JP4239511B2 - Rubber composition and method for producing the same, rubber molded product and method for producing the same - Google Patents

Description

【００２０】
上記（Ｂ−１）成分として具体的には、カルボン酸変性エチレンプロピレンジエン三元共重合体（ＥＰＤＭ）、特に無水マレイン酸変性エチレンプロピレン共重合体（ＥＰＭ）の１種又は２種以上が好ましく挙げられる。
【００２１】
上記（Ｂ−１）成分を得る方法、即ち、（共）重合体中に官能基を含有させる方法は特に限定はない。例えば、（１）官能基を有する重合開始剤を用いて重合を行うことにより導入する方法、（２）官能基を有する不飽和単量体を反応させることにより導入する方法、及び（３）（共）重合体の活性点に官能基を有する重合停止剤を反応させることにより導入する方法等が挙げられる。また、上記の各方法は単独で行ってもよく、又は上記の方法を組み合わせて行ってもよい。
【００２２】
本発明のゴム組成物中の上記（Ｂ−１）成分の含有量は、上記（Ａ）成分及び上記（Ｂ−１）成分の含有量の合計を１００質量部とした場合、１〜６０質量部、好ましくは１〜５０質量部、好ましくは１〜４５質量部、更に好ましくは３〜３５質量部、より好ましくは３〜３０質量部、特に好ましくは３〜２５質量部、最も好ましくは５〜２０質量部である。上記（Ｂ−１）成分の含有量が１質量部未満では、高温時の物性、特に高温時の伸び及び伸張疲労性を改善することができないので好ましくない。一方、上記（Ｂ−１）成分の含有量が６０質量部を越えると、十分な耐熱性及び耐候性が得られないので好ましくない。尚、上記（Ｂ−１）成分の含有量とは、本発明の上記（Ｂ）架橋物を得る際に使用した上記（Ｂ−１）成分の量を意味する。
【００２３】
＜３＞（Ｂ−２）金属化合物
本発明では、上記（Ｂ−２）金属化合物（以下、単に「（Ｂ−２）成分」ということもある。）を含有することにより、静動比を向上させると共に、高温時の物性、特に高温時の伸び及び伸張疲労性を改善することができる。これは上記のように、上記（Ｂ−１）成分との間で金属架橋を形成するためと考えられる。尚、本発明において、「（Ｂ−２）金属化合物を含有する」とは、ゴム組成物中で金属化合物の形で存在する場合だけでなく、金属化合物として添加し、ゴム組成物中でイオン状態に解離して存在している場合も含む。
【００２４】
上記（Ｂ−２）成分としては、添加後、金属イオンを生じさせることができる限り、その種類には特に限定はない。例えば、金属無機化合物でも有機金属塩でもよい。また、上記（Ｂ−２）成分は１種単独でもよく、２種以上併用してもよい。即ち、金属無機化合物又は有機金属塩を１種単独又は２種以上併用してもよく、金属無機化合物の１種以上と有機金属塩の１種以上とを併用してもよい。上記金属無機化合物としては、例えば、金属酸化物、金属水酸化物等の１種又は２種以上が挙げられる。また、金属の種類についても特に限定はなく、例えば、上記金属無機化合物として、アルカリ金属（リチウム、ナトリウム、カリウム等）化合物、アルカリ土類金属（マグネシウム、カルシウム、バリウム等）化合物、アルミニウム化合物、亜鉛化合物、鉄化合物及びチタン化合物等から選ばれる１種又は２種以上が挙げられる。上記金属無機化合物は１種単独で用いてもよく、２種以上併用してもよい。
【００２５】
上記有機金属塩としては、例えば、脂肪酸金属塩等が挙げられる。かかる脂肪酸金属塩は、均一に分散し易いので好ましい。上記脂肪酸の種類については特に限定はなく、飽和脂肪酸、不飽和脂肪酸等の種々の構造の脂肪酸を使用することができる。通常、上記脂肪酸として、炭素数１〜２５、好ましくは５〜２５、更に好ましくは１０〜２３、より好ましくは１３〜２３の脂肪酸が挙げられる。上記脂肪酸として具体的には、ステアリン酸等が挙げられる。また、金属塩の種類についても特に限定はない。例えば、アルカリ金属塩（カリウム塩、ナトリウム塩等）、アルカリ土類金属塩（マグネシウム塩、バリウム塩、カルシウム塩等）、アルミニウム塩、亜鉛塩、鉄塩及びチタン塩等の１種又は２種以上が挙げられる。具体的には、脂肪酸アルカリ金属塩（カリウム塩、ナトリウム塩等）、脂肪酸アルカリ土類金属塩（マグネシウム塩、バリウム塩、カルシウム塩等）、脂肪酸アルミニウム塩、脂肪酸亜鉛塩、脂肪酸鉄塩及び脂肪酸チタン塩等の１種又は２種以上が挙げられる。また、上記脂肪酸金属塩としてより具体的には、ステアリン酸マグネシウム及び／又はステアリン酸亜鉛等が挙げられる。
【００２６】
本発明において、上記（Ｂ−２）成分の割合は、上記（Ｂ−１）成分１００質量部に対して０．０５〜５質量部、好ましくは０．０５〜３質量部、更に好ましくは０．０５〜２質量部、より好ましくは０．０５〜１．５質量部、特に好ましくは０．１〜１．５質量部、最も好ましくは０．１〜１．３質量部である。上記（Ｂ−２）成分の割合が０．０５質量部未満であると、上記（Ｂ−１）成分との金属架橋が十分に進まず、高温時の物性、特に高温時の伸び及び伸張疲労性の改善が十分でないことから好ましくない。一方、上記（Ｂ−２）成分の割合が５質量部を越えると、金属架橋が進み過ぎて、常態時の強度及び伸びの低下を招くので好ましくない。
【００２７】
上記（Ｂ−２）成分として、上記金属無機化合物の少なくとも１種と、脂肪酸金属塩等の上記有機金属塩の少なくとも１種とを併用してもよい。また、上記金属無機化合物と脂肪酸金属塩等の上記有機金属塩とを併用する場合、両者の割合については特に限定はなく、要求されるゴム組成物の特性に応じて種々の範囲とすることができる。上記金属無機化合物と脂肪酸金属塩等の上記有機金属塩との割合は、通常、重量比率で１：（１〜１０）であり、より好ましくは１：（１〜７）、更に好ましくは１：（１〜５）である。
【００２８】
＜４＞（Ｂ）架橋物
本発明のゴム組成物に含まれる上記（Ｂ）架橋物（以下、単に「（Ｂ）成分」ということもある。）は、上記（Ｂ−１）成分を上記（Ｂ−２）成分中の金属成分によって架橋した成分である。該（Ｂ）成分は、通常、上記（Ｂ−１）成分と上記（Ｂ−２）成分とを加熱混合することにより得られる。この場合の条件については特に限定はなく、必要に応じて種々の条件とすることができる。通常、加熱温度は１５０〜２２０℃、好ましくは１５０〜２００℃である。また、混合時間は通常５分以内、好ましくは１〜５分である。かかる範囲とすることにより、上記（Ｂ−１）成分の金属架橋が好適に進行し、静動比を向上させると共に、高温時の物性、特に高温時の伸び及び伸張疲労性を改善することができるので好ましい。また、混合方法としては、バンバリーミキサーに代表される密閉型混合機、連続的に混合可能な押出機等を用いることができる。
【００２９】
＜５＞その他の成分
更に、本発明のゴム組成物では、本発明の目的を阻害しない範囲で、上記（Ａ）成分及び（Ｂ−１）成分以外のゴム成分を含んでいてもよい。このようなゴム成分としては、例えば、官能基を有しないＳＢＲ、ＢＲ、イソプレンゴム（ＩＲ）、ＮＲ等が挙げられる。もっとも、ＮＲを多量に配合すると、ゴム組成物の耐熱性が低下するおそれがあることから、ＮＲを含有させる場合、その含有量は１５質量部以下とすることが好ましい。また、本発明のゴム組成物には、本発明の目的を阻害しない範囲で、種々の添加剤を必要に応じて適宜添加することができる。上記添加剤としては、例えば、本発明の（Ｂ−２）成分に該当する脂肪酸金属塩以外の脂肪酸塩、補強剤、ゴム用伸展油、充填剤、架橋剤、架橋促進剤及び架橋活性化剤等が挙げられる。
【００３０】
本発明の（Ｂ−２）成分に該当する脂肪酸金属塩以外の脂肪酸塩としては、例えば、脂肪酸アンモニウム塩等が挙げられる。上記脂肪酸の種類については特に限定はなく、飽和脂肪酸、不飽和脂肪酸等の種々の構造の脂肪酸を使用することができる。通常、上記脂肪酸として、炭素数１〜２５、好ましくは５〜２５、更に好ましくは１０〜２３、より好ましくは１３〜２３の脂肪酸が挙げられる。上記脂肪酸として具体的には、ステアリン酸等が挙げられる。かかる脂肪酸塩を含有することにより、上記（Ｂ−２）成分を均一に分散させることができるので好ましい。
【００３１】
上記補強剤としては、カーボンブラック及びシリカ等を使用することができる。また、上記補強剤は、１種単独で用いてもよく、２種以上を併用してもよい。例えば、上記カーボンブラック又はシリカを単独で用いてもよく、シリカとカーボンブラックとを併用してもよい。
【００３２】
上記カーボンブラックの種類等は特に限定されず、ファーネスブラック、アセチレンブラック、サーマルブラック、チャンネルブラック、グラファイト等が挙げられる。これらのうちでは特にファーネスブラックが好ましく、その具体例としては、ＭＴ、ＳＲＦ、ＧＰＦ、ＭＡＦ、ＦＥＦ、ＳＡＦ、ＩＳＡＦ、ＩＳＡＦ−ＨＳ、ＩＳＡＦ−ＬＳ、ＩＩＳＡＦ−ＨＳ、ＨＡＦ、ＨＡＦ−ＨＳ、ＨＡＦ−ＬＳ等が挙げられる。これらのカーボンブラックは１種のみを用いてもよいし、２種以上を併用することもできる。また、ＡＳＴＭ Ｄ３０３７−８１に準拠してＢＥＴ法により測定したカーボンブラックの窒素吸着比表面積は特に限定されないが、架橋ゴムの引張強度等を十分に向上させるためには、５〜２００ｍ^２／ｇ、特に５０〜１５０ｍ^２／ｇ、更には８０〜１３０ｍ^２／ｇであることが好ましい。また、カーボンブラックのＤＢＰ吸着量も特に限定されないが、架橋ゴムの強度等を十分に向上させるためには、５〜３００ｍｌ／１００ｇ、特に５０〜２００ｍｌ／１００ｇ、更には８０〜１６０ｍｌ／１００ｇであることが好ましい。
【００３３】
上記シリカとしては、一般に合成ゴムの明色補強配合剤として用いられているものを使用することができる。その種類等は特に限定されず、湿式法ホワイトカーボン、乾式法ホワイトカーボン、コロイダルシリカ等を使用することができる。これらのうちでは、含水ケイ酸を主成分とする湿式法ホワイトカーボンが好ましい。これらのシリカ系化合物は、それぞれ１種のみを用いてもよいし、２種以上を併用することもできる。シリカのＡＳＴＭ Ｄ３０３７−８１に準拠してＢＥＴ法により測定した窒素吸着比表面積は特に限定されないが、通常、５０〜４００ｍ^２／ｇ、特に５０〜２２０ｍ^２／ｇ、更には７０〜２２０ｍ^２／ｇであることが好ましい。
【００３４】
上記ゴム用伸展油としては、石油系配合油であるパラフィン系プロセスオイル、芳香族系プロセスオイル、ナフテン系プロセスオイル等を使用することができる。このゴム用伸展油としては、パラフィン系のプロセスオイルが好ましい。
【００３５】
上記充填剤としては、タルク、クレー、炭酸カルシウム及び炭酸マグネシウム等を適量配合することができる。
【００３６】
上記架橋剤としては、ジクミルパーオキシド、ジ−ｔ−ブチルパーオキシド等の有機過酸化物、粉末硫黄、沈降硫黄、コロイド硫黄、不溶性硫黄、高分散性硫黄等の硫黄、一塩化硫黄、二塩化硫黄等のハロゲン化硫黄、ｐ−キノンジオキシム、ｐ，ｐ’−ジベンゾイルキノンジオキシム等のキノンジオキシム、トリエチレンテトラミン、ヘキサメチレンジアミンカルバメート、４，４’−メチレンビス−ｏ−クロロアニリン等の有機多価アミン化合物、メチロール基を有するアルキルフェノール樹脂等を使用することができる。架橋剤は各々の種類のうちの１種のみを用いてもよいし、２種以上を併用することもでき、異なった種類のものを併用することもできる。
【００３７】
架橋促進剤としては、以下の各種のものを使用することができる。
（ａ）Ｎ−シクロヘキシル−２−ベンゾチアゾールスルフェンアミド、Ｎ−ｔ−ブチル−２−ベンゾチアゾールスルフェンアミド、Ｎ−オキシエチレン−２−ベンゾチアゾールスルフェンアミド、Ｎ−オキシエチレン−２−ベンゾチアゾールスルフェンアミド、Ｎ，Ｎ’−ジイソプロピル−２−ベンゾチアゾールスルフェンアミドなどのスルフェンアミド系架橋促進剤、
（ｂ）ジフェニルグアニジン、ジオルトトリルグアニジン、オルトトリルビグアニジン等のグアニジン系架橋促進剤、
（ｃ）チオカルボアニリド、ジオルトトリルチオウレア、エチレンチオウレア、ジエチルチオウレア、トリメチルチオウレア等のチオウレア系架橋促進剤、
（ｄ）２−メルカプトベンゾチアゾール、ジベンゾチアジルジスルフィド、２−メルカプトベンゾチアゾール亜鉛塩、２−メルカプトベンゾチアゾールナトリウム塩、２−メルカプトベンゾチアゾールシクロヘキシルアミン塩、２−（２，４−ジニトロフェニルチオ）ベンゾチアゾール等のチアゾール系架橋促進剤、
（ｅ）テトラメチルチウラムモノスルフィド、テトラメチルチウラムジスルフィド、テトラエチルチウラムジスルフィド、テトラブチルチウラムジスルフィド、ジペンタメチレンチウラムテトラスルフィド等のチウラム系架橋促進剤、
（ｆ）ジメチルジチオカルバミン酸ナトリウム、ジエチルジチオカルバミン酸ナトリウム、ジ−ｎ−ブチルジチオカルバミン酸ナトリウム、ジメチルジチオカルバミン酸鉛、ジメチルジチオカルバミン酸亜鉛、ジエチルジチオカルバミン酸亜鉛、ジ−ｎ−ブチルジチオカルバミン酸亜鉛、ペンタメチレンジチオカルバミン酸亜鉛、エチルフェニルジチオカルバミン酸亜鉛、ジエチルジチオカルバミン酸テルル、ジメチルジチオカルバミン酸セレン、ジエチルジチオカルバミン酸セレン、ジメチルジチオカルバミン酸銅、ジメチルジチオカルバミン酸鉄、ジエチルジチオカルバミン酸ジエチルアミン、ペンタメチレンジチオカルバミン酸ピペリジン、メチルペンタメチレンジチオカルバミン酸ピペコリン等のジチオカルバミン酸系架橋促進剤、
（ｇ）イソプロピルキサントゲン酸ナトリウム、イソプロピルキサントゲン酸亜鉛、ブチルキサントゲン酸亜鉛等のキサントゲン酸系架橋促進剤。
【００３８】
上記架橋促進剤は各々の種類のうちの１種のみを用いてもよいし、２種以上を併用することもでき、異なる種類のものを併用することもできる。尚、有機過酸化物を架橋剤として使用し、これに少量（有機過酸化物１００質量部に対して１〜５質量部、特に２〜４質量部）の硫黄を架橋助剤として組み合わせて用いることもできる。
【００３９】
上記架橋活性化剤としては、ステアリン酸等の高級脂肪酸及び酸化亜鉛等を使用することができる。酸化亜鉛としては、表面活性が高く、粒径が５μｍ以下のものが好ましい。そのような酸化亜鉛としては、粒径が０．０５〜０．２μｍの活性亜鉛華、あるいは０．３〜１μｍの亜鉛華等が挙げられる。また、アミン系の分散剤又は湿潤剤により表面処理した酸化亜鉛等を使用することもできる。これらの架橋活性化剤は、各々の種類のうちの１種のみを用いてもよいし、２種以上を併用することもでき、異なる種類のものを併用することもできる。架橋活性化剤は、その種類により適宜の配合量とすることができる。
【００４０】
尚、本発明のゴム組成物を得るための上記（Ａ）成分、（Ｂ−１）成分及び（Ｂ−２）成分の混合パターンについては、上記（Ｂ−１）成分を上記（Ｂ−２）成分中の金属成分により金属架橋することができる限り特に限定はない。例えば、上記（Ａ）成分と上記（Ｂ−１）成分とを混合し、得られた混合物と、上記（Ｂ−２）成分とを加熱混合してもよい。また、上記（Ａ）成分と上記（Ｂ−２）成分とを混合し、得られた混合物と、上記（Ｂ−１）成分とを加熱混合してもよい。更に、上記（Ａ）成分、（Ｂ−１）成分及び（Ｂ−２）成分を同時に加熱混合してもよい。
【００４１】
＜６＞用途・物性
本発明のゴム組成物は、上記構成を有することにより、十分な耐熱性及び耐久性を有すると共に、優れた防振性能を有する。例えば、実施例に記載の方法により測定した高温時（１２０℃）での引張強さＴ_Ｂが５．２ＭＰａ以上、好ましくは５．５ＭＰａ以上とし、切断時伸びＥ_Ｂ（％）が１７５％以上、好ましくは１８０％以上、更に好ましくは１９０％以上とすることができる。また、実施例に記載の方法により求めた静動比を１．３５以下、好ましくは１．３３以下、更に好ましくは１．３以下とすることができる。更に、実施例に記載の方法により求めた硬さの変化Ａ_Ｈを＋１０以下、好ましくは＋７以下、更に好ましくは＋５以下とすることができる。
【００４２】
本発明のゴム組成物をゴム成形品とする場合、通常、本発明のゴム組成物を用いて所定形状に成形した後、架橋剤（過酸化物等）と、必要に応じて架橋助剤（硫黄等）とを加えて上記（Ａ）成分の架橋を行う。本発明のゴム成形品は、架橋剤により、本発明のゴム組成物中の上記（Ａ）成分の架橋を行うことにより得られるものである。例えば、本発明のエンジンマウント用防振ゴムは、本発明のゴム組成物を用いてエンジンマウントの形状に成形した後、架橋剤（過酸化物等）と、必要に応じて架橋助剤（硫黄等）とを加えて上記（Ａ）成分の架橋を行って、エンジンマウント用防振ゴムとする。上記架橋剤及び上記架橋助剤は、上述の架橋剤及び架橋助剤を用いることができる。
【００４３】
本発明のゴム成形品としては、例えば、エンジンマウント、マフラーハンガー等の防振ゴム類、ダイヤフラム、ロール、ラジエータホース、エアーホース等の各種ホース類及びホースカバー類、パッキン、ガスケット、ウェザーストリップ、Ｏ−リング、オイルシール等のシール類、ベルト、ライニング、ダストブーツ等が挙げられる。上記のように、本発明のゴム組成物は、十分な耐熱性及び耐久性を有すると共に、優れた防振性能を有することから、本発明のゴム成形品としては、防振ゴム、特に、エンジンマウント用防振ゴムのように、高温状態となる環境下で使用する防振ゴムに好適である。
【００４４】
＜７＞ゴム組成物及び成形品の製造方法
本発明のゴム組成物の製造方法では、上記（Ｂ−１）成分と上記（Ｂ−２）成分とを加熱混合して上記（Ｂ）架橋物を調製する。これにより、上記（Ｂ−１）成分を金属架橋させることができるので好ましい。上記（Ｂ−１）成分と上記（Ｂ−２）成分とを加熱混合する場合の条件については特に限定はなく、必要に応じて種々の条件とすることができる。通常、加熱温度は１５０〜２２０℃、好ましくは１５０〜２００℃である。また、混合時間は通常５分以内、好ましくは１〜５分である。かかる範囲とすることにより、上記（Ｂ−１）成分の金属架橋が好適に進行し、静動比を向上させると共に、高温時の物性、特に高温時の伸び及び伸張疲労性を改善することができるので好ましい。また、混合方法としては、バンバリーミキサー又はミキシングロール等を用いて混合する方法等が挙げられる。この段階で、必要に応じて他の成分を添加し、混合してもよい。
【００４５】
次いで、上記方法により得られた混合物と、上記（Ａ）成分とを混合する。この場合の混合条件についても特に限定はない。通常、加熱温度は５０〜１００℃、好ましくは６０〜８０℃である。また、混合時間は通常５分以内、好ましくは１〜５分である。また、この段階でも、必要に応じて他の成分を添加し、混合してもよい。
【００４６】
また、本発明の他のゴム組成物の製造方法のように、上記（Ａ）成分、上記（Ｂ−１）成分、及び上記（Ｂ−２）成分を同時に加熱混合してもよい。かかる混合によっても、上記（Ｂ−１）成分を金属架橋させることができるので好ましい。この場合の加熱混合する場合の条件については特に限定はなく、必要に応じて種々の条件とすることができる。通常、加熱温度は１５０〜２２０℃、好ましくは１５０〜２００℃である。また、混合時間は通常５分以内、好ましくは１〜５分である。かかる範囲とすることにより、上記（Ｂ−１）成分の金属架橋が好適に進行し、静動比を向上させると共に、高温時の物性、特に高温時の伸び及び伸張疲労性を改善することができるので好ましい。また、混合方法としては、上記の同様の方法で行うことができる。
【００４７】
その他、上記（Ａ）成分、上記（Ｂ−１）成分、及び上記（Ｂ−２）成分の混合パターンについては、上記（Ｂ−１）成分を上記（Ｂ−２）成分により架橋することができる限り特に限定はない。例えば、上記（Ａ）成分と上記（Ｂ−１）成分とを混合し、得られた混合物と、上記（Ｂ−２）成分とを加熱混合してもよい。また、上記（Ａ）成分と上記（Ｂ−２）成分とを混合し、得られた混合物と、上記（Ｂ−１）成分とを加熱混合してもよい。
【００４８】
その後、必要に応じて過酸化物とを混練りすることにより、上記（Ａ）成分の架橋を行うことができる。この場合の混練り条件としては、通常、温度は４０〜８０℃、好ましくは５０〜７０℃であり、混練り時間は通常１０分以内、好ましくは５分以内である。また、この段階において、その他の添加剤を配合してもよい。
【００４９】
本発明のゴム成形品の製造方法は、本発明のゴム組成物と架橋剤とを混合することにより、本発明のゴム組成物中の上記（Ａ）成分の架橋を行うことにより得られるものである。この場合、必要に応じて架橋助剤を加えてもよい。上記架橋剤及び上記架橋助剤は、上述の架橋剤及び架橋助剤を用いることができる。この場合の混合条件としては、通常、温度は４０〜８０℃、好ましくは５０〜７０℃であり、混合時間は通常１０分以内、好ましくは５分以内である。混合方法としては、バンバリーミキサ又はミキシングロール等を用いて混合する方法等が挙げられる。また、この段階において、その他の添加剤を配合してもよい。
【００５０】
【実施例】
以下、実施例を挙げて、本発明を更に具体的に説明する。尚、本発明は、これらの実施例に何ら制約されるものではない。また、実施例中の「％」及び「部」は、特に断らない限り重量基準である。
（１）ゴム組成物の調製
以下に示す配合成分を表１に記載した割合で１．７リットルのバンバリーミキサー及び６インチのオープンロールで混練りし、各ゴム組成物を得た。即ち、以下の配合成分中、（Ｂ−１）成分及び（Ｂ−２）成分をバンバリーミキサーを用いて１８０℃で３分間混練りして（Ｂ）架橋物を得た。次いで、該（Ｂ）架橋物と（Ａ）成分及びその他の成分とを７０℃で５分間混練りして、混合物１を得た。その後、該混合物１とその他の成分である架橋剤及び架橋助剤とを上記オープンロールにより、５０〜７０℃で５分間混練りして、実施例１〜８及び比較例１〜５の各ゴム組成物を得た。
【００５１】
（Ａ）成分
▲１▼ＥＰＤＭ；ＪＳＲ社製 商品名「Ｔ７５０１ＥＦ」
▲２▼天然ゴム；ＲＳＳ１号（国際規格）
（Ｂ−１）成分
▲１▼無水マレイン酸変性ＥＰＭ；ＪＳＲ社製 商品名「Ｔ７７６１Ｐ」
▲２▼カルボン酸変性ＥＰＤＭ；ＪＳＲ社製 試作カルボン酸変性ＥＰＤＭ
（Ｂ−２）成分
▲１▼酸化亜鉛；白水化学工業社製 商品名「酸化亜鉛２種」
▲２▼ステアリン酸亜鉛；和光純薬工業社製 商品名「ステアリン酸亜鉛」
▲３▼水酸化マグネシウム；協和化学工業社製 商品名「キスマ５ＮＨ」
▲４▼ステアリン酸マグネシウム；和光純薬工業社製 商品名「ステアリン酸マグネシウム」
その他の成分
▲１▼老化防止剤；チバガイギー社製 商品名「イルガノックス１０１０」
大内新興化学工業社製 商品名「ノクラックＭＢ」
▲２▼ステアリン酸；花王社製 商品名「ルナックＳ３０」
▲３▼ＭＡＦカーボン；東海カーボン社製 商品名「シースト１１６」
▲４▼軟化剤；出光興産社製 商品名「ダイアナプロセスＰＷ３８０」
▲５▼架橋剤；日本油脂社製 商品名「パークミルＤ―４０」
▲６▼架橋助剤；鶴見化学工業社製 商品名「イオウ」
【００５２】
（２）性能評価
上記の方法により調製した実施例及び比較例の各ゴム組成物を１７０℃のプレス成型機により、プレス圧１５０ｋｇｆ／ｃｍ^２の圧力下で１０分間加熱して、厚さ２ｍｍの試験片（加硫シート）を作製した。また、以下の粘弾性試験に用いた試験片（加硫サンプル）は、上記の方法により調製した実施例及び比較例の各ゴム組成物を１０分間加熱することにより作製した。そして、得られた試験片を用い、以下に記載の方法により、性能評価を行った。その結果を表２に示す。
【００５３】
▲１▼引張試験
ＪＩＳ Ｋ６２５１に準拠し、３号型試験片を用い、測定温度２３℃、引張速度５００ｍｍ／分の条件で、引張強さＴ_Ｂ（ＭＰａ）及び切断時伸びＥ_Ｂ（％）を測定した（常態物性）。また、高温物性の評価は、槽内を１２０℃に調整し、試験片を槽内に５分保持した後、上記条件で測定した。
▲２▼硬さ試験
ＪＩＳ Ｋ６２５３に準拠し、試験片のスプリング硬さ（デュロメーターＡ硬度）を測定した。
▲３▼粘弾性（ＲＤＡ）試験
ＪＩＳ Ｋ６３９４に準拠し、ブロック状の試験片を用い、レオメトリックス社製「レオメトリックスダイナミックアナライザー（ＲＤＡ）」により、動的歪０．５％、温度２５℃の条件で、１Ｈｚ及び７０Ｈｚでの動的弾性率を測定した。そして、以下の式により、静動比を算出した。
静動比＝（７０Ｈｚ時の動的弾性率）／（１Ｈｚの動的弾性率）
▲４▼伸張疲労試験
インフィニットニシ社製、１６連ゴム疲労試験機にて、３号型試験片を用い、初期ひずみ０％、伸張率１００％、温度１２０℃の条件で繰り返し伸張疲労を実施し、破断回数を測定した。
▲５▼耐熱老化性試験
ＪＩＳ Ｋ６２５７に準拠し、１４０℃、２００時間の条件でノーマルオーブン法にて耐熱老化性試験を行い、硬さの変化Ａ_Ｈ（ポイント）、引張強さＴ_Ｂ及び破断時伸びＥ_Ｂの変化（Ａ_Ｃ、（％））を算出した。このＡ_Ｃ及びＡ_Ｈが０に近いほど、耐熱性に優れていることになる。
【００５４】
【表１】

【００５５】
【表２】

【００５６】
表１及び表２より、本発明の範囲内である実施例１〜８はいずれも、引張試験、硬さ試験、静動比、伸張疲労試験及び耐熱老化試験の値が好適な範囲にあり、防振特性、耐久性及び耐熱性のバランスに優れたゴム組成物であることが分かる。
【００５７】
一方、表１及び表２より、単なるＥＰＤＭのみで構成される比較例１は、耐熱老化試験は実施例とほぼ同程度の値を示し、耐熱性に優れている反面、引張試験においてＥＢ、特に高温時のＥＢの値が小さい。また、伸張疲労試験の値も小さいことから、耐久性も十分でないことが分かる。また、天然ゴムのみで構成される比較例５は、比較例１とは逆に、引張試験においてＥＢ、特に高温時のＥＢの値が大きく、静動比が小さいことから、防振特性に優れている反面、耐熱老化性試験では硬化劣化を引き起こし、耐熱性に劣ることが分かる。更に、単にＥＰＤＭと天然ゴムとを併用したに過ぎない比較例４では、防振特性に若干改善傾向が認められるが、伸張疲労試験の値が小さく、耐熱老化性試験のＡＨが大きいことから、耐久性及び耐熱性に依然として劣るものであることが分かる。
【００５８】
また、（Ｂ−２）成分を含有しない比較例２及び（Ｂ−１）成分の含有量が少なすぎる比較例３では、比較例１と同様に、耐熱性に優れている反面、引張試験においてＥＢ、特に高温時のＥＢの値が小さい。また、伸張疲労試験の値も小さいことから、耐久性も十分でないことが分かる。よって、耐熱性、耐久性及び防振特性の全てについて、バランスよく優れたゴム組成物とするには、（Ｂ−１）成分及び（Ｂ−２）成分を適切な含有量の範囲となるようにして併用することが重要であることが分かる。
【００５９】
【発明の効果】
本発明のゴム組成物は、上記構成を有することにより、防振性能に優れると共に、十分な耐熱性を有することから、本発明のエンジンマウント用防振ゴムのように、エンジンマウント等の高温状態となる環境において、好適に使用することができる。更に、本発明のゴム組成物の製造方法によれば、上記有用な作用効果を有するゴム組成物を容易に得ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rubber composition and a production method thereof, and a rubber molded article and a production method thereof. More specifically, the present invention relates to a rubber composition having sufficient heat resistance and durability and excellent vibration-proof performance, a method for producing the same, a rubber molded product, and a method for producing the same. The rubber composition and molded product of the present invention are used in various industrial applications, for example, anti-vibration rubbers such as engine mounts and muffler hangers, various hoses such as diaphragms, rolls, radiator hoses, air hoses, hose covers, packings, etc. It can be used for gaskets, weather strips, O-rings, seals such as oil seals, industrial products such as belts, linings, dust boots, civil engineering materials, fuel cells, electronic parts, aircraft and automobile parts. . Moreover, it can utilize also for the use of the modifier of another thermoplastic resin or rubber | gum.
[0002]
[Prior art]
Diene rubbers, particularly natural rubber (NR), have sufficient mechanical properties and excellent fatigue properties. Therefore, diene rubber has been widely used as a vibration-proof rubber. And the anti-vibration rubber is often used in various harsh environments such as a high temperature state. For example, an engine mount is in a high temperature state due to a temperature rise in the engine room. Anti-vibration rubber used in such high temperature environment is required to have both anti-vibration performance and heat resistance. However, since diene rubber is not sufficient in terms of heat resistance, it is difficult to use it in an environment that is in a high temperature state, and there is a problem that applications are limited.
[0003]
On the other hand, ethylene-α-olefin copolymer rubber has good heat resistance and weather resistance. Therefore, ethylene-α-olefin copolymer rubber is used in a wide range of applications such as automobile parts, wire coating materials, electrical insulation materials, general industrial rubber products, and civil engineering materials. It is also used as a modifier for various plastics such as polypropylene and polystyrene. However, ethylene-α-olefin copolymer rubber does not have sufficient mechanical properties, vibration-proofing properties, etc., for example, those that sufficiently satisfy the properties required for applications such as vibration-proofing rubbers and vibration damping materials can be obtained. Not.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and provides a rubber composition having sufficient heat resistance and durability, and excellent in vibration-proof performance, a manufacturing method thereof, a rubber molded product, and a manufacturing method thereof. For the purpose.
[0005]
[Means for Solving the Problems]
The rubber composition of the present invention comprises (A) an ethylene-α-olefin copolymer rubber and (B) (B-1) -containing (co) polymer. By adding 0.05 to 5 parts by mass of (B-2) a metal compound to 100 parts by mass of the polymer, the (B-1) functional group-containing (co) polymer is converted to the (B-2) metal. A crosslinked product crosslinked with a metal component in the compound, and a total of 100 parts by mass of the (A) ethylene-α-olefin copolymer rubber and the (B-1) functional group-containing (co) polymer. When the content of the (A) ethylene-α-olefin copolymer is 50 to 99 parts by mass, the content of the (B-1) functional group-containing (co) polymer is 1 to 50 parts by mass. Ah Thus, the functional group contained in the (B-1) functional group-containing (co) polymer contains at least a carboxyl group and constitutes the (B-1) functional group-containing (co) polymer (co). The polymer is styrene-butacene rubber, butadiene rubber, acrylonitrile-butadiene rubber, ethylene-propylene-diene rubber, or a hydrogenated product thereof. The (B-2) metal compound is a metal oxide and / or a fatty acid metal salt. And the metal is one or more selected from alkaline earth metals and zinc It is characterized by that.
[0006]
The rubber composition of the present invention comprises (B-2) metal for (B-1) functional group-containing (co) polymer and 100 parts by mass of (B-1) functional group-containing (co) polymer. (B) a crosslinked product is prepared by heating and mixing 0.05 to 5 parts by mass of a compound, and then the (B) crosslinked product and the (A) ethylene-α-olefin copolymer rubber, It can be obtained by mixing.
[0007]
Rubber molded product of the present invention , Anti-vibration rubber molded products, and anti-vibration rubber molded products for engine mounts Is characterized in that the (A) ethylene-α-olefin copolymer rubber in the rubber composition of the present invention is crosslinked with a crosslinking agent.
[0008]
The production method of the rubber composition of the present invention comprises (B-1) a functional group-containing (co) polymer and (B-1) 100 parts by mass of the functional group-containing (co) polymer (B-2). ) 0.05 to 5 parts by mass of a metal compound is heated and mixed to prepare a (B) crosslinked product, and then the (B-1) functional group-containing (co) polymer and (A) ethylene-α. When the total content of the olefin copolymer rubber is 100 parts by mass, the content of the (A) ethylene-α-olefin copolymer is 50 to 99 parts by mass, and the functional group (B-1) is contained ( The (B) crosslinked product and the (A) ethylene-α-olefin copolymer rubber are mixed so that the content of the (co) polymer is 1 to 50 parts by mass. The functional group contained in the (B-1) functional group-containing (co) polymer contains at least a carboxyl group and constitutes the (B-1) functional group-containing (co) polymer (co). The polymer is styrene-butacene rubber, butadiene rubber, acrylonitrile-butadiene rubber, ethylene-propylene-diene rubber, or a hydrogenated product thereof. The (B-2) metal compound is a metal oxide and / or a fatty acid metal salt. And the metal is one or more selected from alkaline earth metals and zinc It is characterized by that.
[0009]
Rubber molded product of the present invention , Anti-vibration rubber molded products, and anti-vibration rubber molded products for engine mounts This production method is characterized in that the above-mentioned (A) ethylene-α-olefin copolymer rubber is crosslinked by adding a crosslinking agent to the rubber composition of the present invention.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
<1> (A) Ethylene-α-olefin copolymer rubber
The (A) ethylene-α-olefin copolymer rubber (hereinafter sometimes simply referred to as “component (A)”) of the present invention comprises, as repeating units, an ethylene unit and a repeating unit composed of an α-olefin. Have. By containing the component (A), the rubber composition of the present invention can improve heat resistance and weather resistance as compared with a diene rubber, particularly natural rubber (NR). The component (A) may be used alone or in combination of two or more.
[0011]
As said alpha olefin, a C3-C12 alpha olefin is used normally. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 5-methyl-1-hexene, 1-octene, 1-nonene, Examples include 5-ethyl-1-hexene, 1-decene, 1-dodecene, and 3-methyl-1-butene. Among these, propylene, 1-butene, 1-hexene, and 1-octene are preferable. The said alpha olefin may use only 1 type and may use 2 or more types together.
[0012]
In addition to the ethylene unit and the repeating unit composed of an α-olefin, the component (A) may further have a repeating unit composed of a non-conjugated diene. In this case, the said nonconjugated diene may use only 1 type, and may use 2 or more types together. Examples of the non-conjugated diene include linear acyclic dienes such as 1,4-hexadiene, 1,6-hexadiene and 1,5-hexadiene; 5-methyl-1,4-hexadiene, 3,7-dimethyl Branched chains such as -1,6-octadiene, 5,7-dimethylocta-1,6-diene, 3,7-dimethyl-1,7-octadiene, 7-methylocta-1,6-diene, and dihydromyrcene Acyclic dienes of: tetrahydroindene, methyltetrahydroindene, dicyclopentadiene, bicyclo- (2,2,1) -hepta-2,5-diene, 5-methylene-2-norbornene, 5-ethylidene-2-norbornene, 5-propenyl-2-norbornene, 5-isopropylidene-2-norbornene, 5-cyclohexylidene-2-norbornene, and - alicyclic dienes such as vinyl-2-norbornene. Particularly preferred examples of the non-conjugated diene include 1,4-hexadiene, dicyclopentadiene, and 5-ethylidene-2-norbornene.
[0013]
Specific examples of the component (A) include ethylene-propylene copolymer rubber, ethylene-1-butene copolymer rubber, ethylene-1-pentene copolymer rubber, ethylene-1-hexene copolymer rubber, and ethylene-1. -An octene copolymer rubber etc. are mentioned. Further, examples of the copolymer rubber having a non-conjugated diene unit include ethylene-propylene-5-ethylidene-2-norbornene.
[0014]
Content of the said (A) component in the rubber composition of this invention made the sum total of content of the said (A) component and the below-mentioned (B-1) functional group containing (co) polymer 100 mass parts. In this case, 40 to 99 parts by mass, preferably 50 to 99 parts by mass, preferably 55 to 99 parts by mass, more preferably 65 to 97 parts by mass, more preferably 70 to 97 parts by mass, particularly preferably 75 to 97 parts by mass. Most preferably, it is 80-95 mass parts. When the content of the component (A) is less than 40 parts by mass, sufficient heat resistance and weather resistance cannot be obtained, which is not preferable. On the other hand, when the content of the component (A) exceeds 99 parts by mass, the content of the (B-1) functional group-containing (co) polymer described later becomes too small. It is not preferable because the elongation and elongation fatigue resistance of the resin cannot be improved.
[0015]
<2> (B-1) Functional group-containing (co) polymer
The (B-1) functional group-containing (co) polymer constituting the (B) cross-linked product contained in the rubber composition of the present invention (hereinafter also referred to simply as “(B-1) component”). Is a polymer having a structure in which a functional group is contained in the polymer. By containing the component (B-1), the static / dynamic ratio can be improved, and physical properties at high temperatures, particularly elongation and elongation fatigue properties at high temperatures can be improved. This is considered to be a result of metal cross-linking caused by the metal in (B-2) metal compound described later. The said (B-1) component may be used individually by 1 type, or may be used 2 or more types. When two or more kinds are used, two or more kinds of (co) polymers that are the same base and different functional groups may be used, or the (co) polymers that are the bases are different, but the functional groups are the same. Two or more kinds may be used.
[0016]
There is no particular limitation on the type and structure of the (co) polymer constituting the component (B-1). The (co) polymer may be a homopolymer or a copolymer. Examples of the (co) polymer include SBR, BR, NBR, EPDM, and the like. A hydrogenated product obtained by partially or selectively hydrogenating a (co) polymer such as SBR, BR, NBR, or EPDM can also be used as the (co) polymer. Examples of the hydrogenated product that can be used as the (co) polymer include a styrene ethylene / butene styrene hydrogenated block copolymer, a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene, and the like. . The hydrogenation method and reaction conditions are not particularly limited. Usually, it is carried out by hydrogenation in the presence of a hydrogenation catalyst under 20 to 150 ° C. and hydrogen pressure of 0.1 to 10 MPa. In this case, the hydrogenation rate can be arbitrarily selected by changing the amount of the hydrogenation catalyst, the hydrogen pressure during the hydrogenation reaction, or the reaction time. In addition, the hydrogenation catalyst is usually a compound containing any one of Group Ib, IVb, Vb, VIb, VIIb, and Group VIII metals, such as Ti, V, Co, Ni, Zr, Ru, Rh, Pd. , Hf, Re, and a compound containing a Pt atom can be used. Specific examples of the hydrogenation catalyst include metallocene compounds such as Ti, Zr, Hf, Co, Ni, Pd, Pt, Ru, Rh, and Re, and metals such as Pd, Ni, Pt, Rh, and Ru. Homogeneous Ziegler type that combines a supported heterogeneous catalyst supported on a carrier such as carbon, silica, alumina, or diatomaceous earth, an organic salt of a metal element such as Ni or Co, or an acetylacetone salt and a reducing agent such as organoaluminum. Examples include catalysts, organometallic compounds or complexes such as Ru and Rh, and fullerenes and carbon nanotubes in which hydrogen is occluded.
[0017]
Among these, a metallocene compound containing any of Ti, Zr, Hf, Co, and Ni is preferable in that it can be hydrogenated in a homogeneous system in an inert organic solvent. Furthermore, a metallocene compound containing any of Ti, Zr, and Hf is preferable. In particular, a hydrogenation catalyst obtained by reacting a titanocene compound with an alkyl lithium is preferable because it is an inexpensive and industrially useful catalyst. Specific examples include, for example, JP-A-1-275605, JP-A-5-271326, JP-A-5-271325, JP-A-5-222115, JP-A-11-292924, and JP-A-11-292924. JP 2000-37632 A, JP 59-133203 A, JP 63-5401 A, JP 62-218403 A, JP 7-90017 A, JP 43-19960 A, Examples thereof include the hydrogenation catalyst described in JP-B 47-40473. In addition, the said hydrogenation catalyst may be used only 1 type, or can also use 2 or more types together.
[0018]
The functional group contained in the component (B-1) is not particularly limited as long as it has the property of being capable of metal crosslinking with the metal contained in the metal compound (B-2) described later. Examples of such a functional group include a carboxyl group, an alkoxysilyl group, an epoxy group, an amino group, a hydroxyl group, a sulfonic acid group, a halogen (fluorine, chlorine, bromine or one or more of elements), an oxazoline group, Preferred is at least one selected from an isocyanate group and a thiol group. Here, the carboxyl group includes not only a normal carboxyl group (—COOH) but also a group that generates a carboxyl group by hydrolysis, for example, the following anhydrous carboxyl group, ester group, amide group, and the like. Moreover, there is no limitation in particular also about the position of the said functional group, You may be located in the terminal or may be located in places other than the terminal.
[0019]
[Chemical 1]

[0020]
Specifically, as the component (B-1), one or more of carboxylic acid-modified ethylene propylene diene terpolymer (EPDM), particularly maleic anhydride-modified ethylene propylene copolymer (EPM) is preferable. Can be mentioned.
[0021]
The method for obtaining the component (B-1), that is, the method for incorporating a functional group in the (co) polymer is not particularly limited. For example, (1) a method of introducing by polymerization using a polymerization initiator having a functional group, (2) a method of introducing by reacting an unsaturated monomer having a functional group, and (3) ( Examples thereof include a method of introducing a polymerization terminator having a functional group at the active site of the (co) polymer by reaction. Each of the above methods may be performed alone or in combination with the above methods.
[0022]
Content of the said (B-1) component in the rubber composition of this invention is 1-60 masses when the sum total of content of the said (A) component and the said (B-1) component is 100 mass parts. Parts, preferably 1-50 parts by weight, preferably 1-45 parts by weight, more preferably 3-35 parts by weight, more preferably 3-30 parts by weight, particularly preferably 3-25 parts by weight, most preferably 5-5 parts by weight. 20 parts by mass. When the content of the component (B-1) is less than 1 part by mass, the physical properties at high temperatures, particularly elongation and elongation fatigue at high temperatures cannot be improved, which is not preferable. On the other hand, when the content of the component (B-1) exceeds 60 parts by mass, it is not preferable because sufficient heat resistance and weather resistance cannot be obtained. In addition, content of the said (B-1) component means the quantity of the said (B-1) component used when obtaining the said (B) crosslinked material of this invention.
[0023]
<3> (B-2) Metal compound
In the present invention, by including the above-mentioned (B-2) metal compound (hereinafter, sometimes simply referred to as “component (B-2)”), the static-motion ratio is improved, and physical properties at high temperature, particularly Elongation at high temperature and elongation fatigue can be improved. This is considered to form a metal bridge with the component (B-1) as described above. In the present invention, “(B-2) containing a metal compound” is not only present in the form of a metal compound in the rubber composition, but is added as a metal compound and is ionized in the rubber composition. This includes cases where they exist in a dissociated state.
[0024]
The component (B-2) is not particularly limited as long as it can generate metal ions after addition. For example, a metal inorganic compound or an organic metal salt may be used. Moreover, the said (B-2) component may be used individually by 1 type, and may be used together 2 or more types. That is, one or more metal inorganic compounds or organic metal salts may be used alone, or one or more metal inorganic compounds and one or more organic metal salts may be used in combination. As said metal inorganic compound, 1 type (s) or 2 or more types, such as a metal oxide and a metal hydroxide, are mentioned, for example. Also, the type of metal is not particularly limited, and examples of the metal inorganic compound include alkali metal (lithium, sodium, potassium, etc.) compounds, alkaline earth metal (magnesium, calcium, barium, etc.) compounds, aluminum compounds, zinc The 1 type (s) or 2 or more types chosen from a compound, an iron compound, a titanium compound, etc. are mentioned. The said metal inorganic compound may be used individually by 1 type, and may be used together 2 or more types.
[0025]
Examples of the organic metal salt include fatty acid metal salts. Such fatty acid metal salts are preferred because they are easily dispersed uniformly. There is no limitation in particular about the kind of the said fatty acid, Fatty acids of various structures, such as a saturated fatty acid and an unsaturated fatty acid, can be used. Usually, as said fatty acid, C1-C25, Preferably it is 5-25, More preferably, it is 10-23, More preferably, it is 13-23. Specific examples of the fatty acid include stearic acid. Moreover, there is no limitation in particular also about the kind of metal salt. For example, one or more of alkali metal salts (potassium salts, sodium salts, etc.), alkaline earth metal salts (magnesium salts, barium salts, calcium salts, etc.), aluminum salts, zinc salts, iron salts, titanium salts, etc. Is mentioned. Specifically, fatty acid alkali metal salts (potassium salt, sodium salt, etc.), fatty acid alkaline earth metal salts (magnesium salt, barium salt, calcium salt, etc.), fatty acid aluminum salt, fatty acid zinc salt, fatty acid iron salt and fatty acid titanium 1 type or 2 types or more, such as a salt, is mentioned. More specific examples of the fatty acid metal salt include magnesium stearate and / or zinc stearate.
[0026]
In the present invention, the ratio of the component (B-2) is 0.05 to 5 parts by mass, preferably 0.05 to 3 parts by mass, and more preferably 0 with respect to 100 parts by mass of the component (B-1). 0.05 to 2 parts by mass, more preferably 0.05 to 1.5 parts by mass, particularly preferably 0.1 to 1.5 parts by mass, and most preferably 0.1 to 1.3 parts by mass. When the proportion of the component (B-2) is less than 0.05 parts by mass, metal crosslinking with the component (B-1) does not proceed sufficiently, and physical properties at high temperatures, particularly elongation and elongation fatigue at high temperatures. It is not preferable because the improvement of the property is not sufficient. On the other hand, when the proportion of the component (B-2) exceeds 5 parts by mass, the metal crosslinking proceeds excessively, and the strength and elongation during normal conditions are reduced, which is not preferable.
[0027]
As said (B-2) component, you may use together at least 1 sort (s) of the said metal inorganic compound, and at least 1 sort (s) of said organometallic salts, such as a fatty-acid metal salt. Moreover, when using the said metal inorganic compound and said organic metal salts, such as a fatty-acid metal salt together, there is no limitation in particular about the ratio of both, It can be made into various ranges according to the characteristic of the required rubber composition. it can. The ratio between the metal inorganic compound and the organic metal salt such as a fatty acid metal salt is usually 1: (1 to 10) by weight, more preferably 1: (1 to 7), and still more preferably 1: (1-5).
[0028]
<4> (B) Cross-linked product
The (B) crosslinked product (hereinafter sometimes simply referred to as “component (B)”) contained in the rubber composition of the present invention is obtained by replacing the component (B-1) with the component (B-2). It is a component cross-linked by a metal component. The component (B) is usually obtained by heating and mixing the component (B-1) and the component (B-2). There are no particular limitations on the conditions in this case, and various conditions may be used as necessary. Usually, heating temperature is 150-220 degreeC, Preferably it is 150-200 degreeC. The mixing time is usually within 5 minutes, preferably 1 to 5 minutes. By setting it as such a range, the metal cross-linking of the component (B-1) suitably proceeds and improves the static / dynamic ratio, and improves physical properties at high temperatures, particularly elongation and elongation fatigue at high temperatures. It is preferable because it is possible. Moreover, as a mixing method, a closed mixer represented by a Banbury mixer, an extruder capable of continuous mixing, or the like can be used.
[0029]
<5> Other ingredients
Furthermore, the rubber composition of the present invention may contain a rubber component other than the components (A) and (B-1) as long as the object of the present invention is not impaired. Examples of such a rubber component include SBR, BR, isoprene rubber (IR), and NR that do not have a functional group. However, when NR is blended in a large amount, the heat resistance of the rubber composition may be lowered. Therefore, when NR is contained, the content is preferably 15 parts by mass or less. In addition, various additives can be appropriately added to the rubber composition of the present invention as necessary within a range not impairing the object of the present invention. Examples of the additive include fatty acid salts other than the fatty acid metal salt corresponding to the component (B-2) of the present invention, reinforcing agents, rubber extending oils, fillers, crosslinking agents, crosslinking accelerators, and crosslinking activators. Etc.
[0030]
Examples of fatty acid salts other than the fatty acid metal salt corresponding to the component (B-2) of the present invention include fatty acid ammonium salts. There is no limitation in particular about the kind of the said fatty acid, Fatty acids of various structures, such as a saturated fatty acid and an unsaturated fatty acid, can be used. Usually, as said fatty acid, C1-C25, Preferably it is 5-25, More preferably, it is 10-23, More preferably, a 13-23 fatty acid is mentioned. Specific examples of the fatty acid include stearic acid. By containing this fatty acid salt, the component (B-2) can be uniformly dispersed, which is preferable.
[0031]
As the reinforcing agent, carbon black and silica can be used. Moreover, the said reinforcing agent may be used individually by 1 type, and may use 2 or more types together. For example, the above carbon black or silica may be used alone, or silica and carbon black may be used in combination.
[0032]
The type of the carbon black is not particularly limited, and examples thereof include furnace black, acetylene black, thermal black, channel black, and graphite. Of these, furnace black is particularly preferable, and specific examples thereof include MT, SRF, GPF, MAF, FEF, SAF, ISAF, ISAF-HS, ISAF-LS, IISAF-HS, HAF, HAF-HS, and HAF-. LS etc. are mentioned. These carbon blacks may be used alone or in combination of two or more. Moreover, the nitrogen adsorption specific surface area of carbon black measured by the BET method in accordance with ASTM D3037-81 is not particularly limited, but in order to sufficiently improve the tensile strength and the like of the crosslinked rubber, it is 5 to 200 m. ² / G, especially 50-150m ² / G, and 80-130m ² / G is preferable. Also, the DBP adsorption amount of carbon black is not particularly limited, but in order to sufficiently improve the strength and the like of the crosslinked rubber, it is 5 to 300 ml / 100 g, particularly 50 to 200 ml / 100 g, and further 80 to 160 ml / 100 g. It is preferable.
[0033]
As said silica, what is generally used as a light color reinforcement compounding agent of a synthetic rubber can be used. The kind etc. are not specifically limited, Wet method white carbon, dry method white carbon, colloidal silica, etc. can be used. Among these, wet method white carbon mainly containing hydrous silicic acid is preferable. These silica compounds may be used alone or in combination of two or more. Although the nitrogen adsorption specific surface area measured by BET method based on ASTM D3037-81 of silica is not particularly limited, it is usually 50 to 400 m. ² / G, especially 50-220m ² / G, and 70-220m ² / G is preferable.
[0034]
As the rubber extending oil, a paraffinic process oil, an aromatic process oil, a naphthenic process oil, or the like, which is a petroleum-based blended oil, can be used. As the rubber extending oil, paraffinic process oil is preferable.
[0035]
As said filler, talc, clay, a calcium carbonate, magnesium carbonate, etc. can be mix | blended an appropriate quantity.
[0036]
Examples of the crosslinking agent include organic peroxides such as dicumyl peroxide and di-t-butyl peroxide, sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur, sulfur monochloride, Sulfur halides such as sulfur chloride, p-quinone dioxime, quinone dioximes such as p, p'-dibenzoylquinone dioxime, triethylenetetramine, hexamethylenediamine carbamate, 4,4'-methylenebis-o-chloroaniline An organic polyvalent amine compound such as an alkylphenol resin having a methylol group can be used. As the crosslinking agent, only one kind of each kind may be used, two or more kinds may be used in combination, and different kinds may be used in combination.
[0037]
As the crosslinking accelerator, the following various types can be used.
(A) N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N-oxyethylene-2-benzo Sulfenamide crosslinking accelerators such as thiazole sulfenamide, N, N′-diisopropyl-2-benzothiazole sulfenamide,
(B) Guanidine-based crosslinking accelerators such as diphenylguanidine, diortolylguanidine, orthotolylbiguanidine,
(C) thiourea-based crosslinking accelerators such as thiocarboanilide, diortolylthiourea, ethylenethiourea, diethylthiourea, and trimethylthiourea;
(D) 2-mercaptobenzothiazole, dibenzothiazyl disulfide, 2-mercaptobenzothiazole zinc salt, 2-mercaptobenzothiazole sodium salt, 2-mercaptobenzothiazolecyclohexylamine salt, 2- (2,4-dinitrophenylthio) Thiazole-based crosslinking accelerators such as benzothiazole,
(E) a thiuram crosslinking accelerator such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, dipentamethylenethiuram tetrasulfide,
(F) Sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodium di-n-butyldithiocarbamate, lead dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc di-n-butyldithiocarbamate, pentamethylenedithiocarbamate Zinc, zinc ethylphenyldithiocarbamate, tellurium diethyldithiocarbamate, selenium dimethyldithiocarbamate, selenium diethyldithiocarbamate, copper dimethyldithiocarbamate, iron dimethyldithiocarbamate, diethylaminediethyldithiocarbamate, piperidine dipentadidicarbamate, piperidine methylpentamethylenedithiocarbamate Dithiocarbamic acid crosslinking accelerators such as
(G) Xantogenic acid-based crosslinking accelerators such as sodium isopropylxanthate, zinc isopropylxanthate, and zinc butylxanthate.
[0038]
As the crosslinking accelerator, only one kind of each kind may be used, two or more kinds may be used in combination, and different kinds may be used in combination. In addition, an organic peroxide is used as a crosslinking agent, and a small amount (1 to 5 parts by mass, particularly 2 to 4 parts by mass with respect to 100 parts by mass of the organic peroxide) is used in combination as a crosslinking aid. You can also
[0039]
As the crosslinking activator, higher fatty acids such as stearic acid and zinc oxide can be used. Zinc oxide is preferably one having high surface activity and a particle size of 5 μm or less. Examples of such zinc oxide include active zinc white having a particle size of 0.05 to 0.2 μm, zinc white having a particle size of 0.3 to 1 μm, and the like. Further, zinc oxide surface-treated with an amine-based dispersant or wetting agent can also be used. These crosslinking activators may use only 1 type of each kind, can also use 2 or more types together, and can also use a different type together. A crosslinking activator can be made into a suitable compounding quantity with the kind.
[0040]
In addition, about the mixed pattern of said (A) component for obtaining the rubber composition of this invention, (B-1) component, and (B-2) component, said (B-1) component is said (B-2). There is no particular limitation as long as the metal can be cross-linked by the metal component in the component. For example, the component (A) and the component (B-1) may be mixed, and the resulting mixture may be heated and mixed with the component (B-2). Moreover, the said (A) component and the said (B-2) component may be mixed, and the obtained mixture and the said (B-1) component may be heat-mixed. Furthermore, you may heat-mix the said (A) component, (B-1) component, and (B-2) component simultaneously.
[0041]
<6> Applications and physical properties
The rubber composition of the present invention has sufficient heat resistance and durability as well as excellent vibration-proof performance by having the above configuration. For example, the tensile strength T at a high temperature (120 ° C.) measured by the method described in Examples. _B Is 5.2 MPa or more, preferably 5.5 MPa or more, and elongation at break E _B (%) Can be 175% or more, preferably 180% or more, and more preferably 190% or more. In addition, the static ratio obtained by the method described in the examples can be 1.35 or less, preferably 1.33 or less, more preferably 1.3 or less. Further, change in hardness A obtained by the method described in Examples _H Can be +10 or less, preferably +7 or less, more preferably +5 or less.
[0042]
When the rubber composition of the present invention is formed into a rubber molded product, it is usually molded into a predetermined shape using the rubber composition of the present invention, and then a crosslinking agent (peroxide, etc.) and a crosslinking assistant (if necessary) ( (Sulfur etc.) is added to crosslink the component (A). The rubber molded article of the present invention is obtained by crosslinking the component (A) in the rubber composition of the present invention with a crosslinking agent. For example, the anti-vibration rubber for an engine mount of the present invention is molded into the shape of an engine mount using the rubber composition of the present invention, and then a crosslinking agent (peroxide, etc.) and a crosslinking assistant (sulfur if necessary). Etc.) and the above component (A) is cross-linked to obtain an anti-vibration rubber for engine mounts. As the crosslinking agent and the crosslinking aid, the above-mentioned crosslinking agent and crosslinking aid can be used.
[0043]
As the rubber molded product of the present invention, For example, Anti-vibration rubbers such as engine mounts, muffler hangers, various hoses such as diaphragms, rolls, radiator hoses, air hoses and hose covers, seals such as packings, gaskets, weather strips, O-rings, oil seals, belts Lining, dust boots and the like. As described above, since the rubber composition of the present invention has sufficient heat resistance and durability and excellent vibration-proof performance, the rubber molded product of the present invention includes a vibration-proof rubber, particularly an engine. The anti-vibration rubber used in an environment where the temperature is high, such as the anti-vibration rubber for mounting, is suitable.
[0044]
<7> Manufacturing method of rubber composition and molded article
In the method for producing a rubber composition of the present invention, the component (B-1) and the component (B-2) are heated and mixed to prepare the crosslinked product (B). This is preferable because the component (B-1) can be metal-crosslinked. There is no limitation in particular about the conditions in the case of mixing the said (B-1) component and the said (B-2) component, and it can be set as various conditions as needed. Usually, heating temperature is 150-220 degreeC, Preferably it is 150-200 degreeC. The mixing time is usually within 5 minutes, preferably 1 to 5 minutes. By setting it as such a range, the metal cross-linking of the component (B-1) suitably proceeds and improves the static / dynamic ratio, and improves physical properties at high temperatures, particularly elongation and elongation fatigue at high temperatures. It is preferable because it is possible. Moreover, as a mixing method, the method of mixing using a Banbury mixer or a mixing roll etc. is mentioned. At this stage, other components may be added and mixed as necessary.
[0045]
Subsequently, the mixture obtained by the said method and the said (A) component are mixed. There is no particular limitation on the mixing conditions in this case. Usually, heating temperature is 50-100 degreeC, Preferably it is 60-80 degreeC. The mixing time is usually within 5 minutes, preferably 1 to 5 minutes. Also at this stage, other components may be added and mixed as necessary.
[0046]
Moreover, you may heat-mix the said (A) component, the said (B-1) component, and the said (B-2) component simultaneously like the manufacturing method of the other rubber composition of this invention. Such mixing is also preferable because the component (B-1) can be metal-crosslinked. There are no particular limitations on the conditions for heating and mixing in this case, and various conditions may be used as necessary. Usually, heating temperature is 150-220 degreeC, Preferably it is 150-200 degreeC. The mixing time is usually within 5 minutes, preferably 1 to 5 minutes. By setting it as such a range, the metal cross-linking of the component (B-1) suitably proceeds and improves the static / dynamic ratio, and improves physical properties at high temperatures, particularly elongation and elongation fatigue at high temperatures. It is preferable because it is possible. Moreover, as a mixing method, it can carry out by the same method as described above.
[0047]
In addition, regarding the mixed pattern of the component (A), the component (B-1), and the component (B-2), the component (B-1) may be crosslinked with the component (B-2). There is no particular limitation as much as possible. For example, the component (A) and the component (B-1) may be mixed, and the resulting mixture may be heated and mixed with the component (B-2). Moreover, the said (A) component and the said (B-2) component may be mixed, and the obtained mixture and the said (B-1) component may be heat-mixed.
[0048]
Thereafter, the component (A) can be crosslinked by kneading with a peroxide as necessary. As kneading conditions in this case, the temperature is usually 40 to 80 ° C., preferably 50 to 70 ° C., and the kneading time is usually within 10 minutes, preferably within 5 minutes. Moreover, you may mix | blend another additive in this step.
[0049]
The method for producing a rubber molded article of the present invention is obtained by crosslinking the component (A) in the rubber composition of the present invention by mixing the rubber composition of the present invention and a crosslinking agent. is there. In this case, a crosslinking aid may be added as necessary. As the crosslinking agent and the crosslinking aid, the above-mentioned crosslinking agent and crosslinking aid can be used. As mixing conditions in this case, the temperature is usually 40 to 80 ° C., preferably 50 to 70 ° C., and the mixing time is usually within 10 minutes, preferably within 5 minutes. Examples of the mixing method include a method of mixing using a Banbury mixer or a mixing roll. Moreover, you may mix | blend another additive in this step.
[0050]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not restrict | limited at all by these Examples. In the examples, “%” and “parts” are based on weight unless otherwise specified.
(1) Preparation of rubber composition
The compounding components shown below were kneaded at a ratio described in Table 1 with a 1.7 liter Banbury mixer and a 6 inch open roll to obtain each rubber composition. That is, in the following blending components, the component (B-1) and the component (B-2) were kneaded at 180 ° C. for 3 minutes using a Banbury mixer to obtain a crosslinked product (B). Next, the (B) crosslinked product, the component (A) and the other components were kneaded at 70 ° C. for 5 minutes to obtain a mixture 1. Thereafter, the mixture 1 and other components, ie, a crosslinking agent and a crosslinking aid, were kneaded at 50 to 70 ° C. for 5 minutes with the above open rolls, and rubbers of Examples 1 to 8 and Comparative Examples 1 to 5 were mixed. A composition was obtained.
[0051]
(A) component
(1) EPDM; product name “T7501EF” manufactured by JSR
(2) Natural rubber; RSS1 (International standard)
(B-1) Component
(1) Maleic anhydride-modified EPM; product name “T7761P” manufactured by JSR
(2) Carboxylic acid-modified EPDM; Prototype carboxylic acid-modified EPDM manufactured by JSR
(B-2) Component
(1) Zinc oxide; manufactured by Hakusui Chemical Industry Co., Ltd.
(2) Zinc stearate: Wako Pure Chemical Industries, Ltd. Trade name “Zinc stearate”
(3) Magnesium hydroxide; manufactured by Kyowa Chemical Industry Co., Ltd. “Kisuma 5NH”
(4) Magnesium stearate; product name “magnesium stearate” manufactured by Wako Pure Chemical Industries, Ltd.
Other ingredients
(1) Anti-aging agent: Product name “Irganox 1010” manufactured by Ciba Geigy
Product name “NOCRACK MB” manufactured by Ouchi Shinsei Chemical Co., Ltd.
(2) Stearic acid; product name “Lunac S30” manufactured by Kao Corporation
(3) MAF carbon; product name “Seast 116” manufactured by Tokai Carbon
(4) Softener: Idemitsu Kosan Co., Ltd. trade name “Diana Process PW380”
(5) Crosslinking agent: Product name “Park Mill D-40” manufactured by NOF Corporation
(6) Crosslinking aid: Tsurumi Chemical Co., Ltd. trade name “Sulfur”
[0052]
(2) Performance evaluation
The rubber compositions of Examples and Comparative Examples prepared by the above method were pressed with a press molding machine at 170 ° C. and a press pressure of 150 kgf / cm. ² A test piece (vulcanized sheet) having a thickness of 2 mm was produced by heating for 10 minutes under the pressure of. Moreover, the test piece (vulcanized sample) used for the following viscoelasticity test was produced by heating each rubber composition of the Example and comparative example prepared by said method for 10 minutes. And the performance evaluation was performed by the method as described below using the obtained test piece. The results are shown in Table 2.
[0053]
(1) Tensile test
In accordance with JIS K6251, using a No. 3 type test piece, with a measurement temperature of 23 ° C. and a tensile speed of 500 mm / min, the tensile strength T _B (MPa) and elongation at break E _B (%) Was measured (normal physical properties). Moreover, the evaluation of the high temperature physical properties was performed under the above conditions after adjusting the inside of the tank to 120 ° C. and holding the test piece in the tank for 5 minutes.
(2) Hardness test
Based on JIS K6253, the spring hardness (durometer A hardness) of the test piece was measured.
(3) Viscoelasticity (RDA) test
In accordance with JIS K6394, a block-shaped test piece is used, and a rheometrics “Rheometrics Dynamic Analyzer (RDA)” is used to operate at 1 Hz and 70 Hz under conditions of dynamic strain of 0.5% and temperature of 25 ° C. The elastic modulus was measured. And the static-dynamic ratio was computed with the following formula | equation.
Static ratio = (dynamic elastic modulus at 70 Hz) / (dynamic elastic modulus at 1 Hz)
(4) Extension fatigue test
Using No. 3 type test piece, manufactured by Infinite Nishi Co., Ltd., with a 16-bar rubber fatigue tester, repeated fatigue was performed under the conditions of initial strain 0%, elongation rate 100%, temperature 120 ° C, and the number of breaks was measured. .
(5) Heat aging resistance test
In accordance with JIS K6257, a heat aging resistance test is performed by a normal oven method under conditions of 140 ° C. and 200 hours, and the change in hardness A _H (Point), tensile strength T _B And elongation at break E _B Change (A _C , (%)). This A _C And A _H The closer to 0, the better the heat resistance.
[0054]
[Table 1]

[0055]
[Table 2]

[0056]
From Tables 1 and 2, Examples 1 to 8 which are within the scope of the present invention all have values of a tensile test, a hardness test, a static ratio, an extension fatigue test, and a heat aging test within suitable ranges. It can be seen that the rubber composition has an excellent balance of vibration-proof properties, durability and heat resistance.
[0057]
On the other hand, from Table 1 and Table 2, Comparative Example 1 consisting of only EPDM shows almost the same value as the Example in the heat aging test and is excellent in heat resistance, while EB in the tensile test, especially EB value at high temperature is small. Moreover, since the value of an extension | exhaustion fatigue test is also small, it turns out that durability is not enough. Further, in contrast to Comparative Example 1, Comparative Example 5 composed of only natural rubber has excellent vibration-proof characteristics because the value of EB in the tensile test, particularly EB at high temperatures is large and the static ratio is small. On the other hand, in the heat aging resistance test, it can be seen that it causes hardening deterioration and is inferior in heat resistance. Furthermore, in Comparative Example 4 in which only EPDM and natural rubber were used in combination, a slight improvement tendency was recognized in the vibration proof property, but the value of the stretch fatigue test was small, and the AH of the heat aging test was large. It turns out that it is still inferior to durability and heat resistance.
[0058]
Moreover, in Comparative Example 2 that does not contain the component (B-2) and Comparative Example 3 in which the content of the component (B-1) is too small, as in Comparative Example 1, the heat resistance is excellent, but in the tensile test. The value of EB, particularly EB at high temperatures is small. Moreover, since the value of an extension | exhaustion fatigue test is also small, it turns out that durability is not enough. Therefore, in order to make an excellent rubber composition in a well-balanced manner with respect to all of heat resistance, durability, and vibration proofing properties, the components (B-1) and (B-2) are in an appropriate content range. It turns out that it is important to use together.
[0059]
【The invention's effect】
Since the rubber composition of the present invention has the above-described configuration, it has excellent vibration-proof performance and sufficient heat resistance. Thus, like the vibration-proof rubber for engine mounts of the present invention, the engine mount and the like are in a high temperature state. It can be suitably used in the environment. Furthermore, according to the method for producing a rubber composition of the present invention, a rubber composition having the above useful effects can be easily obtained.

Claims (9)

In (A) ethylene-α-olefin copolymer rubber, (B) (B-1) functional group- containing (co) polymer, (B-1) functional group-containing (co) polymer in 100 parts by mass. On the other hand, by containing 0.05 to 5 parts by mass of the (B-2) metal compound, the (B-1) functional group-containing (co) polymer is changed by the metal component in the (B-2) metal compound. A cross-linked product,
When the total amount of the (A) ethylene-α-olefin copolymer rubber and the (B-1) functional group-containing (co) polymer is 100 parts by mass, the (A) ethylene-α-olefin copolymer The content of (B-1) the functional group-containing (co) polymer is 1 to 50 parts by mass,
The functional group contained in the (B-1) functional group-containing (co) polymer contains at least a carboxyl group,
The (co) polymer constituting the (B-1) functional group-containing (co) polymer is a styrene-butacene rubber, a butadiene rubber, an acrylonitrile-butadiene rubber, an ethylene-propylene-diene rubber, or a hydrogenated product thereof.
The (B-2) metal compound is a metal oxide and / or a fatty acid metal salt, and the metal is one or more selected from alkaline earth metals and zinc. object.   (B-2) 0.05-5 parts by mass of a metal compound with respect to 100 parts by mass of the (B-1) functional group-containing (co) polymer and the (B-1) functional group-containing (co) polymer. And (B) a crosslinked product is prepared by heating and mixing, and then the (B) crosslinked product and the (A) ethylene-α-olefin copolymer rubber are mixed. Item 2. The rubber composition according to Item 1.   A rubber molded article obtained by crosslinking the (A) ethylene-α-olefin copolymer rubber in the rubber composition according to claim 1 or 2 with a crosslinking agent.   A vibration-proof rubber molded article obtained by crosslinking the (A) ethylene-α-olefin copolymer rubber in the rubber composition according to claim 1 or 2 with a crosslinking agent.   An anti-vibration rubber molded article for engine mounts, wherein the (A) ethylene-α-olefin copolymer rubber in the rubber composition according to claim 1 or 2 is crosslinked with a crosslinking agent. (B-1) Functional group-containing (co) polymer, and (B-2) 0.05-5 parts by mass of a metal compound with respect to 100 parts by mass of the (B-1) functional group-containing (co) polymer, (B) to prepare a crosslinked product by heating and mixing,
Next, when the total content of the (B-1) functional group-containing (co) polymer and the (A) ethylene-α-olefin copolymer rubber is 100 parts by mass, the (A) ethylene-α-olefin The (B) cross-linked product and the above so that the content of the system copolymer is 50 to 99 parts by mass, and the content of the (B-1) functional group-containing (co) polymer is 1 to 50 parts by mass. (A) ethylene-α-olefin copolymer rubber is mixed,
The functional group contained in the (B-1) functional group-containing (co) polymer contains at least a carboxyl group,
The (co) polymer constituting the (B-1) functional group-containing (co) polymer is a styrene-butacene rubber, a butadiene rubber, an acrylonitrile-butadiene rubber, an ethylene-propylene-diene rubber, or a hydrogenated product thereof.
The (B-2) metal compound is a metal oxide and / or a fatty acid metal salt, and the metal is one or more selected from alkaline earth metals and zinc. Manufacturing method.   A method for producing a rubber molded article, comprising adding a crosslinking agent to the rubber composition according to claim 1 or 2 to crosslink the (A) ethylene-α-olefin copolymer rubber.   A method for producing an anti-vibration rubber molded article, wherein a crosslinking agent is added to the rubber composition according to claim 1 or 2 to crosslink the (A) ethylene-α-olefin copolymer rubber.   A method for producing an anti-vibration rubber molded article for an engine mount, comprising adding a cross-linking agent to the rubber composition according to claim 1 or 2 to cross-link the (A) ethylene-α-olefin copolymer rubber.