JP2006117793A

JP2006117793A - Vibration-damping material

Info

Publication number: JP2006117793A
Application number: JP2004307054A
Authority: JP
Inventors: Tomoji Deguchi; 智司出口; Teruaki Sukeoka; 輝明祐岡
Original assignee: Kitagawa Industries Co Ltd
Current assignee: Kitagawa Industries Co Ltd
Priority date: 2004-10-21
Filing date: 2004-10-21
Publication date: 2006-05-11

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration-damping material having good hardness and a low resonance frequency. <P>SOLUTION: The vibration-damping material is constituted by dispersing heat-expandable microcapsules in a base material comprising a styrene/ethylene/propylene/styrene elastomer, a softener, and a hydrogenated petroleum resin. When such constitution is adopted, it is possible to obtain a material characterized in respect to vibration frequency characteristics by exhibiting soft (low resonance frequency) properties and in respect to material by having hardness equivalent to that in a comparative example (a material not containing the heat-expandable microcapsules). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、音響機器、情報関連機器、情報伝達機器等に使用される制振性材料に関する。 The present invention relates to a vibration damping material used for audio equipment, information-related equipment, information transmission equipment, and the like.

近年、ＣＤ−ＲＯＭ、ミニディスク、ＤＶＤ等の光ディスクや光磁気ディスクが汎用されており、また、情報機器の普及に伴ってハードディスクの需要も増大している。これらの機器は機構上、振動に弱い部分を有するので、振動を減衰させるために制振性材料が装着されている。スチレン系エラストマは、このような制振性材料として知られており、本願出願人も、スチレン−エチレン−プロピレン−スチレン系エラストマ等に軟化剤及び水添石油樹脂を添加することで、その制振性を向上させることを提案している（例えば、特許文献１参照）。 In recent years, optical disks and magneto-optical disks such as CD-ROMs, minidisks, and DVDs have been widely used, and the demand for hard disks has increased with the spread of information equipment. Since these devices have a portion that is weak against vibration due to the mechanism, a damping material is attached to attenuate the vibration. Styrene-based elastomers are known as such vibration-damping materials, and the applicant of the present application can also add a softening agent and hydrogenated petroleum resin to styrene-ethylene-propylene-styrene-based elastomers, etc. It is proposed to improve the performance (see, for example, Patent Document 1).

一方、スチレン系エラストマでは、軽量化を目的としてマイクロカプセルを充填することも考えられている（例えば、特許文献２参照）。但し、特許文献２に記載のエラストマは、特許文献１に記載のエラストマとは全く異なっている。
特許第３３６８２３２号公報特開２００３−１８３４４１号公報 On the other hand, for styrene elastomers, it is also considered to fill microcapsules for the purpose of weight reduction (for example, see Patent Document 2). However, the elastomer described in Patent Document 2 is completely different from the elastomer described in Patent Document 1.
Japanese Patent No. 3368232 JP 2003-183441 A

ところが、特にＦＡ機器、工作機械、自販機、精密機器、通信機器、コンピュータ、ＯＡ機器、自動車、車両、航空機、医療機器、計測機器、ＡＶ機器、家電、アミューズメントなどの機器に利用される制振性材料は、防振可能領域を広く持たせる必要があるため、共振周波数が低いことが要求される。共振周波数を低くするためには、オイルなどの添加量を増やして制振性材料を軟らかくすることが考えられるが、制振性材料がゲルのように軟らかくなると、耐荷重性、耐熱性が低下する。また、その制振性材料を機器に装着する際の作業性が低下し、オイルブリードが発生し易くなる。 However, vibration control is used especially for equipment such as FA equipment, machine tools, vending machines, precision equipment, communication equipment, computers, OA equipment, automobiles, vehicles, aircraft, medical equipment, measuring equipment, AV equipment, home appliances, and amusements. Since the material needs to have a wide vibration-proof region, the resonance frequency is required to be low. In order to lower the resonance frequency, it may be possible to increase the amount of oil added to soften the vibration damping material. However, if the vibration damping material becomes soft like a gel, the load resistance and heat resistance will decrease. To do. In addition, workability when the vibration damping material is mounted on a device is reduced, and oil bleed is likely to occur.

このように、制振性材料には、振動の周波数特性としては軟らかい（共振周波数が低い）特性が求められる一方で、材料としてはある程度の硬度が必要とされる場合があったが、従来の制振性材料はこのような要望に充分に応えることができなかった。そこで、本発明は、良好な硬度を有し、かつ、共振周波数の低い制振性材料を提供することを目的としてなされた。 As described above, the vibration damping material is required to have a soft (low resonance frequency) characteristic as a vibration frequency characteristic, while the material may require a certain degree of hardness. The damping material has not been able to sufficiently meet such a demand. Therefore, the present invention has been made for the purpose of providing a vibration-damping material having good hardness and a low resonance frequency.

上記目的を達するためになされた本発明は、スチレン−エチレン−プロピレン−スチレン系エラストマと、軟化剤と、水添石油樹脂とを含む基材に、熱膨張性マイクロカプセルを分散させてなることを特徴とする制振性材料を要旨としている。 The present invention, which has been made to achieve the above object, comprises dispersing thermally expandable microcapsules in a base material containing a styrene-ethylene-propylene-styrene elastomer, a softening agent, and a hydrogenated petroleum resin. The gist is the characteristic damping material.

本願出願人は、特許文献１と同様に製造した制振性材料に熱膨張性マイクロカプセルを混練して分散させる実験を行った。その結果、アスカーＣなどによって測定される硬度は殆ど変化させることなく、共振周波数を良好に低くすることができることを発見した。そこで、本発明では、スチレン−エチレン−プロピレン−スチレン系エラストマと、軟化剤と、水添石油樹脂とを含む基材に、熱膨張性マイクロカプセルを分散させている。このため、共振周波数を低くしてゲイン（倍率）が０ｄＢ以下となる周波数帯を広げ、その周波数帯における振動を良好に吸収することができる。また、硬度は殆ど変化せず、熱膨張性マイクロカプセルを分散させたことにより低密度化して軽量化することができるので、機器に装着する際の作業性も向上させることができる。 The applicant of the present application conducted an experiment in which thermally expandable microcapsules were kneaded and dispersed in a vibration damping material manufactured in the same manner as in Patent Document 1. As a result, it has been found that the resonance frequency can be satisfactorily lowered without changing the hardness measured by Asker C or the like. Therefore, in the present invention, the thermally expandable microcapsules are dispersed in a base material containing a styrene-ethylene-propylene-styrene elastomer, a softening agent, and a hydrogenated petroleum resin. For this reason, the resonance frequency can be lowered to widen the frequency band where the gain (magnification) is 0 dB or less, and vibrations in that frequency band can be absorbed well. In addition, the hardness hardly changes, and by dispersing the thermally expandable microcapsules, the density can be reduced and the weight can be reduced, so that the workability at the time of mounting on the device can also be improved.

なお、特許文献１にも示されたように、スチレン−エチレン−プロピレン−スチレン系エラストマの代わりにスチレン−エチレン−ブチレン−スチレン系エラストマを用いても、同様の作用・効果が生じる。 In addition, as shown also in patent document 1, even if it uses a styrene-ethylene-butylene-styrene-type elastomer instead of a styrene-ethylene-propylene-styrene-type elastomer, the same effect | action and effect will arise.

また、本発明は熱膨張マイクロカプセルの添加量を特に限定しないが、上記基材９９〜９５重量部に対して、１〜５重量部の上記熱膨張性マイクロカプセルを分散させた場合、硬度は殆ど変化させることなく共振周波数を低くすることができるといった前述の効果が一層顕著に表れる。 Further, the present invention does not particularly limit the amount of thermal expansion microcapsules added, but when 1 to 5 parts by weight of the thermal expansion microcapsules are dispersed with respect to 99 to 95 parts by weight of the base material, the hardness is The above-mentioned effect that the resonance frequency can be lowered with almost no change appears more remarkably.

次に、本発明の実施の形態を説明する。本実施の形態の制振材料を構成する基材は、例えば、スチレン−エチレン−プロピレン−スチレン系エラストマと、軟化剤と、水添石油樹脂とを含み、共振周波数ｆ0 と共振曲線の最大値から３ｄＢ下がった所の周波数Δｆとから
ｔａｎδ＝Δｆ／ｆ0
にて求められる損失係数ｔａｎδが１以上であるものとなっている。 Next, an embodiment of the present invention will be described. The base material constituting the vibration damping material of the present embodiment includes, for example, a styrene-ethylene-propylene-styrene elastomer, a softening agent, and a hydrogenated petroleum resin. From the frequency Δf of 3 dB lower than tan δ = Δf / f 0
The loss coefficient tan δ obtained in (1) is 1 or more.

水添石油樹脂は、ＳＰ値（溶解性パラメータ）が熱可塑性高分子有機材料に近い（例：スチレン系エラストマのＳＰ値は８．２〜８．５、水添石油樹脂のＳＰ値は８．３）ため、相溶性が良い。また、水添石油樹脂は、水添された脂環族系石油であるので、耐熱性、耐候性に優れている。更に、このような基材を利用した場合、ベースとなるポリマーが熱可塑性であるため、圧縮成形、押出成形、射出成形等、種々の成形方法が適用でき、量産化が容易である。 Hydrogenated petroleum resin has an SP value (solubility parameter) close to that of a thermoplastic polymer organic material (eg, SP value of styrene-based elastomer is 8.2 to 8.5, and SP value of hydrogenated petroleum resin is 8. 3) Therefore, compatibility is good. Further, since hydrogenated petroleum resin is a hydrogenated alicyclic petroleum oil, it has excellent heat resistance and weather resistance. Furthermore, when such a substrate is used, since the base polymer is thermoplastic, various molding methods such as compression molding, extrusion molding, and injection molding can be applied, and mass production is easy.

なお、前述のスチレン−エチレン−プロピレン−スチレン系エラストマの代わりに、スチレン−エチレン−ブチレン−スチレン系エラストマを用いてもよい。また軟化剤としては、鉱物油系、植物油系、合成系などの各種ゴム用または樹脂用軟化剤が挙げられる。鉱物油系としては、パラフィン系、ナフテン系、アロマ系などのプロセスオイルが挙げられ、植物油系としては、ひまし油、綿実油、亜麻仁油、菜種油、大豆油、パーム油、椰子油、落花生油、木蝋、パインオイル、オリーブ油などが挙げられる。これらの軟化剤は単独で用いてもよいが、互いの相溶性が良好な２種以上を混合して用いてもよい。 In place of the styrene-ethylene-propylene-styrene elastomer described above, a styrene-ethylene-butylene-styrene elastomer may be used. Examples of softeners include various rubber or resin softeners such as mineral oil, vegetable oil, and synthetic. Examples of mineral oils include paraffinic, naphthenic, and aromatic process oils, and vegetable oils include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, wood wax, Examples include pine oil and olive oil. These softeners may be used alone or in combination of two or more having good compatibility with each other.

特に、軟化剤としてパラフィン系、ナフテン系、アロマ系から選択される１種または２種以上を混合したものとすれば、基材自体の硬度を充分に低下させることができ、延いては、後述の共振倍率を一層良好に低下させることができる。 In particular, if the softener is a mixture of one or more selected from paraffin, naphthene, and aroma, the hardness of the substrate itself can be sufficiently reduced, and will be described later. The resonance magnification can be reduced more satisfactorily.

本実施の形態では、このような基材に熱膨張性マイクロカプセルを混練し、成形した後、加熱して発泡させた。熱膨張性マイクロカプセルは、上記基材９９〜９５重量部に対して、１〜５重量部使用するのが望ましい。 In the present embodiment, thermally expandable microcapsules are kneaded and molded into such a base material, and then heated to be foamed. It is desirable to use 1 to 5 parts by weight of the thermally expandable microcapsule with respect to 99 to 95 parts by weight of the base material.

以下に、具体的な実施例について説明する。先ず、制振性材料の基材の成分として以下の物質を用意した。
スチレン−エチレン−プロピレン−スチレン系エラストマ…３６．７重量部
軟化剤（パラフィン系プロセスオイル）…１８．３重量部
水添石油樹脂…４５．０重量部
次に、上記エラストマ及び軟化剤を混合し、更に上記水添石油樹脂を加えて基材を作製した。この基材１００重量部に対して、熱膨張性マイクロカプセル５重量部を加え、ニーダにて混練した。混練条件は、基材に熱膨張性マイクロカプセルが均一に分散させることができ、なおかつ、熱膨張性マイクロカプセルが膨張しない温度で混練を行った。 Specific examples will be described below. First, the following substances were prepared as components of the base material of the vibration damping material.
Styrene-ethylene-propylene-styrene elastomer ... 36.7 parts by weight softener (paraffinic process oil) ... 18.3 parts by weight hydrogenated petroleum resin ... 45.0 parts by weight Next, the above elastomer and softener are mixed. Further, the above hydrogenated petroleum resin was added to prepare a substrate. 5 parts by weight of thermally expandable microcapsules were added to 100 parts by weight of the base material and kneaded with a kneader. The kneading conditions were such that the heat-expandable microcapsules could be uniformly dispersed in the base material and kneaded at a temperature at which the heat-expandable microcapsules did not expand.

続いて、基材が目的の形状になる温度で加熱した金型に入れ圧縮して加熱プレスを行い、更に、圧力をできるだけ抜かないように冷却プレスを行った。なお、加熱プレスのプレス圧力は形状を確実に維持できる圧力とし、冷却時の圧力は加熱プレス時に成形した形状が変形しない圧力として冷却させて行った。 Subsequently, the substrate was put into a mold heated at a temperature at which the base material had a desired shape, compressed and heated, and further cooled so as not to remove pressure as much as possible. The pressing pressure of the heating press was set to a pressure that can maintain the shape with certainty, and the cooling pressure was set to a pressure that did not deform the shape formed during the heating press.

続いて、成形後の制振性材料を、チャンバに入れて加熱し、熱膨張性マイクロカプセルを発泡させた。なお、チャンバにおける加熱温度はマイクロカプセルが確実に膨張する温度とし、加熱時間はマイクロカプセルが膨張しきるまでとした。この結果、図１の顕微鏡写真に示すように、マイクロカプセルの気泡が均一に分散した良好な発泡材が得られた。 Subsequently, the molded damping material was placed in a chamber and heated to foam the thermally expandable microcapsules. Note that the heating temperature in the chamber was set to a temperature at which the microcapsules were surely expanded, and the heating time was set until the microcapsules were fully expanded. As a result, as shown in the micrograph of FIG. 1, a good foam material in which the bubbles of the microcapsules were uniformly dispersed was obtained.

次に、上記のようにして得られた実施例の制振性材料の物性を、熱膨張性マイクロカプセルを混練せずに作製した比較例と比較した。図２は、実施例及び比較例の共振曲線を表している。この共振曲線は、厚さ３mmの５mm角に切断した実施例または比較例の制振性材料により、４００ｇの荷重を４点支持にて支持し、振動の周波数を５〜５００Ｈｚの間で変化させて測定したものである。また、この共振曲線は、２４．７℃の雰囲気温度で、加速度０．４Ｇ、掃引速度を２．５min／sweepとして測定した。 Next, the physical properties of the vibration damping material of the example obtained as described above were compared with a comparative example prepared without kneading the thermally expandable microcapsules. FIG. 2 shows resonance curves of the example and the comparative example. This resonance curve is obtained by supporting a 400 g load with a four-point support by using the vibration damping material of Example or Comparative Example cut to a 5 mm square with a thickness of 3 mm, and changing the vibration frequency between 5 and 500 Hz. Measured. The resonance curve was measured at an ambient temperature of 24.7 ° C., an acceleration of 0.4 G, and a sweep speed of 2.5 min / sweep.

図２に基づいて算出された共振周波数，共振倍率，及び損失係数を、別途測定した硬度（アスカーＣ）及び密度と共に表１に示す。なお、密度は、５つのサンプルの平均値として算出した。 The resonance frequency, resonance magnification, and loss factor calculated based on FIG. 2 are shown in Table 1 together with hardness (Asker C) and density measured separately. The density was calculated as an average value of five samples.

図２及び表１に示すように、本実施例では、共振周波数を、比較例が１００Ｈｚ程度であるのに対して５０Ｈｚ程度まで低くすることができ、共振倍率も６ｄＢ程度の良好な制振性が得られた。このため、図２に示すように、ゲイン（倍率）が０ｄＢ以下となる周波数帯を、比較例の１１０Ｈｚ以上の範囲から８０Ｈｚ以上の範囲まで広げ、その周波数帯における振動を極めて良好に吸収することができる。 As shown in FIG. 2 and Table 1, in this embodiment, the resonance frequency can be lowered to about 50 Hz, compared to about 100 Hz in the comparative example, and the good vibration damping performance with a resonance magnification of about 6 dB. was gotten. For this reason, as shown in FIG. 2, the frequency band where the gain (magnification) is 0 dB or less is expanded from the range of 110 Hz or higher in the comparative example to the range of 80 Hz or higher, and vibrations in that frequency band are absorbed very well. Can do.

また、本実施例では、表１に示すように硬度は殆ど変化せず、振動の周波数特性としては軟らかい（共振周波数が低い）特性を呈する一方で、材料としては比較例と同等の硬度が得られた。このため、機器に装着する際の作業性も損なわれていない。従って、本実施例は、ＦＡ機器、工作機械、自販機、精密機器、通信機器、コンピュータ、ＯＡ機器、自動車、車両、航空機、医療機器、計測機器、ＡＶ機器、家電、アミューズメントなどの利用分野には、極めて適切な制振性材料といえる。 In this example, as shown in Table 1, the hardness hardly changes and the frequency characteristic of vibration is soft (resonance frequency is low), while the material has the same hardness as the comparative example. It was. For this reason, the workability | operativity at the time of mounting | wearing with an apparatus is not impaired. Therefore, this embodiment is not applicable to fields of use such as FA equipment, machine tools, vending machines, precision equipment, communication equipment, computers, OA equipment, automobiles, vehicles, aircraft, medical equipment, measuring equipment, AV equipment, home appliances, and amusements. It can be said that it is a very suitable damping material.

更に、本実施例の制振材料は、熱膨張性マイクロカプセルを分散させたことにより低密度化して軽量化することができたので、機器に装着する際の作業性を一層向上させることができる。また、本実施例の制振材料は、基材が熱可塑性であるため、圧縮成形、射出成形、押出成形等、種々の成形方法が適用でき、量産化が容易である。しかも、塩素等を含まないものも製造可能なので、リサイクル性にも優れていて環境に優しい。 Furthermore, since the vibration damping material of the present embodiment was able to reduce the density and weight by dispersing the thermally expandable microcapsules, it is possible to further improve the workability when mounting on the device. . In addition, since the base material is thermoplastic, the vibration damping material of this embodiment can be applied to various molding methods such as compression molding, injection molding, and extrusion molding, and mass production is easy. Moreover, since it can also be manufactured without chlorine, it has excellent recyclability and is environmentally friendly.

なお、本発明は上記実施例に何ら限定されるものではなく、本発明の要旨を逸脱しない範囲で種々の形態で実施することができる。例えば、スチレン−エチレン−プロピレン−スチレン系エラストマの代わりに、スチレン−エチレン−ブチレン−スチレン系のエラストマを用いてもよい。 In addition, this invention is not limited to the said Example at all, It can implement with a various form in the range which does not deviate from the summary of this invention. For example, instead of a styrene-ethylene-propylene-styrene elastomer, a styrene-ethylene-butylene-styrene elastomer may be used.

本発明の実施例である制振性材料の断面を表す顕微鏡写真である。It is a microscope picture showing the cross section of the damping material which is an Example of this invention. その制振性材料の制振特性を、マイクロカプセルを含まない比較例と対比して表す共振曲線である。It is the resonance curve showing the damping characteristic of the damping material compared with the comparative example which does not contain a microcapsule.

Claims

A vibration-damping material obtained by dispersing thermally expandable microcapsules in a base material containing a styrene-ethylene-propylene-styrene elastomer, a softening agent, and a hydrogenated petroleum resin.

A vibration-damping material obtained by dispersing thermally expandable microcapsules in a base material containing a styrene-ethylene-butylene-styrene elastomer, a softening agent, and a hydrogenated petroleum resin.

The vibration-damping material according to claim 1 or 2, wherein 1 to 5 parts by weight of the thermally expandable microcapsule is dispersed with respect to 99 to 95 parts by weight of the base material.