Vibration isolation and damping member and method for manufacturing the same

Abstract

To provide an anti-vibration damping member and a method for manufacturing the same, which have excellent mechanical properties such as high-temperature durability and excellent reproducibility, and can reduce manufacturing costs.SOLUTION: In an anti-vibration damping member made of a polyurethane, a polyol component of the polyurethane consists of polyester polyols, excluding short chain polyols, and an isocyanate component of the polyurethane is mainly composed of 1,5-naphthalene diisocyanate. The anti-vibration damping member is made of a thermoplastic urethane composition foam with an NCO index of 0.9 to 1.04.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to vibration-damping and vibration-isolating members used as vibration isolation members and vibration damping members, and more specifically, to vibration-damping and vibration-isolating members made of foamed polyurethane, and to a method for manufacturing the same. [Background technology]

[0002] Examples of vibration-damping and vibration-isolating members made of foamed polyurethane include bumper springs for vehicles. As shown in Figure 1, the bumper spring 2 is a substantially cylindrical (bellows-shaped) structure that is fitted onto the piston rod 31 of the shock absorber 30 that constitutes the vehicle's suspension, and is used by being positioned between the cylinder (absorber plate) 32 of the shock absorber 30 and the mounting part (upper support 33) on the vehicle body side (see Patent Document 1).

[0003] The aforementioned bumper springs are required to have high energy absorption capacity when the vehicle is in motion or when there is a high input, and low energy absorption capacity when there is a low input, in order to achieve both vibration absorption and ride comfort. Furthermore, in order to achieve efficient low-energy absorption at low input levels, bumper springs made of foamed polyurethane with diphenylmethane diisocyanate (MDI) or the like as the isocyanate component are generally used. Furthermore, for components used in applications requiring high-temperature durability (resistance to heat deformation) and flexibility, such as the aforementioned bumper springs, thermally cross-linked foamed polyurethane is generally used (see Patent Document 2). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 3758343 [Patent Document 2] Japanese Patent Publication No. 2004-293697 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, manufacturing vibration-damping and isolation components using thermo-crosslinked foamed polyurethane requires equipment to pour the material into molds and heat it, which presents a problem in terms of significant capital investment. Furthermore, thermally cross-linked foamed polyurethane presents challenges in manufacturing vibration-damping and isolation components with complex shapes, due to the difficulty in reducing the material viscosity during casting.

[0006] Furthermore, given the current demand for materials that do not burden the global environment, there is a growing need for the development of vibration-damping and isolation materials that are highly recyclable (reproducible) and can also achieve high mechanical properties. However, because thermally crosslinked foamed polyurethane does not melt when heated, it has poor reproducibility and poses environmental problems.

[0007] This invention has been made in view of these circumstances, and aims to provide a vibration-damping member and a method for manufacturing the same that have excellent mechanical properties such as high-temperature durability, excellent reproducibility, and also reduce manufacturing costs. [Means for solving the problem]

[0008] The inventors diligently conducted research to solve the aforementioned problems. In the course of this research, the inventors considered manufacturing vibration-damping members made of thermoplastic polyurethane foam. Conventional vibration-damping members using thermosetting polyurethane soften with heat, but many contain an excess of isocyanate, and in reality, some crosslinking occurs, making it difficult to reproduce vibration-damping members that exhibit their original mechanical properties by thermally melting old vibration-damping members. Furthermore, it has been conventionally thought that thermoplastic polyurethane cannot be used as a material for vibration-damping members such as bumper springs because they generate heat due to high deformation under high loads. However, based on this common technical knowledge, the inventors conducted further research and considered adopting a vibration-damping member made of a non-crosslinked thermoplastic urethane foam, in which the polyol component is a polyester polyol, the isocyanate component is 1,5-naphthalenediisocyanate (NDI), and the NCO index [the equivalent ratio of NCO groups in the isocyanate to hydroxyl groups in the polyol (NCO groups / OH groups)] is in the range of 0.9 to 1.04. As a result of this approach, we found that the crystallinity of the polyester polyol and the toughness of NDI result in a foam with excellent mechanical properties such as high-temperature durability, even when the NCO index is set low (in the range of 0.9 to 1.04) as described above. Furthermore, by using a vibration-damping member made from a non-crosslinked thermoplastic urethane composition with a low NCO index, the recyclability (reproduction) of the vibration-damping member is improved.

[0009] However, the gist of the present invention is as follows: [1] to [8]. [1] A vibration-damping and vibration-isolating member made of polyurethane, wherein the polyol component of the polyurethane consists of polyester polyols, excluding short-chain polyols, the isocyanate component of the polyurethane mainly consists of 1,5-naphthalene diisocyanate, and the member is made of a foam of a thermoplastic polyurethane composition having an NCO index of 0.9 to 1.04. [2] The vibration-damping member according to [1], wherein the proportion of the isocyanate component in the thermoplastic urethane composition is 10 to 30% by mass. [3] The vibration damping member according to [1] or [2], wherein the weight-average molecular weight of the polyurethane is 50,000 to 500,000. [4] The vibration-damping member according to any one of [1] to [3], wherein the polyester polyol is at least one selected from the group consisting of polyethylene adipate, polycaprolactam, and polycarbonate diol. [5] The density of the foam is 0.3 to 0.8 g / cm³ 3The vibration isolation and damping member according to any one of [1] to [4]. [6] The vibration isolation and damping member according to any one of [1] to [5], wherein the number average diameter of the foam cells in the foam is 50 to 500 μm. [7] A method for manufacturing the vibration isolation and damping member according to any one of [1] to [6], comprising: a step of preparing a urethane prepolymer from a polyester-based polyol and an isocyanate component mainly composed of 1,5-naphthalene diisocyanate; a step of mixing the urethane prepolymer and the remaining polyol component to prepare a thermoplastic urethane composition having an NCO index of 0.9 to 1.04; a step of molding a polyurethane foam comprising the thermoplastic urethane composition; a step of demolding the polyurethane foam from a mold; A method for manufacturing a vibration isolation and damping member, comprising the above steps. [8] The step of molding a polyurethane foam comprising the thermoplastic urethane composition is a step of once pelletizing the thermoplastic urethane composition, melting the pellets by an injection molding machine, casting the melted pellets into a mold in a foamed state, and molding a polyurethane foam, which is the method for manufacturing a vibration isolation and damping member according to [7]. [Advantages of the Invention]

[0010] From the above, the vibration isolation and damping member of the present invention is excellent in mechanical properties such as high-temperature durability, excellent in reproducibility, and can further reduce the manufacturing cost. [Brief Description of the Drawings]

[0011] [Figure 1] It is an explanatory diagram showing an embodiment of a urethane bumper spring. [Modes for Carrying Out the Invention]

[0012] Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to this embodiment. In this invention, when "X~Y" (where X and Y are any numbers) is used, unless otherwise specified, it means "X or greater and Y or less," and also includes the meaning of "preferably greater than X" or "preferably less than Y." Furthermore, when expressed as "greater than or equal to X" (where X is any number) or "less than or equal to Y" (where Y is any number), it also implies the intention that "greater than X is preferable" or "less than Y is preferable."

[0013] The vibration-damping and isolation member of the present invention (hereinafter referred to as "this vibration-damping and isolation member") is made of polyurethane, wherein the polyol component of the polyurethane consists of polyester-based polyols, excluding short-chain polyols, and the isocyanate component of the polyurethane mainly consists of 1,5-naphthalenediisocyanate, and the member is made of a foam of a thermoplastic urethane composition having an NCO index of 0.9 to 1.04. The term "main component" refers to the fact that 70% or more by mass, preferably 80% or more by mass, and more preferably 95-100% by mass of the isocyanate component is 1,5-naphthalenediisocyanate. Furthermore, the phrase "the polyol component of the polyurethane consists of polyester-based polyols, excluding short-chain polyols" does not mean that short-chain polyols are not used as the polyol component of the polyurethane, but rather that, apart from short-chain polyols, only polyester-based polyols are used as the polyol component in the polyurethane. Here, short-chain polyols refer to polyols with a number-average molecular weight (Mn) of 500 or less.

[0014] The components of the thermoplastic urethane composition are described in detail below.

[0015] [Polyol components] In the aforementioned thermoplastic urethane composition, only polyester-based polyols are used as the polyol component, excluding short-chain polyols. Examples of the polyester-based polyols include polyethylene adipate, polypropanediol adipate, polybutanediol adipate, polypentanediol adipate, polyhexanediol adipate, polyheptanediol adipate, polyoctanediol adipate, polynonanediol adipate, polydecanediol adipate, polydodecanediol adipate, polycaprolactam, polylauryllactam, polylaurolactam, and polycarbonatediol. These can be used individually or in combination of two or more. Among these, polyethylene adipate, polycaprolactam, and polycarbonatediol are preferred due to their excellent heat resistance.

[0016] The aforementioned polyester polyol is preferably one with a number-average molecular weight (Mn) of 1000 to 4000, more preferably 1250 to 3000, and even more preferably 1500 to 2500. In other words, by using polyester polyols of such molecular weight, it is possible to produce thermoplastic urethanes with the desired molecular weight and molecular structure. The number-average molecular weight (Mn) can be determined by methods such as gel permeation chromatography (GPC). The proportion of polyester polyol in the thermoplastic urethane composition is preferably 50 to 90% by mass, more preferably 55 to 88% by mass, and even more preferably 60 to 85% by mass.

[0017] Furthermore, in the thermoplastic urethane composition, short-chain polyols can be used as needed. Examples of such short-chain polyols include 1,4-butanediol, ethylene glycol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. These can be used alone or in combination of two or more. Among these, 1,4-butanediol is preferred due to its excellent fluidity. The proportion of short-chain polyols in the thermoplastic urethane composition is preferably 0.1 to 20% by mass, more preferably 0.3 to 15% by mass, and even more preferably 0.5 to 12% by mass.

[0018] [Isocyanate component] In the thermoplastic urethane composition, the isocyanate component mainly consists of 1,5-naphthalenediisocyanate (NDI), and preferably only NDI is used. When NDI is used in combination with other isocyanate components, for example, aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, and phenylene diisocyanate; and aliphatic diisocyanates such as 1,2-ethylene diisocyanate, 1,3-propylene diisocyanate, 1,4-butane diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, isophorone diisocyanate, and hydrogenated 4,4'-phenylmethane diisocyanate may be used alone or in combination of two or more.

[0019] The proportion of the isocyanate component in the thermoplastic urethane composition is preferably 10 to 30% by mass, more preferably 12 to 28% by mass, and even more preferably 14 to 22% by mass. Furthermore, the NCO index [the equivalent ratio of NCO groups in the isocyanate to hydroxyl groups in the polyol (NCO groups / OH groups)] in the thermoplastic urethane composition is in the range of 0.9 to 1.04, preferably in the range of 0.9 to 1.0, and more preferably in the range of 0.95 to 1.0. In other words, by defining it in this way, a good foaming state can be achieved, and both high-temperature durability and reproducibility can be successfully balanced.

[0020] [Other ingredients] The thermoplastic urethane composition contains polyol components, isocyanate components, and, as necessary, foaming agents, chain extenders, catalysts, foam stabilizers, hydrolysis inhibitors, flame retardants, viscosity reducers, stabilizers, fillers, colorants, and the like. Examples of the foaming agents include sodium bicarbonate, azo compounds such as azodicarbonamide, azide compounds such as p-toluenesulfonyl azide, and nitroso compounds such as N,N'-dinitrosopentamethylenetetramine. Furthermore, in this invention, since the thermoplastic urethane composition is non-crosslinked, it does not contain any crosslinking agents (including those that contribute to crosslinking).

[0021] Preferably, a urethane prepolymer is prepared from a part (or all) of the polyester polyol and an isocyanate component mainly composed of 1,5-naphthalenediisocyanate. Then, the urethane prepolymer is mixed with the remaining polyol component (the remainder of the polyester polyol or short-chain polyol) to prepare a thermoplastic urethane composition with an NCO index of 0.9 to 1.04. This allows for a good foaming state and provides a non-crosslinked thermoplastic urethane composition that offers both high-temperature durability and reproducibility. The aforementioned preparation process is preferably carried out under an ambient temperature of 80 to 120°C. Furthermore, if other components are to be added, it is preferable to add them at the stage of mixing the urethane prepolymer with the remaining polyol components. The urethane composition may be prepared using either a one-shot method, in which a long-chain polyol, a chain extender (short-chain glycol), and a diisocyanate are polymerized simultaneously, or a prepolymer method, in which the long-chain polyol and diisocyanate are reacted beforehand to synthesize a prepolymer, after which the short-chain glycol is added and polymerized. The manufacturing method may be a batch method, a band casting method, or a reaction extrusion method.

[0022] The weight-average molecular weight (Mw) of the polyurethane in the thermoplastic urethane composition is preferably 50,000 to 500,000, more preferably 75,000 to 400,000, and even more preferably 100,000 to 300,000. With such a weight-average molecular weight, a good foaming state can be achieved, and a non-crosslinked thermoplastic urethane composition that balances high-temperature durability and reproducibility well can be obtained. The weight-average molecular weight of the polyurethane can be determined by methods such as gel permeation chromatography (GPC). In this GPC method, for example, a high-speed GPC apparatus (HLC-8320GPC, manufactured by Tosoh Corporation) is used as the measuring instrument. The relationship between the known weight-average molecular weight and elution time using standard samples is determined in advance, and a calibration curve is created from which the weight-average molecular weight can be determined from the elution time. Next, the elution time of polyurethane is measured using the following apparatus and operating conditions, and the weight-average molecular weight (polystyrene equivalent) is calculated by referring to the calibration curve. <Equipment and operating conditions> Separation column: TSKgelSuperAWM-H manufactured by Tosoh Corporation (two columns connected in series) Detector: Differential refractometer Column temperature: 40℃ Mobile phase: N,N-dimethylformamide (10 mmol / L LiBr), manufactured by Kanto Chemical Co., Ltd. Standard sample: Standard polystyrene kit (Tosoh Corporation, PStQuick B) Sample concentration: 0.1% by mass Sample injection volume: 30 μL Flow rate: 0.5mL / min

[0023] The thermoplastic urethane composition prepared as described above may, if necessary, be pelletized, and then the pellets are melted and injected into a mold (such as a metal mold) in a foamed state using an injection molding machine. Alternatively, instead of pelletizing the thermoplastic urethane composition, it may be poured into a mold in a molten foam state.

[0024] As described above, the thermoplastic urethane composition can be brought into a molten foam state by, for example, pre-adding a foaming agent to the thermoplastic urethane composition, adding a foaming agent when the thermoplastic urethane composition is melted, dry-blending a foaming agent into the pellets before melting, or physically foaming the thermoplastic urethane composition by blowing in carbon dioxide or nitrogen gas when it is melted. The melting of the thermoplastic urethane composition is carried out at 150 to 290°C using a molding machine such as an injection molding machine.

[0025] As described above, after pouring the thermoplastic urethane composition into a mold in a molten foam state, a polyurethane foam made from the thermoplastic urethane composition can be formed.

[0026] Then, by demolding the polyurethane foam from the mold, the desired vibration-damping and vibration isolation member can be obtained.

[0027] In the vibration-damping and isolation member obtained in this manner, the density is 0.3 to 0.8 g / cm³. 3 It is preferable to use 0.4 to 0.8 g / cm³. 3 It is more preferable to do so at 0.5-0.6 g / cm³. 3 It is even more preferable to do so. By achieving such a density, the mechanical properties such as high-temperature durability (resistance to heat degradation) and flexibility become superior. The density can be measured, for example, using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd.

[0028] Furthermore, the number-average diameter of the foam cells in this vibration-damping and vibration isolation member is preferably 50 to 500 μm, and more preferably 100 to 300 μm. By setting the number-average diameter of the foam cells in this manner, the mechanical properties such as high-temperature durability (resistance to heat deformation) and flexibility are improved. The number-average diameter of the foam cells was calculated by preparing a 2mm square measurement sample from the vibration-damping member, measuring the diameter of 50 foam cells in a 1mm square field of view using a scanning electron microscope (SEM), and calculating the average.

[0029] Because this vibration isolation and damping material has high reproducibility, it is possible, for example, to reproduce vibration isolation and damping material that exhibits its original mechanical properties by thermally melting old vibration isolation and damping material, or to recycle it into other materials.

[0030] Furthermore, this vibration-damping and vibration-isolating material is suitable for applications requiring high-temperature durability (resistance to heat deformation), and can be effectively applied as various vibration-damping and vibration-isolating materials, such as bumper springs attached to the piston rods of shock absorbers, as well as engine mounts, transmission mounts, body mounts, cab mounts, member mounts, connecting rods, torque rods, strut bar cushions, center bearing supports, torsional dampers, steering rubber couplings, tension rod bushings, bushings, bound stoppers, FF engine roll stoppers, and muffler hangers in automobiles and other vehicles. [Examples]

[0031] Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples unless it exceeds the essence of the invention.

[0032] First, prior to the examples and comparative examples, the following materials were prepared.

[0033] [PEA] Polyethylene adipate with a number-average molecular weight of 2000 (POLYLITE OD-X-2610, manufactured by DIC Corporation)

[0034] [PCL] Polycaprolactam with a number-average molecular weight of 2000 (POLYLITE OD-X-640, manufactured by DIC Corporation)

[0035] [NDI] 1,5-Naphthalene diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0036] [Short-chain polyols] 1,4-Butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0037] [Foam stabilizer] NIAX silicone L-5388 (manufactured by Momentive Performance Materials)

[0038] [catalyst] N,N-dimethylcyclohexylamine (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0039] [Hydrolysis inhibitor] Stabacsol I (manufactured by Rhein Chemie)

[0040] [Example 1] A urethane prepolymer was prepared by mixing 56% by mass of PEA, a polyol component, and 14% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 26% by mass of the same PEA, 2.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.00. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and the result was 200,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.26 g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 100 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was 0.5 g / cm³. 3 That was the case.

[0041] [Example 2] A urethane prepolymer was prepared by mixing 54% by mass of PEA, a polyol component, and 13% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 29% by mass of the same PEA, 2.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 0.90. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and was found to be 180,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.26 g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 110 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was that the density was 0.5 g / cm³. 3 That was the case.

[0042] [Example 3] A urethane prepolymer was prepared by mixing 57% by mass of PEA, a polyol component, and 15% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 24% by mass of the same PEA, 2.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.04. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and the result was 180,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.26 g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 90 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was that the density was 0.5 g / cm³. 3 That was the case.

[0043] [Example 4] A urethane prepolymer was prepared by mixing 40% by mass of PEA, a polyol component, and 10% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 47% by mass of the same PEA, 0.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 2.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.00. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and was found to be 300,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.26 g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 100 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was that the density was 0.5 g / cm³. 3 That was the case.

[0044] [Example 5] A urethane prepolymer was prepared by mixing 59% by mass of PEA, a polyol component, and 30% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, a urethane composition with an NCO index of 1.00 was prepared by mixing 10.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 0.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and was found to be 300,000. Next, the urethane composition was pelletized using a uniaxial high-speed grinder (PSF-40, manufactured by Tani Kogyo Co., Ltd.). Subsequently, using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), the pellets were melted at 200°C, nitrogen gas was added under the condition of a gas injection amount of 0.26 g to make it foamed, and then injection molded into a mold. Then, by demolding from the mold, a polyurethane molded body (sample) was obtained. From the said sample, a measurement sample with a size of 2 mm square was prepared. Using a scanning electron microscope (SEM), the cell diameters of 50 cells were measured in a field of view of 1 mm square, and the average was obtained. As a result, the cell diameter (number average diameter of the cells) was 110 μm. Also, density measurement was performed on the said measurement sample using an automatic densitometer DSG-1 manufactured by Toyo Seiki Co., Ltd. As a result, the density was 0.5 g / cm 3 It was.

[0045] [Example 6] 56 mass% of PEA which is a polyol component and 14 mass% of NDI which is an isocyanate component were mixed at a liquid temperature of 130°C to prepare a urethane prepolymer. Next, the urethane prepolymer, 26 mass% of the same PEA as above newly, 2.5 mass% of a short-chain polyol, 0.03 mass% of a foam stabilizer, 0.03 mass% of a catalyst, and 1.44 mass% of a hydrolysis inhibitor were mixed at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.00. The weight average molecular weight (Mw) of the polyurethane in the urethane composition was measured using a high-speed GPC device (HLC-8320GPC manufactured by Tosoh Corporation) according to the above-mentioned conditions. As a result, it was 50000. Next, the urethane composition was pelletized using a uniaxial high-speed grinder (PSF-40, manufactured by Tani Kogyo Co., Ltd.). Subsequently, using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), the pellets were melted at 200°C, nitrogen gas was added under the condition of a gas injection amount of 0.26 g to make it foamed, and then injection molded into a mold. Then, by demolding from the mold, a polyurethane molded body (sample) was obtained. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 90 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was that the density was 0.5 g / cm³. 3 That was the case.

[0046] [Example 7] A urethane prepolymer was prepared by mixing 56% by mass of PEA, a polyol component, and 14% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 26% by mass of the same PEA, 2.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.00. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and the result was 500,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.26 g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 100 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was that the density was 0.5 g / cm³. 3 That was the case.

[0047] [Example 8] A urethane prepolymer was prepared by mixing 56% by mass of PCL, a polyol component, and 14% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 26% by mass of the same PCL, 2.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.00. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and the result was 100,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.26 g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 110 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was that the density was 0.5 g / cm³. 3 That was the case.

[0048] [Example 9] A urethane prepolymer was prepared by mixing 56% by mass of PEA, a polyol component, and 14% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 26% by mass of the same PEA, 2.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.00. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and the result was 200,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.32 g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 50 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was that the density was 0.5 g / cm³. 3 That was the case.

[0049] [Example 10] A urethane prepolymer was prepared by mixing 56% by mass of PEA, a polyol component, and 14% by mass of NDI, an isocyanate component, at an ambient temperature of 127°C. Next, the urethane prepolymer was mixed with 26% by mass of the same PEA, 2.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.00. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and the result was 200,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.2g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. From the aforementioned sample, a 2 mm square measurement sample was prepared, and the diameter of 50 foam cells was measured in a 1 mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 500 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was that the density was 0.5 g / cm³. 3 That was the case.

[0050] [Example 11] A urethane prepolymer was prepared by mixing 56% by mass of PEA, a polyol component, and 14% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 26% by mass of the same PEA, 2.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.00. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and the result was 200,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.32 g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 90 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was that the density was 0.3 g / cm³. 3 That was the case.

[0051] [Example 12] A urethane prepolymer was prepared by mixing 56% by mass of PEA, a polyol component, and 14% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 26% by mass of the same PEA, 2.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.00. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and the result was 200,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.2g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 110 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was 0.8 g / cm³. 3 That was the case.

[0052] [Comparative Example 1] A urethane prepolymer was prepared by mixing 54% by mass of PEA, a polyol component, and 13% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 29% by mass of the same PEA, 2.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 0.87. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and the result was 100,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.26 g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 90 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was that the density was 0.5 g / cm³. 3 That was the case.

[0053] [Comparative Example 2] A urethane prepolymer was prepared by mixing 60% by mass of PEA, a polyol component, and 15% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 21% by mass of the same PEA, 2.6% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.34% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.05. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and the result was 100,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.), nitrogen gas was added at a gas injection rate of 0.26 g to induce a foamed state, and the mixture was injection molded into a mold. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample, and the diameter of 50 foam cells was measured in a 1mm square field of view using a scanning electron microscope (SEM). The average of these measurements was found to be 110 μm. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result was that the density was 0.5 g / cm³. 3 That was the case.

[0054] [Comparative Example 3] A urethane prepolymer was prepared by mixing 56% by mass of PEA, a polyol component, and 14% by mass of NDI, an isocyanate component, at a liquid temperature of 130°C. Next, the urethane prepolymer was mixed with 26% by mass of the same PEA, 2.5% by mass of short-chain polyol, 0.03% by mass of foam stabilizer, 0.03% by mass of catalyst, and 1.44% by mass of hydrolysis inhibitor at a liquid temperature of 100°C to prepare a urethane composition with an NCO index of 1.00. The weight-average molecular weight (Mw) of the polyurethane in the aforementioned urethane composition was measured using a high-speed GPC instrument (HLC-8320GPC manufactured by Tosoh Corporation) according to the conditions described above, and was found to be 300,000. Next, the urethane composition was pelletized using a single-screw high-speed mill (PSF-40, manufactured by Tani Industries Co., Ltd.), and then the pellets were melted at 200°C using an injection molding machine (J110AD-180H, manufactured by Japan Steel Works, Ltd.) and injected into a mold in a non-foamed state. Finally, a polyurethane molded body (sample) was obtained by demolding from the mold. A 2mm square measurement sample was prepared from the aforementioned sample and observed using a scanning electron microscope (SEM), but no foam cells were found. Furthermore, the density of the aforementioned sample was measured using an automatic hydrometer DSG-1 manufactured by Toyo Seiki Co., Ltd., and the result showed a density of 1 g / cm³. 3 That was the case.

[0055] Next, the polyurethane molded articles (samples of vibration-damping and vibration-isolating members) of the examples and comparative examples obtained as described above were measured and evaluated according to the following criteria. These results are also shown in Table 1 below.

[0056] <Reproduction> The state of 2g of pellets obtained by cutting the aforementioned polyurethane molded body was evaluated visually according to the following criteria after heating in a 200°C oven for 15 minutes, and this was used to evaluate the reproducibility. ◎: The pellets melted and flowed to an area 1.5 times larger than the area on which they were placed. ○: The pellets melted and flowed over an area less than 1.5 times the area on which the pellets were placed. ×: The pellets did not melt.

[0057] <High temperature durability> A cylindrical sample measuring φ29 mm × height 12 mm was prepared from the aforementioned polyurethane molded body. After repeatedly compressing it 100 times with 7000 N in an 80°C atmosphere, the percentage decrease in the height of the sample (sagging) was measured, and the high-temperature durability was evaluated according to the following criteria. ◎: The percentage decrease (sagging) in the height of the sample is less than 20%. ○: The percentage decrease in sample height (sagging) is 20% or more but less than 40%. ×: The percentage decrease (sagging) in the height of the sample is 40% or more.

[0058] <Flexibility> A cylindrical sample measuring φ29 mm × height 12 mm was prepared from the aforementioned polyurethane molded body. Its hardness was measured using a Type A hardness tester in a 23°C atmosphere, and its flexibility was evaluated according to the following criteria. ○: The hardness of the HA sample is less than 95. ×: The hardness of the sample HA is 95 or higher.

[0059] [Table 1]

[0060] The results in Table 1 above show that the polyurethane molded articles of the examples achieve both reproducibility and high-temperature durability, and also exhibit high flexibility.

[0061] In contrast, while the polyurethane molded article of Comparative Example 1 exhibited good foaming, its NCO index of the forming material was lower than that specified in the present invention (0.9 to 1.04), resulting in poor high-temperature durability. The polyurethane molded article of Comparative Example 2 also exhibited good foaming, but its NCO index of the forming material was higher than that specified in the present invention (0.9 to 1.04), resulting in poor remanufacturability. The polyurethane molded article of Comparative Example 3 had an NCO index of the forming material within the range specified in the present invention (0.9 to 1.04), but it did not foam, resulting in poor flexibility. [Industrial applicability]

[0062] This vibration-damping and isolation component is suitable for applications requiring high-temperature durability (resistance to heat deformation), and can be effectively applied to various vibration-damping and isolation components such as bumper springs attached to the piston rods of shock absorbers, as well as engine mounts, transmission mounts, body mounts, cab mounts, member mounts, connecting rods, torque rods, strut bar cushions, center bearing supports, torsional dampers, steering rubber couplings, tension rod bushings, bushings, bound stoppers, FF engine roll stoppers, and muffler hangers in automobiles and other vehicles. Furthermore, because this vibration isolation and damping material has high reproducibility, it is possible, for example, to regenerate vibration isolation and damping material that exhibits its original mechanical properties by thermally melting old vibration isolation and damping material, or to recycle it into other materials.

Claims

1. A vibration-damping member made of polyurethane, wherein the polyol component of the polyurethane consists of polyester-based polyols, excluding short-chain polyols, and the polyester-based polyol is one or more selected from the group consisting of polyethylene adipate, polypropanediol adipate, polybutanediol adipate, polypentanediol adipate, polyhexanediol adipate, polyheptanediol adipate, polyoctanediol adipate, polynonanediol adipate, polydecanediol adipate, polydodecanediol adipate, polycaprolactam, polylauryllactam, polylaurolactam, and polycarbonatediol, and the polyester-based polyol A vibration-damping and vibration-isolating member comprising a foam of a thermoplastic urethane composition having a number-average molecular weight of 1,000 to 4,000 riols, 70% or more by mass of the isocyanate component of the polyurethane being 1,5-naphthalenediisocyanate, and an NCO index of 0.9 to 1.04, wherein the weight-average molecular weight of the polyurethane in the thermoplastic urethane composition is 50,000 to 500,000, the proportion of polyester polyols in the thermoplastic urethane composition is 50 to 90% by mass, the proportion of short-chain polyols in the thermoplastic urethane composition is 0.1 to 20% by mass, the proportion of isocyanate components in the thermoplastic urethane composition is 10 to 30% by mass, the density of the foam is 0.3 to 0.8 g / cm³, and the number-average diameter of the foam cells in the foam is 50 to 500 μm.

2. The vibration damping and vibration isolation member according to claim 1, wherein the proportion of the isocyanate component in the thermoplastic urethane composition is 12 to 28% by mass.

3. The vibration damping and vibration isolation member according to claim 1 or 2, wherein the weight-average molecular weight of the polyurethane is 75,000 to 400,000.

4. The density of the foam is 0.4 to 0.8 g / cm³. 3 The vibration-damping member according to any one of claims 1 to 3.

5. The vibration damping member according to any one of claims 1 to 4, wherein the number average diameter of the foam cells in the foam is 100 to 500 μm.

6. A method for manufacturing a vibration-damping member according to any one of claims 1 to 5, A step of preparing a urethane prepolymer from the polyester polyol and the isocyanate component, A step of mixing the urethane prepolymer with the remaining polyol component to prepare a thermoplastic urethane composition having an NCO index of 0.9 to 1.04, A step of molding a polyurethane foam made from the thermoplastic urethane composition, The process of demolding the polyurethane foam from the mold, A method for manufacturing vibration-damping and isolation members, comprising the features described above.

7. The process of molding a polyurethane foam made from the aforementioned thermoplastic urethane composition is as follows: A method for manufacturing a vibration-damping member according to claim 6, comprising the steps of first pelletizing the thermoplastic urethane composition, and then using an injection molding machine to melt the pellets and pour them into a mold in a foamed state to form a polyurethane foam.

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