JP2004010665A - Ethylenic polymer and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce an ethylenic polymer which has good flow characteristics and excellent thermal stability. <P>SOLUTION: The method for producing the ethylenic polymer, comprising polymerizing ethylene by using a metallocene catalyst and an organic peroxide at a polymerization pressure of 40 to 400 MPa in a polymerization temperature range of the melting point of the polymer to 300°C, is characterized by dividing the inside of a polymerizer into at least two polymerization zones with partition plates, supplying the metallocene catalyst into an arbitrary polymerization zone and supplying the organic peroxide into an arbitrary polymerization zone different from the metallocene catalyst-supplied polymerization zone. <P>COPYRIGHT: (C)2004,JPO

Description

【化２】

（式中、Ｍ^１はチタニウム、ジルコニウムまたはハフニウムであり、Ｘは各々独立して水素原子、ハロゲン原子、炭素数１〜２０のアルキル基、または炭素数６〜２０のアリール基、アリールアルキル基もしくはアルキルアリール基であり、Ｒ^１およびＲ^２は下記一般式（３）、（４）、（５）または（６）
【００２７】
【化３】

（式中、Ｒ^６は各々独立して水素原子、炭素数１〜２０のアルキル基、または炭素数６〜２０のアリール基、アリールアルキル基もしくはアルキルアリール基である。）
で表される配位子であり、該配位子はＭ^１と一緒にサンドイッチ構造を形成し、Ｒ^４およびＲ^５は下記一般式（７）、（８）、（９）または（１０）
【００２８】
【化４】

（式中、Ｒ^７は各々独立して水素原子、炭素数１〜２０のアルキル基、または炭素数６〜２０のアリール基、アリールアルキル基もしくはアルキルアリール基である。）
で表される配位子であり、該配位子はＭ^１と一緒にサンドイッチ構造を形成し、Ｒ^３は下記一般式（１１）
【００２９】
【化５】

（式中、Ｒ^８は各々独立して水素原子、炭素数１〜２０のアルキル基、または炭素数６〜２０のアリール基、アリールアルキル基もしくはアルキルアリール基であり、Ｍ^２は炭素原子または珪素原子である。）
で表され、Ｒ^４およびＲ^５を架橋するように作用しており、ｐは１〜５の整数である。）
で表される遷移金属化合物が挙げられる。
【００３０】
前記一般式（１）または（２）で表される化合物としては、例えば、ビス（シクロペンタジエニル）ジルコニウムジクロライド、メチレンビス（シクロペンタジエニル）チタニウムジクロライド、エチレンビス（インデニル）ハフニウムジクロライド、ジフェニルメチレン（シクロペンタジエニル−２，７−ジメチル−９−フルオレニル）ジルコニウムジクロライド、ジフェニルメチレン（シクロペンタジエニル−２，７−ジ−ｔ−ブチル−９−フルオレニル）ジルコニウムジクロライド、ジエチルシランジイルビス（２，４，５−トリメチルシクロペンタジエニル）チタニウムジクロライド、ジフェニルシランジイルビス（２，４，５−トリメチルシクロペンタジエニル）ジルコニウムジクロライド等のジクロル体および上記のジメチル体、ジエチル体、ジヒドロ体、ジフェニル体、ジベンジル体等を例示することができる。
【００３１】
本発明に用いられるプロトン酸は、下記一般式（１２）
［ＨＬ^１ _１］［Ｍ^３Ｒ^９ _４］　　　　　（１２）
（式中、Ｈはプロトンであり、Ｌ^１は各々独立してルイス塩基であり、ｌは０＜ｌ≦２であり、Ｍ^３はホウ素原子、アルミニウム原子またはガリウム原子であり、Ｒ^９は各々独立して炭素数６〜２０のハロゲン置換アリール基である。）
で表される化合物であり、ルイス酸は下記一般式（１３）
［Ｃ］［Ｍ^３Ｒ^９ _４］　　　　　（１３）
（式中、Ｃはカルボニウムカチオンまたはトロピリウムカチオンであり、Ｍ^３はホウ素原子、アルミニウム原子またはガリウム原子であり、Ｒ^９は各々独立して炭素数６〜２０のハロゲン置換アリール基である。）
で表される化合物であり、イオン化イオン性化合物は下記一般式（１４）
［Ｍ^４Ｌ^２ｍ］［Ｍ^３Ｒ^９ _４］　　　　　（１４）
（式中、Ｍ^４は周期表の第２族、第８族、第９族、第１０族、第１１族または第１２族から選ばれる金属の陽イオンであり、Ｌ^２はルイス塩基またはシクロペンタジエニル基であり、ｍは０≦ｍ≦２であり、Ｍ^３はホウ素原子、アルミニウム原子またはガリウム原子であり、Ｒ^９は各々独立して炭素数６〜２０のハロゲン置換アリール基である。）
で表される化合物であり、ルイス酸性化合物は下記一般式（１５）
Ｍ^３Ｒ^９ _３（１５）
（式中、Ｍ^３はホウ素原子、アルミニウム原子またはガリウム原子であり、Ｒ^９は各々独立して炭素数６〜２０のハロゲン置換アリール基である。）
で表される化合物である。
【００３２】
本発明の触媒の構成成分として用いられる一般式（１２）で表されるプロトン酸、一般式（１３）で表されるルイス酸、一般式（１４）で表されるイオン化イオン性化合物および一般式（１５）で表されるルイス酸性化合物、層状粘土化合物、層状粘土化合物をプロトン酸放出可能な有機カチオンで処理した変性粘土化合物は、上記の遷移金属化合物をカチオン性化合物にしうる化合物であり、生成したカチオン性化合物に対して弱く配位および／または相互作用するが、反応しない対アニオンを提供する化合物である。
【００３３】
一般式（１２）で表されるプロトン酸の具体例として、ジエチルオキソニウムテトラキス（ペンタフルオロフェニル）ボレート、ヒドロニウムテトラキス（ペンタフルオロフェニル）ボレート、Ｎ，Ｎ−ジメチルアニリニウムテトラキス（ペンタフルオロフェニル）ボレート、トリ−ｎ−ブチルアンモニウムテトラキス（ペンタフルオロフェニル）ボレート等を挙げることができるが、これらに限定されるものではない。
【００３４】
一般式（１３）で表されるルイス酸として、具体的にはトリチルテトラキス（ペンタフルオロフェニル）ボレート、トロピリウムテトラキス（ペンタフルオロフェニル）ボレート等を挙げることができるが、これらに限定されるものではない。
【００３５】
一般式（１４）で表されるイオン化イオン性化合物としては、具体的にはリチウムテトラキス（ペンタフルオロフェニル）ボレート、フェロセニウムテトラキス（ペンタフルオロフェニル）ボレート等を挙げることができるが、これらに限定されるものではない。
【００３６】
一般式（１５）で表されるルイス酸性化合物の具体的な例として、フェニルビス（パーフルオロフェニル）ボラン、トリス（３，４，５−トリフルオロフェニル）アルミニウム等を挙げることができるが、これらに限定されるものではない。
【００３７】
層状粘土化合物は、モンモリロナイト、ヘクトライト、カオリナイト等が挙げられるが、これらに限定されるものではない。
【００３８】
有機カチオンとしては、トリメチルアミン塩酸塩、トリブチルアミン塩酸塩およびこれらのハロゲン化水素酸、またはトリ（ｐ−トリル）ホスフィンヒドロブロマイドおよびこれらのヒドロクロライド、ヒドロアイオダイド、ヒドロフルオライド等が挙げられる。
【００３９】
さらに、本発明において用いられる有機アルミニウム化合物は、下記一般式（１６）
ＡｌＲ^１０ _３（１６）
（式中、Ｒ^１０は各々独立して水素原子、炭素数１〜２０のアルキル基もしくはアルコキシ基、または炭素数６〜２０のアリール基、アリールオキシ基、アリールアルキル基、アリールアルコキシ基、アルキルアリール基もしくはアルキルアリールオキシ基であり、少なくとも１つのＲ^１０は水素原子、炭素数１〜２０のアルキル基、または炭素数６〜２０のアリール基、アリールアルキル基もしくはアルキルアリール基である。）
で表される化合物である。
【００４０】
前記一般式（１６）で表される化合物としては、例えば、トリメチルアルミニウム、トリエチルアルミニウム、トリ（イソブチル）アルミニウム；ジ（イソブチル）アルミニウムハイドライド等の水素化ジアルキルアルミニウム；ジエチルアルミニウムクロライド等のジアルキルアルミニウムハライド；イソブチルアルミニウムジクロライド等のアルキルアルミニウムジハライド；ジエチルアルミニウムエトキサイド等のジアルキルアルミニウムアルコキシドが例示されるが、これらに限定されるものではない。このうち、好ましくはトリアルキルアルミニウムである。
【００４１】
上記のａ）周期表第４族の遷移金属化合物、ｂ）プロトン酸、ルイス酸、イオン化イオン性化合物、ルイス酸性化合物、または層状粘土化合物およびその有機カチオン処理化合物、およびｃ）有機アルミニウム化合物から触媒を調製する方法としては、例えば、これらの化合物を不活性な溶媒下で混合する方法が挙げられるが、これに限定されるものではない。また、触媒においてプロトン酸、ルイス酸、イオン化イオン性化合物またはルイス酸性化合物の量は遷移金属化合物に対して０．１〜１００倍ｍｏｌとするのが好ましく、特に０．５〜３０倍ｍｏｌとすることが好ましい。さらに、有機アルミニウム化合物の量は特に限定されないが、好ましくは遷移金属化合物に対して１〜１００００倍ｍｏｌである。
【００４２】
本発明において使用される有機過酸化物は、単官能、多官能有機過酸化物のいずれも使用することができる。単官能の有機過酸化物としては、例えば、オクタノイルパーオキサイドのようなジアシルパーオキサイド、ジクミルパーオキサイドのようなジアルキルパーオキサイド、クミルパーオキシネオデカネートのようなパーオキシエステル、２，２−ビス（ｔ−ブチルパーオキシ）ブタンのようなパーオキシケタール、ジ（３−メトキシ）ブチルパーオキシジカーボネートのようなパーオキシジカーボネート、ジイソプロピルベンゼンハイドロパーオキサイドのようなハイドロパーオキサイド、ｔ−ブチルトリメチルシリルパーオキサイド等が挙げられる。また、多官能の有機過酸化物としては、２，５−ジメチル−２，５−ジ（ｔ−ブチルパーオキシ）ヘキシン−３、２，５−ジメチル−２，５−ビス（ｔ−ブチルパーオキシ）ヘキサンのようなジアルキルパーオキサイドが挙げられる。
【００４３】
供給される有機過酸化物溶液の調製は、炭化水素溶媒にて希釈を行い調製する方法が挙げられるが、これに限定されるものではない。
【００４４】
このとき、重合器内におけるメタロセン触媒の供給される重合帯域と有機過酸化物が供給される重合帯域とは、１つ以上の重合帯域を間において供給されることが重合活性の低下を最小限に止めるために有効である。
【００４５】
このような個別供給方法を採用することで、メタロセン触媒と有機過酸化物を同一の重合器内部に同時に供給してもエチレン系重合体が得られる。
【００４６】
本発明によるメタロセン触媒と有機過酸化物を用いた重合は、メタロセン触媒が供給される重合帯域以外の重合帯域に有機過酸化物を供給するだけで進行する。このようにして実質上メタロセン触媒から得られるエチレン系重合体と有機過酸化物から得られるエチレン系重合体の特性を併せ持つエチレン系重合体が製造可能となる。
【００４７】
【実施例】
本発明を実施例および比較例により詳細に説明するが、本発明はこれら実施例に制限されるものではない。
【００４８】
実施例中に記載のＭＦＲ（メルトフローレート）は、ＡＳＴＭ　Ｄ１２３８条件Ｅに準ずる方法にて測定を行った。
【００４９】
本発明で得られたエチレン系重合体の密度は、ＪＩＳ　Ｋ７１０６に規定された試験条件のＤ法（密度勾配管法）にて測定を行った。
【００５０】
本発明で得られたエチレン系重合体のＭｗ／Ｍｎは、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）（ＷＡＴＥＲＳ社製　１５０Ｃ型）を用い、カラムとしてＴＳＫ−ＧＥＬ　ＧＭＨＨＲ−Ｈ（Ｓ）（東ソー（株）製）、溶媒としてｏ−ジクロロベンゼンを用い、測定温度１４０℃、測定濃度７ｍｇサンプル／１０ｍｌ（ｏ−ジクロロベンゼン）の条件下で測定した。
【００５１】
本発明で得られたエチレン系重合体の融点は、示差走査熱量計（ＤＳＣ）（セイコー電子工業製　示差走査型熱量計（ＤＳＣ−２００））を用いて、ＤＳＣ内で２００℃の温度で５分間エチレン系重合体を融解させた後、１０℃／分の速度で温度を３０℃まで下げて固化させ、１０℃／分の速度で昇温させて測定した。
【００５２】
本発明で得られたエチレン系重合体の黄色度は、自動分光式色差計（日本電色工業製（ＮＤＨ−１００１−ＤＰ））を用いて測定した。
【００５３】
実施例１
エチレン系重合体の製造プロセスにおいて、水素濃度を０．５８ｍｏｌ％、ｎ−ブタン濃度を０．５７ｍｏｌ％となるように調整し、仕切板によって４つの重合帯域に分割された７Ｌの撹拌機付き重合器（図２のａ）タイプ）を用いて、重合圧力１０３ＭＰａで、重合器への上流から一番目の重合帯域へメタロセン触媒（Ａ）を６０ｃｃ／時で供給し、その重合帯域の温度を１６０℃とし、重合器への上流から三番目の重合帯域へ有機過酸化物（Ｈ）を５０ｃｃ／時で供給し、その重合帯域の温度を２１０℃とした。
【００５４】
生成したエチレン系重合体は、未重合ガス分離器にて未重合ガスと分離され、未重合ガス分離器下部の押出機を経て、ペレットとして排出された。得られたエチレン系重合体の生産速度は５ｋｇ／時であった。なお、メタロセン触媒（Ａ）には、ジフェニルメチレン（シクロペンタジエニル）（２，７−ジ−ｔ−ブチルフルオレニル）ジルコニウムジクロライド、Ｎ，Ｎ−ジメチルアニリニウムテトラキス（ペンタフルオロフェニル）ボレート、トリエチルアルミニウムをホウ素／ジルコニウムのｍｏｌ比が１．１、アルミニウム／ジルコニウムのｍｏｌ比が２４０で、ジルコニウム濃度５６０μｍｏｌ／ｌに調製したトルエン溶液を用いた。有機過酸化物（Ｈ）には、ｔ−ブチルパーオキシピバレートを２０ｗｔ％に調製したｎ−ヘプタン溶液を用いた。
【００５５】
ＭＦＲ＝１２ｇ／１０分、密度＝０．９２８ｇ／ｃｍ^３、Ｍｗ／Ｍｎ＝４．７、黄色度＝−２．６、また、図１に示すように、１１１℃と１２９℃に２つの融点を持つエチレン系重合体が得られた。
【００５６】
実施例２
水素濃度を０．７７ｍｏｌ％、ｎ−ブタン濃度を１．０１ｍｏｌ％とし、メタロセン触媒での重合帯域温度を１９０℃とした以外は実施例１と同様に行った。
【００５７】
ＭＦＲ＝３３ｇ／１０分、密度＝０．９２５ｇ／ｃｍ^３、Ｍｗ／Ｍｎ＝５．５、黄色度＝−２．８、１０９℃と１２８℃に２つの融点を持つエチレン系重合体が得られた。
【００５８】
実施例３
水素濃度を０．５６ｍｏｌ％、ｎ−ブタン濃度を０ｍｏｌ％とし、有機過酸化物での重合帯域温度を１６０℃とした以外は実施例１と同様に行った。
【００５９】
ＭＦＲ＝５．６ｇ／１０分、密度＝０．９３４ｇ／ｃｍ^３、Ｍｗ／Ｍｎ＝３．１、黄色度＝−２．５、１１１℃と１２８℃に２つの融点を持つエチレン系重合体が得られた。
【００６０】
比較例１
水素濃度を０．０５ｍｏｌ％、ｎ−ブタン濃度を１．２０ｍｏｌ％とし、メタロセン触媒（Ａ）の供給をしなかった以外は実施例１と同様に行った。
【００６１】
ＭＦＲ＝２．２ｇ／１０分、密度＝０．９２１ｇ／ｃｍ^３、Ｍｗ／Ｍｎ＝３．９、黄色度＝−３．０、融点＝１０８℃のエチレン系重合体が得られた。融点は実施例１〜３と異なり、単一ピークであった。
【００６２】
比較例２
水素濃度を０．５６ｍｏｌ％、ｎ−ブタン濃度を０ｍｏｌ％とし、メタロセン触媒での重合帯域温度を１６０℃とし、有機過酸化物（Ｈ）の供給をしなかった以外は実施例２と同様に行った。
【００６３】
ＭＦＲ＝４１０ｇ／１０分、密度＝０．９５０ｇ／ｃｍ^３、Ｍｗ／Ｍｎ＝２．８、黄色度＝−２．７、融点＝１３４℃のエチレン系重合体が得られた。融点は比較例１と同様に、単一のピークであった。
【００６４】
比較例３
水素濃度を０．５６ｍｏｌ％、ｎ−ブタンの濃度を０ｍｏｌ％とし、有機過酸化物での重合帯域温度を１６０℃とした以外は比較例１と同様に行った。
【００６５】
重合器下流の減圧弁下流で、エチレン系重合体のＭＦＲの低下に伴う閉塞がおこり、エチレン系重合体を連続的に製造することは不可能となった。重合器を開放し、得られたエチレン系重合体の物性確認を行ったところ、ＭＦＲ＝０．０８ｇ／１０分、密度＝０．９２３ｇ／ｃｍ^３、Ｍｗ／Ｍｎ＝３．７、黄色度＝−２．５、融点＝１０９℃のエチレン系重合体であった。融点は比較例１と同様に、単一のピークであった。
【００６６】
比較例４
比較例１で得られたエチレン系重合体と比較例２で得られたエチレン系重合体をペレットの状態で各１ｋｇずつ１：１の比率で均一に分散させた上で、２５ｍｍΦ溶融混練機で１６０℃にて溶融混練を実施した。この溶融混練機はシリンダー部分に２箇所とダイス部分に１箇所の温度調整ができる構造を有しており、Ｌ／Ｄ＝２５である。結果、ＭＦＲ＝２９ｇ／１０分、密度＝０．９３６ｇ／ｃｍ^３、Ｍｗ／Ｍｎ＝３．３、黄色度＝−０．４、融点＝１０６℃、１２６℃のエチレン系重合体が吐出量＝３．５ｋｇ／時で得られた。
【００６７】
実施例１〜３と比較して黄色度が劣る結果となった。
【００６８】
各実施例、比較例の結果を表１に示す。
【００６９】
【表１】

【発明の効果】
本発明の効果は、以下の点にある。
（１）メタロセン触媒で得られるエチレン系重合体の優れた特性と有機過酸化物で得られるエチレン系重合体の良好な流動特性を併せ持ち、熱安定性にも優れたエチレン系重合体が得られる。
（２）仕切板の作用により、有機過酸化物の含酸素部位がメタロセン触媒によるエチレン重合を阻害することなく、有機過酸化物触媒で得られる低融点のエチレン系重合体とメタロセン触媒で得られる高融点のエチレン系重合体の優れた特性を併せ持つエチレン系重合体の生産が可能である。
（３）莫大な投資によるプロセスの改造を必要とせずに、得られるエチレン系重合体の改良が可能となる。
【図面の簡単な説明】
【図１】実施例１により得られたエチレン系重合体の示差走査型熱量計（ＤＳＣ）チャートである。
【図２】本発明に使用する重合器の一例を示す図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a novel ethylene polymer and a method for producing the same at high temperature and pressure. More specifically, an ethylene polymer having both excellent properties of an ethylene polymer obtained with a metallocene catalyst and good flow properties of an ethylene polymer obtained with an organic peroxide, and also having excellent thermal stability, and The present invention relates to a method for producing the same under the conditions of high temperature and high pressure in one polymerization vessel in the presence of a metallocene catalyst and an organic peroxide.
[0002]
[Prior art]
As the ethylene polymer, those having a relatively narrow molecular weight distribution produced using a metallocene catalyst and those having a relatively wide molecular weight distribution produced using an organic peroxide are known.
[0003]
Among these, the ethylene-based polymer produced using a metallocene catalyst has a feature that, in addition to a narrow molecular weight distribution, a comonomer composition obtained by copolymerization is uniform. Therefore, in applications requiring cleanliness, such as medical container applications and food packaging applications, the amount of low molecular weight components that elute into the inside of the package or the contents in the container is small, which is an advantageous characteristic. However, since the molecular weight distribution is narrow, the melt flow characteristics during molding are poor, and there is room for improvement.
[0004]
On the other hand, ethylene polymers produced under high temperature and high pressure using organic peroxides have good melt flow properties due to their wide molecular weight distribution and long chain branches in the polymer molecules. Has excellent properties. However, this ethylene-based polymer generally has a low density, a low melting point, and a large molecular weight distribution, and thus contains many low molecular weight components, so that it elutes into the inside of the package or the contents of the container in medical container applications or food packaging applications. The amount was large and it was difficult to use for these applications.
[0005]
As a method for combining the excellent properties of the ethylene polymer obtained with the metallocene catalyst and the ethylene polymer obtained with the organic peroxide as described above, the ethylene polymer obtained with the metallocene catalyst and the organic peroxide are used. It is generally known that an ethylene polymer obtained at a high temperature and a high pressure is independently obtained, and then mixed at an arbitrary ratio by melt kneading.
[0006]
However, in this melt-kneading method, 1) the ethylene-based polymer receives an extra heat history due to the melt-kneading, so that the thermal stability is reduced to cause coloration and gelation, and the appearance of the final product packaging film or molded container is deteriorated. 2) Increasing the number of steps of melt-kneading causes a problem that labor is increased and power consumption of the granulator is increased.
[0007]
By the way, a method for producing an ethylene-based polymer using a metallocene catalyst and an organic peroxide simultaneously has not been known so far. The reason is that a catalyst using a transition metal component as a catalytically active species, such as a metallocene catalyst or a Ziegler catalyst, is poisoned by an oxygen-containing compound, and thus organic peroxides become catalyst poisons. This is because the pieces and the organic peroxide are poisoned by the reducing compound, and the metallocene catalyst becomes a catalyst poison. As an example showing this concretely, for example, there is a proposal of Japanese Patent Application Laid-Open No. 58-225106. This proposal is based on a method for producing an ethylene / α-olefin copolymer in a continuous polymerization process under high temperature and high pressure using a Ziegler-type catalyst. This is a technique of supplying an organic peroxide as a reactant.
[0008]
This proposal relates to reduction of low molecular weight wax components and oligomer components by-produced in an ethylene / α-olefin copolymer obtained by production using a Ziegler-type catalyst. The ethylene / α-olefin copolymer obtained with the Ziegler-type catalyst generates a low molecular weight wax component and an oligomer component when the residual active species of the catalyst cannot be deactivated, and is used for the purpose of deactivating the residual active species. Supplies organic peroxides. That is, it is a proposal to prevent the post-reaction after the polymerization reactor by supplying an organic peroxide which is a catalyst poison to the Ziegler catalyst.
[0009]
As is clear from this example, when the metallocene catalyst and the organic peroxide are simultaneously supplied to the polymerization reactor, the transition metal component, which is a catalytically active species of the metallocene catalyst, easily reacts with oxygen of the organic peroxide. As a result, there was a technically high barrier that no longer exhibited catalytic activity with each other.
[0010]
[Problems to be solved by the invention]
The present inventors have combined the excellent properties of an ethylene polymer obtained with a metallocene catalyst and the good flow properties of an ethylene polymer obtained with an organic peroxide, and have excellent thermal stability. Various studies were conducted to obtain. As a result, they have found that the above-mentioned ethylene-based polymer can be obtained in a process of continuously polymerizing ethylene under high temperature and high pressure, and completed the present invention. An object of the present invention is to provide an ethylene polymer having a small amount of components eluted into the inside of a package or a molded container, excellent in processability, and excellent in thermal stability, and a method for producing the same.
[0011]
[Means for Solving the Problems]
That is, the present invention is an ethylene-based ethylene-based polymer,
(A) Density is 0.910 to 0.960 g / cm³,
(B) a melt flow rate (MFR) under a load of 2.16 kg is 0.1 to 100 g / 10 minutes,
(C) It has two or more melting point peaks determined by a differential scanning calorimeter (DSC), has at least one low-temperature side melting peak at 118 ° C. or lower, and has a low-temperature side melting peak and a constant-temperature base line (obtained by holding at a constant temperature). The area ratio of an area S1 composed of a base line to be measured and a perpendicular to the temperature axis of 118 ° C., and an area ratio of an upper-side melting point peak of 118 ° C. or more to an area S2 composed of a constant temperature baseline and a perpendicular to the temperature axis of 118 ° C. S1 / S2) is 0.05 ≦ (S1 / S2) ≦ 20,
Ethylene-based polymer characterized by the fact that, using a metallocene catalyst and an organic peroxide, an ethylene-based polymer which is polymerized at a polymerization pressure of 40 to 400 MPa and a polymerization temperature range of the melting point of the polymer to 300 ° C. In the production method, the inside of the polymerization vessel is divided into at least two or more polymerization zones by a partition plate, a metallocene catalyst is added to an arbitrary polymerization zone, and an organic peroxide is added to an arbitrary polymerization zone different from the polymerization zone for supplying the metallocene catalyst. The present invention relates to a method for producing an ethylene-based polymer, characterized in that ethylene is polymerized by supplying an ethylene polymer.
[0012]
Further, a) a transition metal compound of Group 4 of the periodic table, b) a protonic acid, a Lewis acid, an ionized ionic compound, a Lewis acidic compound, or a layered clay compound and an organic cation-treated compound thereof, and c) an organoaluminum compound. The present invention also relates to a method for producing an ethylene polymer, which comprises using a metallocene catalyst as a constituent component and an organic peroxide.
[0013]
Hereinafter, the present invention will be described in more detail.
[0014]
The ethylene polymer in the present invention has a density of 0.910 to 0.960 g / cm.³1. Melt flow rate (MFR) under a load of 2.16 kg, 0.1 to 100 g / 10 min, having two or more melting point peaks determined by a differential scanning calorimeter (DSC) as shown in FIG. Below, there is at least one low-temperature side melting point peak, an area S1 composed of a low-temperature side melting point peak, a constant-temperature base line, and a perpendicular to the temperature axis of 118 ° C. Is an ethylene homopolymer having an area ratio (S1 / S2) of 0.05 ≦ (S1 / S2) ≦ 20 with respect to an area S2 constituted by a perpendicular to the temperature axis. The area S1 and the area S2 are divided by a line perpendicular to the temperature axis of 118 ° C., which is generally an ethylene-based polymer obtained from an organic peroxide having a melting point peak at 118 ° C. or lower in an ethylene-based polymer. And a density of 0.93 g / cm obtained with a metallocene catalyst exhibiting a melting point peak at 118 ° C. or higher in the ethylene polymer.³The above ethylene-based polymer is set as a dividing line for dividing.
[0015]
The density of the ethylene polymer in the present invention is 0.910 g / cm.³If it is less than this, the heat resistance will be reduced, and it will be difficult to develop it for medical container applications and food packaging applications. 0.960 g / cm³If it exceeds, the transparency is undesirably reduced. If the melt flow rate (MFR) at a load of 2.16 kg is less than 0.1 g / 10 min, the gloss of the product deteriorates, and if it exceeds 100 g / 10 min, disadvantages such as poor moldability occur, which is not preferable. .
[0016]
The ethylene polymer, wherein (S1 / S2) satisfies 0.05 ≦ (S1 / S2) ≦ 20, reduces an elution component, which is a feature of the ethylene polymer obtained with a metallocene catalyst, A good balance of the processability characteristic of the ethylene polymer obtained under high temperature and high pressure by using an organic peroxide. When (S1 / S2) <0.05 or (S1 / S2)> 20, an ethylene polymer obtained by using a metallocene catalyst or an ethylene polymer obtained by using an organic peroxide at high temperature and high pressure Is preferentially indicated, so that the effect of improvement is reduced.
[0017]
In the present invention, as a result of diligent studies on ethylene polymerization by simultaneously supplying a metallocene catalyst and an organic peroxide to a polymerization reactor, metallocene was added to an arbitrary polymerization zone in a polymerization reactor divided into two or more polymerization zones by a partition plate. By supplying the catalyst and supplying the organic peroxide to a polymerization zone different from the zone where the metallocene catalyst is supplied, the ethylene polymer obtained with the metallocene catalyst and the ethylene polymer obtained with the organic peroxide are excellent. It has been found that an ethylene-based polymer having the above-mentioned properties can be obtained without a melt-kneading step. Furthermore, by using the individual feeding method to the polymerization zone divided by the partition plate as described above, the metallocene catalyst is suppressed from reacting with the oxygen-containing site of the organic peroxide and being deactivated, and the polymerization reactor is controlled. The inventors have found that the inhibition of the polymerization reaction for obtaining an ethylene-based polymer therein is minimized, and have completed the present invention.
[0018]
The polymerization vessel in the present invention is divided into two or more polymerization zones, preferably four or more polymerization zones as shown in FIG. 2 by a partition plate. The dividing method may be either a method of attaching a partition plate to an internal stirring type stirrer or a method of attaching a partition plate to a polymerization vessel main body. The area (Sb) ratio Sb / Sr of the partition plate to the polymerization vessel cross-sectional area (Sr) is preferably 0.25 ≦ Sb / Sr ≦ 0.96, and considering practicality, 0.36 ≦ Sb / Sr ≦ 0. 90 is more preferred.
[0019]
Ethylene supplied to the polymerization vessel is individually supplied to the polymerization zone divided by these partition plates at an arbitrary flow rate through a flow control valve.
[0020]
The metallocene catalyst and the organic peroxide may be supplied to any polymerization zone unless they are in the same polymerization zone of the polymerization vessel, but it is preferable to supply them in one or more polymerization zones in consideration of practicality. . At this time, the residence time of the metallocene catalyst in the polymerization zone for supplying the metallocene catalyst is preferably 30 seconds or more, and more preferably 120 to 400 seconds in consideration of practicality. The residence time of the organic peroxide in the polymerization zone for supplying the organic peroxide is also preferably 30 seconds or more, and more preferably 120 to 400 seconds in consideration of practicality.
[0021]
The polymerization temperature is preferably in the range of the melting point of the ethylene polymer to 300 ° C.
[0022]
The polymerization pressure is preferably in the range of 40 to 400 MPa, and more preferably in the range of 50 to 200 MPa in consideration of practicality.
[0023]
In the polymerization in the present invention, the ethylene polymer and the unpolymerized gas exiting the polymerization vessel are depressurized by a pressure reducing valve, and are separated in a separator located at a later stage. The separated and recovered recycle gas is a continuous polymerization that is treated again as a supply gas.
[0024]
The metallocene catalyst used in the present invention includes, for example, a) a transition metal compound of Group 4 of the periodic table, b) a protonic acid, a Lewis acid, an ionized ionic compound, a Lewis acidic compound, or a layered clay compound and an organic cation-treated compound thereof. And c) a catalyst comprising an organoaluminum compound, and these are used in combination of two or more, and more preferably in combination of two to four.
[0025]
The transition metal compound of Group 4 of the periodic table used in the present invention has the following general formula (1) or (2)
[0026]
Embedded image

Embedded image

(Where M¹Is titanium, zirconium or hafnium, X is each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, an arylalkyl group or an alkylaryl group, R¹And R²Is the following general formula (3), (4), (5) or (6)
[0027]
Embedded image

(Where R⁶Is independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group, an arylalkyl group or an alkylaryl group having 6 to 20 carbon atoms. )
A ligand represented by the formula:¹To form a sandwich structure with⁴And R⁵Is the following general formula (7), (8), (9) or (10)
[0028]
Embedded image

(Where R⁷Is independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group, an arylalkyl group or an alkylaryl group having 6 to 20 carbon atoms. )
A ligand represented by the formula:¹To form a sandwich structure with³Is the following general formula (11)
[0029]
Embedded image

(Where R⁸Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group, an arylalkyl group or an alkylaryl group having 6 to 20 carbon atoms;²Is a carbon atom or a silicon atom. )
And R⁴And R⁵And p is an integer of 1 to 5. )
The transition metal compound represented by these is mentioned.
[0030]
Examples of the compound represented by the general formula (1) or (2) include bis (cyclopentadienyl) zirconium dichloride, methylenebis (cyclopentadienyl) titanium dichloride, ethylenebis (indenyl) hafnium dichloride, and diphenylmethylene (Cyclopentadienyl-2,7-dimethyl-9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl-2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, diethylsilanediylbis (2 Dichloride such as 2,4,5-trimethylcyclopentadienyl) titanium dichloride, diphenylsilanediylbis (2,4,5-trimethylcyclopentadienyl) zirconium dichloride and the above-mentioned dimethyl form Diethyl body, dihydro derivative, diphenyl body, can be exemplified dibenzyl and the like.
[0031]
The protonic acid used in the present invention has the following general formula (12)
[HL¹ ₁] [M³R⁹ ₄] (12)
Wherein H is a proton and L¹Are each independently a Lewis base, 1 is 0 <l ≦ 2,³Is a boron, aluminum or gallium atom;⁹Are each independently a halogen-substituted aryl group having 6 to 20 carbon atoms. )
Wherein the Lewis acid is represented by the following general formula (13)
[C] [M³R⁹ ₄] (13)
Wherein C is a carbonium cation or a tropylium cation;³Is a boron, aluminum or gallium atom;⁹Are each independently a halogen-substituted aryl group having 6 to 20 carbon atoms. )
Wherein the ionized ionic compound is represented by the following general formula (14)
[M⁴L²m] [M³R⁹ ₄] (14)
(Where M⁴Is a cation of a metal selected from the second, eighth, ninth, tenth, tenth, and eleventh groups of the periodic table;²Is a Lewis base or a cyclopentadienyl group, m is 0 ≦ m ≦ 2,³Is a boron, aluminum or gallium atom;⁹Are each independently a halogen-substituted aryl group having 6 to 20 carbon atoms. )
The Lewis acidic compound is represented by the following general formula (15)
M³R⁹ ₃(15)
(Where M³Is a boron, aluminum or gallium atom;⁹Are each independently a halogen-substituted aryl group having 6 to 20 carbon atoms. )
It is a compound represented by these.
[0032]
The protonic acid represented by the general formula (12), the Lewis acid represented by the general formula (13), the ionized ionic compound represented by the general formula (14), and the general formula used as the components of the catalyst of the present invention. The Lewis acidic compound, the layered clay compound, and the modified clay compound obtained by treating the layered clay compound with an organic cation capable of releasing a proton acid represented by (15) are compounds capable of converting the above transition metal compound into a cationic compound. Are compounds that weakly coordinate and / or interact with a cationic compound, but provide a non-reactive counter anion.
[0033]
Specific examples of the protonic acid represented by the general formula (12) include diethyloxonium tetrakis (pentafluorophenyl) borate, hydronium tetrakis (pentafluorophenyl) borate, and N, N-dimethylanilinium tetrakis (pentafluorophenyl) Borate, tri-n-butylammonium tetrakis (pentafluorophenyl) borate, and the like, but are not limited thereto.
[0034]
Specific examples of the Lewis acid represented by the general formula (13) include trityltetrakis (pentafluorophenyl) borate and tropyliumtetrakis (pentafluorophenyl) borate, but are not limited thereto. Absent.
[0035]
Specific examples of the ionized ionic compound represented by the general formula (14) include lithium tetrakis (pentafluorophenyl) borate and ferrocenium tetrakis (pentafluorophenyl) borate, but are not limited thereto. It is not done.
[0036]
Specific examples of the Lewis acidic compound represented by the general formula (15) include phenylbis (perfluorophenyl) borane and tris (3,4,5-trifluorophenyl) aluminum. However, the present invention is not limited to this.
[0037]
Examples of the layered clay compound include, but are not limited to, montmorillonite, hectorite, kaolinite, and the like.
[0038]
Examples of the organic cation include trimethylamine hydrochloride, tributylamine hydrochloride and their hydrohalic acids, or tri (p-tolyl) phosphine hydrobromide and their hydrochlorides, hydroiodides and hydrofluorides.
[0039]
Further, the organoaluminum compound used in the present invention has the following general formula (16)
AlR¹⁰ ₃(16)
(Where R¹⁰Each independently represents a hydrogen atom, an alkyl group or an alkoxy group having 1 to 20 carbon atoms, or an aryl group, an aryloxy group, an arylalkyl group, an arylalkoxy group, an alkylaryl group, or an alkylaryloxy group having 6 to 20 carbon atoms. And at least one R¹⁰Is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group, arylalkyl group or alkylaryl group having 6 to 20 carbon atoms. )
It is a compound represented by these.
[0040]
Examples of the compound represented by the general formula (16) include trimethylaluminum, triethylaluminum, tri (isobutyl) aluminum; dialkylaluminum hydride such as di (isobutyl) aluminum hydride; dialkylaluminum halide such as diethylaluminum chloride; Examples thereof include, but are not limited to, alkylaluminum dihalides such as isobutylaluminum dichloride; and dialkylaluminum alkoxides such as diethylaluminum ethoxide. Of these, trialkylaluminum is preferred.
[0041]
A catalyst comprising a) a transition metal compound of Group 4 of the Periodic Table, b) a protonic acid, a Lewis acid, an ionized ionic compound, a Lewis acidic compound, or a layered clay compound and an organic cation-treated compound, and c) an organoaluminum compound. Examples of a method for preparing a compound include, but are not limited to, a method of mixing these compounds in an inert solvent. In the catalyst, the amount of the protonic acid, Lewis acid, ionized ionic compound or Lewis acidic compound is preferably 0.1 to 100 times mol, particularly 0.5 to 30 times mol, of the transition metal compound. Is preferred. Furthermore, the amount of the organoaluminum compound is not particularly limited, but is preferably 1 to 10000 times the mol of the transition metal compound.
[0042]
As the organic peroxide used in the present invention, any of monofunctional and polyfunctional organic peroxides can be used. Examples of the monofunctional organic peroxide include diacyl peroxides such as octanoyl peroxide, dialkyl peroxides such as dicumyl peroxide, peroxyesters such as cumylperoxyneodecanate, and 2,2. Peroxyketals such as -bis (t-butylperoxy) butane, peroxydicarbonates such as di (3-methoxy) butylperoxydicarbonate, hydroperoxides such as diisopropylbenzene hydroperoxide, t- Butyltrimethylsilyl peroxide and the like. Examples of the polyfunctional organic peroxide include 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 and 2,5-dimethyl-2,5-bis (t-butylperoxy). Dialkyl peroxides such as oxy) hexane.
[0043]
The method of preparing the supplied organic peroxide solution includes, for example, a method of preparing the solution by dilution with a hydrocarbon solvent, but is not limited thereto.
[0044]
At this time, the polymerization zone in which the metallocene catalyst is supplied and the polymerization zone in which the organic peroxide is supplied in the polymerization vessel may be supplied between at least one polymerization zone to minimize a decrease in polymerization activity. It is effective to stop at.
[0045]
By employing such an individual supply method, an ethylene polymer can be obtained even if the metallocene catalyst and the organic peroxide are simultaneously supplied into the same polymerization vessel.
[0046]
The polymerization using the metallocene catalyst and the organic peroxide according to the present invention proceeds only by supplying the organic peroxide to a polymerization zone other than the polymerization zone to which the metallocene catalyst is supplied. In this way, it is possible to produce an ethylene polymer having substantially the characteristics of an ethylene polymer obtained from a metallocene catalyst and an ethylene polymer obtained from an organic peroxide.
[0047]
【Example】
The present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
[0048]
The MFR (melt flow rate) described in the examples was measured by a method according to ASTM D1238 condition E.
[0049]
The density of the ethylene polymer obtained in the present invention was measured by the method D (density gradient tube method) under the test conditions specified in JIS K7106.
[0050]
The Mw / Mn of the ethylene-based polymer obtained in the present invention was determined by gel permeation chromatography (GPC) (150C type manufactured by WATERS) and using TSK-GEL @ GMHHR-H (S) as a column (Tosoh Corporation). And o-dichlorobenzene as a solvent at a measurement temperature of 140 ° C. and a measurement concentration of 7 mg sample / 10 ml (o-dichlorobenzene).
[0051]
The melting point of the ethylene polymer obtained in the present invention was determined at a temperature of 200 ° C. in a DSC using a differential scanning calorimeter (DSC) (a differential scanning calorimeter (DSC-200) manufactured by Seiko Instruments Inc.). After melting the ethylene polymer for 10 minutes, the temperature was lowered to 30 ° C. at a rate of 10 ° C./min to solidify, and the temperature was increased at a rate of 10 ° C./min for measurement.
[0052]
The yellowness of the ethylene polymer obtained in the present invention was measured using an automatic spectroscopic color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd. (NDH-1001-DP)).
[0053]
Example 1
In the production process of the ethylene polymer, the hydrogen concentration was adjusted to 0.58 mol% and the n-butane concentration to 0.57 mol%, and 7 L of polymerization with a stirrer divided into four polymerization zones by a partition plate. A metallocene catalyst (A) was supplied to the first polymerization zone from the upstream to the polymerization reactor at a polymerization pressure of 103 MPa at a polymerization pressure of 103 MPa using a reactor (type a in FIG. 2A), and the temperature of the polymerization zone was raised to 160 ° C, an organic peroxide (H) was supplied at 50 cc / hour to the third polymerization zone from the upstream to the polymerization vessel, and the temperature of the polymerization zone was 210 ° C.
[0054]
The produced ethylene polymer was separated from the unpolymerized gas by the unpolymerized gas separator, and was discharged as pellets through an extruder below the unpolymerized gas separator. The production rate of the obtained ethylene polymer was 5 kg / hour. The metallocene catalyst (A) includes diphenylmethylene (cyclopentadienyl) (2,7-di-t-butylfluorenyl) zirconium dichloride, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, A toluene solution of triethylaluminum prepared with a boron / zirconium mole ratio of 1.1, an aluminum / zirconium mole ratio of 240, and a zirconium concentration of 560 μmol / l was used. As the organic peroxide (H), an n-heptane solution in which t-butyl peroxypivalate was adjusted to 20 wt% was used.
[0055]
MFR = 12 g / 10 min, density = 0.928 g / cm³, Mw / Mn = 4.7, yellowness = −2.6, and, as shown in FIG. 1, an ethylene polymer having two melting points at 111 ° C. and 129 ° C. was obtained.
[0056]
Example 2
Example 1 was repeated except that the hydrogen concentration was 0.77 mol%, the n-butane concentration was 1.01 mol%, and the polymerization zone temperature with the metallocene catalyst was 190 ° C.
[0057]
MFR = 33 g / 10 min, density = 0.925 g / cm³, Mw / Mn = 5.5, yellowness = −2.8, and an ethylene polymer having two melting points at 109 ° C. and 128 ° C. was obtained.
[0058]
Example 3
Example 1 was repeated except that the hydrogen concentration was 0.56 mol%, the n-butane concentration was 0 mol%, and the polymerization zone temperature with organic peroxide was 160 ° C.
[0059]
MFR = 5.6 g / 10 min, density = 0.934 g / cm³, Mw / Mn = 3.1, yellowness = −2.5, and an ethylene polymer having two melting points at 111 ° C. and 128 ° C. was obtained.
[0060]
Comparative Example 1
The procedure was performed in the same manner as in Example 1 except that the hydrogen concentration was 0.05 mol%, the n-butane concentration was 1.20 mol%, and the metallocene catalyst (A) was not supplied.
[0061]
MFR = 2.2 g / 10 min, density = 0.921 g / cm³, Mw / Mn = 3.9, yellowness = −3.0, melting point = 108 ° C. An ethylene polymer was obtained. The melting point was a single peak different from Examples 1 to 3.
[0062]
Comparative Example 2
As in Example 2, except that the hydrogen concentration was 0.56 mol%, the n-butane concentration was 0 mol%, the polymerization zone temperature with the metallocene catalyst was 160 ° C., and the supply of the organic peroxide (H) was not performed. went.
[0063]
MFR = 410 g / 10 min, density = 0.950 g / cm³, Mw / Mn = 2.8, yellowness = −2.7, melting point = 134 ° C., were obtained. The melting point was a single peak as in Comparative Example 1.
[0064]
Comparative Example 3
Comparative Example 1 was carried out in the same manner as in Comparative Example 1 except that the hydrogen concentration was 0.56 mol%, the concentration of n-butane was 0 mol%, and the polymerization zone temperature of the organic peroxide was 160 ° C.
[0065]
On the downstream side of the pressure reducing valve downstream of the polymerization vessel, clogging occurred due to a decrease in the MFR of the ethylene-based polymer, making it impossible to continuously produce the ethylene-based polymer. When the polymerization vessel was opened and the physical properties of the obtained ethylene polymer were confirmed, the MFR was 0.08 g / 10 min, and the density was 0.923 g / cm.³, Mw / Mn = 3.7, yellowness = −2.5, melting point = 109 ° C. The melting point was a single peak as in Comparative Example 1.
[0066]
Comparative Example 4
The ethylene-based polymer obtained in Comparative Example 1 and the ethylene-based polymer obtained in Comparative Example 2 were uniformly dispersed in the form of pellets at a ratio of 1: 1 for each 1 kg, and then melted with a 25 mmΦ melt kneader. Melt kneading was performed at 160 ° C. This melt kneader has a structure in which the temperature can be adjusted in two places in the cylinder part and one place in the die part, and L / D = 25. Result, MFR = 29 g / 10 min, density = 0.936 g / cm³, Mw / Mn = 3.3, yellowness = −0.4, melting point = 106 ° C., 126 ° C. An ethylene polymer having a discharge rate of 3.5 kg / hour was obtained.
[0067]
As a result, the yellowness was inferior to those of Examples 1 to 3.
[0068]
Table 1 shows the results of the examples and the comparative examples.
[0069]
[Table 1]

【The invention's effect】
The effects of the present invention are as follows.
(1) An ethylene polymer having both the excellent properties of an ethylene polymer obtained with a metallocene catalyst and the good flow properties of an ethylene polymer obtained with an organic peroxide, and also having excellent thermal stability can be obtained. .
(2) By the action of the partition plate, the oxygen-containing site of the organic peroxide is obtained by the metallocene catalyst and the low-melting-point ethylene polymer obtained by the organic peroxide catalyst without inhibiting the ethylene polymerization by the metallocene catalyst. It is possible to produce an ethylene polymer having excellent characteristics of a high melting point ethylene polymer.
(3) The obtained ethylene-based polymer can be improved without requiring a remodeling of the process with a huge investment.
[Brief description of the drawings]
FIG. 1 is a differential scanning calorimeter (DSC) chart of the ethylene-based polymer obtained in Example 1.
FIG. 2 is a diagram showing an example of a polymerization vessel used in the present invention.

Claims (3)

An ethylene polymer of ethylene alone,
(A) a density of 0.910 to 0.960 g / cm ³ ,
(B) a melt flow rate (MFR) under a load of 2.16 kg is 0.1 to 100 g / 10 minutes,
(C) It has two or more melting point peaks determined by a differential scanning calorimeter (DSC), has at least one low-temperature side melting peak at 118 ° C. or lower, and has a low-temperature side melting peak and a constant-temperature base line (obtained by holding at a constant temperature). The area ratio of an area S1 composed of a base line to be measured and a perpendicular to the temperature axis of 118 ° C., and an area ratio of an upper-side melting point peak of 118 ° C. or more to an area S2 composed of a constant temperature baseline and a perpendicular to the temperature axis of 118 ° C. S1 / S2) is 0.05 ≦ (S1 / S2) ≦ 20,
An ethylene-based polymer, characterized in that: In a method for producing an ethylene-based polymer which is polymerized at a polymerization pressure of 40 to 400 MPa and a polymerization temperature range of the melting point of the polymer to 300 ° C. using a metallocene catalyst and an organic peroxide, at least two parts of the inside of the polymerization vessel are separated by a partition plate. It is characterized in that ethylene is polymerized by dividing the polymerization zone into the above polymerization zones, supplying a metallocene catalyst to an arbitrary polymerization zone, and supplying an organic peroxide to an arbitrary polymerization zone different from the polymerization zone for supplying the metallocene catalyst. A method for producing the ethylene-based polymer according to claim 1. a) a transition metal compound of Group 4 of the periodic table, b) a protonic acid, a Lewis acid, an ionized ionic compound, a Lewis acidic compound, or a layered clay compound and an organic cation-treated compound, and c) an organoaluminum compound as constituents. The method for producing an ethylene-based polymer according to claim 2, wherein a metallocene catalyst to be used and an organic peroxide are used.

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