Resin composition for vibration damping material, and vibration damping material

Abstract

To provide a resin composition for damping materials, designed to produce a damping material with excellent vibration absorption performance, and to provide such a damping material.SOLUTION: A resin composition for damping materials is provided, including a thermoplastic resin with 20-65 wt.% of chlorine groups present on its side chain, and liquid chlorinated paraffin with an HSP distance from the thermoplastic resin of 2.0-8.0, a viscosity (20°C) of 1.0-5000 poise, and an average carbon atom count of 10-50, and a chlorine content of 30-70 wt.%. Relative to 100 pts.wt. of the thermoplastic resin, the liquid chlorinated paraffin is 200-800 pts.wt. Also provided is a damping material that includes the resin composition.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition for a vibration damping material and a vibration damping material.

Background Art

[0002] Conventionally, vibration damping sheets have been used to reduce vibrations and noises generated in various structures such as residential buildings such as houses, condominiums, and office buildings, various structures such as highways, elevated bridges, and railway tracks, various vehicles such as automobiles, railway vehicles, and ships, and devices such as home appliances and OA equipment.

[0003] As an index of vibration damping performance, generally, the loss tangent (tanδ = E″ / E′) obtained by dividing the loss elastic coefficient (E″) by the storage elastic coefficient (E′) of the material is used. The larger the loss tangent, the better the vibration absorption performance of the material. When this value exceeds 1, it is said to be an excellent vibration damping material, but further improvement in vibration damping performance is desired. As an excellent vibration damping material, for example, Patent Document 1 discloses a high-damping resin composition comprising 100 parts by weight of a chlorine-containing thermoplastic resin and 30, 50, or 100 parts by weight of a liquid chlorinated paraffin having an average carbon number of 20 to 50.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, further improvement in vibration damping performance has been desired, and a material having a loss tangent exceeding 4 has been desired. However, the high-damping resin composition described in Patent Document 1 had a loss tangent value of 1.6 at room temperature (20°C) and did not exceed 4.

[0006] In view of the above, the object of the present invention is to provide a resin composition for vibration damping materials and a vibration damping material for obtaining a vibration damping material that exhibits excellent vibration damping and absorption properties such that the loss tangent value at room temperature (20°C) exceeds 4. [Means for solving the problem]

[0007] The inventors of the present invention conducted extensive research to solve the above problems. As a result, they discovered that the above problems could be solved by using a thermoplastic resin having specific conditions and liquid chlorinated paraffin, and by blending the thermoplastic resin and liquid chlorinated paraffin in specific proportions, thus arriving at the present invention. In other words, the present invention provides the following [1] to [6]. [1] A resin composition for vibration damping material comprising a thermoplastic resin having 20 to 65% by weight of chlorine groups in its side chains, and a liquid chlorinated paraffin having an HSP distance of 2.0 to 8.0 with the thermoplastic resin, a viscosity (20°C) of 1.0 to 5000 poise, an average carbon number of 10 to 50, and containing 30 to 70% by weight of chlorinated material, wherein the liquid chlorinated paraffin is present in an amount of 200 to 800 parts by weight per 100 parts by weight of the thermoplastic resin. [2] The resin composition for vibration damping materials according to [1], wherein the content of chlorine groups in the thermoplastic resin is 35 to 50% by weight. [3] The resin composition for vibration damping materials according to [1] or [2], wherein the liquid chlorinated paraffin has an HSP distance of 3.0 to 6.0 with respect to the thermoplastic resin, a viscosity (20°C) of 500 to 3000 poise, an average carbon number of 12 to 28, and contains 45 to 65% by weight of chlorinated material. [4] A resin composition for vibration damping materials according to any one of [1] to [3], comprising 450 to 700 parts by weight of the liquid chlorinated paraffin per 100 parts by weight of the thermoplastic resin. A vibration damping material comprising a resin composition for vibration damping materials as described in any of [5], [1], to [4]. [6] The vibration damping material according to [5], wherein the vibration damping material is a vibration damping sheet. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a resin composition for vibration damping materials and a vibration damping material that can exhibit excellent vibration damping and absorption properties such that the loss tangent (hereinafter sometimes referred to as "tanδ") value exceeds 4. [Modes for carrying out the invention]

[0009] The following describes in detail embodiments of the vibration-damping resin composition and vibration-damping material of the present invention. However, the following description is merely an example of an embodiment of the present invention, and the present invention is not limited to these embodiments. In this specification, the symbol "~" representing a numerical range means a range that includes the numbers before and after it.

[0010] [Resin composition for vibration damping materials] The vibration-damping resin composition of the present invention comprises a thermoplastic resin having 20 to 65% by weight of chlorine groups in its side chains, and a liquid chlorinated paraffin having an HSP distance of 2.0 to 8.0 from the thermoplastic resin, a viscosity (at 20°C) of 1.0 to 5000 poise, an average carbon number of 10 to 50, and containing 30 to 70% by weight of chlorinated material, wherein the composition contains 200 to 800 parts by weight of liquid chlorinated paraffin per 100 parts by weight of thermoplastic resin.

[0011] (thermoplastic resin) The thermoplastic resin used in this invention is not particularly limited as long as it is a thermoplastic resin having 20 to 65% by weight of chlorine groups in its side chains. If the amount of chlorine groups in the thermoplastic resin is less than 20% by weight, the crystals of the thermoplastic resin grow more easily, which increases the storage modulus and decreases the loss tangent value, thus reducing the vibration damping performance. If the amount of chlorine groups exceeds 65% by weight, the intermolecular forces become too strong, which increases the storage modulus and decreases the loss tangent value, thus reducing the vibration damping performance. The amount of chlorine groups in the thermoplastic resin is preferably 35 to 50% by weight.

[0012] Furthermore, the thermoplastic resin may contain substituents other than chlorine, such as cyano groups, hydroxyl groups, acetyl groups, methyl groups, ethyl groups, bromine, fluorine, etc. The proportion of such substituents other than chlorine is preferably 5% by weight or less. If it exceeds 5% by weight, the vibration damping performance may decrease.

[0013] Examples of thermoplastic resins used in the present invention include chlorinated polyethylene, polyvinyl chloride, and vinyl chloride-vinyl acetate copolymers. Preferred thermoplastic resins are amorphous resins with a low storage modulus and therefore a large loss tangent, and chlorinated polyethylene is preferred.

[0014] (Liquid chlorinated paraffin) The liquid chlorinated paraffin used in this invention has an HSP distance of 2.0 to 8.0 with respect to the thermoplastic resin, a viscosity (at 20°C) of 1.0 to 5000 poise, an average carbon number of 10 to 50, and contains 30 to 70% by weight of chlorinated material. The following describes each of these conditions.

[0015] The HSP distance between the liquid chlorinated paraffin and the thermoplastic resin of the present invention is 2.0 to 8.0. As the HSP distance between the liquid chlorinated paraffin and the thermoplastic resin decreases, the compatibility with the thermoplastic resin increases, and as a result, the free rotational motion of the thermoplastic resin is mitigated, and the vibration damping performance (peak value of loss tangent) increases. On the other hand, as the HSP distance with the thermoplastic resin increases, the compatibility with the thermoplastic resin decreases, and as a result, the free rotational motion of the thermoplastic resin is inhibited, and the vibration damping performance decreases. Therefore, the HSP distance with the thermoplastic resin is 2.0 to 8.0, preferably 3.0 to 6.0, more preferably 3.0 to 4.2, and even more preferably 3.2 to 4.0.

[0016] The HSP (Hansen solubility parameter) distance is defined by the following formula (1), focusing on two specific molecules (solvent and solute: in this invention, liquid chlorinated paraffin and thermoplastic resin), and serves as a solubility index indicating whether the two molecules are miscible. HSP distance ={4(δD1-δD2) 2 +(δP1-δP2) 2 +(δH1-δH2) 2} 0.5 (1) Here, in Equation (1), δD1, δP1, δH1, δD2, δP2, and δH2 are the Hansen solubility parameters of specific two molecules, and the solubility is represented in a three-dimensional space with the dispersion term as δD, the polar term as δP, and the hydrogen bond term as δH. The dispersion term δD represents the effect of the dispersion force, the polar term δP represents the effect of the dipole-dipole force, and the hydrogen bond term δH represents the effect of the hydrogen bond force. The HSP of a specific substance can be obtained by conducting a test in which a sample of the substance is dissolved in a number of different solvents with known Hansen solubility parameters to measure the solubility.

[0017] The liquid chlorinated paraffin of the present invention has a viscosity (at 20°C) of 1.0 to 5000 poises. If the viscosity of the liquid chlorinated paraffin is too low, the peak of the loss tangent shifts to the low-temperature side, and if it is too high, the peak of the loss tangent shifts to the high-temperature side, resulting in low vibration damping performance at room temperature (20°C). Therefore, the viscosity (at 20°C) is 1.0 to 5000 poises, preferably 500 to 3000 poises, and more preferably 1000 to 2500 poises.

[0018] The liquid chlorinated paraffin of the present invention has an average carbon number of 10 to 50. When the proportion of the liquid chlorinated paraffin in the resin composition for vibration damping material is constant, the smaller the average carbon number, the larger the molar amount of the liquid chlorinated paraffin, and as a result, the crystals of the thermoplastic resin are less likely to grow, and the vibration damping performance (peak value of the loss tangent) becomes higher. However, when the average carbon number is small, the liquid chlorinated paraffin is likely to bleed out, resulting in a decrease in the vibration damping performance. Also, when the average carbon number is large, sufficient vibration damping performance may not be exhibited. Therefore, the average carbon number is 10 to 50, preferably 12 to 28.

[0019] The liquid chlorinated paraffin of the present invention contains 30 to 70% by weight of chlorinated material. If the amount of chlorinated material in the liquid chlorinated paraffin is too low, crystals in the thermoplastic resin will grow more easily. Conversely, if the amount of chlorinated material is too high, the intermolecular forces of the thermoplastic resin will become too strong, increasing the storage modulus (E') of the vibration damping material. Therefore, since both too little and too much chlorinated material result in a small tanδ value, the amount of chlorinated material is limited to 30 to 70% by weight, preferably 45 to 65% by weight, and more preferably 48 to 62% by weight.

[0020] The liquid chlorinated paraffin of the present invention preferably has an HSP distance of 3.0 to 6.0 with respect to the thermoplastic resin, a viscosity (at 20°C) of 500 to 3000 poise, an average carbon number of 12 to 28, and contains 45 to 65% by weight of chlorinated material. More preferably, the liquid chlorinated paraffin has an HSP distance of 3.2 to 4.0 with respect to the thermoplastic resin, a viscosity (at 20°C) of 1000 to 2500 poise, an average carbon number of 12 to 28, and contains 48 to 62% by weight of chlorinated material.

[0021] (Ratio of thermoplastic resin to liquid chlorinated paraffin) The liquid chlorinated paraffin of the present invention is contained in an amount of 200 to 800 parts by weight per 100 parts by weight of thermoplastic resin. If the amount of liquid chlorinated paraffin is too small, crystals in the thermoplastic resin tend to grow easily. On the other hand, if the amount of liquid chlorinated paraffin is too large, the mechanical strength of the resulting vibration damping material tends to decrease, and it may become difficult to maintain its shape. Therefore, the amount of liquid chlorinated paraffin is 200 to 800 parts by weight per 100 parts by weight of thermoplastic resin, and preferably 400 to 800 parts by weight.

[0022] (Other additives) The resin composition for vibration damping materials of the present invention may contain other additive components as needed, as long as the objectives of the present invention are not impaired. As for other additive components, if transparency is required for the vibration damping material, a rosin-based compound may be included. Rosin-based compounds such as rosin metal salts and rosin esters can be used.

[0023] Furthermore, a tin-based stabilizer may be included as a heat stabilizer during the molding of the vibration-damping resin composition. The tin-based stabilizer is not particularly limited and includes dialkyltin malate, dialkyltin bis(monoalkylmalate), dibutyltin malate polymer, dialkyltin laurate, dialkyltin mercapto, dialkyltin bis(mercapto fatty acid ester), dialkyltin sulfide, dioctyltin malate polymer, and the like. These may be used individually or in combination of two or more.

[0024] Furthermore, the material may contain, as needed, plasticizers, fillers, lubricants, shrinkage inhibitors, nucleating agents, colorants (pigments, dyes, etc.), UV absorbers, antioxidants, anti-aging agents, reinforcing agents, flame retardant aids, antistatic agents, surfactants, vulcanizing agents, and surface treatment agents.

[0025] [Vibration damping materials] The vibration damping material of the present invention is obtained by shaping the resin composition for vibration damping material of the present invention described above. The shape of the vibration damping material is not particularly limited and may be in the form of a sheet, plate, rod, or block, but a sheet-shaped vibration damping sheet is preferred. Note that the term "sheet" is not strictly defined based on thickness and includes thin materials commonly called "films" and thick materials commonly called "plates". The thickness of the vibration damping sheet is not particularly limited, but if it is too thin, the vibration damping effect may be reduced, and if it is too thick, it may be inconvenient to handle when installing it at the source of vibration, so 0.05 to 50 mm is preferred.

[0026] Furthermore, the loss tangent (tanδ) of the vibration damping material is 4 or greater at 20°C. This range ensures excellent vibration damping performance under normal operating conditions.

[0027] (action) The vibration damping resin composition of the present invention comprises a thermoplastic resin having specific conditions and a liquid chlorinated paraffin having specific conditions, and is obtained by blending this liquid chlorinated paraffin with the chlorine-containing thermoplastic resin in a specific ratio. The vibration damping material obtained from this vibration damping resin composition exhibits excellent vibration damping and absorption properties such that the loss tangent value exceeds 4. [Examples]

[0028] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0029] [Measurement method] The methods for measuring each physical property in this specification are as follows: <Loss tangent> The loss tangent of a sheet-type vibration damping material was measured using a viscoelasticity measuring instrument (Rheorograph, manufactured by Toyo Seiki Seisakusho Co., Ltd.) under conditions of -40 to 40°C and a frequency of 50 Hz. The loss tangent was calculated from the Young's modulus (E', E'') using a conventional method, and the loss tangent at 20°C, the peak value of the loss tangent, and the temperature at which the peak value was obtained were determined.

[0030] <Compatibility Evaluation> The chlorinated polyethylene and liquid chlorinated paraffin used in the examples and comparative examples were dissolved in approximately 30 solvents selected from the Master database, which contains confirmed HSP (Hansen solubility parameters) (δDi, δPi, δHi), to evaluate their solubility. The HSPs of polyethylene and liquid chlorinated paraffin were then estimated using the computer software Hansen Solubility Parameters in Practice (HSPiP) Ver. 4.0.05. Subsequently, the index HSP distance was calculated using the estimated HSPs according to the following formula (1). HSP distance ={4(δD1-δD2) 2 +(δP1-δP2) 2 +(δH1-δH2) 2} 0.5 (1)

[0031] [Example 1] (Making vibration damping sheets) 100 parts by weight of chlorinated polyethylene (Showa Denko Corporation, product number "SDM-451B", chlorine content 45% by weight), 517 parts by weight of liquid chlorinated paraffin 1 (Tosoh Corporation, product name "Toyoparax A50", viscosity (20℃) 1500 poise, chlorine content 50% by weight, average carbon number 25), 100 parts by weight of rosin ester (Arakawa Chemical Industries, product number "KE-359"), and 13 parts by weight of tin-based stabilizer (Nitto Kasei Co., Ltd., product number "TVS#8570") were mixed in a roll mill and pressed at 150℃ to obtain a vibration damping sheet with a thickness of 1000 μm. The evaluation results of the obtained vibration damping sheet are shown in Table 1.

[0032] [Example 2] A vibration damping sheet was prepared in the same manner as in Example 1, except that the amount of liquid chlorinated paraffin 1 was 670 parts by weight per 100 parts by weight of chlorinated polyethylene. The evaluation results of the obtained vibration damping sheet are shown in Table 1.

[0033] [Example 3] A vibration damping sheet was prepared in the same manner as in Example 1, except that liquid chlorinated paraffin 2 (manufactured by Tosoh Corporation, trade name "Toyopalux 160", viscosity (20℃) 2000 poise, chlorine content 60 wt%, average carbon number 15) was used instead of liquid chlorinated paraffin 1 in Example 1. The evaluation results of the obtained vibration damping sheet are shown in Table 1.

[0034] [Example 4] A vibration damping sheet was prepared in the same manner as in Example 3, except that the amount of liquid chlorinated paraffin 2 was 670 parts by weight per 100 parts by weight of chlorinated polyethylene. The evaluation results of the obtained vibration damping sheet are shown in Table 1.

[0035] [Comparative Example 1] A vibration damping sheet was prepared in the same manner as in Example 1, except that liquid chlorinated paraffin 3 (manufactured by Tosoh Corporation, trade name "Toyopalux 150", viscosity (20℃) 20 poise, chlorine content 50 wt%, average carbon number 15) was used instead of liquid chlorinated paraffin 1 in Example 1. The evaluation results of the obtained vibration damping sheet are shown in Table 1.

[0036] [Comparative Example 2] A vibration damping sheet was prepared in the same manner as in Example 1, except that liquid chlorinated paraffin 4 (manufactured by Tosoh Corporation, trade name "Toyoparax 145", viscosity (20℃) 4.0 poise, chlorine content 45 wt%, average carbon number 15) was used instead of liquid chlorinated paraffin 1 in Example 1. The evaluation results of the obtained vibration damping sheet are shown in Table 1.

[0037] [Table 1]

[0038] As is clear from Table 1, the vibration damping sheets produced in Examples 1 to 4 were able to be obtained with excellent vibration damping and absorption properties, with a loss tangent of 4 or more at 20°C. Furthermore, the vibration damping sheets of Examples 1 to 4 showed peak values ​​of loss tangent at 20°C or around room temperature. The vibration damping sheets of Comparative Examples 1 and 2 had loss tangents of 1.1 and 1.2, respectively, at 20°C, and were unable to obtain sufficient vibration damping and absorption properties.

Claims

1. A thermoplastic resin having 20-65% by weight of chlorine groups in its side chains, A liquid chlorinated paraffin having an HSP distance of 2.0 to 8.0 with respect to the thermoplastic resin, a viscosity (at 20°C) of 1.0 to 5000 poise, an average carbon number of 10 to 50, and containing 30 to 70% by weight of chlorinated material, Includes, A resin composition for vibration damping materials comprising 100 parts by weight of the thermoplastic resin and 450 to 700 parts by weight of the liquid chlorinated paraffin.

2. The resin composition for vibration damping material according to claim 1, wherein the chlorine group content of the thermoplastic resin is 35 to 50% by weight.

3. The resin composition for vibration damping materials according to claim 1 or 2, wherein the liquid chlorinated paraffin has an HSP distance of 3.0 to 6.0 with respect to the thermoplastic resin, a viscosity (at 20°C) of 500 to 3000 poise, an average carbon number of 12 to 28, and contains 45 to 65% by weight of chlorinated material.

4. A vibration damping material comprising the resin composition for vibration damping materials according to any one of claims 1 to 3.

5. The vibration damping material according to claim 4, wherein the vibration damping material is a vibration damping sheet.

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