JP4015844B2 - Additive for rubber composition, additive composition for rubber composition, rubber composition using the same, and tire - Google Patents

Description

〔式（Ｉ）中、ｍは平均重合度を表わす１以上の数であり、ｎ及びｐはそれぞれ１以上の整数を示し、Ａは飽和または不飽和の脂肪族鎖、Ｒ¹はアルキレン基、Ｒ²はアルキル基、アルケニル基、アルキルアリール基又はアシル基である。〕
【００１０】
前記一般式（Ｉ）において、より好ましくは、Ａが不飽和結合を有する脂肪族鎖であり、更に好ましくはｎ＝１、ｐ＝１、Ｒ¹が炭素数２〜４のアルキレン基、Ｒ²が炭素数２〜２８のアルキル基又はアルケニル基であり、特に好ましくはＡが不飽和結合を有する炭素数２〜８の脂肪族鎖であり、ｍが１〜１０、Ｒ¹がエチレン基またはプロピレン基、Ｒ²が炭素数８〜１８のアルキル基又はアルケニル基である。
【００１１】
本発明の前記ゴム組成物用添加剤（ｂ）は、（ｉ）二価のカルボン酸、三価のカルボン酸又はこれらの無水物と、（ii）（ポリ）オキシアルキレン誘導体とを反応させることで得られる。ここで、（ｉ）二価のカルボン酸、三価のカルボン酸又はこれらの無水物としては、（無水）コハク酸、グルタル酸、アジピン酸、セバシン酸などの飽和脂肪族二価カルボン酸、（無水）マレイン酸、フマル酸、（無水）イタコン酸、（無水）シトラコン酸、（無水）アルケニルコハク酸などの不飽和脂肪族二価カルボン酸、マレイン化脂肪酸などの脂肪族三価カルボン酸などが挙げられるが、不飽和結合を有する二価のカルボン酸またはその無水物であることが好ましく、無水マレイン酸であることが最も好ましい。
上記（ｉ）二価のカルボン酸、三価のカルボン酸又はこれらの無水物は、単独で用いてもよく、また２種以上を併用してもよい。
【００１２】
また、（ii）（ポリ）オキシアルキレン誘導体としては、例えば、１個以上の水酸基を持った平均重合度１以上の（ポリ）オキシアルキレン基を有する化合物が挙げられ、好ましくは１〜２個の水酸基を持った（ポリ）オキシアルキレン基を有する化合物であり、特に好ましくは１個の水酸基を持った（ポリ）オキシアルキレン基を有する化合物である。（ポリ）オキシアルキレン誘導体としては、（ポリ）オキシアルキレンアルキルエーテルなどのエーテル型；（ポリ）オキシアルキレン脂肪酸モノエステルなどのエステル型；（ポリ）オキシアルキレングリセリン脂肪酸エステルなどのエーテルエステル型；（ポリ）オキシアルキレン脂肪酸アミド、（ポリ）オキシアルキレンアルキルアミンなどの含窒素型などが挙げられるが、本発明で使用する（ポリ）オキシアルキレン誘導体としてはエーテル型とエステル型が好ましく、エーテル型が特に好ましい。
【００１３】
エーテル型の（ポリ）オキシアルキレン誘導体としてはポリオキシエチレンラウリルエーテル、ポリオキシエチレンデシルエーテル、ポリオキシエチレンオクチルエーテル、ポリオキシエチレン２−エチルヘキシルエーテル、ポリオキシエチレンポリオキシプロピレンラウリルエーテル、ポリオキシプロピレンステアリルエーテル、ポリオキシエチレンオレイルエーテルなどのポリオキシアルキレン脂肪族エーテル；ポリオキシエチレンベンジルエーテル、ポリオキシエチレンアルキルフェニルエーテル、ポリオキシエチレンベンジル化フェニルエーテルなどのポリオキシアルキレン芳香族エーテルなどが挙げられるが、ポリオキシアルキレン脂肪族エーテルが好ましい。
さらにはポリオキシエチレンアルキルまたはアルケニルエーテル及びポリオキシプロピレンアルキルまたはアルケニルエーテルが好ましく、特にポリオキシエチレンまたはポリオキシプロピレンの平均重合度が１〜１０、アルキル基またはアルケニル基の炭素数が８〜１８であることが好ましい。具体的には、ポリオキシエチレンをＰＯＥ（ｑ）、ポリオキシプロピレンをＰＯＰ（ｒ）と略し、ｑ，ｒを各々平均重合度とすれば、ＰＯＥ（３）オクチルエーテル、ＰＯＥ（４）２−エチルヘキシルエーテル、ＰＯＥ（３）デシルエーテル、ＰＯＥ（５）デシルエーテル、ＰＯＥ（３）ラウリルエーテル、ＰＯＥ（８）ラウリルエーテル、ＰＯＥ（１）ステアリルエーテル、ＰＯＰ（３）ラウリルエーテル、ＰＯＰ（５）ミリスチルエーテルなどが挙げられる。
上記（ii）（ポリ）オキシアルキレン誘導体は、単独で用いてもよく、また２種以上を併用してもよい。
また、本発明の（ｉ）脂肪族多価カルボン酸またはその無水物と（ii）（ポリ）オキシアルキレン誘導体とのエステル（ｂ）は、原料の（ｉ）脂肪族多価カルボン酸またはその無水物を含有してもよい。該脂肪族多価カルボン酸またはその無水物の含有量は好ましくは１０重量％以下、特に好ましくは５重量％以下である。一方、（ｉ）脂肪族多価カルボン酸またはその無水物と（ii）（ポリ）オキシアルキレン誘導体とのエステル（ｂ）は、原料の（ii）（ポリ）オキシアルキレン誘導体を含有してもよい。該（ii）（ポリ）オキシアルキレン誘導体の含有量は好ましくは４０重量％以下、特に好ましくは２０重量％以下である。
【００１４】
また、本発明のゴム組成物用添加剤組成物（Ｂ）は、補強性充填剤（ａ）と、分子中にカルボキシル基を少なくとも一つ有する、脂肪族多価カルボン酸と（ポリ）オキシアルキレン誘導体とのエステル（ｂ）とを含有する。
また、該（ａ）成分の（ｂ）成分に対する重量配合比（ａ）／（ｂ）が７０／３０〜３０／７０であることが作業性の点から好ましい。この点から、さらに（ａ）／（ｂ）は６０／４０〜４０／６０（重量配合比）の範囲が好ましい。
前記ゴム組成物用添加剤組成物（Ｂ）は、さらに（ｃ）成分として、（ポリ）オキシアルキレン誘導体、アルコール及びその脂肪酸エステルの中から選ばれる少なくとも１種類を含有することができる。その配合量は、（ａ）成分及び（ｂ）成分の合計１００重量部に対して、１０重量部以下であることが好ましく、それ以上加えても利点が少ない。
前記（ｃ）成分の融点が２０℃以下であり、かつ沸点が１５０℃以上であることが好ましい。（ｃ）成分の融点は、ゴム組成物用添加剤組成物又はゴム組成物製造時の粉塵抑制の観点から２０℃以下が好ましく、また沸点はゴム組成物加工時の安全性の観点から１５０℃以上であることが好ましい。
ここで、（ｃ）成分としての（ポリ）オキシアルキレン誘導体は、前記（ii）の（ポリ）オキシアルキレン誘導体と同様で、エーテル型、エステル型、エーテルエステル型、含窒素型などが挙げられ、エーテル型又はエステル型のポリオキシアルキレン誘導体が好ましい。
本発明で用いられる上記の（ｃ）成分の中では、エーテル型又はエステル型のポリオキシエチレン誘導体が特に好ましい。具体的には、ポリオキシエチレンをＰＯＥ（ｎ）と略し、ｎには平均重合度を示すと、ＰＯＥ（３）ラウリルエーテル、ＰＯＥ（５）デシルエーテル、ＰＯＥ（４）オレイルエーテル、ＰＯＥ（１０）モノラウレート、ＰＯＥ（１０）モノオレエートなどが挙げられる。
また、上記（ｃ）成分は、単独で用いてもよく、２種以上を併用してもよい。
上記のゴム組成物用添加剤組成物を得るためにはミキサーを使用して各成分を混合すれば良く、例えばヘンシェルミキサー、ナウターミキサー、タンブラーミキサーなどが挙げられ、それぞれのミキサーに対して、回転数、攪拌温度、攪拌時間など最適な範囲が選択される。
本発明のゴム組成物用添加剤組成物（Ｂ）は、前述の（ａ）（ｂ）及び（ｃ）の他に、ゴム組成物用の配合剤を適宜添加することができるが、その添加量は添加剤組成物の１０重量％以下であることが好ましい。
【００１５】
次に、本発明における第一のゴム組成物は、ゴム成分（Ａ）と、分子中にカルボキシル基を少なくとも一つ有する、脂肪族多価カルボン酸と（ポリ）オキシアルキレン誘導体とのエステル（ｂ）を配合して得られ、補強性充填剤（Ｃ）を併用することができる。ここで（ｂ）成分は、前記の一般式（Ｉ）で表されるエステルが好ましく、具体的には、モノ〔ＰＯＥ（３）ラウリルエーテル〕マレイン酸エステル，モノ〔ＰＯＰ（３）ラウリルエーテル〕マレイン酸エステル，モノ〔ＰＯＥ（３）２−エチルヘキシルエーテル〕マレイン酸エステルなどが挙げられる。
また、本発明における第二のゴム組成物は、ゴム成分（Ａ）に、前記分子中にカルボキシル基を少なくとも一つ有する、脂肪族多価カルボン酸と（ポリ）オキシアルキレン誘導体とのエステル（ｂ）と、前記補強性充填剤（ａ）とを配合することにより得られるゴム組成物用添加剤組成物（Ｂ）を配合して得られる。
【００１６】
本発明のゴム組成物において使用されるゴム成分（Ａ）の種類は特に限定されないが、天然ゴム単独、天然ゴムと合成ゴムのブレンドゴムの系において加工性の改良効果が顕著である。用い得る合成ゴムとしては、例えばスチレンブタジエンゴム（ＳＢＲ）、ブタジエンゴム（ＢＲ）、イソプレンゴム（ＩＲ）、ブチルゴム（ＩＩＲ）、ハロゲン化ブチルゴム（Ｘ−ＩＩＲ）、エチレンプロピレンゴム（ＥＰＤＭ）等、及びこれらの混合物が挙げられる。
本発明のゴム組成物は、ゴム成分（Ａ）が天然ゴムを含む場合には、天然ゴム分子の分子量を低下させずに天然ゴムのポリマーゲル量を低減することができ、かつゴム分子間でのすべりを増加させることにより成形作業性を向上させると共に、未加硫又は加硫ゴムの物性低下が抑制される。また、ゴム成分が天然ゴムを含まない場合には、ゴム分子間でのすべりを増加させることで成形作業性を向上させ、この場合もゴムの分子量の低下は伴わないため、未加硫又は加硫ゴムの物性低下が起きない。いずれにしても、本発明においては、加硫ゴム組成物の物性に悪影響を与えることなく、優れたゴム加工性を得ることができる。
【００１７】
前記補強性充填剤（ａ）または（Ｃ）としては、一般的なゴム組成物に用いることができる充填剤であればいずれも使用することができ、これらのうちの一種又は二種以上のものを混合して使用してもよい。具体的には、カーボンブラック及び無機充填剤を挙げることができ、無機充填剤としては、シリカ及び下記一般式（II）で表される化合物が好ましい。
aＭ₁ ・bＳｉＯc・dＨ₂ Ｏ ・・・（II）
ここで、式（II）中、Ｍ₁ は、アルミニウム、マグネシウム、チタン、カルシウムからなる群から選ばれる金属、これらの金属の酸化物又は水酸化物、及びそれらの水和物から選ばれる少なくとも一種であり、a、b、c及びdは、それぞれ１〜５の整数、０〜１０の整数、２〜５の整数、及び０〜１０の整数である。
さらに、カリウム、ナトリウム、鉄、マグネシウム等の金属、フッ素等の元素及びＮＨ₄−等の官能基を含有していてもよい。
【００１８】
上記一般式（II）の具体例としては、アルミナ一水和物（Ａｌ₂Ｏ₃・Ｈ₂Ｏ）、ギブサイト、バイヤライト等の水酸化アルミニウム［Ａｌ（ＯＨ）₃］、水酸化マグネシウム［Ｍｇ（ＯＨ）₂］、酸化マグネシウム（ＭｇＯ）、タルク（３ＭｇＯ・４ＳｉＯ₂・Ｈ₂Ｏ）、アタパルジャイト（５ＭｇＯ・８ＳｉＯ₂・９Ｈ₂Ｏ）、チタン白（ＴｉＯ₂）、チタン黒（ＴｉＯ_2n-1）、酸化カルシウム（ＣａＯ）、水酸化カルシウム［Ｃａ（ＯＨ）₂］、酸化アルミニウムマグネシウム（ＭｇＯ・Ａｌ₂Ｏ₃）、クレー（Ａｌ₂Ｏ₃・２ＳｉＯ₂）、カオリン（Ａｌ₂Ｏ₃・２ＳｉＯ₂・２Ｈ₂Ｏ）、パイロフィライト（Ａｌ₂Ｏ₃・４ＳｉＯ₂・Ｈ₂Ｏ）、ベントナイト（Ａｌ₂Ｏ₃・４ＳｉＯ₂・２Ｈ₂Ｏ）、ケイ酸アルミニウム（Ａｌ₂ＳｉＯ₅ 、Ａｌ₄・３ＳｉＯ₄・５Ｈ₂Ｏ等）、ケイ酸マグネシウム（Ｍｇ₂ＳｉＯ₄、ＭｇＳｉＯ₃等）、ケイ酸カルシウム（Ｃａ₂・ＳｉＯ₄等）、ケイ酸アルミニウムカルシウム（Ａｌ₂Ｏ₃・ＣａＯ・２ＳｉＯ₂等）、ケイ酸マグネシウムカルシウム（ＣａＭｇＳｉＯ₄）、各種ゼオライト、長石、マイカ等が例示でき、Ｍ₁がアルミニウムであることが好ましい。
【００１９】
上記各種充填剤の中で、本発明に用いる補強性充填剤としては、カーボンブラック、シリカ、アルミナ類が好ましい。
カーボンブラックの種類としては、特に制限はなく、ＳＲＦ、ＧＰＦ、ＦＥＦ、ＨＡＦ、ＩＳＡＦ、ＳＡＦ等を用いることができるが、ゴム組成物の用途に応じて適宜選択することが好ましい。例えば、トレッド用のゴム組成物に用いる場合は、ヨウ素吸着（ＩＡ）が６０ｍｇ／ｇ以上、かつジブチルフタレート吸油量（ＤＢＰ）が８０ｍｌ／１００ｇ以上のカーボンブラックが好ましい。トレッドゴムとしてこのようなカーボンブラックを用いることによって、グリップ性能及び耐破壊特性を改良することができるが、さらに、優れた耐摩耗性が要求される場合はＨＡＦ、ＩＳＡＦ、ＳＡＦを用いることが好ましい。
本発明で用い得るシリカも特に制限はなく、例えば湿式シリカ（含水ケイ酸）、乾式シリカ（無水ケイ酸）、ケイ酸カルシウム、ケイ酸アルミニウム等が挙げられ、これらの中でも、耐破壊特性の改良効果、ウェットグリップ性及び転がり抵抗性の両立効果が最も顕著である湿式シリカが好ましい。
アルミナ類とは、上記式（II）で表される化合物のうち、下記一般式（III）で表されるものをいう。
Ａｌ₂Ｏ₃・eＨ₂Ｏ ・・・（III）
（式中、eは１〜３の整数である）
これらの無機充填剤としては、その粒径が１０μｍ以下が好ましく、３μｍ以下がさらに好ましい。該無機充填剤の粒径を１０μｍ以下とすることにより、加硫ゴム組成物の耐破壊特性、耐摩耗性を良好に維持することができる。
これらの補強性充填剤は単独でも、２種以上を併用しても良い。特に本発明のゴム組成物においてシリカを配合した場合、シリカの分散改良効果が得られ、この効果はシリカ比率の高い系で顕著である。
ゴム組成物用添加剤組成物（Ｂ）における補強性充填剤（ａ）の配合量は、上述したのと同様に、（ｂ）成分に対する重量配合比（ａ）／（ｂ）として７０／３０〜３０／７０であることが好ましく、６０／４０〜４０／６０であることが更に好ましい。
また、本発明のゴム組成物における（ｂ）成分の配合量は、ゴム成分（Ａ）１００重量部に対し、０．１〜１０重量部であることが好ましい。０. １重量部以上であれば加工性が向上し、１０重量部以下であればゴム物性は保持され、かつコストの面からも望ましい。この点から、さらに０. ５〜５重量部であることが好ましい。これらの成分は、例えば混練時に配合すればよい。なお、（ｂ）成分が前記ゴム組成物用添加剤組成物（Ｂ）として配合される場合にも同様であり、この場合には、ゴム成分１００重量部に対する（ｂ）成分の配合換算量として好ましくは０．１〜１０重量部、さらに好ましくは０．５〜５重量部となるように配合される。
また、本発明のゴム組成物には、必要に応じて他のゴム配合剤、例えば硫黄、加硫促進剤、プロセスオイル、老化防止剤などを適宜配合できる。
本発明のゴム組成物は、ロール、インターナルミキサー等の混練り機を用いて混練りすることによって得られ、タイヤトレッド，アンダートレッド，カーカス，サイドウォール，ビード部分等のタイヤ用途を始め、防振ゴム，ベルト，ホースその他の工業品等の用途にも用いることができるが、特にタイヤトレッド用ゴム組成物として好適に使用される。
【００２０】
本発明のタイヤは、本発明のゴム組成物を用いて通常の方法によって製造される。すなわち、必要に応じて、上記のように各種薬品を含有させた本発明のゴム組成物が未加硫の段階で各タイヤ用部材に押出し加工され、タイヤ成形機上で通常の方法により貼り付け成形され、生タイヤが成形される。この生タイヤを加硫機中で加熱加圧して、タイヤが得られる。
このようにして得られた本発明のタイヤは、ゴム物性に悪影響を及ぼすことなく、しかも該ゴム組成物の工場作業性は良好であるので、生産性にも優れている。また、本発明のタイヤは、その内部に空気や窒素などの気体を充填して用いることができる。
【００２１】
【実施例】
次に、本発明を実施例によりさらに詳細に説明するが、本発明は、これらの例によってなんら限定されるものではない。
各種の測定は以下の方法により行なった。
＜ムーニー粘度（ＭＬ₁₊₄）＞
ゴム組成物の加工性の評価として、ＳＨＩＭＡＤＺＵ社製ＭＯＯＮＹＶＩＳＣＯＭＥＴＥＲＳＭＶ２０１を用いて、加硫系配合剤を添加して混練した未加硫ゴム試料を、１３０℃で１分間予熱をした後、ロータの回転をスタートさせ４分後の値をＭＬ₁₊₄として測定した。この際、比較例１又は比較例２の測定値の逆数を１００として指数化した。値が大きい程、加工性がよいことを示す。
【００２２】
＜破断強度、破断伸び＞
ダンベル状３号形を試験片に用いた。試験方法及び結果の値は、ＪＩＳ Ｋ６２５１−１９９３に基づく。結果は比較例１又は比較例２の値を１００として指数化した。数値が大きいほど破断強度は良好であり、また破断伸びは大きい。
＜反発弾性＞
ゴム表面に所定のおもりを自由落下させ、そのおもりが跳ね上がった高さ（落とした高さに対する％） をもって値とした。試験方法及び結果の値は、ＪＩＳＫ６３０１−１９９５に基づく。結果は比較例１又は比較例２の値を１００として指数化した。数値が大きいほど反発弾性は大きい。
＜耐摩耗性＞
ランボーン摩耗試験により、ＪＩＳ Ｋ６２６４−１９９３に基づいて摩耗量を測定した。結果は比較例１又は比較例２において得られた摩耗量の逆数を１００として各例の摩耗量の逆数を指数化した。数値が大きいほど耐摩耗性は良好である。
【００２３】
実施例１〜７及び比較例１
天然ゴム（ＲＳＳ＃３）１００重量部に対して、第１表に示す種類と量の（ｂ）成分としてのエステル添加剤、カーボンブラック（ＨＡＦ）５５重量部、ステアリン酸２重量部、老化防止剤６ＰＰＤ〔Ｎ−フェニル−Ｎ’−（１，３−ジメチルブチル）−ｐ−フェニレンジアミン〕１重量部、ワックス１重量部を、バンバリーミキサー^Rを用いてスタート温度を７０℃として、回転数７０ｒｐｍで４分間混練した。得られた混合物を充分に室温放冷した後、さらに亜鉛華３重量部、加硫促進剤ＤＭ（ジベンゾチアジルジスルフィド）１重量部、加硫促進剤ＣＢＳ（Ｎ−シクロヘキシル−２−ベンゾチアジルスルフェンアミド）１重量部、硫黄２重量部を添加し、バンバリーミキサー^Rを用いてスタート温度を７０℃として、回転数７０ｒｐｍで１分間混練した。なお、比較例１ではエステル添加剤（ｂ）は用いなかった。
得られた未加硫ゴム組成物についてはムーニー粘度を測定した。また、これらの未加硫ゴム組成物を１５０℃で３０分間加硫して得た加硫ゴム組成物について、破断強度、破断伸び、反発弾性及び耐摩耗性を前記方法により評価した。結果を第１表に示す。
【００２４】
【表１】

【００２５】
注１；各物性は全て比較例１を基準とした指数表示であり、数値が大きい程良好を示す。
注２；（ｂ）成分量（ｐｈｒ）は、ゴム成分１００重量部に対する配合重量部数を示す。
注３；（ｂ）成分の種類
下記の構造式(IV)及び第２表のｘ，Ｒ³，Ｒ⁴で表わされる化合物Ａ，Ｂ及びＣを用いた。
【００２６】
【化２】

【００２７】
【表２】

【００２８】
実施例８〜１４及び比較例２
予め第３表に示す種類と量の（ｂ）成分とシリカを（ｂ）成分：シリカ＝６：４の割合で混合し、ゴム組成物用添加剤組成物（Ｂ）を調製した。
次に、スチレン−ブタジエン共重合体ゴム（ＳＢＲ１７１２：商標、ジェイエスアール（株）製、アロマティックオイルは３７．５ｐｈｒの油展ゴムであり、配合量はゴム成分のみの値である）１００重量部に対して、上記で調製した各ゴム組成物用添加剤組成物（Ｂ）、カーボンブラック（ＩＳＡＦ）３０重量部、シリカ〔ニプシルＶＮ３；商標、日本シリカ工業（株）製（上記ゴム組成物用添加剤の調製に用いたシリカも同種）〕を総量が３０重量部、ステアリン酸１重量部、老化防止剤６ＰＰＤ〔Ｎ−フェニル−Ｎ’−（１，３−ジメチルブチル）−ｐ−フェニレンジアミン〕１重量部、ワックス１重量部、シランカップリング剤（Ｓｉ６９：商標、デグサ社製）３重量部を、バンバリーミキサー^Rを用いてスタート温度を７０℃として、回転数７０ｒｐｍで４分間混練した。
得られた混合物を充分に室温放冷した後、さらに亜鉛華３重量部、加硫促進剤ＤＭ（ジベンゾチアジルジスルフィド）１重量部、加硫促進剤Ｄ（ジフェニルグアニジン）１重量部、加硫促進剤ＣＢＳ（Ｎ−シクロヘキシル−２−ベンゾチアジルスルフェンアミド）１重量部、硫黄２重量部を添加し、バンバリーミキサー^Rを用いてスタート温度を７０℃として、回転数７０ｒｐｍで１分間混練した。なお、比較例２ではエステル添加剤（ｂ）は用いなかった。
得られた未加硫ゴム組成物についてはムーニー粘度を、また、加硫ゴム組成物については破断強度、破断伸び、反発弾性及び耐摩耗性を前記方法により評価した。結果を第３表に示す。
【００２９】
【表３】

【００３０】
（注）
第１表脚注に記載の注１〜注３に同じ。
上記の結果から、本発明におけるゴム組成物は、いずれも未加硫ゴムにおける加工性に著しく優れており、しかも、加硫ゴムの良好な物性を殆ど低下させることなく維持していることが分かる。
【００３１】
【発明の効果】
本発明のゴム組成物用添加剤、ゴム組成物用添加剤組成物によれば、ゴムの物性は損なうことなく加工性を改良し、未加硫及び加硫ゴムの表面状態にも安定して問題のないゴム組成物を得ることができ、したがって、生産性も向上し、特にタイヤに好適に用いることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an additive for a rubber composition and a rubber composition capable of improving processability and productivity in the production of a rubber product without adversely affecting the physical properties of the unvulcanized rubber composition and the vulcanized rubber composition. The present invention relates to an additive composition, a rubber composition using the same, and a tire.
[0002]
[Prior art]
Generally, rubber products such as tires, belts and hoses are kneaded in order to uniformly disperse compounding agents and fillers in the raw rubber, but also in order to facilitate molding workability in subsequent processing steps. Further, several kneading steps for plasticizing the rubber composition may be required. However, it is not preferable from the viewpoint of the productivity of rubber products to perform the plasticizing operation of the rubber composition many times in this way. On the other hand, it is effective to reduce the number of kneading in order to improve the productivity of rubber products. However, even if the number of kneading is reduced, the unvulcanized rubber composition is not sufficiently plasticized and eventually produced. It does not lead to improvement in sex.
[0003]
For this reason, it is possible to improve the workability of the unvulcanized rubber composition, reduce the number of kneading, and improve the workability of molding by adding a plasticizer or a processing aid. When an agent, a processing aid or the like is used, the physical properties of the unvulcanized rubber composition and the vulcanized rubber composition are lowered, so that it is practically difficult to reduce the number of kneading. In particular, in the processing step in the production of conventional rubber products containing natural rubber, entanglement of natural rubber molecular chains, functional groups in the isoprene chain of natural rubber, or such functional groups and non-rubber components in natural rubber Since there is a polymer gel resulting from the above reaction, it is necessary to increase the number of kneading, and it cannot be said that the productivity is good. Further, if the number of kneading is increased in order to plasticize the unvulcanized rubber composition, the molecular weight of the natural rubber molecule is lowered, and the physical properties of the vulcanized rubber composition are adversely affected.
Therefore, conventionally, there has been a demand for improving the molding workability without lowering the physical properties of the unvulcanized rubber composition and the vulcanized rubber composition, particularly in the production of natural rubber-containing rubber products.
[0004]
On the other hand, several proposals have recently been made to solve these problems. For example, Japanese Patent Application Laid-Open No. 11-209406 describes that an aromatic polycarboxylic acid derivative is added to natural rubber to reduce the amount of natural rubber polymer gel. However, it has been found that this method tends to generate bloom after vulcanization.
In addition, JP-A-6-57040 and JP-A-4-20579 also describe that a specific ester is added to improve processability, but these methods are unique during processing. Odor occurs and there is a problem in the working environment.
[0005]
[Problems to be solved by the invention]
Under such circumstances, the present invention has been made to solve the above-described problems, and improves the processability without causing deterioration in physical properties of the rubber composition and problems in the working environment. An object of the present invention is to provide an improved additive for a rubber composition, an additive composition for a rubber composition, a rubber composition using the same, and a tire capable of stabilizing the surface state of the vulcanized and vulcanized rubber composition .
[0006]
[Means for Solving the Problems]
By utilizing a partial ester of a specific aliphatic polyvalent carboxylic acid and a (poly) oxyalkylene derivative as an additive for a rubber composition, the present inventors do not impair the physical properties of the vulcanized rubber composition, The inventors have found that slip between rubber molecules is increased, and found that this achieves the above-mentioned object, and have completed the present invention.
That is, the present invention provides an additive for a rubber composition, which is an ester of an aliphatic polyvalent carboxylic acid and a (poly) oxyalkylene derivative having at least one carboxyl group in the molecule. It is.
The present invention also relates to an additive composition for a rubber composition containing a reinforcing filler (a) and the additive for rubber composition (b), and further to the component (b) of the component (a). A weight ratio (a) / (b) is 70/30 to 30/70, and provides an additive composition for a rubber composition.
[0007]
Further, the present invention comprises a rubber component (A) and an ester (b) of an aliphatic polyvalent carboxylic acid having at least one carboxyl group in the molecule and a (poly) oxyalkylene derivative. A rubber composition characterized by containing an ester (b) of an aliphatic polyvalent carboxylic acid and a (poly) oxyalkylene derivative having at least one carboxyl group in the molecule and a reinforcing filler (a). A rubber composition comprising a rubber composition additive composition (B) and a rubber component (A), and a fat having at least one carboxyl group in the molecule Also provided is a rubber composition comprising an ester (b) of an aromatic polycarboxylic acid and a (poly) oxyalkylene derivative, a reinforcing filler (C), and a rubber component (A). What to do That.
Furthermore, the present invention provides a tire characterized by using the above rubber composition.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The rubber composition additive (b) of the present invention is an ester of an aliphatic polyvalent carboxylic acid and a (poly) oxyalkylene derivative having at least one carboxyl group in the molecule.
This ester is preferably one represented by the following general formula (I).
[0009]
[Chemical 1]

[In Formula (I), m is a number of 1 or more representing the average degree of polymerization, n and p each represent an integer of 1 or more, A is a saturated or unsaturated aliphatic chain, R ¹ Is an alkylene group, R ² Is an alkyl group, an alkenyl group, an alkylaryl group or an acyl group. ]
[0010]
In the general formula (I), more preferably, A is an aliphatic chain having an unsaturated bond, and more preferably n = 1, p = 1, R ¹ Is an alkylene group having 2 to 4 carbon atoms, R ² Is an alkyl group or alkenyl group having 2 to 28 carbon atoms, particularly preferably A is an aliphatic chain having 2 to 8 carbon atoms having an unsaturated bond, m is 1 to 10, R ¹ Is ethylene group or propylene group, R ² Is an alkyl or alkenyl group having 8 to 18 carbon atoms.
[0011]
The rubber composition additive (b) of the present invention comprises (i) Divalent carboxylic acids, trivalent carboxylic acids or these It can be obtained by reacting an anhydride with (ii) a (poly) oxyalkylene derivative. Where (i) Divalent carboxylic acids, trivalent carboxylic acids or these Examples of anhydrides include (aliphatic) saturated aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, and sebacic acid, (anhydrous) maleic acid, fumaric acid, (anhydrous) itaconic acid, (anhydrous) citraconic acid, (Anhydrous) Unsaturated aliphatic divalent carboxylic acid such as alkenyl succinic acid, aliphatic trivalent carboxylic acid such as maleated fatty acid, etc. are mentioned, but it is a divalent carboxylic acid having an unsaturated bond or its anhydride. And maleic anhydride is most preferred.
(I) above Divalent carboxylic acids, trivalent carboxylic acids or these An anhydride may be used independently and may use 2 or more types together.
[0012]
Examples of (ii) (poly) oxyalkylene derivatives include compounds having (poly) oxyalkylene groups having one or more hydroxyl groups and an average degree of polymerization of 1 or more, preferably 1 to 2 A compound having a (poly) oxyalkylene group having a hydroxyl group, particularly preferably a compound having a (poly) oxyalkylene group having one hydroxyl group. (Poly) oxyalkylene derivatives include ether types such as (poly) oxyalkylene alkyl ethers; ester types such as (poly) oxyalkylene fatty acid monoesters; ether ester types such as (poly) oxyalkylene glycerin fatty acid esters; ) Oxyalkylene fatty acid amides, nitrogen-containing types such as (poly) oxyalkylene alkylamines and the like are mentioned. As the (poly) oxyalkylene derivatives used in the present invention, ether type and ester type are preferable, and ether type is particularly preferable .
[0013]
Examples of ether type (poly) oxyalkylene derivatives include polyoxyethylene lauryl ether, polyoxyethylene decyl ether, polyoxyethylene octyl ether, polyoxyethylene 2-ethylhexyl ether, polyoxyethylene polyoxypropylene lauryl ether, polyoxypropylene stearyl Ethers, polyoxyalkylene aliphatic ethers such as polyoxyethylene oleyl ether; polyoxyalkylene aromatic ethers such as polyoxyethylene benzyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene benzylated phenyl ether, and the like, Polyoxyalkylene aliphatic ethers are preferred.
Furthermore, polyoxyethylene alkyl or alkenyl ether and polyoxypropylene alkyl or alkenyl ether are preferable. Particularly, polyoxyethylene or polyoxypropylene has an average degree of polymerization of 1 to 10, and an alkyl group or alkenyl group having 8 to 18 carbon atoms. Preferably there is. Specifically, polyoxyethylene is abbreviated as POE (q), polyoxypropylene is abbreviated as POP (r), and q and r are average degrees of polymerization, respectively, POE (3) octyl ether, POE (4) 2− Ethylhexyl ether, POE (3) decyl ether, POE (5) decyl ether, POE (3) lauryl ether, POE (8) lauryl ether, POE (1) stearyl ether, POP (3) lauryl ether, POP (5) myristyl Examples include ether.
The above (ii) (poly) oxyalkylene derivatives may be used alone or in combination of two or more.
The ester (b) of (i) an aliphatic polyvalent carboxylic acid or an anhydride thereof and (ii) a (poly) oxyalkylene derivative of the present invention is the raw material (i) an aliphatic polyvalent carboxylic acid or an anhydride thereof. You may contain a thing. The content of the aliphatic polycarboxylic acid or its anhydride is preferably 10% by weight or less, particularly preferably 5% by weight or less. On the other hand, the ester (b) of (i) an aliphatic polyvalent carboxylic acid or its anhydride and (ii) (poly) oxyalkylene derivative may contain the raw material (ii) (poly) oxyalkylene derivative. . The content of the (ii) (poly) oxyalkylene derivative is preferably 40% by weight or less, particularly preferably 20% by weight or less.
[0014]
The additive composition (B) for rubber composition of the present invention comprises a reinforcing filler (a), an aliphatic polyvalent carboxylic acid having at least one carboxyl group in the molecule, and (poly) oxyalkylene. And ester (b) with a derivative.
Further, the weight blending ratio (a) / (b) of the component (a) to the component (b) is preferably 70/30 to 30/70 from the viewpoint of workability. From this point, (a) / (b) is preferably in the range of 60/40 to 40/60 (weight blend ratio).
The additive composition for rubber composition (B) may further contain at least one selected from (poly) oxyalkylene derivatives, alcohols and fatty acid esters thereof as the component (c). The blending amount is preferably 10 parts by weight or less with respect to 100 parts by weight of the total of the component (a) and the component (b), and even if added more, there are few advantages.
It is preferable that the melting point of the component (c) is 20 ° C. or lower and the boiling point is 150 ° C. or higher. The melting point of the component (c) is preferably 20 ° C. or less from the viewpoint of dust control during production of the rubber composition additive composition or rubber composition, and the boiling point is 150 ° C. from the viewpoint of safety during processing of the rubber composition. The above is preferable.
Here, the (poly) oxyalkylene derivative as the component (c) is the same as the (poly) oxyalkylene derivative of the above (ii), and examples thereof include an ether type, an ester type, an ether ester type, and a nitrogen-containing type. Ether type or ester type polyoxyalkylene derivatives are preferred.
Among the components (c) used in the present invention, ether type or ester type polyoxyethylene derivatives are particularly preferable. Specifically, polyoxyethylene is abbreviated as POE (n), and n represents an average degree of polymerization. POE (3) lauryl ether, POE (5) decyl ether, POE (4) oleyl ether, POE (10 ) Monolaurate, POE (10) monooleate and the like.
Moreover, the said (c) component may be used independently and may use 2 or more types together.
In order to obtain the additive composition for rubber composition, each component may be mixed using a mixer, for example, Henschel mixer, Nauter mixer, tumbler mixer, etc. The optimum range such as the rotation speed, stirring temperature, stirring time and the like is selected.
The rubber composition additive composition (B) of the present invention can be appropriately added with a compounding agent for the rubber composition in addition to the above-mentioned (a), (b) and (c). The amount is preferably 10% by weight or less of the additive composition.
[0015]
Next, the first rubber composition of the present invention comprises an ester (b) of a rubber component (A) and an aliphatic polyvalent carboxylic acid having at least one carboxyl group in the molecule and a (poly) oxyalkylene derivative. ) And a reinforcing filler (C) can be used in combination. Here, the component (b) is preferably an ester represented by the above general formula (I), specifically, mono [POE (3) lauryl ether] maleic acid ester, mono [POP (3) lauryl ether]. Maleic acid ester, mono [POE (3) 2-ethylhexyl ether] maleic acid ester and the like can be mentioned.
The second rubber composition of the present invention comprises an ester (b) of an aliphatic polyvalent carboxylic acid and a (poly) oxyalkylene derivative having at least one carboxyl group in the molecule in the rubber component (A). And an additive composition (B) for rubber composition obtained by blending the reinforcing filler (a).
[0016]
The type of the rubber component (A) used in the rubber composition of the present invention is not particularly limited, but the effect of improving processability is remarkable in the system of natural rubber alone or a blend rubber of natural rubber and synthetic rubber. Examples of synthetic rubbers that can be used include styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), butyl rubber (IIR), halogenated butyl rubber (X-IIR), ethylene propylene rubber (EPDM), and the like. These mixtures are mentioned.
When the rubber component (A) contains natural rubber, the rubber composition of the present invention can reduce the amount of the natural rubber polymer gel without reducing the molecular weight of the natural rubber molecule, and between the rubber molecules. By increasing the slippage, the molding workability is improved, and the physical properties of the unvulcanized or vulcanized rubber are prevented from lowering. In addition, when the rubber component does not contain natural rubber, the molding workability is improved by increasing the slip between the rubber molecules, and in this case as well, there is no decrease in the molecular weight of the rubber. The physical properties of vulcanized rubber do not deteriorate. In any case, in the present invention, excellent rubber processability can be obtained without adversely affecting the physical properties of the vulcanized rubber composition.
[0017]
As the reinforcing filler (a) or (C), any filler can be used as long as it can be used for a general rubber composition. One or more of these fillers can be used. May be used in combination. Specific examples include carbon black and inorganic fillers. As the inorganic filler, silica and a compound represented by the following general formula (II) are preferable.
aM ₁ ・ BSiOc ・ dH ₂ O (II)
Here, in formula (II), M ₁ Is at least one selected from metals selected from the group consisting of aluminum, magnesium, titanium, calcium, oxides or hydroxides of these metals, and hydrates thereof, and a, b, c, and d are And an integer of 1 to 5, an integer of 0 to 10, an integer of 2 to 5, and an integer of 0 to 10, respectively.
Furthermore, metals such as potassium, sodium, iron and magnesium, elements such as fluorine, and NH _Four It may contain a functional group such as-.
[0018]
Specific examples of the general formula (II) include alumina monohydrate (Al ₂ O _Three ・ H ₂ O), aluminum hydroxide such as gibbsite, bayerite [Al (OH) _Three ], Magnesium hydroxide [Mg (OH) ₂ ], Magnesium oxide (MgO), talc (3MgO.4SiO ₂ ・ H ₂ O), attapulgite (5MgO · 8SiO) ₂ ・ 9H ₂ O), titanium white (TiO ₂ ), Titanium Black (TiO _2n-1 ), Calcium oxide (CaO), calcium hydroxide [Ca (OH) ₂ ], Aluminum magnesium oxide (MgO · Al ₂ O _Three ), Clay (Al ₂ O _Three ・ 2SiO ₂ ), Kaolin (Al ₂ O _Three ・ 2SiO ₂ ・ 2H ₂ O), pyrophyllite (Al ₂ O _Three ・ 4SiO ₂ ・ H ₂ O), bentonite (Al ₂ O _Three ・ 4SiO ₂ ・ 2H ₂ O), aluminum silicate (Al ₂ SiO _Five , Al _Four ・ 3SiO _Four ・ 5H ₂ O), magnesium silicate (Mg ₂ SiO _Four MgSiO _Three Etc.), calcium silicate (Ca ₂ ・ SiO _Four Etc.), aluminum calcium silicate (Al ₂ O _Three ・ CaO ・ 2SiO ₂ Etc.), magnesium calcium silicate (CaMgSiO) _Four ), Various zeolites, feldspar, mica, etc., M ₁ Is preferably aluminum.
[0019]
Among the various fillers, carbon black, silica, and alumina are preferable as the reinforcing filler used in the present invention.
There is no restriction | limiting in particular as a kind of carbon black, Although SRF, GPF, FEF, HAF, ISAF, SAF, etc. can be used, It is preferable to select suitably according to the use of a rubber composition. For example, when used in a rubber composition for tread, carbon black having iodine adsorption (IA) of 60 mg / g or more and dibutyl phthalate oil absorption (DBP) of 80 ml / 100 g or more is preferable. By using such carbon black as a tread rubber, grip performance and fracture resistance can be improved. However, when excellent wear resistance is required, it is preferable to use HAF, ISAF, or SAF. .
The silica that can be used in the present invention is not particularly limited, and examples thereof include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and the like. Wet silica is most preferable because it has the most remarkable effect of achieving both the effect, wet grip property and rolling resistance.
Alumina means what is represented by the following general formula (III) among the compounds represented by the above formula (II).
Al ₂ O _Three ・ EH ₂ O (III)
(In the formula, e is an integer of 1 to 3)
These inorganic fillers preferably have a particle size of 10 μm or less, more preferably 3 μm or less. By setting the particle size of the inorganic filler to 10 μm or less, the fracture resistance and wear resistance of the vulcanized rubber composition can be maintained well.
These reinforcing fillers may be used alone or in combination of two or more. In particular, when silica is compounded in the rubber composition of the present invention, an effect of improving the dispersion of silica is obtained, and this effect is remarkable in a system having a high silica ratio.
The compounding amount of the reinforcing filler (a) in the additive composition (B) for the rubber composition is 70/30 as the weight blending ratio (a) / (b) to the component (b), as described above. It is preferable that it is -30/70, and it is still more preferable that it is 60 / 40-40 / 60.
Moreover, it is preferable that the compounding quantity of (b) component in the rubber composition of this invention is 0.1-10 weight part with respect to 100 weight part of rubber components (A). If it is 0.1 parts by weight or more, the processability is improved, and if it is 10 parts by weight or less, the rubber physical properties are maintained, and it is desirable from the viewpoint of cost. From this point, it is further preferably 0.5 to 5 parts by weight. These components may be blended at the time of kneading, for example. The same applies to the case where the component (b) is blended as the rubber composition additive composition (B). In this case, as the blended conversion amount of the component (b) with respect to 100 parts by weight of the rubber component. Preferably it mix | blends so that it may become 0.1-10 weight part, More preferably, it is 0.5-5 weight part.
In addition, other rubber compounding agents such as sulfur, vulcanization accelerators, process oils, anti-aging agents and the like can be appropriately compounded with the rubber composition of the present invention as necessary.
The rubber composition of the present invention is obtained by kneading using a kneading machine such as a roll or an internal mixer, and is used for tires such as tire treads, under treads, carcass, sidewalls, bead portions, and the like. Although it can be used for applications such as vibration rubber, belts, hoses and other industrial products, it is particularly suitably used as a rubber composition for tire treads.
[0020]
The tire of the present invention is produced by an ordinary method using the rubber composition of the present invention. That is, if necessary, the rubber composition of the present invention containing various chemicals as described above is extruded to each tire member at an unvulcanized stage and pasted on a tire molding machine by a usual method. The green tire is molded. The green tire is heated and pressed in a vulcanizer to obtain a tire.
The tire of the present invention thus obtained does not adversely affect the physical properties of the rubber, and since the factory workability of the rubber composition is good, it is excellent in productivity. The tire of the present invention can be used by filling the inside thereof with a gas such as air or nitrogen.
[0021]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Various measurements were performed by the following methods.
<Mooney viscosity (ML _{1 + 4} )>
As an evaluation of the processability of the rubber composition, an unvulcanized rubber sample obtained by adding and kneading a vulcanizing compound was pre-heated at 130 ° C. for 1 minute using MOIMAVISCOMETERSMV201 manufactured by SHIMADZU, and then rotating the rotor. Start and ML after 4 minutes _{1 + 4} As measured. At this time, the reciprocal of the measured value of Comparative Example 1 or Comparative Example 2 was indexed as 100. Larger values indicate better workability.
[0022]
<Breaking strength, breaking elongation>
A dumbbell shape No. 3 was used as a test piece. Test methods and result values are based on JIS K6251-1993. The results were indexed with the value of Comparative Example 1 or Comparative Example 2 as 100. The larger the value, the better the breaking strength and the larger the breaking elongation.
<Rebound resilience>
A predetermined weight was allowed to fall freely on the rubber surface, and the height at which the weight jumped up (% with respect to the dropped height) was used as a value. The test method and the value of the result are based on JISK6301-1995. The results were indexed with the value of Comparative Example 1 or Comparative Example 2 as 100. The larger the value, the greater the resilience.
<Abrasion resistance>
The amount of wear was measured based on JIS K6264-1993 by the Lambourne wear test. As a result, the reciprocal of the wear amount obtained in Comparative Example 1 or Comparative Example 2 was taken as 100, and the reciprocal of the wear amount in each example was indexed. The higher the value, the better the wear resistance.
[0023]
Examples 1-7 and Comparative Example 1
For 100 parts by weight of natural rubber (RSS # 3), the ester additive as component (b) of the types and amounts shown in Table 1, 55 parts by weight of carbon black (HAF), 2 parts by weight of stearic acid, anti-aging Agent 6PPD [N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine] 1 part by weight, wax 1 part by weight, Banbury mixer ^R The kneading was carried out at a starting temperature of 70 ° C. for 4 minutes at a rotational speed of 70 rpm. After the resulting mixture was sufficiently allowed to cool to room temperature, 3 parts by weight of zinc white, 1 part by weight of vulcanization accelerator DM (dibenzothiazyl disulfide), and vulcanization accelerator CBS (N-cyclohexyl-2-benzothiazyl) 1 part by weight of sulfenamide) and 2 parts by weight of sulfur are added, and a Banbury mixer ^R Was used, and the kneading was carried out for 1 minute at a rotation speed of 70 rpm. In Comparative Example 1, the ester additive (b) was not used.
The Mooney viscosity was measured for the obtained unvulcanized rubber composition. Moreover, about the vulcanized rubber composition obtained by vulcanizing these unvulcanized rubber compositions for 30 minutes at 150 degreeC, the breaking strength, breaking elongation, impact resilience, and abrasion resistance were evaluated by the said method. The results are shown in Table 1.
[0024]
[Table 1]

[0025]
Note 1; All the physical properties are displayed as indexes based on Comparative Example 1. The larger the value, the better.
Note 2: The amount of component (phr) (b) indicates the number of parts by weight based on 100 parts by weight of the rubber component.
Note 3: Type of component (b)
The following structural formula (IV) and x and R in Table 2 ^Three , R ^Four Compounds A, B and C represented by
[0026]
[Chemical formula 2]

[0027]
[Table 2]

[0028]
Examples 8 to 14 and Comparative Example 2
The rubber composition additive composition (B) was prepared by previously mixing the component (b) and silica in the ratio of component (b): silica = 6: 4 in the types and amounts shown in Table 3.
Next, 100 parts by weight of styrene-butadiene copolymer rubber (SBR1712: trademark, manufactured by JSR Corporation, aromatic oil is 37.5 phr oil-extended rubber, and the amount is only the rubber component) For each rubber composition additive composition (B) prepared above, 30 parts by weight of carbon black (ISAF), silica [Nippsil VN3; trademark, manufactured by Nippon Silica Kogyo Co., Ltd. (for the rubber composition) The silica used for the preparation of the additive is the same type)] in a total amount of 30 parts by weight, 1 part by weight of stearic acid, and an antioxidant 6PPD [N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine ] 1 part by weight, 1 part by weight of wax, 3 parts by weight of silane coupling agent (Si69: trademark, manufactured by Degussa) were added to a Banbury mixer. ^R The kneading was carried out at a starting temperature of 70 ° C. for 4 minutes at a rotational speed of 70 rpm.
After the resulting mixture was sufficiently allowed to cool to room temperature, 3 parts by weight of zinc white, 1 part by weight of vulcanization accelerator DM (dibenzothiazyl disulfide), 1 part by weight of vulcanization accelerator D (diphenylguanidine), vulcanization Add 1 part by weight of accelerator CBS (N-cyclohexyl-2-benzothiazylsulfenamide), 2 parts by weight of sulfur, Banbury mixer ^R Was used, and the kneading was carried out for 1 minute at a rotation speed of 70 rpm. In Comparative Example 2, the ester additive (b) was not used.
The Mooney viscosity was evaluated for the obtained unvulcanized rubber composition, and the rupture strength, elongation at break, rebound resilience, and wear resistance of the vulcanized rubber composition were evaluated by the above methods. The results are shown in Table 3.
[0029]
[Table 3]

[0030]
(note)
Same as Note 1 to Note 3 in the first table footnote.
From the above results, it can be seen that all the rubber compositions in the present invention are remarkably excellent in processability in the unvulcanized rubber, and maintain the good physical properties of the vulcanized rubber with almost no deterioration. .
[0031]
【The invention's effect】
According to the additive for rubber composition and the additive composition for rubber composition of the present invention, the processability is improved without deteriorating the physical properties of the rubber, and the surface condition of unvulcanized and vulcanized rubber is stable. A rubber composition having no problem can be obtained, and thus productivity is improved, and it can be suitably used particularly for tires.

Claims (13)

An additive for a rubber composition, which is an ester of a divalent carboxylic acid, a trivalent carboxylic acid or an anhydride thereof and a (poly) oxyalkylene derivative, having at least one carboxyl group in the molecule . The additive for a rubber composition according to claim 1, wherein the ester is an ester of a divalent carboxylic acid or an anhydride thereof and a (poly) oxyalkylene derivative. The rubber composition additive according to claim 2, wherein the divalent carboxylic acid has an unsaturated bond. The additive for rubber composition according to claim 3, wherein the divalent carboxylic acid is maleic acid or maleic anhydride. The additive for a rubber composition according to any one of claims 1 to 3, wherein the (poly) oxyalkylene derivative is a (poly) oxyalkylene alkyl ether. The additive for a rubber composition according to claim 4, wherein the (poly) oxyalkylene derivative is a (poly) oxyalkylene alkyl ether. Reinforcing filler and (a), wherein the rubber composition for additive according to any one of claim 1 to 6 (b) and the rubber composition for the additive composition characterized by containing a. The additive composition for a rubber composition according to claim 7 , wherein a weight ratio (a) / (b) of the component (a) to the component (b) is 70/30 to 30/70. object. A rubber component (A) and an ester (b) of a divalent carboxylic acid, a trivalent carboxylic acid or an anhydride thereof and a (poly) oxyalkylene derivative having at least one carboxyl group in the molecule are blended. A rubber composition characterized by comprising: Furthermore, the rubber composition of Claim 9 formed by mix | blending a reinforcing filler (C). An ester (b) of a divalent carboxylic acid, a trivalent carboxylic acid or an anhydride thereof and a (poly) oxyalkylene derivative having at least one carboxyl group in the molecule and a reinforcing filler (a); A rubber composition comprising the rubber composition (A) and the rubber composition additive composition (B) contained therein. A rubber composition additive composition (B) having a weight blending ratio (a) / (b) of 70 to 30/70 with respect to the component (b) to the component (b) is used as the rubber component (A). The rubber composition according to claim 11, which is compounded. A tire using the rubber composition according to any one of claims 9 to 12 .