over a wide temperature range, R １ and R ２are each preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom. ３ From the viewpoint of vibration damping properties over a wide temperature range, is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a methyl group.

[0016] In general formula (a1), R ４ represents a (meth)acryloyl group, a vinylphenyl group, or an alkenyl group having 2 to 6 carbon atoms. ４ From the viewpoint of vibration damping properties over a wide temperature range, the alkenyl group having 2 to 6 carbon atoms represented by is preferably an alkenyl group having 2 to 4 carbon atoms, more preferably an alkenyl group having 2 or 3 carbon atoms. １ ~R ３ The same as in the case of R ４ From the viewpoint of vibration damping properties over a wide temperature range, is preferably a (meth)acryloyl group or a vinylphenyl group, more preferably a (meth)acryloyl group, and even more preferably a methacryloyl group.

[0017] In general formula (a1), n ​​represents an integer of 1 to 6. From the viewpoint of vibration damping properties over a wide temperature range, n is preferably an integer of 1 to 4, more preferably an integer of 1 to 3, even more preferably 1 or 2, and particularly preferably 1.

[0018] From the above, R in general formula (I) １ and R ２ is a hydrogen atom, and R ３ is a hydrogen atom or a methyl group, n is an integer of 1 to 4, and R ４ is also a preferred embodiment in which is a (meth)acryloyl group or a vinylphenyl group, and more preferred embodiments are as described above.

[0019] From the viewpoint of vibration damping properties over a wide temperature range, the component (A) is preferably a polyfunctional polymerizable compound represented by the following general formula (a2). [In general formula (a2), R ５ represents a hydrogen atom or a methyl group.] In general formula (a2), R ５ is preferably a methyl group.

[0020] The polyfunctional polymerizable compound represented by the general formula (a2) can be obtained, for example, by reacting (meth)acrylic acid with an alcohol having an unsaturated double bond structure corresponding to the structure by a known esterification reaction. Note that the polyfunctional polymerizable compound (A) represented by the general formula (a1) can be easily produced by referring to or applying a method for producing the polyfunctional polymerizable compound represented by the general formula (a2).

[0021] (Content of Polyfunctional Polymerizable Compound (A)) The vibration damping composition of this embodiment (hereinafter sometimes simply referred to as the "composition") contains 0.05 to 9.5 mass %, preferably 0.10 to 9.0 mass %, more preferably 0.15 to 8.0 mass %, even more preferably 0.15 to 5.0 mass %, particularly preferably 0.15 to 3.0 mass %, and most preferably 0.15 to 1.5 mass % of the component (A). When the content of the component (A) in the composition of this embodiment is equal to or greater than the above-mentioned lower limit, the temperature range over which the tan δ value is 0.5 or greater is broadened. Furthermore, when the content of the component (A) in the composition of this embodiment is equal to or less than the above-mentioned upper limit, a decrease in vibration damping properties can be suppressed, and the temperature range over which the tan δ value is 0.5 or greater tends to be suppressed from narrowing. Here, from the viewpoint of suppressing a decrease in vibration damping properties and suppressing a narrowing of the temperature range in which the value of tan δ is 0.5 or greater, it is preferable that the content of component (A) in the composition of the present embodiment is not too large; for example, it is preferably 8.0 mass% or less, more preferably 5.0 mass% or less, even more preferably 3.0 mass% or less, and particularly preferably 1.5 mass% or less.

[0022] (Polymerizable Monomer (B)) The component (B) is a polymerizable monomer (however, not including the component (A)). From the viewpoint of vibration damping properties over a wide temperature range, the component (B) may contain a monofunctional polymerizable monomer (B1) [hereinafter also referred to as the component (B1)], a polyfunctional polymerizable monomer (B2) [hereinafter also referred to as the component (B2)], or both the monofunctional polymerizable monomer (B1) and the polyfunctional polymerizable monomer (B2).

[0023] - Monofunctional polymerizable monomer (B1) - The component (B1) is a monomer having one polymerizable functional group. Examples of the polymerizable functional group include a (meth)acryloyl group, a vinylphenyl group, and an alkenyl group having 2 to 6 carbon atoms. Examples of the alkenyl group having 2 to 6 carbon atoms include R ４ Examples of the polymerizable functional group include those similar to those in the case of (1). From the viewpoint of reactivity, the polymerizable functional group is preferably a (meth)acryloyl group or a vinylphenyl group, more preferably a (meth)acryloyl group, and even more preferably an acryloyl group. The component (B1) may be used alone or in combination of two or more types. Although not particularly limited, it is preferable to use two or more types of the component (B1) in combination, more preferably two to six types in combination, even more preferably two to four types in combination, and particularly preferably three types in combination.

[0024] Examples of the component (B1) having a (meth)acryloyl group include alkyl or cycloalkyl (meth)acrylates (B1-1) such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, and isobornyl (meth)acrylate [however, excluding the hydroxyalkyl (meth)acrylates (B1-2) and halogenated alkyl (meth)acrylates (B1-3) described below]. hydroxyalkyl (meth)acrylates (B1-2) such as 4-hydroxybutyl (meth)acrylate; halogenated alkyl (meth)acrylates (B1-3) such as 2,3-dibromopropyl (meth)acrylate; aromatic (meth)acrylates (B1-4) such as benzyl (meth)acrylate and phenyl (meth)acrylate; silyl group-containing (meth)acrylates (B1-5) such as 3-(meth)acryloyloxypropyltrimethoxysilane and 11-(meth)acryloyloxyundecyltrimethoxysilane. The component (B1) having a (meth)acryloyl group preferably contains at least one selected from the group consisting of alkyl or cycloalkyl (meth)acrylates (B1-1) and hydroxyalkyl (meth)acrylates (B1-2), more preferably contains at least one selected from the group consisting of isobornyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and lauryl (meth)acrylate, and even more preferably contains at least one selected from the group consisting of isobornyl acrylate, 4-hydroxybutyl acrylate, and lauryl acrylate.

[0025] The alkyl or cycloalkyl (meth)acrylate (B1-1) tends to improve heat resistance and vibration-damping properties, and the hydroxyalkyl (meth)acrylate (B1-2) tends to improve adhesion to the member on which the vibration-damping material is installed, so the composition of this embodiment preferably contains both of these as component (B1). When the composition of this embodiment contains both the alkyl or cycloalkyl (meth)acrylate (B1-1) and the hydroxyalkyl (meth)acrylate (B1-2) as component (B1), the content ratio thereof [(B1-1) / (B1-2)] is preferably 40 / 60 to 90 / 10, more preferably 50 / 50 to 90 / 10, even more preferably 55 / 45 to 85 / 15, particularly preferably 60 / 40 to 85 / 15, and most preferably 65 / 35 to 85 / 15 by mass. Furthermore, when the composition of the present embodiment contains both an alkyl(meth)acrylate and a cycloalkyl(meth)acrylate as the component (B1-1), the mass ratio thereof [alkyl(meth)acrylate / cycloalkyl(meth)acrylate] is preferably 10 / 90 to 60 / 40, more preferably 15 / 85 to 50 / 50, even more preferably 20 / 80 to 45 / 55, and particularly preferably 25 / 75 to 45 / 55.

[0026] The alkyl group or cycloalkyl group contained in the alkyl or cycloalkyl (meth)acrylate (B1-1) is preferably an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms, more preferably an alkyl group having 4 to 18 carbon atoms or a cycloalkyl group having 4 to 14 carbon atoms, and even more preferably an alkyl group having 8 to 14 carbon atoms or a cycloalkyl group having 5 to 10 carbon atoms.

[0027] As the component (B1), a monomer other than the above-mentioned monomers may be used as long as it is a monomer having one polymerizable functional group.

[0028] (Content of Component (B1)) When the component (B) includes the monofunctional polymerizable monomer (B1), the content of the component (B1) in the composition of the present embodiment is, from the viewpoint of vibration damping properties over a wide temperature range, preferably 60 to 98.5 mass%, more preferably 65 to 98.5 mass%, and may be 70 to 98.5 mass%, or may be 80 to 98.5 mass%.

[0029] - Polyfunctional Polymerizable Monomer (B2) - Component (B2) is a monomer having two or more polymerizable functional groups. Therefore, component (B2) can also function as a crosslinking agent. The polymerizable functional group is explained in the same manner as in the case of (B1), and the preferred groups are also the same. Component (B2) may contain a poly(meth)acrylate. Examples of the poly(meth)acrylate include urethane poly(meth)acrylate and epoxy poly(meth)acrylate, but other poly(meth)acrylates may also be used. Preferably, the poly(meth)acrylate contains at least one selected from the group consisting of urethane poly(meth)acrylate and epoxy poly(meth)acrylate.

[0030] The urethane poly(meth)acrylate is a poly(meth)acrylate having a polyurethane skeleton. The polyurethane skeleton may contain an aliphatic skeleton (excluding the rubber skeleton and hydrogenated rubber skeleton described below), one or more rubber skeletons selected from the group consisting of polybutadiene and polyisoprene, one or more hydrogenated rubber skeletons selected from the group consisting of hydrogenated polybutadiene and hydrogenated polyisoprene, or one or more skeletons selected from the group consisting of polyether skeletons, polycarbonate skeletons, and polyester skeletons. The urethane poly(meth)acrylate may be a urethane di(meth)acrylate. There are no particular restrictions on the weight average molecular weight (Mw) of the urethane poly(meth)acrylate, but from the viewpoint of operability, it is preferably 1,000 to 30,000, more preferably 2,500 to 15,000, even more preferably 3,000 to 10,000, and particularly preferably 3,500 to 7,500. In this specification, the weight average molecular weight is a weight average molecular weight calculated in terms of polystyrene obtained by measurement using gel permeation chromatography (GPC). Commercially available products can be used as the urethane poly(meth)acrylate. Examples of commercially available products include UV-3700B (manufactured by Mitsubishi Chemical Corporation, Mw: 38,000), UA10000B (manufactured by KSM Corporation, Mw: 25,000), UN7700 (manufactured by Negami Chemical Industrial Co., Ltd., Mw: 20,000), UN-9200A (manufactured by Negami Chemical Industrial Co., Ltd., Mw: 15,000), UN-9000H (manufactured by Negami Chemical Industrial Co., Ltd., Mw: 5,000), and EBECRYL (registered trademark) 230 (manufactured by Daicel-Allnex Corporation, Mw: 5,000).

[0031] Examples of the epoxy poly(meth)acrylate include bisphenol-type epoxy(meth)acrylate, novolac-type epoxy(meth)acrylate, aliphatic-type epoxy(meth)acrylate, etc. The weight-average molecular weight of the epoxy poly(meth)acrylate is not particularly limited, but from the viewpoint of operability, it is preferably 200 to 3,000, more preferably 300 to 1,700, even more preferably 300 to 1,300, and particularly preferably 300 to 1,000.

[0032] Other poly(meth)acrylates, that is, poly(meth)acrylates other than the urethane poly(meth)acrylate and the epoxy poly(meth)acrylate, include, for example, di(meth)acrylates such as dipropylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and tricyclodecane dimethanol di(meth)acrylate; tri(meth)acrylates such as trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxy tri(meth)acrylate, and pentaerythritol tri(meth)acrylate; tetra(meth)acrylates such as dipentaerythritol ethoxy tetra(meth)acrylate and ditrimethylolpropane tetra(meth)acrylate; and hexa(meth)acrylates such as dipentaerythritol hexa(meth)acrylate.

[0033] (Content of Component (B2)) When the component (B) contains the monofunctional polymerizable monomer (B2), the content of the component (B2) in the composition of this embodiment is, from the viewpoint of vibration damping properties over a wide temperature range, preferably 1 to 40% by mass, more preferably 3 to 35% by mass, and may be 5 to 30% by mass, or may be 5 to 15% by mass. Furthermore, from the viewpoint of vibration damping properties over a wide temperature range, the content of the component (B2) relative to the total amount of the component (B) is preferably 20% by mass or less, more preferably 15% by mass or less, with no particular lower limit, and may be 1% by mass or more, 3% by mass or more, or 5% by mass or more.

[0034] (Content of Polymerizable Monomer (B)) From the viewpoint of vibration damping properties over a wide temperature range, the composition of the present embodiment contains the component (B) in an amount of 90.5 to 99.95 mass%, preferably 91 to 99.90 mass%, more preferably 92 to 99.85 mass%, even more preferably 95 to 99.85 mass%, particularly preferably 97 to 99.85 mass%, and most preferably 98.5 to 99.85 mass%.

[0035] In the composition for vibration damping materials of this embodiment, the total content of the components (A) and (B) may be 100% by mass, or the total content including the component (C) described below [(A) + (B) + (C)] may be 100% by mass, or the total content including the component (C) and other components described below [(A) + (B) + (C) + other components] may be 100% by mass.

[0036] (C) Polymerization Initiator From the viewpoint of further improving vibration damping properties and curing speed, the composition of the present embodiment preferably further contains 0.1 to 3 mass % of (C) polymerization initiator, and more preferably contains 0.5 to 2 mass % of (C) polymerization initiator. The polymerization initiator may be a photopolymerization initiator, a thermal polymerization initiator, or both a photopolymerization initiator and a thermal polymerization initiator.

[0037] As the photopolymerization initiator, known photopolymerization initiators can be used, such as acetophenone-based polymerization initiators, benzophenone-based polymerization initiators, Michler's ketone-based polymerization initiators, benzoin-based polymerization initiators, thioxanthone-based polymerization initiators, acylphosphine oxide-based polymerization initiators, and titanocene-based polymerization initiators. Among these, acetophenone-based polymerization initiators and benzophenone-based polymerization initiators are preferred, with acetophenone-based polymerization initiators being more preferred. One type of photopolymerization initiator may be used alone, or two or more types may be used in combination. When the composition of this embodiment contains a photopolymerization initiator, it may further contain a sensitizer. Examples of sensitizers include n-butylamine, di-n-butylamine, tri-n-butylphosphine, allylthiouric acid, triethylamine, and diethylaminoethyl methacrylate.

[0038] As the thermal polymerization initiator, known thermal polymerization initiators can be used, such as azo compounds, peroxides, persulfates, and pinacol. Among these, azo compounds, peroxides, and persulfates are preferred as the thermal polymerization initiator. One type of thermal polymerization initiator may be used alone, or two or more types may be used in combination. When the composition of the present embodiment contains a thermal polymerization initiator, it may further contain a reducing agent. By containing a reducing agent, the amount of thermal polymerization initiator used can be reduced. Examples of combinations of thermal polymerization initiators and reducing agents include a combination of the persulfates with a reducing agent such as sodium metabisulfite and sodium bisulfite; and a combination of the peroxide with a tertiary amine.

[0039] (Other Components) The composition of this embodiment may or may not further contain other components. When the composition for vibration damping of this embodiment contains other components, the content of the other components is preferably 0.1 to 5 mass %, more preferably 0.1 to 2 mass %, from the viewpoint of vibration damping properties over a wide temperature range. When the composition for vibration damping of this embodiment contains two or more other components, it is preferable that the content of each of them is within the above range. Examples of the other components include, but are not limited to, sensitizers, reducing agents, plasticizers, fillers, antioxidants, preservatives, thickeners, pigments, etc. The other components may be used alone or in combination.

[0040] The composition of the present embodiment can be obtained by mixing the component (A), the component (B), and optionally the component (C), as well as other components as necessary, preferably at 5 to 60° C., more preferably at 15 to 55° C., and even more preferably at 20 to 50° C. Among these, when a component having a weight-average molecular weight of 4,000 or more is used, it is preferable to use a higher mixing temperature from the viewpoint of operability; for example, 30 to 60° C. is preferred, and 40 to 60° C. is more preferred, although this temperature is not particularly limited.

[0041] [Vibration Damping Material] When the composition of this embodiment contains a photopolymerization initiator, a cured product of the composition, i.e., a vibration damping material obtained by curing the vibration damping material composition, can be obtained by irradiating it with active energy rays. The active energy rays can be light rays, electromagnetic waves, particle rays, or a combination of these. However, from the viewpoints of curing speed, availability of irradiation equipment, cost, etc., ultraviolet rays and electron beams are preferred, with ultraviolet rays being more preferred. For ultraviolet irradiation, high-pressure mercury lamps, ultra-high-pressure mercury lamps, carbon arc lamps, metal halide lamps, xenon lamps, chemical lamps, LEDs, etc., which emit light in the wavelength range of 150 to 450 nm can be used. The cumulative light dose of the active energy rays is preferably 500 to 10,000 mJ / cm. 2 , more preferably 1,000 to 5,000 mJ / cm 2 , and more preferably 3,000 to 4,000 mJ / cm 2 When the integrated light amount of the active energy rays is equal to or greater than the lower limit, the curability of the composition can be improved, and when it is equal to or less than the upper limit, deterioration of the composition and the vibration-damping material can be suppressed. When the composition of this embodiment contains a thermal polymerization initiator, a cured product of the composition can be obtained by heating. The heating temperature is preferably 50 to 250°C, more preferably 70 to 200°C. The heating time varies depending on the type of thermal polymerization initiator, the types of components in the composition, the reaction temperature, etc., and can be adjusted appropriately.

[0042] From the viewpoint of vibration damping properties, it is ideal for the vibration damping material of this embodiment to maintain as high a tan δ value as possible over a wide temperature range. Tan δ in the temperature range to which the composition is applied is preferably 0.18 or higher, more preferably 0.4 or higher, even more preferably 0.6 or higher, particularly preferably 0.7 or higher, and most preferably 1.0 or higher. There is no particular upper limit, and the tan δ may be 1.5 or lower, or 1.3 or lower. The temperature range to which the composition is applied includes, for example, a temperature range including 50°C. Furthermore, the vibration damping material of this embodiment has a wide temperature range in which the tan δ value is 0.5 or higher, and the temperature width (the absolute value of the difference between the lowest and highest temperatures at which the tan δ value is 0.5 or higher) is preferably 51°C or higher, more preferably 53°C or higher, and may be 60°C or higher, 80°C or higher, or even 90°C or higher. There is no particular upper limit to the temperature width, and the temperature width may be 130°C or lower, 110°C or lower, or 100°C or lower.

[0043] [Component] The present invention also provides a component comprising the vibration-damping material of this embodiment. Components comprising the vibration-damping material of this embodiment are not particularly limited, and examples thereof include automotive components such as automotive interior materials and exterior panels; home appliances; packaging materials; building materials; civil engineering materials; fishery materials; other industrial materials; information equipment; video equipment, etc. The vibration-damping material of this embodiment may be installed under the component, on the surface of the component, or inside the component, or in any combination of these modes, or in other modes, and the installation mode is not particularly limited.

[0044] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these.

[0045] In the examples and comparative examples, vibration damping properties were evaluated according to the following method. (1. Method for evaluating vibration damping properties) Using a dynamic viscoelasticity measuring device "Reogel-E4000" (manufactured by UBM Corporation), loss tangent (tan δ) was measured at a frequency of 15 Hz, a heating rate of 3°C / min, and a temperature range of -50 to 150°C, and the obtained tan δ was used as an index of vibration damping properties. Table 1 shows the maximum value of tan δ, tan δ at 50°C, the temperature range where tan δ is 0.5 or more, and the temperature width where tan δ is 0.5 or more.

[0046] [Examples 1 to 3 and Comparative Example 1] In Example 1 and Comparative Example 1, the components shown in Table 1 were mixed in the amounts shown in Table 1 at 50°C, and in the other examples at 25°C, to obtain compositions for vibration dampers. The obtained compositions for vibration dampers were sandwiched between PET film (manufactured by Toyobo Co., Ltd.) and alkali-free glass (manufactured by AS ONE Corporation) so that the thickness of the composition before curing was 100 μm, and irradiated with 3,200 mJ / cm using a UV irradiator "CSOT-40D" (manufactured by GS Yuasa Corporation). ２ A component was obtained in which the vibration-damping composition was sandwiched between a PET film and alkali-free glass by irradiating the component with UV light from the alkali-free glass side with an integrated light amount of 1000 kJ / cm. This component was used as an evaluation sample, and its vibration-damping properties were evaluated according to the method described above. The results are shown in Table 1. Figure 1 also shows a graph of the loss tangent (tan δ) measured to evaluate the vibration-damping properties in Examples 1 to 3 and Comparative Example 1.

[0047]

[0048] The compounds represented by the abbreviations in Table 1 are as follows: Component (A) IPEMA: isoprenyl methacrylate, manufactured by Kuraray Co., Ltd. AMA: Allyl methacrylate, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0049] Component (B) Component (B1) IBOA: isobornyl acrylate LA: lauryl acrylate 4HBA: 4-hydroxybutyl acrylate Component (B2) EB230: "EBECRYL (registered trademark) 230", aliphatic urethane diacrylate, weight average molecular weight 5,000, manufactured by Daicel Allnex Corporation

[0050] Component (C): 1-hydroxycyclohexyl phenyl ketone, manufactured by Tokyo Chemical Industry Co., Ltd., an acetophenone-based polymerization initiator

[0051] As shown in Table 1 and Figure 1, in the case of compositions containing both component (A) and component (B) in predetermined amounts (each Example), the vibration-damping material had a wide temperature range in which the tan δ value was 0.5 or more. It can also be seen that the tan δ value at 50°C was high. On the other hand, in Comparative Example 1, which was a composition not containing component (A), the temperature range in which the tan δ value was 0.5 or more was narrow. Furthermore, in Comparative Example 1, the tan δ value at 50°C was low.

Claims

1. 0.05 to 9.5% by mass of a polyfunctional polymerizable compound (A) represented by the following general formula (a1), and Polymerizable monomer (B) 90.5 to 99.95% by mass A composition for vibration damping material comprising: 【Chemistry 1】 [In general formula (a1), R １ ~R ３ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms; R ４ represents a (meth)acryloyl group, a vinylphenyl group, or an alkenyl group having 2 to 6 carbon atoms; and n represents an integer of 1 to 6.

2. R in the general formula (I) １ and R ２ is a hydrogen atom, R ３ is a hydrogen atom or a methyl group, n is an integer from 1 to 4, and R ４ The vibration damping composition according to claim 1, wherein is a (meth)acryloyl group or a vinylphenyl group.

3. The vibration damping material composition according to claim 1 , wherein the component (B) comprises a monofunctional polymerizable monomer (B1).

4. The vibration damping composition according to claim 3 , wherein the component (B1) has a (meth)acryloyl group.

5. The vibration damping material composition according to claim 3, wherein the component (B1) comprises at least one selected from the group consisting of alkyl or cycloalkyl (meth)acrylates (B1-1) and hydroxyalkyl (meth)acrylates (B1-2).

6. The vibration damping material composition according to claim 1 , wherein the component (B) comprises a polyfunctional polymerizable monomer (B2).

7. The vibration damping composition according to claim 6 , wherein the component (B2) comprises a poly(meth)acrylate.

8. The vibration damping material composition according to claim 7 , wherein the poly(meth)acrylate comprises at least one selected from the group consisting of urethane poly(meth)acrylates and epoxy poly(meth)acrylates.

9. 7. The vibration damping material composition according to claim 6, wherein the content of the component (B2) is 20 mass % or less based on the total amount of the component (B).

10. 2. The vibration damping composition according to claim 1, wherein the component (A) is a polyfunctional polymerizable compound represented by the following general formula (a2): 【Chemistry 2】 [In general formula (a2), R ５ represents a hydrogen atom or a methyl group.

11. The vibration damping composition according to claim 1, further comprising 0.1 to 3 mass % of a polymerization initiator (C).

12. A vibration damping material obtained by curing the vibration damping material composition according to any one of claims 1 to 11.

13. A component comprising the vibration-damping material according to claim 12.

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