JP3561156B2 - Continuous production method of propylene-based block copolymer - Google Patents

Description

【００２５】
（一般式（Ｉ）中、Ａ^１ およびＡ^２ は、置換基を有していてもよい共役五員環配位子（同一化合物内においてＡ^１ およびＡ^２ は同一でも異なっていてもよい）を示し、Ｑは、２つの共役五員環配位子を任意の位置で架橋する結合性基、Ｍは、周期律表４〜６族から選ばれる金属原子を示し、そして、ＸおよびＹは、それぞれ独立して、Ｍと結合した水素原子、ハロゲン原子、炭化水素基、アミノ基、ハロゲン化炭化水素基、酸素含有炭化水素基、窒素含有炭化水素基、リン含有炭化水素基またはケイ素含有炭化水素基を示す。）ものが好ましい。またＡ^１ およびＡ^２ が、共役五員環配位子（同一化合物内においてＡ^１ およびＡ^２ は同一でも異なっていてもよい）を示し、そのうち少なくとも一方は、共役五員環配位子上の隣接した置換基が結合し五員環の２原子を含めて７〜１０員のベンゼン環、またはナフタレン環等の縮合環を有し、Ｑは、２つの共役五員環配位子を任意の位置で架橋する結合性基、Ｍは周期律表４〜６族から選ばれる金属原子を示し、そして、ＸおよびＹは、それぞれ独立して、Ｍと結合した水素原子、ハロゲン原子、炭化水素基、アミノ基、ハロゲン化炭化水素基、酸素含有炭化水素基、窒素含有炭化水素基、リン含有炭化水素基またはケイ素含有炭化水素基を示す。）ものも好ましい。
【００２６】
これらのメタロセン錯体としては、ジメチルシリレンビス｛１，１′−（２−メチル−４フェニル−４−ヒドロアズレニル）｝ジルコニウムジクロリド、ジメチルシリレンビス｛１，１′−（２−エチル−４−フェニル−４ヒドロアズレニル）｝ジルコニウムジクロリド、ジメチルシリレンビス｛１，１′−（２−メチル−４−フェニル−４ヒドロアズレニル）｝ハフニウムジクロリド、ジメチルゲルミレンビス｛１，１′−（２−メチル−４−フェニル−４ヒドロアズレニル）｝ジルコニウムジクロリド、ジメチルシリレンビス［１，１′−｛２−メチル−４−（４−クロロフェニル）−４ヒドロアズレニル｝］ジルコニウムジクロリド、ジメチルシリレンビス［１，１′−｛２−メチル−４−（４−クロロフェニル）−４ヒドロアズレニル｝］ハフニウムジクロリド、ジメチルシリレンビス［１，１′−｛２−メチル−４−（４−トリフルオロメチルフェニル）−４ヒドロアズレニル｝］ジルコニウムジクロリド、ジメチルシリレンビス［１，１′−｛２−メチル−４−（３−クロロフェニル）−４ヒドロアズレニル｝］ハフニウムジクロリド、ジメチルシリレンビス｛１，１′−（２−メチル−４−フェニル−７−イソプロピル−４ヒドロアズレニル｝ジルコニウムジクロリド、ジメチルシリレンビス｛１，１′−２−ベンジル−４−フェニル−４ヒドロアズレニル｝ジルコニウムジクロリド、ジメチルシリレンビス｛１，１′−（２−ベンジル−４−フェニル−７−イソプロピル−４ヒドロアズレニル｝ジルコニウムジクロリド、ジメチルシリレンビス（１，１′−（２−メチル−４，５ベンゾインデニル）ジルコニウムジクロリド、ジメチルシリレンビス（１，１′−（２−メチル−５−フェニルインデニル）ジルコニウムジクロリド、ジメチルシリレンビス（１，１′−（２−メチル−５−ナフチルインデニル）ジルコニウムジクロリド等が挙げられる。
【００２７】
固体触媒の調製に用いられる、微粒子状担体としては通常５μｍから５ｍｍ、好ましくは１０μｍから２ｍｍの粒径を有する微粒子状であるイオン交換性層状化合物または無機珪酸塩、あるいは金属酸化物、複合酸化物が用いられる。
上記のイオン交換性層状化合物としては、六方最密パッキング型、アンチモン型、ＣｄＣｌ_２ 型、Ｃｄｌ_２ 型などの層状の結晶構造を有するイオン結晶性化合物が挙げられ、その具体例としては、α−Ｚｒ（ＨＡｓＯ_４ ）_２ ・Ｈ_２ Ｏ、α−Ｚｒ（ＨＰＯ_４ ）_２ 、α−Ｚｒ（ＫＰＯ_４ ）_２ ・３Ｈ_２ Ｏ、α−Ｔｉ（ＨＰＯ_４ ）_２ 、α−Ｔｉ（ＨＡｓＯ_４ ）_２ ・Ｈ_２ Ｏ、α−Ｓｎ（ＨＰＯ_４ ）_２ ・Ｈ_２ Ｏ、γ−Ｚｒ（ＨＰＯ_４ ）_２ 、γ−Ｔｉ（ＨＰＯ_４ ）_２ 、γ−Ｔｉ（ＮＨ_４ ＰＯ_４ ）_２ ・Ｈ_２ Ｏ等の多価金属の結晶性酸性塩が挙げられる。
【００２８】
上記のイオン交換性層状化合物は、必要に応じて塩類処理および／または酸処理を行って使用してもよい。塩類処理も酸処理も施されていない状態の、珪酸塩を除くイオン交換性層状化合物は、イオン結合等によって構成される面が互いに弱い結合力で平行に積み重なった結晶構造をとる化合物であり、含有するイオンの交換が可能である。
上記の無機珪酸塩としては、粘土、粘土鉱物、ゼオライト、珪藻土などが挙げられる。これらは、合成品を使用してもよいし、天然に産出する鉱物を使用してもよい。粘土および粘土鉱物の具体例としては、アロフェン等のアロフェン族、ディッカイト、ナクライト、カオリナイト、アノーキサイト等のカオリン族、メタハロイサイト、ハロイサイト等のハロイサイト族、クリソタイル、リザルダイト、アンチゴライト等の蛇紋石族、モンモリロナイト、ソーコナイト、バイデライト、ノントロナイト、サポナイト、ヘクトライト等のスメクタイト、バーミキュライト等のバーミキュライト鉱物、イライト、セリサイト、海緑石などの雲母鉱物、アタパルジャイト、セピオライト、パリゴルスカイト、ベントナイト、木節粘土、ガイロメ粘土、ヒシンゲル石、バイロフィライト、リョクデイ石群などが挙げられる。これらは混合層を形成していてもよい。また、人工合成物としては、合成雲母、合成ヘクトライト、合成サポナイト、合成テニオライト等が挙げられる。
【００２９】
上記の無機珪酸塩の中では、カオリン族、ハロサイト族、蛇紋石族、スメクタイト、バーミキュライト鉱物、雲母鉱物、合成雲母、合成ヘクトライト、合成サポナイト、合成テニオライトが好ましく、スメクタイト、バーミキュライト鉱物、合成雲母、合成ヘクトライト、合成サポナイト、合成テニオライトが更に好ましい。これらは、特に処理を行うことなくそのまま使用してもよいし、ボールミル、篩い分け等の処理を行った後に使用してもよい。また、単独で使用しても、２種以上を混合して使用してもよい。
【００３０】
上記のイオン交換性層状化合物および無機珪酸塩は、塩類処理および／または酸処理により、固体の酸強度を変えることができ、また、塩類処理においては、イオン複合体、分子複合体、有機誘導体などを形成することにより、表面積や層間距離を変えることが出来る。すなわち、イオン交換性を利用し、層間の交換性イオンを別の大きな嵩高いイオンと置換することにより、層間が拡大した状態の層状物質を得ることが出来る。
【００３１】
上記の前処理を行っていない化合物においては、含有される交換可能な金属陽イオンを次に示す塩類および／または酸より解離した陽イオンとイオン交換することが好ましい。
上記のイオン交換に使用する塩類は、１〜１４族原子から成る群より選ばれた少なくとも一種の原子を含む陽イオンを含有する化合物であり、好ましくは、１〜１４族原子から成る群より選ばれた少なくとも一種の原子を含む陽イオンと、ハロゲン原子、無機酸および有機酸から成る群より選ばれた少なくとも一種の原子または原子団より誘導される陰イオンとから成る化合物であり、更に好ましくは、２〜１４族原子から成る群より選ばれた少なくとも一種の原子を含む陽イオンと、Ｃｌ、Ｂｒ、Ｉ、Ｆ、ＰＯ_４ 、ＳＯ_４ 、ＮＯ_３ 、ＣＯ_３ 、Ｃ_２ Ｏ_４ 、ＣｌＯ_４ 、ＯＯＣＣＨ_３ 、ＣＨ_３ ＣＯＣＨＣＯＣＨ_３ 、ＯＣｌ_２ 、Ｏ（ＮＯ_３ ）_２ 、Ｏ（ＣｌＯ_４ ）_２ 、Ｏ（ＳＯ_４ ）、ＯＨ、Ｏ_２ Ｃｌ_２ 、ＯＣｌ_３ 、ＯＯＣＨおよびＯＯＣＣＨ_２ ＣＨ_３ から成る群より選ばれた少なくとも一種の陰イオンとから成る化合物である。また、これら塩類は２種以上を同時に使用してもよい。
【００３２】
上記のイオン交換に使用する酸は、好ましくは、塩酸、硫酸、硝酸、酢酸、シュウ酸から選択され、これらは、２種以上を同時に使用してもよい。塩類処理と酸処理を組み合わせる方法としては、塩類処理を行った後に酸処理を行う方法、酸処理を行った後に塩類処理を行う方法、塩類処理と酸処理を同時に行う方法、塩類処理を行った後に塩類処理と酸処理を同時に行う方法などがある。なお、酸処理は、イオン交換や表面の不純物を取り除く効果の他、結晶構造のＡｌ、Ｆｅ、Ｍｇ、Ｌｉ等の陽イオンの一部を溶出させる効果がある。
【００３３】
塩類および酸による処理条件は特に制限されない。しかしながら、通常、塩類および酸濃度は０．１〜３０重量％、処理温度は室温から使用溶媒の沸点の範囲の温度、処理時間は５分から２４時間の条件を選択し、被処理化合物の少なくとも一部を溶出する条件で行うことが好ましい。また、塩類および酸は一般的には水溶液で使用される。
【００３４】
上記の塩類処理および／または酸処理を行う場合、処理前、処理間、処理後に粉砕や造粒などで形状制御を行ってもよい。また、アルカリ処理や有機物処理などの他の化学処理を併用してもよい。この様にして得られる成分（Ｂ）としては、水銀圧入法で測定した半径２０Å以上の細孔容積が０．１ｃｃ／ｇ以上、特には０．３〜５ｃｃ／ｇであることが好ましい。斯かる成分（Ｂ）は、通常、吸着水および層間水を含む。ここで、吸着水とは、イオン交換性層状化合物または無機珪酸塩の表面あるいは結晶破面に吸着された水であり、層間水とは、結晶の層間に存在する水である。
【００３５】
本発明において、成分（Ｂ）は、上記の様な吸着水および層間水を除去してから使用することが好ましい。脱水方法は、特に制限されないが、加熱脱水、気体流通下の加熱脱水、減圧下の加熱脱水および有機溶媒との共沸脱水などの方法が使用される。加熱温度は、吸着水および層間水が残存しない様な温度範囲とされ、通常１００℃以上、好ましくは１５０℃以上とされるが、構造破壊を生じる様な高温条件は好ましくない。加熱時間は、０．５時間以上、好ましくは１時間以上である。その際、脱水乾燥した後の成分（Ｂ）の重量減量は、温度２００℃、圧力１ｍｍＨｇの条件下で２時間吸引した場合の値として３重量％以下であることが好ましい。本発明においては、重量減量が３重量％以下に調整された成分（Ｂ）を使用する場合、成分（Ａ）および後述の成分（Ｃ）と接触する際にも、同様の重量減量が保持される様に取り扱うことが好ましい。
【００３６】
無機酸化物、複合酸化物としては、例えば、ＳｉＯ_２ 、Ａｌ_２ Ｏ_３ 、ＭｇＯ、ＺｒＯ、ＴｉＯ_２ 、Ｂ_２ Ｏ_３ 、ＺｎＯ等の酸化物、ＳｉＯ_２ −ＭｇＯ、ＳｉＯ_２ −Ａｌ_２ Ｏ_３ 、ＳｉＯ_２ −ＴｉＯ_２ 、ＳｉＯ_２ −Ｃｒ_２ Ｏ_３ 、ＳｉＯ_２ −Ａｌ_２ Ｏ_３ −ＭｇＯ等の複合酸化物などが挙げられる。
次に、有機アルミニウム化合物（成分Ｃ）については先に挙げたものが用いられるが、具体例としては、トリメチルアルミニウム、トリエチルアルミニウム、トリプロピルアルミニウム、トリイソブチルアルミニウム等のトリアルキルアルミニウム、ジエチルアルミニウムモノクロライド、ジエチルアルミニウムモノメトキシド等のハロゲンまたはアルコキシ含有アルキルアルミニウムが挙げられる。これらの中では、トリアルキルアルミニウムが好ましい。
【００３７】
また、有機アルミニウム化合物（成分Ｃ）としてアルミニウムオキシ化合物を使用することができ、具体的にはアルモキサンとも呼ばれる化合物であって、一種類のトリアルキルアルミニウムまたは二種類以上のトリアルキルアルミニウムと水との反応により得られる。具体的には、（ａ）一種類のトリアルキルアルミニウムと水から得られる、メチルアルモキサン、エチルアルモキサン、プロピルアルモキサン、ブチルアルモキサン、イソブチルアルモキサン、（ｂ）二種類のトリアルキルアルミニウムと水から得られる、メチルエチルアルモキサン、メチルブチルアルモキサン、メチルイソブチルアルモキサン等が例示される。これらの中では、メチルアルモキサン及びメチルイソブチルアルモキサンが好ましい。上記のアルモキサンは、各群内および各群間で複数種併用することも可能である。
また、メタロセン錯体と反応してメタロセン錯体をカチオンに変換することが可能なイオン性化合物としては、一般式（ＩＩ）で表される化合物が挙げられる。
【００３８】
【化２】
［Ｋ］^ｅ ＋［Ｚ］^ｅ− （ＩＩ）
【００３９】
一般式（ＩＩ）中、Ｋはカチオン成分であって、例えば、カルボニウムカチオン、トリピリウムカチオン、アンモニウムカチオン、オキソニウムカチオン、スルホニウムカチオン、ホスフォニウムカチオン等が挙げられる。また、それ自身が還元され易い金属の陽イオンや有機金属の陽イオン等も挙げられる。
上記のカチオンの具体例としては、トリフェニルカルボニウム、ジフェニルカルボニウム、シクロヘプタトリエニウム、インデニウム、トリエチルアンモニウム、トリプロピルアンモニウム、トリブチルアンモニウム、Ｎ，Ｎ−ジメチルアニリニウム、ジプロピルアンモニウム、ジシクロヘキシルアンモニウム、トリフェニルホスホニウム、トリメチルホスホニウム、トリス（ジメチルフェニル）ホスホニウム、トリス（メチルフェニル）ホスホニウム、トリフェニルスルホニウム、トリフェニルオキソニウム、トリエチルオキソニウム、ピリリウム、銀イオン、金イオン、白金イオン、銅イオン、パラジウムイオン、水銀イオン、フェロセニウムイオン等が挙げられる。
【００４０】
上記の一般式（ＩＩ）中、Ｚは、アニオン成分であり、成分（Ａ）が変換されたカチオン種に対して対アニオンとなる成分（一般には非配位の成分）である。Ｚとしては、例えば、有機ホウ素化合物アニオン、有機アルミニウム化合物アニオン、有機ガリウム化合物アニオン、有機リン化合物アニオン、有機ヒ素化合物アニオン、有機アンチモン化合物アニオン等が挙げられ、具体的には次の化合物が挙げられる。
（ａ）テトラフェニルホウ素、テトラキス（３，４，５−トリフルオロフェニル）ホウ素、テトラキス｛３，５−ビス（トリフルオロメチル）フェニル｝ホウ素、テトラキス｛３，５−ジ（ｔ−ブチル）フェニル｝ホウ素、テトラキス（ペンタフルオロフェニル）ホウ素など
（ｂ）テトラフェニルアルミニウム、テトラキス（３，４，５−トリフルオロフェニル）アルミニウム、テトラキス｛３，５−ビス（トリフルオロメチル）フェニル｝アルミニウム、テトラキス（３，５−ジ（ｔ−ブチル）フェニル）アルミニウム、テトラキス（ペンタフルオロフェニル）アルミニウム等
【００４１】
（ｃ）テトラフェニルガリウム、テトラキス（３，４，５−トリフルオロフェニル）ガリウム、テトラキス｛３，５−ビス（トリフルオロメチル）フェニル｝ガリウム、テトラキス（３，５−ジ（ｔ−ブチル）フェニル）ガリウム、テトラキス（ペンタフルオロフェニル）ガリウム等
（ｄ）テトラフェニルリン、テトラキス（ペンタフルオロフェニル）リン等
（ｅ）テトラフェニルヒ素、テトラキス（ペンタフルオロフェニル）ヒ素など
（ｆ）テトラフェニルアンチモン、テトラキス（ペンタフルオロフェニル）アンチモン等
（ｇ）デカボレート、ウンデカボレート、カルバドデカボレート、デカクロロデカボレート等
【００４２】
また、ルイス酸、特にメタロセン錯体をカチオンに変換可能なルイス酸としては、種々の有機ホウ素化合物、金属ハロゲン化合物、固体酸などが例示され、その具体的例としては次の化合物が挙げられる。
（ａ）トリフェニルホウ素、トリス（３，５−ジフルオロフェニル）ホウ素、トリス（ペンタフルオロフェニル）ホウ素等の有機ホウ素化合物
（ｂ）塩化アルミニウム、臭化アルミニウム、ヨウ化アルミニウム、塩化マグネシウム、臭化マグネシウム、ヨウ化マグネシウム、塩化臭化マグネシウム、塩化ヨウ化マグネシウム、臭化ヨウ化マグネシウム、塩化マグネシウムハイドライド、塩化マグネシウムハイドロオキシド、臭化マグネシウムハイドロオキシド、塩化マグネシウムアルコキシド、臭化マグネシウムアルコキシド等の金属ハロゲン化合物
（ｃ）アルミナ、シリカ−アルミナ等の固体酸
例えば、ＳｉＯ_２ 、Ａｌ_２ Ｏ_３ 、ＭｇＯ、ＺｒＯ、ＴｉＯ_２ 、Ｂ_２ Ｏ_３ 、ＺｎＯ等の酸化物、ＳｉＯ_２ −ＭｇＯ、ＳｉＯ_２ −Ａｌ_２ Ｏ_３ 、ＳｉＯ_２ −ＴｉＯ_２ 、ＳｉＯ_２ −Ｃｒ_２ Ｏ_３ 、ＳｉＯ_２ −Ａｌ_２ Ｏ_３ −ＭｇＯ等の複合酸化物などが挙げられる。
【００４３】
固体触媒成分、有機アルミニウム化合物、あるいは必要に応じて用いられる電子供与性化合物、および有機アルミニウム以外の活性化剤は、重合槽中であるいは重合槽外で、重合させるべきモノマーの存在下あるいは不存在下で互いに接触し、この接触によって、本発明の立体規則性触媒が形成される。
各触媒成分は、重合槽に独立に供給しても良いし、任意の各成分を接触させたうえで供給しても良い。この場合、接触方法は任意である。すなわち各成分を同時に接触させても良いし、任意の各成分を逐次接触させても良い。これらの各成分を重合槽に供給する方法については、特に制限はない。プロパン、ブタン、ペンタン、ヘキサン、ヘプタン、オクタン、ノナン、デカン、トルエン、キシレンなどの不活性炭化水素溶媒に溶解もしくは懸濁させて供給しても良いし、実質的にこれらの不活性炭化水素溶媒を使用することなく、直接供給することもできる。
【００４４】
以下、図１を参照して本発明プロピレン系ブロック共重合体を連続製造する方法を説明する。
本発明において、第１段階重合工程は、先ず第１重合槽１で行なわれ、次いで第２重合槽５によって行なわれる。
本発明において、第１段階重合工程における重合は、液体プロピレンを媒体とする重合方法が用いられる。プロピレン自身を媒体とする重合方法は、第１段階重合工程において、短時間で高い触媒効率が得られるため、コスト上有利であるばかりでなく、後述する分級システムとして、湿式分級の採用が可能になるという利点がある。なお、湿式分級は、乾式分級よりも一般に高い分級効率が得られるため、第１段階重合工程におけるショート・パスを抑制するうえで有利である。さらに、本発明では、沈降液力分級器４による湿式分級が適するがこの場合、分級用の媒体として液体プロピレンが使用できるため、ことさら他の媒体を使用する必要がないという利点もある。さらに、重合体と未反応プロピレンの分離が容易であるという利点もある。
【００４５】
本発明において、各重合槽の重合温度に特に制限はないが、通常、４０〜１２０℃、好ましくは、５０〜９０℃で行われる。圧力にも特に制限はないが、通常１〜１００ａｔｍ、好ましくは、５〜５０ａｔｍの圧力で行われる。
重合は水素の存在下で行われる。重合槽への水素の供給量に特に制限はなく、所望のメルトフローレート（以下、ＭＦＲと称する）を得るために必要な水素を供給することができる。第１段階重合工程の各重合槽１、５で得られるプロピレン系重合体のＭＦＲは、任意に設定できるが、通常は成形性を考慮して、ＭＦＲ＝０．１〜３０００ｇ／１０ｍｉｎ、好ましくは、０．２〜３００ｇ／１０ｍｉｎとなるように重合条件を設定する。特に成形性向上のために各々のＭＦＲに格差を付ける重合方法も可能である。第１段階重合工程の重合体生成量が、最終的に得られる重合体中にしめる割合に特に制限はない。しかし、剛性と耐衝撃性のバランスを考慮すると、３０〜９５重量％、なかんずく５０〜９３重量％となるようにするのが好ましい。すなわち、第２段階重合工程におけるプロセス性能を考慮して、このような比率になるように、第１段階重合工程における運転条件を設定する。
【００４６】
第１段階重合工程における平均滞留時間は、０．１〜８時間、好ましくは、０．５〜５時間、さらに好ましくは、０．７〜３．０時間程度になるように設定する。ここで、平均滞留時間は、第１段階重合工程における重合体滞留量を、単位時間あたりに第１段階重合工程から第２段階重合工程に抜き出す重合体量で割ったものである。なお、第１段階重合工程から抜き出され、第２段階重合工程に送られる重合体の平均ＣＥは、あるレベルよりも高い方が好ましい。
【００４７】
ここで、ＣＥとは触媒効率を表し、単位固体触媒重量あたりの生成重合体量を意味する。平均ＣＥが低い場合には、触媒コストが上がるばかりでなく、最終的に得られる重合体に含まれる触媒残渣が多くなるため、重合体の熱安定性や耐候性が低下する欠点がある。これを防止するためには、添加剤のフィード量を増やしたり、脱灰処理をしたりする方法が可能であるが、いずれもコストアップ要因であって、好ましいとは言えない。したがって、上述の平均ＣＥとしては、５０００ｇ／ｇ以上が好ましく、さらに好ましくは、１００００ｇ／ｇ以上、最も好ましくは３０，０００ｇ／ｇ以上である。
【００４８】
本発明においては、第１段階重合工程から第２段階重合工程へのショートパスを抑制するために、沈降液力分級器４と濃縮器３からなる分級システムが主に使用される。システムの構成としては、ショートパスを抑制するという目的が達成されるものであれば、特に制限はない。更に本発明では第１重合槽１の出口に接続された分級器４の出口側に追加接続された第２重合槽５によりショートパスをより一層抑制し最終的にゲルを抑制し高耐衝撃強度の重合体を得ることができる。
【００４９】
ここで、液力分級器４とは、第１重合槽１から抜き出したスラリーを、装置内部において分級用媒体（好ましくは、濃縮器３により得られた低濃度スラリーの上澄み液）と向流接触させることによって、重合体粒子を粒径によって分離する装置のことである。この液力分級器４においては、分級器に供給された重合体粒子のうち、大粒径粒子は分級器４内を向流液に逆らって沈降する確率が高く、このようにして沈降した大粒径粒子を多く含むスラリーは、分級器４胴部の抜出し口より抜き出され、第２重合槽５へと送られる。一方、小粒径粒子は、上記向流液に同伴して上昇する確率が高い。かくして小粒径粒子を多く含むスラリーは、分級器上部から抜き出され、粒径による分離が行われることになる。このようにして得られた小粒径粒子を多く含むスラリーの全部、もしくは大部分は濃縮器３経由で元の第１重合槽１に戻され、引き続き重合を継続させる。場合により一部はライン１２経由で低圧ガス後処理系９、もしくはライン１１経由で第２重合槽５へ移送することにより、第１重合槽１での微粉蓄積を防止させる。その割り振りについては、当然ながら、第１重合槽１内での微粉蓄積速度に依存するが、本来の分級システムの効果をそぐわないために５０〜１００ｗｔ％未満、好ましくは９０〜１００ｗｔ％未満を元の第１重合槽１へ戻すことが望ましい。
【００５０】
本発明においては、液力分級器４は、スラリーの濃縮器３と組み合わせて使用される。この場合、濃縮器３としては、液体サイクロン、遠心分離器、濾過器などが用いられるが、連続運転の場合、液体サイクロンが操作性に優れ、装置も小型かつ安価で、設置面積も少なくてすむことから、好適に用いられる。
液体サイクロンの操作条件を適切に選ぶと、粒子をほとんど含まない上澄液と濃厚スラリーとに分離することが可能である。このようにして得られた重合体粒子をほとんど含まない上澄液を分級器の向流に使用すれば、プロセスで使用する液量の低減が可能となり、プロセスに対する負荷を下げることができて有利である。
【００５１】
第１段階重合工程における第１重合槽１から抜き出したスラリーを、濃縮器３に先に供給するか、沈降液力分級器４に先に供給するかについては任意であるが、沈降液力分級器４に先に供給する方が、圧力損失が小さいので、スラリー供給ポンプ２の小型化が可能となり有利である。さらに、濃縮器３から得られた上澄液の流量操作領域を大きく取れるというメリットもある。
このようにして、第１重合槽１から得られた重合体のうち、比較的大きな粒径を有する粒子を多く含む粒子群と場合により一部小粒径粒子が第２重合槽５へと送られる。
【００５２】
第１重合槽１および第２重合槽５での重合量比は第２段階重合工程へのショートパスへ大きく影響する。例えば第１重合槽１での重合量比率が第２重合槽５のそれに比べて、極めて低い場合は分級器４での負担が相対的に大きくなり、同一の分級性能で考えるとショートパスし易い状態となる。その逆も同じである。第１重合槽１と第２重合槽５との重合量比率としては、３５：６５から９９：１、好ましくは５０：５０から８５：１５に振り分けた重合条件がより効率的に第１重合工程からの重合体粒子のショートパスを抑制し、ひいてはゲルの生成を抑制する。
【００５３】
上述の粒子群は、重合体と液体プロピレンからなるスラリーとして得られるが、こうした液体プロピレンを含有する状態で、重合体が第２段階重合工程の共重合槽８として用いられる気相重合槽に供給された場合には、気相重合槽内の温度分布が大きくなったり、重合体の流動状態の不均一性が増大するといった好ましくない事態が生じやすい。こうした事態を避けるためには、第２段階重合工程の気相重合槽に重合体スラリーが供給される前に、重合体が実質的に液を含まない状態にしておくことが望ましい。
【００５４】
本発明においては、第１段階重合工程が液体プロピレンを媒体とする重合であるため、脱ガスシステムで液体プロピレンを気化させることによって、上述の問題を避けることができる。脱ガスシステムに特に制限はないが、二重管式熱交換器６と流動フラッシュ槽７から構成されるシステムが好適に使用される。
第２段階重合工程においては、第１段階重合工程で生成したプロピレン系重合体の存在下に、第１段階重合工程で導入された立体規則性重合触媒の作用下に、プロピレンとα−オレフィンの共重合を行わせる。ここで、「第１段階重合工程で導入された立体規則性触媒の作用下に」とは、第２段階重合工程での共重合反応の少なくとも一部が第１段階重合工程で使用された立体規則性触媒活性によって生起ないし継続することを意味するものである。したがって、この第２段階重合工程の共重合反応は、第１段階重合工程で生成された重合体に同伴されて第２段階重合工程に存在することになった立体規則性触媒の活性によって、その実質的に全ての共重合反応がもたらされるもの、および第１段階重合工程由来の触媒活性と第２段階重合工程で新たに追加された触媒ないし触媒成分による活性とによって共重合反応がもたらされるものがある。
【００５５】
第２段階重合工程で使用されるα−オレフィンとしては、好ましくは炭素数２〜１２のもの、例えば、エチレン、１−ブテン、１−ペンテン、１−ヘキセンなどを挙げることができる。このうち好ましく用いられるのは、エチレン、１−ブテンであり、最も好ましいものはエチレンである。気相中のプロピレン濃度は、一般に、９０モル％未満であればよいが、好ましくは、３０〜８５モル％である。気相中のプロピレン濃度をこのような範囲に制御することによって、最終的に得られるブロック共重合体の衝撃強度が改良されやすい。
【００５６】
第２段階重合工程に供給する失活化合物とは、重合触媒の機能を抑制する機能を有する化合物で、活性水素化合物、電子供与性化合物等が挙げられる。活性水素化合物としては、水、アルコール、フェノール、カルボン酸、スルホン酸、第３級アミンを除くアミンなどを挙げることができる。
具体的には、アルコールとしては、炭素数１〜１２程度の脂肪族アルコール、例えば、メタノール、エタノール、ｎ−プロピルアルコール、ｉ−プロピルアルコール、ｎ−ブチルアルコール、ｎ−ヘキシルアルコール、ｎ−オクチルアルコール、ｎ−ドデカノール、２−エチルヘキシルアルコール、シクロヘキサノール、エチレングリコール、プロピレングリコールなどを、官能基を有するアルコール、例えば、メトキシエタノール、エトキシエタノール、ジエチレングリコールなどを挙げることができる。
【００５７】
フェノールとしては、フェノール、クレゾール、キシレノール、ｔ−ブチルフェノール、２，６−ジメチル−４−ｔ−ブチルフェノールなどを挙げることができる。
カルボン酸としては、炭素数１〜１２程度のもの、例えば、ギ酸、酢酸、プロピオン酸、酪酸、ステアリン酸、アクリル酸、メタクリル酸、安息香酸、サリチル酸などを挙げることができる。
【００５８】
スルホン酸としては、メタンスルホン酸、エタンスルホン酸、ベンゼンスルホン酸、トルエンスルホン酸、４−エチルベンゼンスルホン酸などを挙げることができる。
第３級アミンを除くアミンとしては、メチルアミン、エチルアミン、ｎ−プロピルアミン、ｉ−プロピルアミン、ｎ−ブチルアミン、ｎ−オクチルアミン、シクロヘキシルアミン、アニリン、ベンジルアミン、ジメチルアミン、ジエチルアミン、ジ−ｎ−プロピルアミン、ジ−ｉ−プロピルアミン、ジ−ｎ−ブチルアミン、ジ−ｎ−オクチルアミン、ジシクロヘキシルアミン、ジフェニルアミン、ジベンジルアミンなどを挙げることができる。
【００５９】
電子供与性化合物としてはアルデヒド、ケトン、エステル、エーテル等の化合物を挙げることができる。具体的には、アルデヒドとしては炭素数２〜１２程度の脂肪族アルデヒド、例えばアセトアルデヒド、エチルアルデヒド、プロピルアルデヒド、ブチルアルデヒド等々、ケトンとしては、炭素数３〜１２程度の脂肪族ケトン、例えばアセトン、メチルエチルケトン、メチルイソブチルケトン等々、エステルとしては、炭素数２〜１５の脂肪族、あるいは芳香族カルボン酸エステル、例えば、ギ酸メチル、酢酸メチル、酢酸エチル、アクリル酸メチル、安息香酸エチル、パラトルイル酸メチル等が挙げられ、エーテルとしては、炭素数２〜１５の脂肪族エーテル、例えばジエチルエーテル、ジプロピルエーテル、ジブチルエーテル等が挙げられる。
【００６０】
なお、これらの失活化合物は、単独で用いてもよいし、混合物を用いてもよい。これらの失活化合物のうち、好ましいものは、比較的沸点が低く、かつ臭いがあまり強くないものである。とりわけ、比較的低炭素数のアルコールが好ましく、なかでも、エタノールが最も好ましい。
失活化合物の供給量に特に制限はないが、好ましくは、第２段階重合工程に供給される有機アルミニウム化合物中のアルミニウムに対して、１．０モル比を越える量とする。１．０モル比よりも少ない供給量の場合、耐衝撃性および／または粒子流動性の改良効果が、１．０モル比よりも多い場合に比べて、やや小さい傾向がある。耐衝撃性を改良する観点からは、該モル比は高い方が良いが、高すぎると、ゴムの重合活性の低下が顕著となり、生産性の点から好ましくない。したがって、活性水素化合物の好ましい供給量は、第２段階重合工程に供給される有機アルミニウム化合物中のアルミニウムに対して、１．０モル比を越え、３．０モル比未満、さらに好ましくは、１．１モル比以上、２．５モル比以下である。
【００６１】
失活化合物の供給方法は任意である。ｎ−ヘキサン、トルエンなどの溶媒に溶解させて供給してもよいし、溶媒を使用することなく直接供給してもよい。
また、供給位置は、第２段階重合工程におけるプロピレン・α−オレフィン共重合を失活化合物の存在下で行うという目的が達成されるものであれば、任意の位置で供給することが可能である。
【００６２】
具体的には、第２段階重合工程における気相重合槽８の分散板下部より供給する方法、気相重合槽の循環ガスラインに供給する方法、気相重合槽内の重合粒子からなるベッド層に供給する方法、該ベッド層の上部から供給する方法、第１段階重合工程と第２段階重合工程の間の脱ガス槽に供給する方法、該脱ガス槽７と第２段階重合工程における共重合槽８との間の移送配管内に供給する方法などを挙げることができる。供給位置は、１ケ所でもよいし、必要に応じて、２ケ所以上の供給位置を設定してもよい。これらのうち、失活化合物の効果的な分散を考慮すると、気相重合槽分散板の下部から供給する方法が好ましい。
【００６３】
第２段階重合工程における重合体生成量は、第１段階重合工程における重合体生成量に応じて、設定することができる。通常は、剛性と耐衝撃性のバランスを考慮して、５〜７０重量％、好ましくは、７〜５０重量％となるような範囲から選ばれる。
重合温度、重合時間、重合圧力にも特に制限はないが、上述の重合比率を考慮して、重合温度＝０〜１００℃、好ましくは、２５〜９０℃、重合時間＝０．１〜６時間、好ましくは、０．５〜３時間、重合圧力＝０．１〜１００ａｔｍ、好ましくは、１〜４０ａｔｍの範囲から選択される。なお、ここで重合時間は、第２段階重合工程における重合体の平均滞留時間で定義される。
【００６４】
第２段階重合工程で得られる共重合体の分子量は、任意に設定できるが、通常は、物性と成形性とのバランスから、重量平均分子量Ｍｗとして、２０万〜３００万、好ましくは、４０万〜２００万になるようにする。なお、分子量の制御には、通常水素が用いられる。第２段階重合工程で得られた共重合体の分子量と、共重合体が全重合体中にしめる比率によって、最終的に得られるブロック共重合体のＭＦＲが決まる。このＭＦＲの範囲に特に制限はないが、成形性を考慮すると、通常は０．０１〜３０００ｇ／１０ｍｉｎ、好ましくは０．１〜１０００ｇ／１０ｍｉｎとなるようにするのが好ましい。第２段階重合工程の気相重合に用いられる重合槽の形式は、特に限定されない。すなわち、公知の流動床、撹拌流動床、撹拌槽などが使用可能である。
【００６５】
なお、これら第１段階および第２段階の重合の後、引き続き第３段階以降の重合を行うこともできる。該重合段階では、気相中のプロピレン濃度が９０モル％未満となるような重合、すなわち、プロピレンとエチレンの共重合や、エチレン単独重合、エチレンと他のα−オレフィンとの共重合などを行うことができる。低圧ガス後処理系９としては、未反応のプロピレンおよびα−オレフィンの回収を行うための低圧脱ガス槽と付随した圧縮機、並びにポリマー中に含まれる触媒と助触媒の失活とあるいは溶媒等の乾燥を行うための装置が配置される。前述した、分級器４をバイパスして移送された小粒径粒子を含むスラリーはここで、正常粒子と混合されて押出機を含む製品系へ移送される。
【００６６】
【実施例】
以下の実施例は、本発明をさらに具体的に説明するためのものである。本発明は、その要旨を逸脱しない限り、これによって限定されるものではない。
［実施例１］
（１）固体触媒成分（Ａ）の製造
バキューム・スターラ、温度計を備えた３Ｌ−丸底四つ口フラスコに、Ｍｇ（ＯＥｔ）_２ ：２．０５８ｍｏｌを仕込み、ついでＴｉ（ＯＢｕ）_４ を、仕込んだＭｇ（ＯＥｔ）_２ 中のマグネシウムに対して、Ｔｉ（ＯＢｕ）_４ ／Ｍｇ＝０．６０（モル比）になるように仕込み、３００ｒｐｍで撹拌しながら昇温した。
１５０℃で１．５時間反応させた後、１２０℃に降温して、ＭｅＳｉ（ＯＰｈ）_３ のトルエン溶液を、仕込んだＭｇ（ＯＥｔ）_２ 中のマグネシウムに対して、ＭｅＳｉ（ＯＰｈ）_３ ／Ｍｇ＝０．６７（モル比）になるように添加した。添加終了後、同温度で１時間反応させた。反応終了後、室温に降温した後、Ｓｉ（ＯＥｔ）_４ を、仕込んだＭｇ（ＯＥｔ）_２ 中のマグネシウムに対して、Ｓｉ（ＯＥｔ）_４ ／Ｍｇ＝０．０５（モル比）になるように添加し、接触生成物（ａ＊）のスラリーを得た。
【００６７】
ここで得られたスラリーの全量を、冷却・加熱用ジャケットに備えた誘導撹拌式１０Ｌ−オートクレーブに移送した後、［Ｍｇ］＝０．６０ｍｏｌ／Ｌトルエンになるように、トルエンで希釈した。
このスラリーを、３００ｒｐｍで撹拌しながら、−１０℃に冷却し、フタル酸ジエチルを、仕込んだＭｇ（ＯＥｔ）_２ 中のマグネシウムに対して、フタル酸ジエチル／Ｍｇ＝０．１０（モル比）になるように添加した。引き続き、ＴｉＣｌ_４ を、仕込んだＭｇ（ＯＥｔ）_２ 中のマグネシウムに対して、ＴｉＣｌ_４ ／Ｍｇ＝４．０（モル比）になるように、１．２時間かけて滴下し、均一溶液を得た。この時、液の粘度が上昇してゲル状になるという現象は、起こらなかった。
【００６８】
得られた均一溶液を０．５℃／ｍｉｎで１５℃まで昇温し、同温度で１時間保持した。ついで、再び０．５℃／ｍｉｎで５０℃まで昇温し、５０℃で１時間保持した。さらに、１．０℃／ｍｉｎで１１７℃まで昇温し、同温度で１時間処理を行った。
処理終了後、加熱・撹拌を停止し、上澄み液を除去した後、トルエンで、残液率＝１／５５となるように洗浄し、固体スラリーを得た。
【００６９】
次に、得られた固体スラリーのトルエン量を、ＴｉＣｌ_４ 濃度＝２．０ｍｏｌ／Ｌトルエンとなるように調整し、室温でＴｉＣｌ_４ を、はじめに仕込んだＭｇ（ＯＥｔ）_２ 中のマグネシウムに対して、ＴｉＣｌ_４ ／Ｍｇ＝５．０（モル比）となるように添加した。このスラリーを、３００ｒｐｍで撹拌しながら昇温し、１１７℃で、１時間反応を行った。反応終了後、加熱・撹拌を停止し、上澄み液を除去した後、トルエンで、残液率＝１／１５０となるように洗浄し、（Ａ＊）のトルエン・スラリーを得た。
【００７０】
（２）前重合の実施
ここで得られた固体スラリーの全量を、内径６６０ｍｍ、直胴部７７０ｍｍの三方後退翼を有する反応槽に移送し、ｎ−ヘキサンで希釈して、（Ａ＊）の濃度として３ｇ／Ｌとなるようにした。このスラリーを３００ｒｐｍで撹拌しながら、２５℃で、トリエチルアルミニウムを、トリエチルアルミニウム／（Ａ＊）＝３．４４ｍｍｏｌ／ｇとなるように添加し、さらに、ｔ−ブチル−ｎ−プロピルジメトキシシランを、ｔ−ブチル−ｎ−プロピルジメトキシシラン／（Ａ＊）＝１．４４ｍｍｏｌ／ｇとなるように添加した。添加終了後、引き続き撹拌しながら、２５℃で３０分間保持した。
【００７１】
次いで、プロピレンガスを液相に、７２分かけて定速フィードした。プロピレンガスのフィードを停止した後、沈降洗浄法にて、ｎ−ヘキサンで洗浄を行い、残液率＝１／１２として、固体触媒成分（Ａ）のスラリーを得た。得られた固体触媒成分（Ａ）は、（Ａ＊）成分１ｇあたり、２．７ｇのプロピレン重合体を含有していた。
【００７２】
（３）プロピレン−エチレンブロック共重合体の製造
（１）で製造した固体触媒成分と共触媒にトリエチルアルミニウム、第３成分としてｔ−ＢｕＥｔＳｉ（ＯＥｔ）_２ を用い水素の存在下、図１に示すプロセスにおいて３槽連続重合を実施した。トリエチルアルミニウム濃度は６０ｍｏｌｐｐｍ対プロピレン、Ｓｉ濃度は２．８ｍｏｌｐｐｍ対プロピレンであった。
【００７３】
重合温度、重合圧力は次の条件である。
重合温度：プロピレン第１重合槽：重合温度＝７５℃、重合圧力＝３７．０ａｔｍ、Ｈ_２ 濃度＝１３ｍｏｌ％対プロピレン、プロピレン第２重合槽：重合温度＝７５℃、重合圧力＝３６．８ａｔｍ、Ｈ_２ 濃度＝１２ｍｏｌ％対プロピレン、気相重合槽：重合温度＝８０℃、重合圧力１６．０ａｔｍ、Ｈ_２ 濃度＝０．７ｍｏｌ％対エチレン＋プロピレン、プロピレン／（プロピレン＋エチレン）＝５５ｍｏｌ％。ここでプロピレン重合槽１とプロピレン重合槽２の重合時間についてはホモ重合体平均ＣＥ＝５００００ｇ／ｇ、重合槽１と重合槽２との重合量比率として、５５：４５（重量比）に振り分けるよう制御した。
【００７４】
重合槽１で重合したスラリーは、スラリーポンプ２を用いて、液力分級器４にフィードした。
液力分級器４上部より抜き出されたスラリーは、微粒子が含まれているため、濃縮器３に送られ、濃縮器下部より元のプロピレン重合槽１に循環させ、濃縮器３上部からは、固体粒子のほとんど存在しない上澄液を取り出し、これを液力分級器４の下部より、ポンプによりフィードした。分級器４下部からは、大粒径粒子を多く含むスラリーを抜き出した。該スラリーはプロピレン第２重合槽に供給された。
【００７５】
第２重合槽からのスラリーは、後流の二重管式交換器６を経て、流動フラッシュ槽７にフィードされた。ここでスラリー中のプロピレン重合体の供給速度が５５ｋｇ／ｈｒとなる様に調節を行った。流動フラッシュ槽７においては、下部より加熱したプロピレンガスをフィードしながら、槽内温度を７０℃に維持した。ここで得られたポリプロピレン粒子を、気相重合槽８に送り、プロピレンとエチレンの共重合を行った。
【００７６】
混合効果を高めるため、補助的に撹拌翼を設けた気相重合槽８では、ガス・ブロアーによって、エチレン、プロピレン、水素、窒素の混合ガスを循環させた。また、活性水素化合物としてエタノールをフィードし、エタノールのフィード量は、気相重合槽に供給される重合体粒子に随伴して供給されるトリエチルアルミニウム中のアルミニウムに対して、１．２モル比となるようにした。
【００７７】
結果として各重合槽の滞留時間は第１重合槽２５分、第２重合槽３５分、第３重合槽３６分であった。
気相重合槽８から抜き出された重合体粒子を分析したところ、ＭＦＲ＝３０．０ｇ／１０ｍｉｎ、かさ密度＝０．５０ｇ／ｃｃ、ＥＰＲ含量＝１４．６重量％、ＥＰＲの分子量は８０万であり、ゲル数は２３０ケ／２５０ｃｍ^２ であった。（２）物性評価
曲げ弾性率＝１４６００ｋｇ／ｃｍ^２ 、Ｉｚｏｄ＝１０．１ｋｇ・ｃｍ／ｃｍ、面衝撃強度＝９９ｋｇ・ｃｍであった。
【００７８】
［実施例２］
実施例１においてホモ重合体平均ＣＥ＝５００００ｇ／ｇ、第１重合槽１と第２重合槽２との重合量比率として、８０：２０（重量比）に振り分けるよう制御した。
重合温度、重合圧力は次の条件である。
重合温度：プロピレン第１重合槽：重合温度＝７５℃、重合圧力＝３７．０ａｔｍ、Ｈ_２ 濃度＝１３ｍｏｌ％対プロピレン、プロピレン第２重合槽：重合温度＝７５℃、重合圧力＝３６．８ａｔｍ、Ｈ_２ 濃度＝１２ｍｏｌ％対プロピレン、気相重合槽：重合温度＝８０℃、重合圧力＝１６．０ａｔｍ、Ｈ_２ 濃度＝０．７ｍｏｌ％対エチレン＋プロピレン、プロピレン／（プロピレン＋エチレン）＝５５ｍｏｌ％。
【００７９】
結果として各重合槽の滞留時間は第１重合槽４５分、第２重合槽２０分、第３重合槽は３６分であった。
気相重合槽８から抜き出された重合体粒子を分析したところ、ＭＦＲ＝３３．０ｇ／１０ｍｉｎ、かさ密度＝０．４８ｇ／ｃｃ、ＥＰＲ含量＝１４．２重量％、ＥＰＲの分子量は８２万であり、ゲル数は１４５ケ／２５０ｃｍ^２ であった。（２）物性評価
曲げ弾性率＝１４，９００ｋｇ／ｃｍ^２ 、Ｉｚｏｄ＝１０．０ｋｇ・ｃｍ／ｃｍ、面衝撃強度＝１０３ｋｇ・ｃｍであった。
【００８０】
［比較例１］
図１において、第２重合槽をバイパスして直接流動フラッシュ槽７にスラリーを供給するようにしたプロセスを用いる以外は、実施例１と同様なプロセスを用い検討を行った。
重合温度、重合圧力は次の条件である。
重合温度：プロピレン重合槽：重合温度＝７５℃、重合圧力＝３６．５ａｔｍ、Ｈ_２ 濃度＝１２ｍｏｌ％対プロピレン、気相重合槽：重合温度＝８０℃、重合圧力＝１６．０ａｔｍ、Ｈ_２ 濃度＝０．７ｍｏｌ％対エチレン＋プロピレン、プロピレン／（プロピレン＋エチレン）＝５５ｍｏｌ％。また、活性水素化合物としてエタノールをフィードし、エタノールのフィード量は、気相重合槽に供給される重合体粒子に随伴して供給されるトリエチルアルミニウム中のアルミニウムに対して、１．１モル比となるようにした。
【００８１】
結果として各重合槽の滞留時間はプロピレンＨＯＭＯ重合槽６６分、気相重合槽は３６分であった。ホモ重合体（プロピレン単独重合）の触媒効率は５０，０００、ＭＦＲ＝６０ｇ／１０ｍｉｎ、ブロック共重合体中、エチレン−プロピレン共重合体含有量＝１４．２ｗｔ％、分子量＝８０万、最終ＭＦＲ＝３２ｇ／１０ｍｉｎ．であった。ρＢ＝０．４８ｇ／ｃｃ
ゲル数は６３０ケ／２５０ｃｍ^２ であった。
【００８２】
曲げ弾性率＝１４，８００ｋｇ／ｃｍ^２ 、Ｉｚｏｄ＝９．５ｋｇ・ｃｍ／ｃｍ、面衝撃強度＝６７ｋｇ・ｃｍであった。
同重合体の一般的用途面からは剛性（ＦＭ）対耐衝撃性（ＤＤＩ）性能としては同一の剛性（ＦＭ）基準では耐衝撃性（ＤＤＩ）が高いものほど優れている。
【００８３】
実施例１、実施例２および比較例１の結果によりプロピレン単独重合槽を２槽とし第１重合槽１と第２重合槽２の重合量比率を最適化制御することで、プロピレン単独重合槽を１槽とする場合に比べ、気相重合槽の滞留時間、圧力条件を同一とした場合ゲルが少なく、剛性（ＦＭ）対耐衝撃性（ＤＤＩ）についてのバランスが向上した重合体を得ることが可能なことが示されている。
【図面の簡単な説明】
【図１】本発明の一様態を示すフローダイアグラム図である。
【符号の説明】
１ 第１重合槽
２ スラリーポンプ
３ 濃縮器
４ 液力分級器
５ 第２重合槽
６ 熱交換器
７ 流動フラッシュ槽
８ 共重合槽
９ 低圧ガス後処理系[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for continuously producing a propylene-based block copolymer, which is capable of producing a propylene-based block copolymer excellent in impact resistance stably and continuously for a long period of time.
[0002]
[Prior art]
Methods for improving the impact resistance of crystalline polypropylene include (1) a method of copolymerizing a small amount of an α-olefin, (2) a method of mechanically blending a rubber component, and (3) a method containing propylene as a main component. There is known a method of performing polymerization and then copolymerizing propylene and an α-olefin other than propylene, that is, performing a so-called block copolymerization.
[0003]
However, the method (1) seems to have a problem that the rigidity is largely reduced in spite of the effect of improving the impact resistance, and as a result, the balance between the rigidity and the impact resistance is reduced. Further, in the method (2), although the balance between rigidity and impact resistance is improved, the rubber used for blending is generally expensive, so that it must be disadvantageous in terms of cost.
[0004]
Based on this background, the block copolymer (3) is most often used as a method for improving the impact resistance of crystalline polypropylene. Block copolymerization consists of generating a rubbery component consisting of a block of a copolymer of propylene and ethylene in the presence of a resinous component consisting of a block mainly composed of propylene. Is also called a chemical blend because it is carried out by subsequent polymerization. By the way, in carrying out this block copolymerization, the present inventors used a magnesium compound-supporting type highly active catalyst having a sharp particle size distribution, and then used a classification system comprising a sedimentation liquid classifier and a concentrator. In addition, in the second stage polymerization step, by causing an active hydrogen compound to coexist, it is possible to produce a propylene-based block copolymer having good impact resistance with low generation of gel due to poor dispersion of a rubber component at low cost. And has already proposed (Japanese Patent Laid-Open No. 10-120741).
[0005]
[Problems to be solved by the invention]
According to the method for producing a propylene-based block copolymer using the above classifier, a polymer having good impact resistance can be obtained, but from the market demand, a polymer having a higher rubber content or a rubber having a higher molecular weight can be obtained. It has been desired to produce a polymer containing a polymer. In such a case, a process capable of producing a polymer having a lower impact and a higher impact resistance than a combination of one reactor and a classifier is desired. It is rare.
[0006]
Further, the production volume per series itself has been increasing year by year for the purpose of improving the productivity, and the capacity of the reactor for that purpose has also reached the production limit level.
An object of the present invention is to provide a method for continuously producing a propylene-based block copolymer which can obtain a propylene-based block copolymer having excellent impact resistance and which is excellent in production efficiency.
[0007]
[Means for Solving the Problems]
The present invention provides a two-stage reactor in series with the first stage polymerization step, which is connected in series, so that a propylene block polymer having a higher rubber content and a higher molecular weight is less likely to generate gel and has a good impact resistance. Polymers with good properties can be secured, the amount of polymerization applied to one polymerization tank can be reduced, and each tank can be downsized. It has been found that it can be contained. Specifically, in the presence of a stereoregular polymerization catalyst, an α-olefin containing liquid propylene as a main component is polymerized in two polymerization tanks in the presence of hydrogen. The first-stage polymerization step, and then the polymer obtained in the first-stage polymerization step is sent to a copolymerization tank, and propylene and an α-olefin other than propylene are reacted by the stereoregular polymerization catalyst in the first-stage polymerization step. The present invention provides a continuous production method of a propylene-based block copolymer, which comprises a second stage polymerization step of substantially copolymerizing in a gas phase and satisfying the following conditions.
[0008]
(1) The polymer slurry extracted from the polymerization tank in the first stage polymerization step is classified into a slurry containing a large amount of large-diameter particles and a slurry containing a large amount of small-diameter particles using a classification system. Sending the slurry rich in particles to the second polymerization tank and returning all or most of the slurry rich in small particle size particles to the first polymerization tank.
(2) transferring the polymer slurry extracted from the second polymerization tank in the first polymerization step to the second polymerization step;
(3) Propylene / α-olefin copolymerization in the second stage polymerization step is performed in the presence of a deactivated compound.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention relates to a first-stage polymerization step in which an α-olefin containing liquid propylene as a main component is polymerized in two polymerization tanks in the presence of hydrogen in the presence of a stereoregular polymerization catalyst; The polymer obtained in the above is sent to a copolymerization tank, and propylene and an α-olefin other than propylene are substantially copolymerized in the gas phase under the action of a stereoregular polymerization catalyst in the first stage polymerization step. And a second stage polymerization step.
[0010]
In the polymerization tank in the first stage polymerization step, polymerization mainly containing propylene is performed. That is, propylene homopolymerization or copolymerization of propylene with a small amount of α-olefin (including ethylene) is performed. Examples of the α-olefin used in the copolymerization include those having 2 to 18 carbon atoms, particularly those having 2 to 8 carbon atoms, such as ethylene, 1-butene, 1-pentene, 1-hexene, and 1-octene. Can be. Of these, ethylene and 1-butene are preferred.
[0011]
Generally, if the copolymerization amount of the α-olefin is increased, the effect of improving the transparency and whitening resistance of the block copolymer is increased, but if too large, the rigidity and heat resistance of the molded article are impaired. Usually, the polymerization amount of the α-olefin in the first stage polymerization step is usually 5% by weight or less, preferably 3% by weight or less.
[0012]
In the polymerization of the first stage polymerization step, a stereoregular catalyst or various components constituting the stereoregular catalyst, for example, a solid catalyst component, a cocatalyst, an electron-donating compound if necessary, or a contact product thereof is added to the polymerization tank. And the monomer, i.e., propylene, and optionally, an alpha-olefin other than propylene, and hydrogen are continuously supplied.
As the stereoregular catalyst in the present invention, those comprising a solid catalyst component and an organoaluminum compound and, if necessary, an electron-donating compound, or those comprising a solid catalyst component and an activator other than organoaluminum are used. . Here, “consisting of” includes those comprising various suitable components in addition to the above main components.
[0013]
Of these, stereoregular catalysts comprising a solid catalyst component, an organoaluminum compound and, if necessary, an electron donating compound are known (for example, JP-A-56-811, JP-A-58-83006, JP-A-58-83006). JP-A-218507, JP-A-6-25338, JP-A-57-63311, JP-A-61-213208, JP-A-62-187706, JP-A-5-331233, JP-A-5-331234, See JP-A-63-289004, JP-A-1-319508, JP-A-52-98706, JP-A-1-54007, and JP-A-3-72503.
[0014]
As the above solid catalyst component, those containing magnesium, titanium, halogen, and an electron donating compound can be used.
Magnesium in the solid catalyst component is magnesium halide such as magnesium chloride, magnesium bromide, magnesium iodide, magnesium fluoride; methoxy magnesium chloride, ethoxy magnesium chloride, isopropoxy magnesium chloride, butoxy magnesium chloride, hexoxy magnesium chloride, Alkoxy magnesium halides such as octoxy magnesium chloride; allyloxy magnesium halides such as phenoxy magnesium chloride and methylphenoxy magnesium chloride; methoxy magnesium, ethoxy magnesium, isopropoxy magnesium, n-butoxy magnesium, n-octoxy magnesium, 2- Alkoxymagnesium such as ethylhexoxymagnesium; phenoxymagnesium, Allyloxy magnesium as Roh alkoxy magnesium; magnesium laurate, can be obtained from such carboxylates of magnesium such as magnesium stearate. In addition, these magnesium compounds may be used alone or as a mixture.
[0015]
The titanium in the solid catalyst component is usually Ti (OR) _g X _4-g (R is a hydrocarbon group, X is a halogen, g is a number satisfying 0 ≦ g ≦ 4), specifically, TiCl ₄ , TiBr ₄ , TiI ₄ Titanium tetrahalide such as Ti; O (OCH ₃ ) Cl ₃ , Ti (OC ₂ H ₅ ) Cl ₃ , Ti (On-C ₄ H ₉ ) Cl ₃ , Ti (OiC ₄ H ₉ ) Cl ₃ , Ti (OCH ₃ ) Br ₃ , Ti (OC ₂ H ₅ ) Br ₃ , Ti (On-C ₄ H ₉ ) Br ₃ , Ti (OiC ₄ H ₉ ) Br ₃ Trihalogenated alkoxytitanium such as: Ti (OCH ₃ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (On-C ₄ H ₉ ) ₂ Cl ₂ , Ti (OiC ₄ H ₉ ) ₂ Cl ₂ , Ti (OCH ₃ ) ₂ Br ₂ , Ti (OC ₂ H ₅ ) ₂ Br ₂ , Ti (On-C ₄ H ₉ ) ₂ Br ₂ , Ti (OiC ₄ H ₉ ) ₂ Br ₂ Dihalogenated alkoxytitanium such as: Ti (OCH ₃ ) ₃ Cl, Ti (OC ₂ H ₅ ) ₃ Cl, Ti (On-C ₄ H ₉ ) ₃ Cl, Ti (OiC ₄ H ₉ ) ₃ Cl, Ti (OCH ₃ ) ₃ Br, Ti (OC ₂ H ₅ ) ₃ Br, Ti (On-C ₄ H ₉ ) ₃ Br, Ti (OiC ₄ H ₉ ) ₃ Monohalogenated alkoxytitanium such as Br: Ti (OCH ₃ ) ₄ ; Ti (OC ₂ H ₅ ) ₄ , Ti (On-C ₄ H ₉ ) ₄ , Ti (OiC ₄ H ₉ ) ₄ Or a mixture thereof, or a mixture thereof with an aluminum compound, a silicon compound, a sulfur compound, another metal compound, hydrogen halide, halogen, or the like. (OR) _g X _4-g (R is a hydrocarbon group, X is a halogen, g is a number satisfying 0 ≦ g ≦ 4), or a tetravalent titanium compound, hydrogen halide, halogen, or the like.
[0016]
As the electron donating compound in the solid catalyst component, a generally known compound used for producing this kind of solid catalyst component can be used. Generally, oxygen-containing compounds and / or nitrogen-containing compounds are preferred. Examples of the oxygen-containing compound generally include ethers, ketones, esters, and alkoxysilanes. Examples of the nitrogen-containing compound include amines, amides, and nitroso compounds.
[0017]
As the organoaluminum compound which is a cocatalyst of the stereoregular catalyst, any suitable one can be used. Specifically, (a) trialkylaluminum, for example, each alkyl group having 1 to 12 carbon atoms, such as trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisobutylaluminum, trihexylaluminum, Trioctylaluminum, tridecylaluminum, tridodecylaluminum, (ii) halogen-containing organoaluminum compounds, specifically, one or two of the alkyl groups of the above trialkylaluminum are substituted with halogen, for example, chlorine, bromine, etc. For example, diethylaluminum chloride, sesquialuminum chloride, (c) a hydride-containing organoaluminum compound, specifically, one or two of the alkyl groups of the above trialkylaluminum are substituted with hydrogen. Such as diethylaluminum hydride, (d) alkoxide-containing organoaluminum compound, specifically, one or two of the above alkyl groups of trialkylaluminum are alkoxy groups (including aryloxy groups), especially carbon Substituted with about 1-8, for example, dimethylaluminum methoxide, diethylaluminum methoxide, diethylaluminum phenoxide, (e) aluminoxane (also referred to as alumoxane), specifically, the alkyl group has 1 to 1 carbon atoms. Alkyl aluminoxane which is 12, for example, methylaluminoxane, ethylaluminoxane, isobutylaluminoxane and the like can be mentioned. Also, a plurality of these can be used within each group and / or between each group.
[0018]
Although there is no particular limitation on the amount of the organoaluminum compound, usually, the molar ratio of aluminum in the organoaluminum compound to titanium in the solid catalyst component is 0.1 to 10,000, preferably 10 to 5,000, Preferably, it is used so as to be 50 to 2000.
As the electron donating compound used as necessary as an external donor, those used in this type of stereoregular catalyst can be used. In the present invention, an oxygen-containing compound and / or a nitrogen-containing compound can be mentioned as preferred.
[0019]
Examples of the nitrogen-containing compound include amines such as triethylamine, ethylenediamine, diisopropylamine, di-t-butylamine, pyridine, piperidine, 2,2,6,6-tetramethylpiperidine and derivatives thereof, tertiary amine, pyridine And nitroso compounds such as N-oxides of quinolines.
Examples of the oxygen-containing compound generally include ethers, ketones, esters, and alkoxysilanes.
[0020]
(A) As ethers, hydrocarbon residues bonded to ether oxygen have a total of about 2 to 18 carbon atoms, preferably about 4 to 12 carbon atoms, and have ether oxygen therein, for example, diethyl ether. Ethers, dipropyl ethers, diethylene glycol dimethyl ether, propylene glycol dimethyl ether, ethylene oxide, tetrahydrofuran, 2,2,5,5-tetramethyltetrahydrofuran, dioxane, and the like. (B) Ketones include hydrocarbon residues bonded to ketone carbonyl groups. Groups having a total of about 2 to 18 carbon atoms, preferably about 4 to 12 carbon atoms, for example, acetone, diethyl ketone, methyl ethyl ketone, acetophenone, etc. (C) As esters, the carboxylic acid moiety is aryl or aralkyl carboxylic acid ( Ally Group or aryl moiety is a phenyl or a lower (C ₁ ~ C ₄ Degree) alkyl and / or lower (C ₁ ~ C ₄ Degree) Alkoxy-substituted phenyl is preferred, and the alkyl moiety of the aralkyl group is ₁ ~ C ₆ And preferably about 1 to 3 carboxyl groups) and an aliphatic carboxylic acid (an ether having a portion other than the carboxyl group (about 1 to 3) having about 1 to 20 carbon atoms, preferably about 2 to 12 carbon atoms). An aliphatic hydrocarbon residue which may contain oxygen), wherein the alcohol moiety has about 1 to 8 carbon atoms, preferably about 1 to 4 carbon atoms (the molecule of the corresponding hydroxy-substituted derivative of the above carboxylic acid) Inner esters), for example, ethyl phenylacetate, methyl benzoate, ethyl benzoate, phenyl benzoate, methyl toluate, ethyl toluate, methyl anisate, ethyl anisate, methyl methoxybenzoate, ethyl methoxybenzoate , Methyl methacrylate, ethyl methacrylate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, phthalic acid Butyl, diisobutyl phthalate, dihexyl phthalate, γ-butyrolactone, ethyl cellosolve, and the like; (d) alkoxysilanes include alkoxy groups (including aryloxy groups and having about 1 to 18 carbon atoms, And preferably the remaining valence of the silicon atom is an alkyl group, an aryl group or an aralkyl group (the general description thereof is the same as that described above), specifically, Are tetramethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isopropyltrimethoxysilane, t-butyltrimethoxysilane, phenyltrimethoxysilane, cyclohexyltrimethoxysilane, 1-methylcyclohexyltrimethoxysilane, 1, 1,2,2-tetramethyl Propyltrimethoxysilane, diethyldimethoxysilane, di-n-propyldimethoxysilane, diisopropyldimethoxysilane, diphenyldimethoxysilane, t-butylmethyldimethoxysilane, t-butylethyldimethoxysilane, t-butyl-n-propyldimethoxysilane, t-butylisopropyldimethoxysilane, cyclohexylmethyldimethoxysilane, dicyclohexyldimethoxysilane, 1-methylcyclohexylmethyldimethoxysilane, 1,1,2,2-tetramethylpropylmethyldimethoxysilane, ethyltriethoxysilane, n-propyltriethoxysilane , Isopropyltriethoxysilane, t-butyltriethoxysilane, phenyltriethoxysilane, cyclohexyltriethoxysilane, 1-methyl Cyclohexyltriethoxysilane, 1,1,2,2-tetramethylpropyltriethoxysilane, diethyldiethoxysilane, di-n-propyldiethoxysilane, diisopropyldiethoxysilane, diphenyldiethoxysilane, t-butylmethyldiethoxy Silane, t-butylethyldiethoxysilane, t-butyl-n-propyldiethoxysilane, cyclohexylmethyldiethoxysilane, cyclohexylethyldiethoxysilane, 1-methylcyclohexylmethyldiethoxysilane, 1,1,2,2- Tetramethylpropylmethyldiethoxysilane and the like can be mentioned.
[0021]
Of these compounds, piperidines or alkoxysilanes are preferably used, and alkoxysilanes are particularly preferable.
The amount of these compounds is not limited, but is usually used so that the molar ratio to aluminum in the organoaluminum compound used as a cocatalyst is 0 to 10, preferably 0 to 2. Further, a plurality of electron donating compounds can be selected and used in each of the above groups and / or between each group.
[0022]
As another stereoregular catalyst used in the present invention, a catalyst obtained by combining a solid catalyst component in which a so-called metallocene complex is supported on a particulate carrier with an organic aluminum compound or an activator other than the organic aluminum compound may be used. it can. As a solid catalyst using the metallocene complex used in the present invention, C ^Thirteen In the NMR measurement, a material whose [mmmm] value is 90% or more is used.
[0023]
Examples of such a catalyst include JP-A-6-239914, JP-A-8-059724, JP-A-8-085708, JP-A-8-183814, JP-A-6-100579, JP-A-6-184179, JP-A-7-224079, JP-A-8-067689 and the like. Can be
Metallocene complex-supported solid catalyst component alone, or a combination of solid catalyst component and organoaluminum compound, ionicity capable of converting metallocene complex to cation by reacting with solid catalyst component and aluminum oxy compound or metallocene complex A catalyst is prepared by combining with a compound or Lewis acid.
The metallocene complex used as the component (A) in the present invention is represented by the general formula (I)
[0024]
Embedded image

[0025]
(In the general formula (I), A ¹ And A ² Is a conjugated five-membered ring ligand which may have a substituent (A ¹ And A ² May be the same or different), Q is a bonding group bridging the two conjugated five-membered ring ligands at an arbitrary position, and M is a metal atom selected from Groups 4 to 6 of the periodic table. And X and Y each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group, an amino group, a halogenated hydrocarbon group, an oxygen-containing hydrocarbon group, a nitrogen-containing hydrocarbon group bonded to M, It represents a phosphorus-containing hydrocarbon group or a silicon-containing hydrocarbon group. ) Are preferred. Also A ¹ And A ² Is a conjugated five-membered ring ligand (A ¹ And A ² May be the same or different), at least one of which is bonded to an adjacent substituent on the conjugated five-membered ring ligand and has a 7 to 10-membered benzene ring including two atoms of the five-membered ring; Or a condensed ring such as a naphthalene ring, Q is a bonding group that bridges two conjugated five-membered ligands at any position, and M is a metal atom selected from Groups 4 to 6 of the periodic table. And X and Y each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group, an amino group, a halogenated hydrocarbon group, an oxygen-containing hydrocarbon group, a nitrogen-containing hydrocarbon group, Shows a hydrocarbon group or a silicon-containing hydrocarbon group. ) Are also preferred.
[0026]
These metallocene complexes include dimethylsilylenebis {1,1 '-(2-methyl-4phenyl-4-hydroazulenyl)} zirconium dichloride and dimethylsilylenebis {1,1'-(2-ethyl-4-phenyl-). 4hydroazulenyl) {zirconium dichloride, dimethylsilylenebis {1,1 '-(2-methyl-4-phenyl-4hydroazulenyl)} hafnium dichloride, dimethylgermylenebis {1,1'-(2-methyl-4-phenyl) -4 hydroazulenyl) zirconium dichloride, dimethylsilylenebis [1,1 '-{2-methyl-4- (4-chlorophenyl) -4hydroazulenyl]] zirconium dichloride, dimethylsilylenebis [1,1'-{2-methyl -4- (4-chlorophenyl) -4 hydroazuleni {} Hafnium dichloride, dimethylsilylenebis [1,1 ′-{2-methyl-4- (4-trifluoromethylphenyl) -4hydroazulenyl}] zirconium dichloride, dimethylsilylenebis [1,1 ′-{2-methyl -4- (3-chlorophenyl) -4hydroazulenyl}] hafnium dichloride, dimethylsilylenebis {1,1 '-(2-methyl-4-phenyl-7-isopropyl-4hydroazulenyl} zirconium dichloride, dimethylsilylenebis} 1, 1'-2-benzyl-4-phenyl-4hydroazulenyl} zirconium dichloride, dimethylsilylenebis {1,1 '-(2-benzyl-4-phenyl-7-isopropyl-4hydroazulenyl} zirconium dichloride, dimethylsilylenebis (1 , 1 '-(2- Tyl-4,5 benzoindenyl) zirconium dichloride, dimethylsilylenebis (1,1 ′-(2-methyl-5-phenylindenyl) zirconium dichloride, dimethylsilylenebis (1,1 ′-(2-methyl-5 -Naphthylindenyl) zirconium dichloride.
[0027]
The fine-particle carrier used for the preparation of the solid catalyst is a fine-particle ion-exchange layered compound or inorganic silicate having a particle size of usually 5 μm to 5 mm, preferably 10 μm to 2 mm, or a metal oxide, a composite oxide. Is used.
As the above-mentioned ion-exchange layered compound, hexagonal close-packed type, antimony type, CdCl ₂ Type, Cdl ₂ Examples include an ionic crystalline compound having a layered crystal structure such as a type, and specific examples thereof include α-Zr (HAsO ₄ ) ₂ ・ H ₂ O, α-Zr (HPO ₄ ) ₂ , Α-Zr (KPO ₄ ) ₂ ・ 3H ₂ O, α-Ti (HPO ₄ ) ₂ , Α-Ti (HAsO ₄ ) ₂ ・ H ₂ O, α-Sn (HPO ₄ ) ₂ ・ H ₂ O, γ-Zr (HPO ₄ ) ₂ , Γ-Ti (HPO ₄ ) ₂ , Γ-Ti (NH ₄ PO ₄ ) ₂ ・ H ₂ Crystalline acidic salts of polyvalent metals such as O are mentioned.
[0028]
The above-mentioned ion-exchange layered compound may be used after being subjected to salt treatment and / or acid treatment as necessary. In the state where neither salt treatment nor acid treatment has been performed, the ion-exchangeable layered compound except silicate is a compound having a crystal structure in which surfaces constituted by ionic bonds and the like are stacked in parallel with weak bonding force to each other, The contained ions can be exchanged.
Examples of the above-mentioned inorganic silicate include clay, clay mineral, zeolite, and diatomaceous earth. These may use synthetic products, or may use naturally occurring minerals. Specific examples of clays and clay minerals include allophane group such as allophane, kaolin group such as dickite, nacrite, kaolinite, anoxite, halloysite group such as metahaloisite and halloysite, and serpentine pattern such as chrysotile, risaldite, and antigolite. Stone group, montmorillonite, sauconite, beidellite, nontronite, smectites such as saponite, hectorite, vermiculite minerals such as vermiculite, illite, sericite, mica minerals such as chlorite, attapulgite, sepiolite, palygorskite, bentonite, and knotushi Clay, gairome clay, hisingelite, bylophilite, ryokudeite group, and the like. These may form a mixed layer. Examples of the artificial composite include synthetic mica, synthetic hectorite, synthetic saponite, and synthetic teniolite.
[0029]
Among the above inorganic silicates, kaolin group, hallocite group, serpentine group, smectite, vermiculite mineral, mica mineral, synthetic mica, synthetic hectorite, synthetic saponite, synthetic teniolite are preferred, and smectite, vermiculite mineral, synthetic mica , Synthetic hectorite, synthetic saponite, and synthetic teniolite are more preferred. These may be used as they are without any particular treatment, or may be used after treatments such as ball milling and sieving. Further, they may be used alone or as a mixture of two or more.
[0030]
The above-mentioned ion-exchange layered compound and inorganic silicate can change the acid strength of the solid by salt treatment and / or acid treatment. In the salt treatment, an ion complex, a molecular complex, an organic derivative, etc. The surface area and the distance between layers can be changed by forming. That is, by using the ion exchange property and replacing the exchangeable ions between the layers with another large bulky ion, it is possible to obtain a layered material in which the layers are expanded.
[0031]
In the compounds that have not been subjected to the above pretreatment, it is preferable that the exchangeable metal cation contained is ion-exchanged with a cation dissociated from the following salts and / or acids.
The salt used for the ion exchange is a compound containing a cation containing at least one kind of atom selected from the group consisting of Group 1 to 14 atoms, and is preferably selected from the group consisting of Group 1 to 14 atoms. A compound comprising at least one cation containing at least one atom and a halogen atom, an anion derived from at least one atom or atomic group selected from the group consisting of inorganic acids and organic acids, more preferably , A cation containing at least one atom selected from the group consisting of Group 2-14 atoms, Cl, Br, I, F, PO ₄ , SO ₄ , NO ₃ , CO ₃ , C ₂ O ₄ , ClO ₄ , OOCCH ₃ , CH ₃ COCHCOCH ₃ , OCI ₂ , O (NO ₃ ) ₂ , O (ClO ₄ ) ₂ , O (SO ₄ ), OH, O ₂ Cl ₂ , OCI ₃ , OOCH and OOCCH ₂ CH ₃ And at least one anion selected from the group consisting of Further, two or more of these salts may be used at the same time.
[0032]
The acid used for the above-mentioned ion exchange is preferably selected from hydrochloric acid, sulfuric acid, nitric acid, acetic acid, and oxalic acid, and two or more of them may be used simultaneously. As a method of combining the salt treatment and the acid treatment, a method of performing an acid treatment after performing the salt treatment, a method of performing the salt treatment after performing the acid treatment, a method of simultaneously performing the salt treatment and the acid treatment, and performing the salt treatment Later, there is a method in which salt treatment and acid treatment are performed simultaneously. Note that the acid treatment has an effect of eluting a part of cations such as Al, Fe, Mg, and Li having a crystal structure, in addition to an ion exchange and an effect of removing surface impurities.
[0033]
Treatment conditions with salts and acids are not particularly limited. However, usually, the salt and acid concentrations are 0.1 to 30% by weight, the treatment temperature is in the range of room temperature to the boiling point of the solvent used, and the treatment time is 5 minutes to 24 hours. It is preferable to carry out under the condition of eluting a part. In addition, salts and acids are generally used in an aqueous solution.
[0034]
When performing the salt treatment and / or the acid treatment, the shape may be controlled by pulverization or granulation before, during, or after the treatment. Further, another chemical treatment such as an alkali treatment or an organic substance treatment may be used in combination. The component (B) thus obtained preferably has a pore volume of a radius of 20 ° or more measured by a mercury intrusion method of 0.1 cc / g or more, particularly preferably 0.3 to 5 cc / g. Such component (B) usually contains adsorbed water and interlayer water. Here, the adsorbed water is water adsorbed on the surface of the ion-exchange layered compound or the inorganic silicate or the crystal fracture surface, and the interlayer water is water existing between the layers of the crystal.
[0035]
In the present invention, the component (B) is preferably used after removing the adsorbed water and interlayer water as described above. The dehydration method is not particularly limited, and methods such as thermal dehydration, thermal dehydration under a gas flow, thermal dehydration under reduced pressure, and azeotropic dehydration with an organic solvent are used. The heating temperature is in a temperature range in which adsorbed water and interlayer water do not remain, and is usually 100 ° C. or higher, preferably 150 ° C. or higher. However, high temperature conditions that cause structural destruction are not preferable. The heating time is at least 0.5 hour, preferably at least 1 hour. At this time, the weight loss of the component (B) after dehydration and drying is preferably 3% by weight or less as a value when sucked for 2 hours at a temperature of 200 ° C. and a pressure of 1 mmHg. In the present invention, when the component (B) whose weight loss is adjusted to 3% by weight or less is used, the same weight loss is maintained even when the component (A) and the component (C) described below come into contact. It is preferable to handle it.
[0036]
Examples of inorganic oxides and composite oxides include, for example, SiO 2 ₂ , Al ₂ O ₃ , MgO, ZrO, TiO ₂ , B ₂ O ₃ , Oxides such as ZnO, SiO ₂ -MgO, SiO ₂ -Al ₂ O ₃ , SiO ₂ -TiO ₂ , SiO ₂ −Cr ₂ O ₃ , SiO ₂ -Al ₂ O ₃ -A composite oxide such as MgO.
Next, as the organoaluminum compound (component C), those mentioned above are used. Specific examples thereof include trialkylaluminums such as trimethylaluminum, triethylaluminum, tripropylaluminum, and triisobutylaluminum, and diethylaluminum monochloride. And halogen- or alkoxy-containing alkylaluminum such as diethylaluminum monomethoxide. Of these, trialkylaluminum is preferred.
[0037]
Further, an aluminum oxy compound can be used as the organoaluminum compound (component C), specifically, a compound also called alumoxane, which is a compound of one kind of trialkylaluminum or two or more kinds of trialkylaluminum and water. Obtained by reaction. Specifically, (a) methylalumoxane, ethylalumoxane, propylalumoxane, butylalumoxane, isobutylalumoxane obtained from one type of trialkylaluminum and water, (b) two types of trialkylaluminum and Methyl ethyl alumoxane, methyl butyl alumoxane, methyl isobutyl alumoxane, etc. obtained from water are exemplified. Of these, methylalumoxane and methylisobutylalumoxane are preferred. The above-mentioned alumoxanes can be used in combination of two or more in each group and between each group.
Examples of the ionic compound capable of converting the metallocene complex into a cation by reacting with the metallocene complex include a compound represented by the general formula (II).
[0038]
Embedded image
[K] ^e + [Z] ^e- (II)
[0039]
In the general formula (II), K is a cation component, and examples thereof include a carbonium cation, a tripyllium cation, an ammonium cation, an oxonium cation, a sulfonium cation, and a phosphonium cation. In addition, metal cations and organic metal cations which are easily reduced by themselves are also included.
Specific examples of the cation include triphenylcarbonium, diphenylcarbonium, cycloheptatrienium, indenium, triethylammonium, tripropylammonium, tributylammonium, N, N-dimethylanilinium, dipropylammonium, dicyclohexylammonium, Triphenylphosphonium, trimethylphosphonium, tris (dimethylphenyl) phosphonium, tris (methylphenyl) phosphonium, triphenylsulfonium, triphenyloxonium, triethyloxonium, pyrylium, silver ion, gold ion, platinum ion, copper ion, palladium ion , Mercury ion, ferrocenium ion and the like.
[0040]
In the above general formula (II), Z is an anion component, which is a component (generally a non-coordinating component) that becomes a counter anion to the converted cation species of component (A). Examples of Z include an organic boron compound anion, an organic aluminum compound anion, an organic gallium compound anion, an organic phosphorus compound anion, an organic arsenic compound anion, an organic antimony compound anion, and the like, and specific examples include the following compounds. .
(A) tetraphenylboron, tetrakis (3,4,5-trifluorophenyl) boron, tetrakis {3,5-bis (trifluoromethyl) phenyl} boron, tetrakis {3,5-di (t-butyl) phenyl ｝ Boron, tetrakis (pentafluorophenyl) boron, etc.
(B) tetraphenylaluminum, tetrakis (3,4,5-trifluorophenyl) aluminum, tetrakis {3,5-bis (trifluoromethyl) phenyl} aluminum, tetrakis (3,5-di (t-butyl) phenyl ) Aluminum, tetrakis (pentafluorophenyl) aluminum, etc.
[0041]
(C) tetraphenylgallium, tetrakis (3,4,5-trifluorophenyl) gallium, tetrakis {3,5-bis (trifluoromethyl) phenyl} gallium, tetrakis (3,5-di (t-butyl) phenyl ) Gallium, tetrakis (pentafluorophenyl) gallium, etc.
(D) tetraphenyl phosphorus, tetrakis (pentafluorophenyl) phosphorus, etc.
(E) Tetraphenylarsenic, tetrakis (pentafluorophenyl) arsenic, etc.
(F) Tetraphenylantimony, tetrakis (pentafluorophenyl) antimony, etc.
(G) decaborate, undecaborate, carbado decaborate, decachloro decaborate, etc.
[0042]
Examples of Lewis acids, particularly Lewis acids capable of converting a metallocene complex to a cation, include various organic boron compounds, metal halide compounds, solid acids, and the like. Specific examples thereof include the following compounds.
(A) Organic boron compounds such as triphenylboron, tris (3,5-difluorophenyl) boron and tris (pentafluorophenyl) boron
(B) aluminum chloride, aluminum bromide, aluminum iodide, magnesium chloride, magnesium bromide, magnesium iodide, magnesium chloride bromide, magnesium chloride iodide, magnesium bromide iodide, magnesium chloride hydride, magnesium chloride hydroxide, Metal halide compounds such as magnesium bromide hydroxide, magnesium chloride alkoxide, magnesium bromide alkoxide
(C) Solid acids such as alumina and silica-alumina
For example, SiO ₂ , Al ₂ O ₃ , MgO, ZrO, TiO ₂ , B ₂ O ₃ , Oxides such as ZnO, SiO ₂ -MgO, SiO ₂ -Al ₂ O ₃ , SiO ₂ -TiO ₂ , SiO ₂ −Cr ₂ O ₃ , SiO ₂ -Al ₂ O ₃ -A composite oxide such as MgO.
[0043]
The solid catalyst component, the organoaluminum compound, or the electron-donating compound used as needed, and the activator other than the organoaluminum in the polymerization tank or outside the polymerization tank in the presence or absence of the monomer to be polymerized. Contact each other below, and this contact forms the stereoregular catalyst of the present invention.
Each of the catalyst components may be independently supplied to the polymerization tank, or may be supplied after arbitrary components are brought into contact with each other. In this case, the contact method is arbitrary. That is, each component may be contacted simultaneously, or arbitrary components may be sequentially contacted. The method for supplying each of these components to the polymerization tank is not particularly limited. It may be supplied by dissolving or suspending it in an inert hydrocarbon solvent such as propane, butane, pentane, hexane, heptane, octane, nonane, decane, toluene, xylene, or substantially these inert hydrocarbon solvents. It is also possible to supply directly without using any.
[0044]
Hereinafter, a method for continuously producing the propylene-based block copolymer of the present invention will be described with reference to FIG.
In the present invention, the first-stage polymerization step is performed first in the first polymerization tank 1 and then in the second polymerization tank 5.
In the present invention, the polymerization in the first stage polymerization step uses a polymerization method using liquid propylene as a medium. The polymerization method using propylene itself as a medium is not only advantageous in terms of cost because a high catalyst efficiency can be obtained in a short time in the first stage polymerization step, but also enables the use of wet classification as a classification system described later. There is an advantage that it becomes. It should be noted that wet classification generally provides higher classification efficiency than dry classification, and is therefore advantageous in suppressing a short path in the first stage polymerization step. Furthermore, in the present invention, wet classification by the sedimentation hydrostatic classifier 4 is suitable. In this case, liquid propylene can be used as a classification medium, so that there is an advantage that it is not necessary to use another medium. Further, there is an advantage that separation of the polymer and unreacted propylene is easy.
[0045]
In the present invention, the polymerization temperature of each polymerization tank is not particularly limited, but is usually 40 to 120 ° C, preferably 50 to 90 ° C. The pressure is not particularly limited, but is usually 1 to 100 atm, preferably 5 to 50 atm.
The polymerization is carried out in the presence of hydrogen. There is no particular limitation on the amount of hydrogen supplied to the polymerization tank, and hydrogen required to obtain a desired melt flow rate (hereinafter, referred to as MFR) can be supplied. The MFR of the propylene-based polymer obtained in each of the polymerization tanks 1 and 5 in the first-stage polymerization step can be set arbitrarily, but is usually MFR = 0.1 to 3000 g / 10 min, preferably in consideration of moldability. , 0.2-300 g / 10 min. In particular, a polymerization method for giving a difference to each MFR to improve the moldability is also possible. There is no particular limitation on the ratio of the amount of polymer produced in the first stage polymerization step in the polymer finally obtained. However, considering the balance between rigidity and impact resistance, it is preferable that the content be 30 to 95% by weight, especially 50 to 93% by weight. That is, the operating conditions in the first-stage polymerization process are set so as to achieve such a ratio in consideration of the process performance in the second-stage polymerization process.
[0046]
The average residence time in the first stage polymerization step is set to be about 0.1 to 8 hours, preferably about 0.5 to 5 hours, and more preferably about 0.7 to 3.0 hours. Here, the average residence time is obtained by dividing the amount of polymer retained in the first stage polymerization step by the amount of polymer extracted from the first stage polymerization step to the second stage polymerization step per unit time. The average CE of the polymer extracted from the first-stage polymerization step and sent to the second-stage polymerization step is preferably higher than a certain level.
[0047]
Here, CE represents the catalyst efficiency and means the amount of the produced polymer per unit solid catalyst weight. When the average CE is low, not only does the cost of the catalyst increase, but also the amount of catalyst residues contained in the polymer finally obtained increases, so that there is a disadvantage that the thermal stability and weather resistance of the polymer decrease. In order to prevent this, it is possible to increase the feed amount of the additive or to perform a decalcification treatment. However, any of these methods is a cost increase factor and is not preferable. Therefore, the above average CE is preferably 5000 g / g or more, more preferably 10,000 g / g or more, and most preferably 30,000 g / g or more.
[0048]
In the present invention, in order to suppress a short path from the first-stage polymerization process to the second-stage polymerization process, a classification system including the sedimentation hydraulic classifier 4 and the concentrator 3 is mainly used. The configuration of the system is not particularly limited as long as the purpose of suppressing the short path is achieved. Further, in the present invention, the short path is further suppressed by the second polymerization tank 5 additionally connected to the outlet side of the classifier 4 connected to the outlet of the first polymerization tank 1 and the gel is finally suppressed, and the high impact strength is achieved. Can be obtained.
[0049]
Here, the hydrodynamic classifier 4 is a countercurrent contact between the slurry extracted from the first polymerization tank 1 and a classification medium (preferably a supernatant of the low-concentration slurry obtained by the concentrator 3) inside the apparatus. This is a device that separates polymer particles according to particle size. In the hydrodynamic classifier 4, large-size particles among the polymer particles supplied to the classifier have a high probability of settling in the classifier 4 against the countercurrent liquid. The slurry containing a large amount of particle size particles is withdrawn from the outlet of the body of the classifier 4 and sent to the second polymerization tank 5. On the other hand, small-sized particles have a high probability of rising together with the countercurrent liquid. Thus, the slurry containing a large amount of small-diameter particles is extracted from the upper part of the classifier, and is separated by the particle size. All or most of the thus-obtained slurry containing many small-diameter particles is returned to the original first polymerization tank 1 via the concentrator 3, and the polymerization is continued. In some cases, the fine powder is prevented from accumulating in the first polymerization tank 1 by transferring partly to the low pressure gas post-processing system 9 via the line 12 or to the second polymerization tank 5 via the line 11. The allocation depends, of course, on the fine powder accumulation rate in the first polymerization tank 1. However, in order to not match the effect of the original classification system, the original amount should be less than 50 to 100 wt%, preferably less than 90 to 100 wt%. It is desirable to return to the first polymerization tank 1.
[0050]
In the present invention, the hydraulic classifier 4 is used in combination with the slurry concentrator 3. In this case, a liquid cyclone, a centrifugal separator, a filter, or the like is used as the concentrator 3. In the case of continuous operation, the liquid cyclone is excellent in operability, the device is small and inexpensive, and the installation area is small. Therefore, it is preferably used.
When the operating conditions of the hydrocyclone are properly selected, it is possible to separate the supernatant into a concentrated slurry containing almost no particles. The use of the supernatant liquid containing little polymer particles thus obtained in the countercurrent flow of the classifier makes it possible to reduce the amount of liquid used in the process and to reduce the load on the process, which is advantageous. It is.
[0051]
Whether the slurry extracted from the first polymerization tank 1 in the first polymerization step is first supplied to the concentrator 3 or first supplied to the sedimentation hydraulic classifier 4 is optional. Since the pressure loss is smaller when the slurry is supplied to the vessel 4 first, the size of the slurry supply pump 2 can be advantageously reduced. Further, there is an advantage that the flow rate control region of the supernatant obtained from the concentrator 3 can be made large.
In this way, of the polymer obtained from the first polymerization tank 1, a particle group containing a large number of particles having a relatively large particle diameter and, in some cases, small particle diameter particles are sent to the second polymerization tank 5. Can be
[0052]
The polymerization amount ratio in the first polymerization tank 1 and the second polymerization tank 5 greatly affects the short path to the second polymerization step. For example, when the polymerization amount ratio in the first polymerization tank 1 is extremely low as compared with that in the second polymerization tank 5, the burden on the classifier 4 becomes relatively large, and short pass is easy when considering the same classification performance. State. The reverse is also true. As the polymerization amount ratio between the first polymerization tank 1 and the second polymerization tank 5, the polymerization conditions distributed from 35:65 to 99: 1, preferably from 50:50 to 85:15 are more efficiently used in the first polymerization step. From the polymer particles, thereby suppressing the formation of gel.
[0053]
The above-mentioned particle group is obtained as a slurry composed of a polymer and liquid propylene. In a state containing such liquid propylene, the polymer is supplied to a gas phase polymerization tank used as a copolymerization tank 8 in the second stage polymerization step. In such a case, undesirable situations such as an increase in the temperature distribution in the gas phase polymerization tank and an increase in the non-uniformity of the flow state of the polymer are likely to occur. In order to avoid such a situation, it is desirable that the polymer is substantially free of liquid before the polymer slurry is supplied to the gas phase polymerization tank in the second stage polymerization step.
[0054]
In the present invention, since the first stage polymerization step is polymerization using liquid propylene as a medium, the above problem can be avoided by vaporizing liquid propylene with a degassing system. Although there is no particular limitation on the degassing system, a system composed of a double tube heat exchanger 6 and a fluidized flash tank 7 is preferably used.
In the second stage polymerization step, in the presence of the propylene-based polymer produced in the first step polymerization step, under the action of the stereoregular polymerization catalyst introduced in the first step polymerization step, propylene and α-olefin Allow copolymerization to take place. Here, “under the action of the stereoregular catalyst introduced in the first-stage polymerization step” means that at least a part of the copolymerization reaction in the second-stage polymerization step was performed using the stereo-regular catalyst used in the first-stage polymerization step. It means that it occurs or continues due to the regular catalytic activity. Therefore, the copolymerization reaction of the second stage polymerization step is caused by the activity of the stereoregular catalyst that is accompanied by the polymer produced in the first stage polymerization step and is present in the second stage polymerization step. Those in which substantially all copolymerization reactions are caused, and those in which the copolymerization reaction is caused by the catalytic activity derived from the first-stage polymerization step and the activity of a catalyst or a catalyst component newly added in the second-stage polymerization step There is.
[0055]
The α-olefin used in the second polymerization step preferably has 2 to 12 carbon atoms, for example, ethylene, 1-butene, 1-pentene, 1-hexene and the like. Of these, ethylene and 1-butene are preferably used, and the most preferred is ethylene. The propylene concentration in the gas phase generally needs to be less than 90 mol%, but is preferably 30 to 85 mol%. By controlling the propylene concentration in the gaseous phase within such a range, the impact strength of the finally obtained block copolymer tends to be improved.
[0056]
The deactivated compound to be supplied to the second polymerization step is a compound having a function of suppressing the function of a polymerization catalyst, and examples thereof include an active hydrogen compound and an electron donating compound. Examples of the active hydrogen compound include water, alcohols, phenols, carboxylic acids, sulfonic acids, and amines other than tertiary amines.
Specifically, as the alcohol, an aliphatic alcohol having about 1 to 12 carbon atoms, for example, methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, n-hexyl alcohol, n-octyl alcohol , N-dodecanol, 2-ethylhexyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, and the like, and alcohols having a functional group, such as methoxyethanol, ethoxyethanol, and diethylene glycol.
[0057]
Examples of phenol include phenol, cresol, xylenol, t-butylphenol, and 2,6-dimethyl-4-t-butylphenol.
Examples of the carboxylic acid include those having about 1 to 12 carbon atoms, such as formic acid, acetic acid, propionic acid, butyric acid, stearic acid, acrylic acid, methacrylic acid, benzoic acid, and salicylic acid.
[0058]
Examples of the sulfonic acid include methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, and 4-ethylbenzenesulfonic acid.
Examples of amines other than tertiary amines include methylamine, ethylamine, n-propylamine, i-propylamine, n-butylamine, n-octylamine, cyclohexylamine, aniline, benzylamine, dimethylamine, diethylamine, and di-n -Propylamine, di-i-propylamine, di-n-butylamine, di-n-octylamine, dicyclohexylamine, diphenylamine, dibenzylamine and the like.
[0059]
Examples of the electron donating compound include compounds such as aldehyde, ketone, ester, and ether. Specifically, as the aldehyde, an aliphatic aldehyde having about 2 to 12 carbon atoms, such as acetaldehyde, ethyl aldehyde, propyl aldehyde, butyraldehyde, etc., and as the ketone, an aliphatic ketone having about 3 to 12 carbon atoms, such as acetone, Examples of esters such as methyl ethyl ketone and methyl isobutyl ketone, and aliphatic or aromatic carboxylic acid esters having 2 to 15 carbon atoms, for example, methyl formate, methyl acetate, ethyl acetate, methyl acrylate, ethyl benzoate, methyl paratoluate and the like And ethers include aliphatic ethers having 2 to 15 carbon atoms, for example, diethyl ether, dipropyl ether, dibutyl ether and the like.
[0060]
These deactivated compounds may be used alone or in a mixture. Among these deactivating compounds, preferred are those having a relatively low boiling point and a low odor. Particularly, alcohols having a relatively low carbon number are preferred, and among them, ethanol is most preferred.
The supply amount of the deactivating compound is not particularly limited, but is preferably set to an amount exceeding 1.0 mole ratio to aluminum in the organoaluminum compound supplied to the second polymerization step. When the supply amount is less than 1.0 mole ratio, the effect of improving impact resistance and / or particle fluidity tends to be slightly smaller than when the supply amount is more than 1.0 mole ratio. From the viewpoint of improving the impact resistance, the higher the molar ratio, the better. However, if the molar ratio is too high, the polymerization activity of the rubber is significantly reduced, which is not preferable from the viewpoint of productivity. Therefore, a preferable supply amount of the active hydrogen compound is more than 1.0 mole ratio and less than 3.0 mole ratio, more preferably, 1 mole ratio with respect to aluminum in the organic aluminum compound supplied to the second stage polymerization step. It is not less than 1 mole ratio and not more than 2.5 mole ratio.
[0061]
The method of supplying the deactivated compound is arbitrary. It may be supplied after being dissolved in a solvent such as n-hexane or toluene, or may be directly supplied without using a solvent.
The supply position may be any position as long as the purpose of performing the propylene / α-olefin copolymerization in the second stage polymerization step in the presence of the deactivating compound is achieved. .
[0062]
Specifically, a method of supplying from the lower part of the dispersion plate of the gas phase polymerization tank 8 in the second stage polymerization step, a method of supplying the gas to the circulating gas line of the gas phase polymerization tank, a bed layer composed of polymer particles in the gas phase polymerization tank , A method of supplying from the upper part of the bed layer, a method of supplying to the degassing tank between the first polymerization step and the second polymerization step, and a method of supplying the degassing tank 7 and the second polymerization step. A method of supplying the solution into the transfer pipe between the polymerization tank 8 and the like can be given. The number of supply positions may be one, or if necessary, two or more supply positions may be set. Among these, in consideration of the effective dispersion of the deactivated compound, the method of supplying from the lower part of the gas-phase polymerization tank dispersion plate is preferable.
[0063]
The amount of polymer produced in the second stage polymerization step can be set according to the amount of polymer produced in the first stage polymerization step. Usually, it is selected from the range of 5 to 70% by weight, preferably 7 to 50% by weight in consideration of the balance between rigidity and impact resistance.
The polymerization temperature, polymerization time, and polymerization pressure are not particularly limited, but in consideration of the above polymerization ratio, the polymerization temperature is 0 to 100 ° C, preferably 25 to 90 ° C, and the polymerization time is 0.1 to 6 hours. Preferably, the polymerization pressure is selected from the range of 0.5 to 3 hours and the polymerization pressure = 0.1 to 100 atm, preferably 1 to 40 atm. Here, the polymerization time is defined by the average residence time of the polymer in the second stage polymerization step.
[0064]
The molecular weight of the copolymer obtained in the second stage polymerization step can be arbitrarily set, but is usually from 200,000 to 3,000,000, preferably 400,000, as a weight average molecular weight Mw from the balance between physical properties and moldability. To be ~ 2 million. Incidentally, hydrogen is usually used for controlling the molecular weight. The MFR of the finally obtained block copolymer is determined by the molecular weight of the copolymer obtained in the second stage polymerization step and the ratio of the copolymer in the whole polymer. Although there is no particular limitation on the range of the MFR, it is usually preferably 0.01 to 3000 g / 10 min, preferably 0.1 to 1000 g / 10 min in consideration of moldability. The type of the polymerization tank used for the gas phase polymerization in the second stage polymerization step is not particularly limited. That is, a known fluidized bed, a stirred fluidized bed, a stirred tank, and the like can be used.
[0065]
After the polymerization in the first and second stages, the polymerization in the third and subsequent stages can be performed. In the polymerization step, polymerization in which the propylene concentration in the gas phase is less than 90 mol%, that is, copolymerization of propylene and ethylene, ethylene homopolymerization, copolymerization of ethylene with another α-olefin, and the like are performed. be able to. The low-pressure gas post-treatment system 9 includes a compressor associated with a low-pressure degassing tank for recovering unreacted propylene and α-olefin, and deactivation of a catalyst and a cocatalyst contained in a polymer and / or a solvent. An apparatus for drying is provided. The slurry containing the small-sized particles transferred by the classifier 4 described above is mixed with normal particles and transferred to a product system including an extruder.
[0066]
【Example】
The following examples serve to further illustrate the invention. The present invention is not limited thereby without departing from the gist thereof.
[Example 1]
(1) Production of solid catalyst component (A)
Vacuum stirrer, Mg (OEt) in 3 L-round bottom four-necked flask equipped with thermometer ₂ : 2.058 mol was charged and then Ti (OBu) ₄ Is charged with Mg (OEt) ₂ Ti (OBu) for magnesium in ₄ /Mg=0.60 (molar ratio), and the temperature was raised while stirring at 300 rpm.
After reacting at 150 ° C. for 1.5 hours, the temperature is lowered to 120 ° C. and MeSi (OPh) ₃ Of the toluene solution of Mg (OEt) ₂ MeSi (OPh) ₃ /Mg=0.67 (molar ratio). After the addition was completed, the reaction was carried out at the same temperature for 1 hour. After the completion of the reaction, the temperature was lowered to room temperature, and then Si (OEt) ₄ Is charged with Mg (OEt) ₂ Si (OEt) for magnesium in ₄ /Mg=0.05 (molar ratio) to obtain a slurry of the contact product (a *).
[0067]
The whole amount of the slurry obtained here was transferred to an induction stirring type 10 L-autoclave provided in a cooling / heating jacket, and then diluted with toluene so that [Mg] = 0.60 mol / L toluene.
This slurry was cooled to −10 ° C. while stirring at 300 rpm, and diethyl phthalate was added to the charged Mg (OEt). ₂ It was added so that diethyl phthalate / Mg = 0.10 (molar ratio) with respect to magnesium therein. Subsequently, TiCl ₄ Is charged with Mg (OEt) ₂ TiCl for magnesium in ₄ /Mg=4.0 (molar ratio), dropwise over 1.2 hours to obtain a homogeneous solution. At this time, the phenomenon that the viscosity of the liquid increased and the liquid became gel-like did not occur.
[0068]
The obtained homogeneous solution was heated to 15 ° C. at a rate of 0.5 ° C./min and kept at the same temperature for 1 hour. Then, the temperature was raised again to 50 ° C. at a rate of 0.5 ° C./min and kept at 50 ° C. for 1 hour. Further, the temperature was raised to 117 ° C. at 1.0 ° C./min, and the treatment was performed at the same temperature for 1 hour.
After the treatment, the heating and stirring were stopped, the supernatant liquid was removed, and the residue was washed with toluene to a residual liquid ratio of 1/55 to obtain a solid slurry.
[0069]
Next, the amount of toluene in the obtained solid slurry was determined using TiCl ₄ The concentration was adjusted to 2.0 mol / L toluene, and TiCl was added at room temperature. ₄ , Mg (OEt) ₂ TiCl for magnesium in ₄ /Mg=5.0 (molar ratio). The temperature of the slurry was increased while stirring at 300 rpm, and the reaction was performed at 117 ° C. for 1 hour. After the completion of the reaction, the heating and stirring were stopped, the supernatant was removed, and the residue was washed with toluene so that the residual liquid ratio was 1/150, to obtain a toluene slurry of (A *).
[0070]
(2) Implementation of prepolymerization
The whole amount of the solid slurry obtained here is transferred to a reaction tank having a three-way swept wing having an inner diameter of 660 mm and a straight body of 770 mm, and diluted with n-hexane to give a concentration of (A *) of 3 g / L. I did it. While stirring this slurry at 300 rpm, triethylaluminum was added at 25 ° C. so that triethylaluminum / (A *) = 3.44 mmol / g, and further, t-butyl-n-propyldimethoxysilane was added. t-Butyl-n-propyldimethoxysilane / (A *) = 1.44 mmol / g was added. After completion of the addition, the mixture was kept at 25 ° C. for 30 minutes while continuously stirring.
[0071]
Next, propylene gas was fed to the liquid phase at a constant speed over 72 minutes. After stopping the feed of the propylene gas, the solid was washed with n-hexane by a sedimentation washing method to obtain a slurry of the solid catalyst component (A) at a residual liquid ratio of 1/12. The obtained solid catalyst component (A) contained 2.7 g of a propylene polymer per 1 g of the component (A *).
[0072]
(3) Production of propylene-ethylene block copolymer
Triethylaluminum is used as the cocatalyst with the solid catalyst component produced in (1), and t-BuEtSi (OEt) is used as the third component. ₂ In the process shown in FIG. 1 in the presence of hydrogen, continuous polymerization of three tanks was carried out. The triethylaluminum concentration was 60 mol ppm to propylene, and the Si concentration was 2.8 mol ppm to propylene.
[0073]
The polymerization temperature and the polymerization pressure are as follows.
Polymerization temperature: propylene first polymerization tank: polymerization temperature = 75 ° C, polymerization pressure = 37.0 atm, H ₂ Concentration = 13 mol% to propylene, propylene 2nd polymerization tank: polymerization temperature = 75 ° C., polymerization pressure = 36.8 atm, H ₂ Concentration = 12 mol% to propylene, gas phase polymerization tank: polymerization temperature = 80 ° C., polymerization pressure 16.0 atm, H ₂ Concentration = 0.7 mol% vs. ethylene + propylene, propylene / (propylene + ethylene) = 55 mol%. Here, regarding the polymerization time of the propylene polymerization tank 1 and the propylene polymerization tank 2, the homopolymer average CE = 50,000 g / g, and the polymerization amount ratio between the polymerization tank 1 and the polymerization tank 2 is 55:45 (weight ratio). Controlled.
[0074]
The slurry polymerized in the polymerization tank 1 was fed to a hydraulic classifier 4 using a slurry pump 2.
The slurry extracted from the upper part of the liquid classifier 4 contains fine particles and is sent to the concentrator 3 and circulated to the original propylene polymerization tank 1 from the lower part of the concentrator. The supernatant liquid containing almost no solid particles was taken out, and fed from the lower part of the hydraulic classifier 4 by a pump. From the lower part of the classifier 4, a slurry containing many large-diameter particles was extracted. The slurry was supplied to a propylene second polymerization tank.
[0075]
The slurry from the second polymerization tank was fed to the fluidized flash tank 7 via the downstream double-tube exchanger 6. Here, the supply rate of the propylene polymer in the slurry was adjusted so as to be 55 kg / hr. In the fluidized flash tank 7, the temperature in the tank was maintained at 70 ° C. while feeding propylene gas heated from below. The polypropylene particles obtained here were sent to the gas-phase polymerization tank 8, where propylene and ethylene were copolymerized.
[0076]
In order to enhance the mixing effect, a mixed gas of ethylene, propylene, hydrogen, and nitrogen was circulated by a gas blower in the gas-phase polymerization tank 8 provided with an auxiliary stirring blade. In addition, ethanol is fed as an active hydrogen compound, and the feed amount of ethanol is 1.2 mol ratio with respect to aluminum in triethylaluminum supplied accompanying the polymer particles supplied to the gas phase polymerization tank. I made it.
[0077]
As a result, the residence time in each polymerization tank was 25 minutes for the first polymerization tank, 35 minutes for the second polymerization tank, and 36 minutes for the third polymerization tank.
Analysis of the polymer particles extracted from the gas phase polymerization tank 8 revealed that MFR = 30.0 g / 10 min, bulk density = 0.50 g / cc, EPR content = 14.6% by weight, and the molecular weight of EPR was 800,000. The number of gels is 230 / 250cm ² Met. (2) Physical property evaluation
Flexural modulus = 14,600 kg / cm ² , Izod = 10.1 kg · cm / cm, and surface impact strength = 99 kg · cm.
[0078]
[Example 2]
In Example 1, the homopolymer average CE was controlled to be 50,000 g / g, and the polymerization amount ratio between the first polymerization tank 1 and the second polymerization tank 2 was distributed to 80:20 (weight ratio).
The polymerization temperature and the polymerization pressure are as follows.
Polymerization temperature: propylene first polymerization tank: polymerization temperature = 75 ° C, polymerization pressure = 37.0 atm, H ₂ Concentration = 13 mol% to propylene, propylene 2nd polymerization tank: polymerization temperature = 75 ° C., polymerization pressure = 36.8 atm, H ₂ Concentration = 12 mol% to propylene, gas phase polymerization tank: polymerization temperature = 80 ° C., polymerization pressure = 16.0 atm, H ₂ Concentration = 0.7 mol% vs. ethylene + propylene, propylene / (propylene + ethylene) = 55 mol%.
[0079]
As a result, the residence time in each polymerization tank was 45 minutes for the first polymerization tank, 20 minutes for the second polymerization tank, and 36 minutes for the third polymerization tank.
When polymer particles extracted from the gas phase polymerization tank 8 were analyzed, MFR was 33.0 g / 10 min, bulk density was 0.48 g / cc, EPR content was 14.2% by weight, and the molecular weight of EPR was 820,000. The number of gels is 145 / 250cm ² Met. (2) Physical property evaluation
Flexural modulus = 14,900 kg / cm ² , Izod = 10.0 kg · cm / cm, and surface impact strength = 103 kg · cm.
[0080]
[Comparative Example 1]
In FIG. 1, a study was conducted using the same process as in Example 1, except that a process in which the slurry was directly supplied to the fluidized flash tank 7 bypassing the second polymerization tank was used.
The polymerization temperature and the polymerization pressure are as follows.
Polymerization temperature: propylene polymerization tank: polymerization temperature = 75 ° C, polymerization pressure = 36.5 atm, H ₂ Concentration = 12 mol% to propylene, gas phase polymerization tank: polymerization temperature = 80 ° C., polymerization pressure = 16.0 atm, H ₂ Concentration = 0.7 mol% vs. ethylene + propylene, propylene / (propylene + ethylene) = 55 mol%. Further, ethanol is fed as an active hydrogen compound, and the feed amount of ethanol is 1.1 mol ratio with respect to aluminum in triethylaluminum supplied accompanying the polymer particles supplied to the gas phase polymerization tank. I made it.
[0081]
As a result, the residence time in each polymerization tank was 66 minutes for the propylene HOMO polymerization tank, and 36 minutes for the gas phase polymerization tank. The catalytic efficiency of the homopolymer (propylene homopolymerization) is 50,000, MFR = 60 g / 10 min, ethylene-propylene copolymer content = 14.2 wt% in the block copolymer, molecular weight = 800,000, final MFR = 32 g / 10 min. Met. ρB = 0.48 g / cc
Gel number is 630 / 250cm ² Met.
[0082]
Flexural modulus = 14,800 kg / cm ² , Izod = 9.5 kg · cm / cm, and surface impact strength = 67 kg · cm.
From the viewpoint of general application of the polymer, the higher the impact resistance (DDI) is, the better the rigidity (FM) vs. impact resistance (DDI) performance is based on the same rigidity (FM) standard.
[0083]
According to the results of Example 1, Example 2, and Comparative Example 1, the propylene homopolymerization tank was set to be two tanks and the polymerization ratio of the first polymerization tank 1 and the second polymerization tank 2 was optimized and controlled. Compared to a single vessel, when the residence time and pressure conditions in the gas phase polymerization vessel are the same, there is less gel and a polymer having an improved balance of rigidity (FM) versus impact resistance (DDI) can be obtained. It shows what is possible.
[Brief description of the drawings]
FIG. 1 is a flow diagram illustrating one embodiment of the present invention.
[Explanation of symbols]
1 First polymerization tank
2 Slurry pump
3 Concentrator
4 Hydraulic classifier
5 Second polymerization tank
6 heat exchanger
7 Fluid flash tank
8 Copolymerization tank
9 Low-pressure gas aftertreatment system

Claims (4)

In the presence of a stereoregular polymerization catalyst, an α-olefin containing liquid propylene as a main component was polymerized in two polymerization tanks in the presence of hydrogen in a first-stage polymerization step, and then in a first-step polymerization step. Second stage polymerization in which the polymer is sent to a copolymerization tank and propylene and an α-olefin other than propylene are copolymerized substantially in the gas phase under the action of a stereoregular polymerization catalyst in the first stage polymerization step. A method for continuously producing a propylene-based block copolymer, comprising the steps of:
(1) The polymer slurry extracted from the first polymerization tank in the first stage polymerization step is classified into a slurry containing a large amount of large-diameter particles and a slurry containing a large amount of small-diameter particles using a classification system. Sending the slurry containing large particles to the second polymerization tank and returning all or most of the slurry containing large particles to the first polymerization tank.
(2) transferring the polymer slurry extracted from the second polymerization tank in the first polymerization step to the second polymerization step;
(3) Propylene / α-olefin copolymerization in the second stage polymerization step is performed in the presence of a deactivated compound. 2. The continuous production of a propylene-based block copolymer according to claim 1, wherein a part of the slurry containing a large amount of small-sized particles extracted and classified from the first polymerization tank in the first-stage polymerization step is sent to a low-pressure gas post-treatment system. Method. The propylene-based block copolymer according to claim 1 or 2, wherein a part of a slurry containing a large amount of small-sized particles extracted and classified from the first polymerization tank in the first polymerization step is transferred to the second polymerization tank. Continuous manufacturing method. The propylene according to any one of claims 1 to 3, wherein the polymerization ratio (first polymerization tank / second polymerization tank) of the first polymerization tank and the second polymerization tank in the first stage polymerization step is 35/65 to 99/1. A continuous production method for a block copolymer.

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