Urethane elastomer composition, cured product thereof, and vibration-damping member having the cured product

Abstract

Provided is a non-foamed urethane elastomer that has hardness suitable for vibration isolation applications and an absolute spring constant that provides desired frequency characteristics. [Solution] The urethane elastomer composition contains the following (A) to (D): (A) one or more polyols selected from lactone-based polyols and adipate-based polyols, (B) an aromatic isocyanate, (C) one or more chain extenders selected from compounds having a molecular weight of 50 to 150, and (D) one or more crosslinking agents selected from compounds having a molecular weight of 50 to 200. When the entire urethane elastomer composition is taken as 100% by mass, the content of (B) is 13.5% to 15.5% by mass, the content of (C) is 0.8% to 1.4% by mass, and the content of (D) is 1.3% to 2.6% by mass. A urethane elastomer is produced by curing the urethane elastomer composition.

Description

[Technical Field]

[0001] The present disclosure relates to urethane elastomers suitable for vibration isolation applications. [Background technology]

[0002] In automobiles and other vehicles, vibration-damping materials are placed at the source of vibration and noise to reduce vibration and noise that enter the vehicle cabin. It is desirable for vibration-damping materials to exhibit effective vibration-damping properties depending on the frequency of the input vibration. For example, in electric vehicles, which have become increasingly popular in recent years, vibration and noise in the high-frequency range of 500 Hz or higher generated by motors and other components must also be reduced.

[0003] As an elastic member constituting a vibration-damping member, conventionally known is a vibration-damping rubber made by compounding a filler such as carbon black with a diene rubber such as natural rubber (see, for example, Patent Document 1).In addition, vibration-damping members using foamed polyurethane are also known from the viewpoint of their relatively low specific gravity, light weight, and high vibration absorption performance (see, for example, Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-105870 [Patent Document 2] Japanese Patent Application Publication No. 2022-57791 [Patent Document 3] Japanese Patent Publication No. 2023-149042 Summary of the Invention [Problem to be solved by the invention]

[0005] Anti-vibration rubber requires a small dynamic ratio (dynamic spring constant / static spring constant) from the viewpoints of high strength and suppression of vibration transmission. Furthermore, reducing the dynamic spring constant is effective in reducing vibration in the high-frequency range. Polyurethane foam contains air bubbles and is relatively flexible, which makes it easy to reduce the dynamic spring constant and easily absorb high-frequency vibration. However, polyurethane foam does not have sufficient durability against repeated deformation, and therefore its application is limited to areas that are relatively less susceptible to load. On the other hand, if conventional compositions are cured without foaming in order to improve durability, the resulting non-foamed product becomes too hard and is unsuitable for vibration-damping applications.

[0006] The present disclosure has been made in consideration of the above circumstances, and an object of the present disclosure is to provide a non-foamed urethane elastomer that has a hardness suitable for vibration-damping applications and an absolute spring constant that has desired frequency characteristics. [Means for solving the problem]

[0007] (1) The urethane elastomer composition of the present disclosure comprises the following (A) to (D), and is characterized in that, when the entire urethane elastomer composition is taken as 100% by mass, the content of (B) is 13.5% by mass or more and 15.5% by mass or less, the content of (C) is 0.8% by mass or more and 1.4% by mass or less, and the content of (D) is 1.3% by mass or more and 2.6% by mass or less. (A) One or more polyols selected from lactone-based polyols and adipate-based polyols. (B) Aromatic isocyanates. (C) One or more chain extenders selected from compounds having a molecular weight of 50 or more and 150 or less. (D) One or more crosslinking agents selected from compounds having a molecular weight of 50 or more and 200 or less.

[0008] The present inventors conducted extensive research into achieving both non-foaming and low hardness in polyurethanes, and as a result, they were able to solve the above-mentioned problems by specifying the types and blending ratios of polyols, isocyanates, chain extenders, and crosslinking agents. Specifically, the urethane elastomer composition of the present disclosure allows for the production of non-foaming urethane elastomers (cured products) with the desired hardness. Because the resulting cured products do not contain bubbles due to foaming, they have improved durability compared to foamed products. Furthermore, the absolute spring constant of the resulting cured products is relatively small over a wide frequency range, from low to high frequencies. Thus, the urethane elastomer composition of the present disclosure allows for the production of urethane elastomers suitable for vibration-damping members.

[0009] (2) In the above configuration, the mass ratio of the chain extender (C) to the crosslinking agent (D) [(C) / (D)] may be 0.4 or more and 1.0 or less. This configuration makes it easier to achieve a hardness of the resulting cured product within a range suitable for vibration-damping applications.

[0010] (3) In any of the above configurations, the number average molecular weight of the polyol (A) may be from 1000 to 3000. This configuration makes it easier to adjust the hardness of the resulting cured product to a range suitable for vibration-damping applications.

[0011] (4) In any of the above configurations, the aromatic isocyanate (B) may have naphthalene diisocyanate.

[0012] (5) In any of the above configurations, the chain extender (C) may have at least one of 1,4 butanediol and ethylene glycol.

[0013] (6) In any of the above configurations, the crosslinking agent (D) may include one or more selected from the group consisting of trimethylolpropane, triisopropanolamine, and diethanolamine.

[0014] (7) In any of the above configurations, the urethane elastomer composition of the present disclosure may be configured to contain no filler. Conventional vibration-damping rubbers have been blended with fillers such as carbon black and silica to achieve the strength required for vibration-damping applications. However, the urethane elastomer composition of the present disclosure can produce a cured product with strength suitable for vibration-damping applications without blending a reinforcing filler. Therefore, this configuration allows for the realization of a lightweight cured product at low cost, since no filler is used. Furthermore, the absence of a filler reduces friction between the polymer and the filler, allowing for a smaller absolute spring constant.

[0015] (8) The cured product of the present disclosure is obtained by curing a urethane elastomer composition having any of the above configurations. The cured product of the present disclosure is a non-foamed urethane elastomer. As described above, the cured product of the present disclosure has a hardness suitable for vibration-damping applications. Furthermore, the absolute spring constant of the cured product of the present disclosure is relatively small over a wide frequency range from low to high frequencies.

[0016] (9) In the configuration of (8) above, the cured product of the present disclosure may have a Type A durometer hardness of not less than 50 and not more than 60. The cured product of this configuration is suitable for vibration-damping applications.

[0017] (10) The vibration-damping member of the present disclosure has a cured product having the configuration described in (8) or (9) above. The vibration-damping member of the present disclosure can achieve both durability and vibration-damping performance, and can particularly improve vibration-damping performance in the high-frequency range. The vibration-damping member of the present disclosure is suitable for use as a strut mount, motor mount, engine mount, member mount, suspension bushing, subframe mount, compressor mount, etc. in vehicles such as automobiles (including gasoline-powered vehicles, electric vehicles, fuel-cell vehicles, hybrid vehicles, etc.). [Effects of the Invention]

[0018] The urethane elastomer composition of the present disclosure allows for the production of non-foamed urethane elastomers with the desired hardness. The cured product (urethane elastomer) of the present disclosure has a hardness suitable for vibration-damping applications, and its absolute spring constant is relatively small over a wide frequency range from low to high. The vibration-damping member of the present disclosure can achieve both durability and vibration-damping performance. [Brief explanation of the drawings]

[0019] [Figure 1] 10 is a graph showing frequency characteristics of absolute spring constants for the sample of Example 3 and a conventional anti-vibration rubber. DETAILED DESCRIPTION OF THE INVENTION

[0020] The following describes embodiments of the urethane elastomer composition, cured product, and vibration-damping member of the present disclosure. Note that the embodiments are not limited to the following embodiments, and various modifications and improvements that can be made by those skilled in the art are possible.

[0021] <Urethane elastomer composition> The urethane elastomer composition of the present disclosure has the following (A) to (D).

[0022] (A) Polyol The polyol is selected from lactone polyols and adipate polyols, which are polyester polyols. The polyol may be one or more types. Examples of lactone polyols include polycaprolactone polyols. Examples of adipate polyols include adipic acid / butanediol polyols and adipic acid / pentanediol polyols. Polyols produced by esterifying two or more glycols with adipic acid may also be used. Examples of glycols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and neopentyl glycol. For example, [adipic acid / ethylene glycol / butanediol] polyol, [butanediol / adipic acid / pentanediol] polyol, etc. may be mentioned.

[0023] The hardness of the resulting urethane elastomer varies depending on the number average molecular weight of the polyol. A high number average molecular weight tends to result in a softer urethane elastomer, while a low number average molecular weight tends to result in a harder urethane elastomer. Therefore, considering the hardness of the urethane elastomer, it is desirable that the number average molecular weight of the polyol be between 1,000 and 3,000. The number average molecular weight (Mn) of the polyol can be determined by gel permeation chromatography (GPC) or the like.

[0024] (B) Aromatic isocyanate In order to impart the physical properties required for vibration-damping applications to urethane elastomers, aromatic isocyanates are more suitable than aliphatic isocyanates. The aromatic isocyanates may be one type or two or more types. Examples of aromatic isocyanates include naphthalene diisocyanate (NDI), diphenylmethane diisocyanate (MDI), tolidine diisocyanate (TODI), tolylene diisocyanate (TDI), and phenylene diisocyanate. Of these, naphthalene diisocyanate is preferred because it can achieve both vibration-damping performance and mechanical properties.

[0025] If the aromatic isocyanate content is too high, the urethane elastomer becomes hard, and if it is too low, its moldability decreases. Therefore, taking into consideration the balance between hardness and moldability, the aromatic isocyanate content is set to 13.5% by mass or more and 15.5% by mass or less, assuming the entire urethane elastomer composition to be 100% by mass.

[0026] (C) Chain extender The chain extender is a bifunctional compound selected from compounds with a molecular weight of 50 to 150. Limiting the molecular weight of the compound used within this range facilitates adjustment of the hardness of the urethane elastomer. One or more chain extenders may be used. Examples of chain extenders include 1,4-butanediol, ethylene glycol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and 1,8-octanediol. Among these, 1,4-butanediol and ethylene glycol are preferred due to their high availability and relatively low cost. To achieve the desired hardness of the urethane elastomer, the content of the chain extender is set to 0.8% by mass or more and 1.4% by mass or less, based on 100% by mass of the entire urethane elastomer composition.

[0027] (D) Crosslinking agent The crosslinking agent is a trifunctional or higher functional compound selected from compounds with a molecular weight of 50 to 200. The use of a crosslinking agent crosslinks the urethane polymer to form a three-dimensional network structure. Limiting the molecular weight of the compound used within this range facilitates adjustment of the hardness of the urethane elastomer. One or more crosslinking agents may be used. Examples of crosslinking agents include trifunctional or higher polyfunctional alcohols and amines, such as trimethylolpropane, triisopropanolamine, diethanolamine, butanetriol, hexanetriol, and triethanolamine. Among these, trimethylolpropane, triisopropanolamine, and diethanolamine are preferred due to their high availability and relatively low cost. To achieve the desired hardness of the urethane elastomer, the content of the crosslinking agent is set to 1.3 to 2.6% by mass, based on 100% by mass of the entire urethane elastomer composition.

[0028] In a urethane elastomer composition, if the amount of chain extender is too large relative to the crosslinking agent, the resulting urethane elastomer tends to be hard, while if the amount of chain extender is too small, the resulting urethane elastomer tends to be soft. Considering the hardness of the urethane elastomer, it is desirable that the content of chain extender does not exceed the content of crosslinking agent. For example, it is desirable that the mass ratio of chain extender to crosslinking agent [(C) / (D)] be 0.4 or more and 1.0 or less.

[0029] The urethane elastomer composition of the present disclosure may contain other components in addition to the above-described components (A) to (D), as long as the effects of the present disclosure are not impaired. Examples of other components include catalysts, viscosity reducers, stabilizers, fillers, flame retardants, antistatic agents, hydrolysis inhibitors, and colorants.

[0030] Among these, examples of the catalyst include amine catalysts such as tetramethylethylenediamine, bis(2-dimethylaminoethyl) ether, triethylenediamine, triethylamine, N,N,N',N'-tetramethylhexane-1,6-diamine, N,N,N',N'',N''-pentamethyl-diethylenetriamine, N,N,N',N'',N'''-hexamethyltriethylenetetraamine, and N,N',N'-trimethylaminoethylpiperazine; acids such as formic acid, citric acid, butylic acid, and 2-ethylhexanoic acid; and organometallic catalysts such as tin laurate and tin octoate.

[0031] Furthermore, with the urethane elastomer composition of the present disclosure, a cured product having strength suitable for vibration-damping applications can be obtained without using fillers such as carbon black, silica, etc. Therefore, although the addition of fillers is not excluded from the urethane elastomer composition of the present disclosure, a form that does not contain fillers is preferable in consideration of weight reduction, vibration-damping properties, etc.

[0032] <Cured product (urethane elastomer)> The cured product of the present disclosure is produced by curing the urethane elastomer composition of the present disclosure. The properties of the cured product of the present disclosure are as follows:

[0033] [Hardness] From the viewpoint of realizing the durability and desired vibration-damping properties required of a vibration-damping member, the Type A durometer hardness of the cured product of the present disclosure is desirably 50 or more and 60 or less. In this specification, the Type A durometer hardness is a value measured using a hardness tester ("ASKER P1-A" manufactured by Kobunshi Keiki Co., Ltd.) in accordance with JIS K 6253-3:2012.

[0034] [Frequency characteristics of absolute spring constant] In the cured product of the present disclosure, it is desirable that the maximum absolute spring constant be 1800 N / mm or less in the frequency range of 90 Hz or more and 1000 Hz or less. The relationship between the absolute spring constant and the dynamic spring constant is shown by the following formula (I). When the absolute spring constant is small, the dynamic spring constant also becomes small. In a wide range from low to high frequencies, an absolute spring constant of 1800 N / mm or less can effectively reduce various vibrations and noises. K d =|K ※ |cosδ Formula (I) [K d : Dynamic spring constant, K ※ : absolute spring constant, δ: phase angle in vibration]

[0035] <Method of manufacturing the cured product> The method for producing the cured product of the present disclosure is not particularly limited, and may be a one-shot method, a prepolymer method, or the like. For example, one embodiment of the production method using the prepolymer method includes a prepolymer preparation step, a urethane elastomer composition preparation step, and a curing step. Each step will be described below.

[0036] [Prepolymer preparation process] This step is a step of preparing a prepolymer by mixing a polyol and an aromatic isocyanate. From the viewpoint of suppressing an increase in the viscosity of the prepolymer, it is desirable to mix the polyol and the aromatic isocyanate under heating. Furthermore, when the aromatic isocyanate is solid at room temperature, it is desirable to heat it to a temperature at which the aromatic isocyanate melts. A homogeneous prepolymer can be obtained by melting the aromatic isocyanate and reacting it with the polyol in advance. For example, this step is preferably carried out at a temperature of 100°C or higher and 130°C or lower. Furthermore, it is desirable to mix the polyol and the aromatic isocyanate under vacuum to suppress the generation of bubbles.

[0037] [Urethane elastomer composition preparation step] This step is a step in which the prepolymer prepared in the previous step is mixed with the remaining components, such as a chain extender and a crosslinking agent, to prepare a urethane elastomer composition. As with the previous step, this step is also preferably carried out under heating to prevent an increase in the viscosity of the prepolymer. For example, this step is preferably carried out at a temperature of 80°C or higher and 110°C or lower. Furthermore, this step is also preferably carried out under vacuum to prevent the formation of bubbles.

[0038] [Curing process] This step is a step of curing the urethane elastomer composition obtained in the previous step. This step may be carried out by pouring the urethane elastomer composition into a mold (cast molding) or by injection molding. The curing temperature may be appropriately determined taking into consideration the crosslinking temperature of the urethane polymer, productivity, etc. For example, the curing may be carried out at a temperature of 50°C or higher and 110°C or lower. The curing time may be set to a time that allows the crosslinking reaction to proceed sufficiently depending on the temperature. [Example]

[0039] Next, the present disclosure will be described more specifically with reference to examples.

[0040] <Sample production> Nine types of samples were produced using the materials listed in Table 1 below. First, (B) aromatic isocyanate was added to (A) polyol and stirred at 130°C while drawing a vacuum to produce a prepolymer. Next, (C) chain extender, (D) crosslinker, and catalyst were added to the prepolymer and stirred at 100°C while drawing a vacuum to produce a urethane elastomer composition. The urethane elastomer composition was then poured into the cavity of a mold, sealed, and cured at 100°C for 30 minutes to obtain a cured product (sample). The produced samples were cylindrical, 50 mm in diameter and 50 mm in height, and were used as is to measure the absolute spring constant, as described below.

[0041] The details of the materials used in producing the samples are as follows: The blending ratios of the materials are shown in Table 1 below. (A) Lactone polyol: polycaprolactone polyol, "Polylite (registered trademark) OD-X-2722" manufactured by DIC Corporation, number average molecular weight 2000. (A) Adipate-based polyol: [adipic acid / ethylene glycol / butanediol] polyol, "Polylite (registered trademark) OD-X-2595" manufactured by DIC Corporation, number average molecular weight 2000. (B) Aromatic isocyanate: naphthalene diisocyanate (NDI). (C) Chain extender: 1,4 butanediol, molecular weight 90. (D) Crosslinker: trimethylolpropane, molecular weight 134. Catalyst: Amine catalyst, "POLYCAT (registered trademark) 8" manufactured by EVONIK.

[0042] <Evaluation method> The hardness and absolute spring constant of the manufactured samples were measured, and based on these results, the suitability as an elastic member (vibration-isolating rubber) constituting the vibration-isolating member was judged.

[0043] [Hardness] The Type A durometer hardness of the sample was measured using a hardness tester (ASKER P1-A type manufactured by Kobunshi Keiki Co., Ltd.) conforming to JIS K 6253-3: 2012. The measurement was carried out by stacking three 2 mm thick test pieces cut out from the produced sample, and the value measured 3 seconds after the indenter came into contact with the test pieces was used.

[0044] [Absolute spring constant] The absolute spring constant of the sample was measured using the dynamic characteristics tester "ASH204-13" manufactured by Saginomiya Seisakusho Co., Ltd. After compressing the sample 2.5 mm in the axial direction with a preload, the sample was subjected to an acceleration of 49 m / s 2 A sweep vibration was performed from 90 Hz to 1000 Hz to determine the absolute spring constant with respect to frequency.

[0045] [judgement] If the measurement results of hardness and absolute spring constant satisfy the following two conditions (a) and (b), the material is deemed suitable as vibration-damping rubber (indicated by a circle in Table 1 below); if either condition is not satisfied, the material is deemed unsuitable as vibration-damping rubber (indicated by an x ​​in the same table). (a) Type A durometer hardness is 50 or more and 60 or less. (b) The absolute spring constant does not exceed 1800 N / mm in the frequency range of 90 Hz to 1000 Hz.

[0046] <Evaluation results> The blending ratios of the materials used to produce each sample and the evaluation results are summarized in Table 1. The samples of Examples 1 to 5 are included in the concept of the cured product of the present disclosure. [Table 1]

[0047] As shown in Table 1, the samples of Examples 1 to 5 had a Type A durometer hardness of 50 or more and 60 or less, which corresponds to condition (a), and a maximum absolute spring constant of 1800 N / mm or less, which corresponds to condition (b), and were all judged to be suitable for use as vibration-damping rubber. In contrast, the samples of Comparative Examples 1 and 2, in which the chain extender content in the urethane elastomer composition was greater than 1.4 mass% and the cross-linking agent content was less than 1.3 mass%, did not satisfy either condition (a) or (b), and were therefore judged to be unsuitable for use as vibration-damping rubber. Similarly, the samples of Comparative Examples 3 and 4, in which the aromatic isocyanate content was greater than 15.5 mass% and the chain extender content was greater than 1.4 mass%, did not satisfy either condition (a) or (b), and were therefore judged to be unsuitable for use as vibration-damping rubber.

[0048] Next, the relationship between frequency and absolute spring constant (frequency characteristics of absolute spring constant) of the sample of Example 3 was compared with that of a conventional vibration-proof rubber made of natural rubber. The conventional vibration-proof rubber sample was manufactured as follows.

[0049] First, natural rubber, zinc oxide, stearic acid, surface-activated carbon black, process oil, and three types of amine-based antioxidants (A, B, and C) were kneaded for 5 minutes at 150°C using a Banbury mixer. Next, two types of vulcanization accelerators (A and B) and sulfur were added to this kneaded mixture, and the mixture was kneaded for 5 minutes at 60°C using an open roll to prepare a natural rubber composition. The resulting natural rubber composition was then press-molded at 150°C for 20 minutes to produce a sample similar to the sample in Example 3, and the hardness and absolute spring constant versus frequency were measured.

[0050] Details of the materials used are as follows: Zinc oxide: "Zinc oxide type 2" manufactured by Sakai Chemical Industry Co., Ltd. Stearic acid: "Lunac (registered trademark) S-70V" manufactured by Kao Corporation. Carbon black: "Seast (registered trademark) 3" manufactured by Tokai Carbon Co., Ltd. Process oil: naphthenic oil, "SUNTHENE (registered trademark) 410" manufactured by Japan Sun Oil Co., Ltd. Antiaging agent A: phenylenediamine-based antiaging agent, "Antigen (registered trademark) 6C" manufactured by Sumitomo Chemical Co., Ltd. Antioxidant B: Amine-based antioxidant, "Nonflex (registered trademark) RD" manufactured by Seiko Chemical Co., Ltd. Antioxidant C: Amine-based antioxidant, "Ozonone (registered trademark) 6C" manufactured by Seiko Chemical Co., Ltd. Vulcanization accelerator A: Thiazole-based vulcanization accelerator, "ACCEL (registered trademark) CZ" manufactured by Kawaguchi Chemical Industry Co., Ltd. Vulcanization accelerator B: Thiuram-based vulcanization accelerator, "ACCEL (registered trademark) TMT" manufactured by Kawaguchi Chemical Industry Co., Ltd. Sulfur: "Finely powdered sulfur" manufactured by Hosoi Chemical Industry Co., Ltd.

[0051] Table 2 shows the components of conventional anti-vibration rubber, its Type A durometer hardness, and the maximum absolute spring constant in the frequency range of 90 Hz to 1000 Hz. Figure 1 also shows the frequency characteristics of the absolute spring constant for the sample of Example 3 and the conventional anti-vibration rubber. [Table 2]

[0052] As shown in Figure 1, with conventional vibration-damping rubber, there was a large peak between 600 Hz and 800 Hz in frequency, and the absolute spring constant exceeded 1800 N / mm between 700 Hz and 750 Hz. In contrast, with the sample of Example 3, the absolute spring constant was 1800 N / mm or less over the entire frequency range of 90 Hz to 1000 Hz, and the curve was broad, with no prominent peaks and a gradual change. As such, with the sample of Example 3, changes in vibration due to changes in frequency are small. This makes it less noticeable when the motor speed increases in an automobile, for example, thereby improving ride comfort.

[0053] From the above, it has been confirmed that the urethane elastomer composition of the present disclosure can realize a non-foamed urethane elastomer that has hardness suitable for vibration-damping applications, has a relatively small absolute spring constant over a wide frequency range from low to high frequencies, and exhibits gradual changes in the absolute spring constant. [Industrial Applicability]

[0054] The urethane elastomer composition of the present disclosure, a cured product thereof, and a vibration-damping member comprising the cured product are suitable for use as a strut mount, motor mount, engine mount, member mount, suspension bushing, subframe mount, compressor mount, and the like in vehicles such as automobiles.

Claims

1. A urethane elastomer composition comprising the following components (A) to (D), wherein, when the entire urethane elastomer composition is taken as 100% by mass, the content of (B) is 13.5% by mass or more and 15.5% by mass or less, the content of (C) is 0.8% by mass or more and 1.4% by mass or less, and the content of (D) is 1.3% by mass or more and 2.6% by mass or less. (A) One or more polyols selected from lactone-based polyols and adipate-based polyols. (B) Aromatic isocyanates. (C) One or more chain extenders selected from compounds having a molecular weight of 50 or more and 150 or less. (D) One or more crosslinking agents selected from compounds having a molecular weight of 50 or more and 200 or less.

2. 2. The urethane elastomer composition according to claim 1, wherein the mass ratio of the chain extender (C) to the crosslinking agent (D) [(C) / (D)] is 0.4 or more and 1.0 or less.

3. 2. The urethane elastomer composition according to claim 1, wherein the number average molecular weight of the polyol (A) is 1,000 or more and 3,000 or less.

4. The urethane elastomer composition according to claim 1, wherein the aromatic isocyanate (B) comprises naphthalene diisocyanate.

5. 2. The urethane elastomer composition according to claim 1, wherein the chain extender (C) comprises at least one of 1,4 butanediol and ethylene glycol.

6. 2. The urethane elastomer composition according to claim 1, wherein the crosslinking agent (D) comprises at least one selected from the group consisting of trimethylolpropane, triisopropanolamine, and diethanolamine.

7. The urethane elastomer composition of claim 1 which is filler-free.

8. A cured product obtained by curing the urethane elastomer composition according to claim 1.

9. 9. The cured product according to claim 8, having a Type A durometer hardness of 50 or more and 60 or less.

10. A vibration-damping member comprising the cured product according to claim 8 or 9.

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