JP3672395B2 - Ethylene copolymer and film comprising the same - Google Patents

Description

【００１７】

カラム内に試料溶液を１３５℃の条件下で導入後、５℃／時間で徐冷してポリマーを充填剤に吸着させたのち、０℃まで冷却後、カラム温度を上記条件で昇温させることにより、各温度で溶出したポリマー濃度を赤外検出器で検出する。
この温度と濃度の関係から、各温度における溶出量を求めることができる。
０℃溶出成分量（％）は、０℃まで冷却した時点で結晶化しなかった成分であり、最初の試料溶液中のポリマー量に対するこの成分中のポリマー量の重量％に相当する。
９５℃以上溶出成分量は、最初の試料溶液中のポリマー量に対する９５℃以上で溶出した成分中のポリマー量の重量％に相当する。
【００１８】
また、０℃を除いた平均溶出温度の標準偏差は、昇温分別における温度Ｔ_i と溶出量Ｗ_i のデータから、下式により先ず平均溶出温度（Ｔｗ）を求め、次いで標準偏差（σ）を求める。一定昇温であるから、溶出成分量のデータを時間間隔を一定にして取り込み、求めることができる。
【００１９】
【数１】

【００２０】
【数２】

【００２１】
（ト）ＧＰＣ・ＭＡＬＬＳ測定による９０°光散乱クロマトグラム本発明のエチレン系共重合体は、（ト）ＧＰＣ・ＭＡＬＬＳ測定による９０°光散乱クロマトグラムにおいて、分子量分布を反映したクロマトグラムの全ピーク面積に対する分子量１０⁶以上に現れる超高分子量成分のピーク面積が１．５％以上、５％未満であるものである。これを５％未満とすることで、フィルムの透明性に優れ、機械的強度が向上する傾向がある。透明性やヘイズの面から、さらに好ましくは、１．５％以上、２％未満である。このＧＰＣ・ＭＡＬＬＳ測定による９０°光散乱クロマトグラムの一例を第３図に示す。図に示すように、超高分子量成分のピークが顕著に表される傾向があり、上記の規定はベースラインからの全ピーク面積に対する分子量１０⁶以上に現れる超高分子量成分のピーク（斜線部分）面積の割合を示すものである。
【００２２】
なお、ＧＰＣ・ＭＡＬＬＳ測定は、以下の装置及び条件で行い、求めたものである。

【００２３】

【００２４】
本発明のエチレン系共重合体は、上記の特性を有するものであれば製造方法は問わないが、以下に示すような〔Ｉ〕固体触媒成分と〔II〕有機アルミニウム混合体からなる触媒の存在下で、エチレンとα−オレフィンを高温溶液重合することで効率よく製造することができる。
〔Ｉ〕固体触媒成分
固体触媒成分は、次の（Ａ）固体生成物、（Ｂ）有機ハロゲン化アルミニウム、（Ｃ）チタン化合物及び（Ｄ）ハロゲン化剤を以下に示すように接触、反応させて得られるものであり、アルミニウム原子の含有量が、５重量％以下、好ましくは３重量％以下であることを特徴とするものである。このアルミニウム原子の含有量が、５重量％を超えると、この固体触媒成分を用いて重合されるエチレン系共重合体の組成分布が拡がり、所望の効果が得られない。
【００２５】
（Ａ）固体生成物
固体生成物は、(a)金属マグネシウム、(b)アルコール及び(c)ハロゲン及び／又はハロゲン含有化合物を反応させて得られるものである。
(a)金属マグネシウムとしては、形状等に特に限定されるものではなく、任意の粒径の金属マグネシウム、例えば、顆粒状、リボン状、粉末状等のマグネシウムを用いることができる。また、金属マグネシウムの表面状態にも特に限定されるものではないが、表面に酸化マグネシウム等の被覆が生成されていないものが好ましい。
【００２６】
(b)アルコールとしては、任意のものを用いることができるが、炭素数１〜６の低級アルコールを用いるのが好ましい。特に、エタノールが好ましい。また、含水率は小さい方が良く、２０００ｐｐｍ以下が好ましく、２００ｐｐｍ以下がより一層好ましい。含水率が高いと金属マグネシウム表面に水酸化マグネシウムが生成する恐れがある。
アルコールの量については特に問わないが、金属マグネシウム１モルに対して好ましくは２〜１００モル、特に好ましくは５〜５０モルである。アルコールが多すぎる場合は、モルフォロジーの良好な固体物質の収率が低下するおそれがあり、少なすぎる場合は、反応槽での攪拌がスムーズに行われなくなる恐れがある。
【００２７】
(c)ハロゲン及びハロゲン含有化合物としては、それらの種類は特に制限されないが、ハロゲンとしては、塩素、臭素、ヨウ素が好ましく、特にヨウ素が好ましい。また、ハロゲン含有化合物としては、ハロゲン原子を化学式に含む化合物であればよいが、ハロゲン含有金属化合物が好ましい。この化合物の具体例としては、ＭｇＣｌ₂ 、ＭｇＩ₂ 、Ｍｇ（ＯＥｔ）Ｉ、Ｍｇ（ＯＥｔ）Ｃｌ、ＭｇＢｒ₂ 、ＣａＣｌ₂ 、ＮａＣｌ、ＫＢｒ等を好ましく挙げることができる。
ハロゲンの使用量は、金属マグネシウム１グラム原子に対して、０．０００１グラム原子以上、好ましくは０．０００５グラム原子以上、さらに好ましくは、０．００１グラム原子以上である。また、ハロゲン含有化合物の使用量は、金属マグネシウム１グラム原子に対して、ハロゲン含有化合物中のハロゲン原子が０．０００１グラム原子以上、好ましくは０．０００５グラム原子以上、さらに好ましくは、０．００１グラム原子以上である。
【００２８】
ハロゲン及びハロゲン含有化合物はそれぞれ１種を単独で使用してもよく、２種以上を併用してもよい。また、ハロゲンとハロゲン含有化合物とを併用してもよい。この場合は、全ハロゲン原子の量を金属マグネシウム１グラム原子に対して、０．０００１グラム原子以上、好ましくは０．０００５グラム原子以上、さらに好ましくは、０．００１グラム原子以上とする。ハロゲン及び／またはハロゲン含有化合物の使用量の上限については特に定めなく、目的とする固体生成物が得られる範囲で適宜選択すればよいが、一般的には全ハロゲン原子の量を金属マグネシウム１グラム原子に対して、０．０６グラム原子未満とするのが好ましい。
【００２９】
金属マグネシウムとアルコールとハロゲン及び／又はハロゲン含有化合物との反応それ自体は、公知の方法と同様に実施することができる。例えば、金属マグネシウムとアルコールとハロゲン及び／又はハロゲン含有化合物とを、還流下で水素ガスの発生が認められなくなるまで（通常２０〜３０時間）反応させて、固体物質を得る方法である。具体的には、例えばハロゲンとしてヨウ素を用いる場合、金属マグネシウムを含むアルコール中に固体状のヨウ素を投入し、その後に加熱還流する方法、金属マグネシウムを含むアルコール中にヨウ素のアルコール溶液を滴下投入後加熱還流する方法、金属マグネシウムを含むアルコールを加熱しながらヨウ素のアルコール溶液を滴下する方法等が挙げられる。いずれの方法においても、不活性ガス（例えば窒素ガス、アルゴンガス）雰囲気下で、場合によっては不活性有機溶媒（例えば、ｎ−ヘキサン等の飽和炭化水素）を用いて行うことが好ましい。
【００３０】
金属マグネシウム、アルコール、ハロゲン及び／又はハロゲン含有化合物の投入については、最初からそれぞれの全量を反応槽に投入しておく必要はなく、分割して投入してもよい。特に好ましい形態は、アルコールを最初から全量投入しておき、金属マグネシウムを数回に分割して投入する方法である。このようにした場合は、水素ガスの一時的な大量発生を防ぐことができ、安全面からも非常に望ましい。また、反応槽も小型にすることが可能となる。さらには、水素ガスの一時的な大量発生により引き起こされるアルコール、ハロゲン及び／又はハロゲン含有化合物の飛沫同伴を防ぐことも可能となる。分割する回数は、反応槽の規模を勘案して決定すればよく、特に問わないが、操作の煩雑さを考えれると通常５〜１０回が好適である。また、反応自体は、バッチ式、連続式のいずれでもよい。さらには、変法として、最初から全量投入したアルコール中に金属マグネシウムを先ず少量投入し、反応により生成した生成物を別の槽に分離して除去した後、再び金属マグネシウムを少量投入するという操作を繰り返すということも可能である。
（Ｂ）有機ハロゲン化アルミニウム
【００３１】
この有機ハロゲン化アルミニウムとしては、一般式(1)
ＡｌＲ¹ _n Ｘ¹ _3-n （０≦ｎ＜３） ・・・(1)
で表される化合物である。
一般式(1) のＲ¹ は、炭化水素基であって、炭素数１〜２０のアルキル基、アルケニル基、シクロアルキル基、シクロアルケニル基、アリール基及びアラルキル基を挙げることができる。このＲ¹ の具体例としては、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、ｓｅｃ−ブチル基、イソブチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、デシル基、オクタデシル基、アリル基、ブテニル基、シクロペンチル基、シクロヘキシル基、フェニル基、トリル基、ベンジル基、フェネチル基等が挙げられる。
また、Ｘ¹ は、フッ素原子、塩素原子、臭素原子及びヨウ素原子のハロゲン原子であって、これらの中では塩素原子又は臭素原子が好ましく、特に塩素原子が好ましい。
【００３２】
一般式(1) で表される有機ハロゲン化アルミニウムの代表的なものとしては、例えば、ｎが１の場合は、メチルアルミニウムジクロリド、エチルアルミニウムジクロリド、ｎ−プロピルアルミニウムジクロリド、イソプロピルアルミニウムジクロリド、ｎ−ブチルアルミニウムジクロリド、イソブチルアルミニウムジクロリド等が、ｎが２の場合は、ジメチルアルミニウムモノクロリド、ジエチルアルミニウムモノクロリド、ジ−ｎ−プロピルアルミニウムモノクロリド、ジイソプロピルアルミニウムモノクロリド、ジ−ｎ−ブチルアルミニウムモノクロリド、ジイソブチルアルミニウムモノクロリド等が挙げられる。これらの有機ハロゲン化アルミニウムは１種用いてもよいし、２種以上を組み合わせて用いてもよい。
【００３３】
（Ｃ）チタン化合物
チタン化合物としては、一般式(2)
Ｔｉ（ＯＲ² ）_m Ｘ² _4-m （０＜ｍ≦４） ・・・(2)
で表される化合物である。
一般式(2) のＸ² は、フッ素原子、塩素原子、臭素原子及びヨウ素原子のハロゲン原子であって、これらの中では塩素原子又は臭素原子が好ましく、特に塩素原子が好ましい。
また、Ｒ² は、炭化水素基であって、炭素数１〜２０のアルキル基、アルケニル基、シクロアルキル基、シクロアルケニル基、アリール基及びアラルキル基を挙げることができる。このＲ² の具体例としては、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、ｓｅｃ−ブチル基、イソブチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、デシル基、オクタデシル基、アリル基、ブテニル基、シクロペンチル基、シクロヘキシル基、フェニル基、トリル基、ベンジル基、フェネチル基等が挙げられる。
【００３４】
一般式(2) で表されるチタン化合物の代表的なものとしては、例えば、ｍが１の場合は、エトキシトリクロロチタン、ｎ−ブトキシトリクロロチタン等が、ｍが２の場合は、ジエトキシジクロロチタン、ジ−ｎ−ブトキシジクロロチタン等が、ｍが３の場合は、トリエトキシモノクロロチタン、トリ−ｎ−ブトキシモノクロロチタン等が、ｍが４の場合は、テトラエトキシチタン、テトラ−ｎ−プロポキシチタン、テトライソプロポキシチタン、テトラ−ｎ−ブトキシチタン等が挙げられる。
これらのチタン化合物は１種用いてもよいし、２種以上を組み合わせて用いてもよい。
【００３５】
（Ｄ）ハロゲン化剤
このハロゲン化剤は、還元力のある有機アルミニウムハロゲン化物ではなく、一般式(3)
ＭＸ³ _k Ｙ¹ _4-k （０＜ｋ≦４） ・・・(3)
で表される化合物の中で、比較的還元力が弱い化合物である。
【００３６】
一般式(3) のＭは、ケイ素や遷移金属元素のチタン等の４価の元素を示す。
また、Ｘ³ は、塩素原子、臭素原子及びヨウ素原子のハロゲン原子であって、これらの中では塩素原子又は臭素原子が好ましく、特に塩素原子が好ましい。
また、Ｙ¹ は、炭化水素基であって、炭素数１〜８のアルキル基が好ましく、具体的には、メチル基、エチル基、プロピル基が挙げられる。
一般式(3) で表されるハロゲン化剤の代表的なものとしては、ＳｉＣｌ₄ 、ＳｉＭｅ₂ Ｃｌ₂ 、ＳｉＭｅＣｌ₃ 、ＳｉＭｅ₃ Ｃｌ等のケイ素化合物や、ＴｉＣｌ₄ 等の遷移金属のハロゲン化合物が挙げられる。好ましくは、ＳｉＣｌ₄ である。これらのハロゲン化剤は１種用いてもよいし、２種以上を組み合わせて用いてもよい。
【００３７】
上記の（Ａ）、（Ｂ）、（Ｃ）、及び（Ｄ）は、この順序で接触させる必要があり、以下に詳細に説明する。
まず、（Ａ）と（Ｂ）は常法に従い、接触・反応させる。得られた固体成分（Ａ＋Ｂ）は、充分に洗浄を行うとよい。
この固体成分中のアルミニウム含有率は、０．１重量％以上、好ましくは、０．５重量％以上であるのがよい。また、この接触・反応は、ヘキサン、ヘプタン、シクロヘキサン、トルエン等の炭化水素溶媒中で行うのがよい。
次に、上記の固体成分（Ａ＋Ｂ）に（Ｃ）を以下の条件に従い、接触・反応させる。（Ｃ）の使用量は、固体成分（Ａ＋Ｂ）のマグネシウムの１モルに対して、（Ｃ）をチタン原子当たり０．０１〜１モル、好ましくは、０．０１〜０．５モルの範囲にするとよい。この使用量が１モル以上では、固体成分の一部が溶解し、損失してしまうことがある。また、０．０１モル未満では、所望のチタン化合物が固体成分に保持されないことがある。
【００３８】
これらの接触・反応を上記の炭化水素溶媒中で行う場合は、（Ｃ）がチタン原子の濃度として、１〜５０ミリモル／リットル、好ましくは、１〜３０ミリモル／リットルの範囲にするとよい。この濃度が５０ミリモル／リットル以上では、固体成分の一部が溶解し、損失してしまうことがある。また、１ミリモル／リットル未満では、所望のチタン化合物が固体成分に保持されないことがある。
【００３９】
この接触条件として、接触温度は通常０〜１００℃の範囲の下、接触時間は通常１分〜４８時間の範囲、好ましくは、３０分〜２４時間の範囲で行う。接触温度が１００℃を超えると固体触媒成分の一部が溶解し、損失してしまい、触媒活性の低下を引き起こすことがある。また、接触時間が１分未満では接触・反応が充分に行われないことがある。
さらに、上記で得られた固体成分（Ａ＋Ｂ＋Ｃ）に（Ｄ）を常法に従い、接触・反応させ、上記の〔Ｉ〕固体触媒成分を得る。（Ｄ）の使用量は、固体成分（Ａ＋Ｂ＋Ｃ）のマグネシウムの１モルに対して、（Ｄ）をハロゲン原子当たり０．０１モル以上にするとよい。この使用量が０．０１モル未満では、所望のハロゲン化を行うことができないことがある。
【００４０】
〔II〕有機アルミニウム混合体
この有機アルミニウム混合体は、（Ｅ）有機アルミニウム、（Ｆ）ハロゲン化炭化水素、及び（Ｇ）含酸素化合物の混合体から調整されるものである。
（Ｅ）有機アルミニウム
この有機アルミニウムとしては、一般式(4)
ＡｌＲ³ _p Ｘ⁴ _3-p （０≦ｐ≦３） ・・・(4)
で表される化合物である。
【００４１】
一般式(4) のＲ³ は炭素数１〜１０のアルキル基、アルケニル基、シクロアルキル基、シクロアルケニル基、アリール基、アラルキル基などの炭化水素基であり、Ｘ⁴ は塩素原子又は臭素原子などのハロゲン原子である。
このような有機アルミニウム化合物としては、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、トリイソプロピルアルミニウム、トリイソブチルアルミニウム、ジエチルアルミニウムモノクロリド、ジイソブチルアルミニウムモノクロリド、ジエチルアルミニウムモノメトキシド、ジエチルアルミニウムモノエトキシド、ジエチルアルミニウムモノブトキシド、ジエチルアルミニウムモノフェノキシド、エチルアルミニウムジクロリド、イソプリピルアルミニウムジクロリド、メチルアルミニウムセスキクロリド、エチルアルミニウムセスキクロリド等を挙げることができる。これらの化合物は、それぞれ単独で用いてもよく、２種以上を組み合わせて用いてもよい。
【００４２】
（Ｆ）ハロゲン化炭化水素
任意のものを用いることができるが、炭素数１〜１８の脂肪族ハロゲン化炭化水素、炭素数６〜１５の芳香族ハロゲン化炭化水素等が好ましい。好ましいものとして、例えば、１，２−ジクロロエタン、１，２−ジクロロプロパン、イソプロピルクロリド、ｓｅｃ−ブチルクロリド等が挙げられる。これらの化合物は、それぞれ単独で用いてもよく、２種以上を組み合わせて用いてもよい。
（Ｇ）含酸素化合物
任意のものを用いることができるが、アルコール類が好ましく、特に炭素数１〜１８の脂肪族アルコールが好ましい。好ましいものとして、例えば、ｎ−ブタノール、イソブタノール、ｔｅｒｔ−ブタノール、ｎ−ヘキサノール、２−エチルヘキサノール等が挙げられる。これらの化合物は、それぞれ単独で用いてもよく、２種以上を組み合わせて用いてもよい。
【００４３】
上記の（Ｅ）有機アルミニウム、（Ｆ）ハロゲン化炭化水素、及び（Ｇ）含酸素化合物の混合比は、（Ｅ）有機アルミニウム１モルに対して、〔（Ｆ）ハロゲン化炭化水素＋（Ｇ）含酸素化合物〕を０．０１〜１０モル、好ましくは０．１〜１モルの範囲にするのがよい。これが１０モルを超えると活性の低下を引き起こす場合がある。
【００４４】
これらの接触は、ヘキサン、ペプタン、シクロヘキサン、トルエン等の炭化水素中で行うのがよい。
また、これらの接触条件として、接触温度は、通常０〜１００℃の範囲の下、接触時間は、通常１分間以上、好ましくは、５分間以上とするのがよい。
本発明のエチレン系共重合体は、前記〔Ｉ〕固体触媒成分と〔II〕有機アルミニウム混合体からなる触媒の存在下で、エチレンとα−オレフィンを高温溶液重合することで効率よく製造することができるものである。具体的には、重合の反応系に上記の固体触媒成分の分散液及び有機アルミニウム混合体を触媒として加え、次いでエチレン及びα−オレフィンを導入する。このエチレンとの共重合に使用されるα−オレフィンは、前記の通りである。
【００４５】
この〔Ｉ〕固体触媒成分と〔II〕有機アルミニウム混合体からなる触媒において、〔Ｉ〕固体触媒成分と〔II〕有機アルミニウム混合体との使用割合は、〔Ｉ〕のチタン１モル当たり〔II〕のアルミニウムが通常１〜１０００モル、好ましくは１０〜１００モルの範囲とするのがよい。
高温溶液重合の製造条件としては、炭素数５〜１８の脂肪族炭化水素、脂環族炭化水素、芳香族炭化水素等の不活性溶剤中で重合が行われる。不活性溶剤の具体例としては、ペンタン、ヘキサン、ヘプタン、オクタン、ノナン、デカン、テトラデカン等の直鎖状又は分岐鎖状炭化水素、シクロヘキサン等の環状炭化水素、ベンゼン、トルエン、キシレン等の芳香族炭化水素が挙げられる。特に好ましい不活性溶剤としては、ｎ−ヘキサンを挙げることができる。
【００４６】
反応温度としては、生成する共重合体が上記の溶剤に溶解する温度、通常１４０℃以上であり、特に１７０〜２２０℃が装置運転上好ましい。
反応圧力は、通常１〜１５ＭＰａの範囲であり、好ましくは、２〜９ＭＰａの範囲である。
また、上記の触媒濃度としては、チタン濃度として０．００１〜１０ミリモル／リットルの範囲であり、好ましくは、０．００１〜０．１ミリモル／リットルの範囲である。
【００４７】
さらに、共重合にあたっては、水素等の公知の分子量調節剤を用いることができる。
生成した共重合体は、公知の方法により、不活性溶剤と分離し、それ単独で、又は、必要に応じて添加剤を配合して、通常、押出機を通してペレットとする。その他、パウダーのまま、フィルム、シートの成形機に供される場合もある。
以上で得られた本発明のエチレン系共重合体は、それ単独で、又は、必要に応じて添加剤を配合してから、通常の成形方法により、フィルム、シート等に成形加工される。
添加剤としては、滑剤、酸化防止剤、中和剤、紫外線吸収剤等の安定剤、帯電防止剤、アンチブロッキング剤、染料等が挙げられる。
【００４８】
成形方法としては、一般的な押出成形法、射出成形法、ブロー成形法、回転成形法が挙げられる。フィルム、シート等の成形には、押出成形法の中のＴダイ成形法やインフレーション成形法が一般的に用いられる。
【００４９】
【実施例】
次に実施例により本発明を具体的に示すが、本発明は下記の実施例に限定されるものではない。なお、フィルムの特性は、以下に示すようにして求めた。
（１）ヒートシール温度（℃）
ＪＩＳ Ｚ−１７０７に準拠して求めた。すなわち、東洋精機製作所製の熱傾斜試験機を用い、設定温度にて、圧力０．５ｋｇ／ｃｍ² 、シール時間１秒でヒートシールした。シール部の面積はＭＤ（機械方向）１０ｍｍ×ＴＤ（横方向）１５ｍｍとし、引張試験法の条件は、ＭＤのＴ型剥離で剥離試験速度２００ｍｍ／分とした。この剥離強度が０．３ｋｇ／１５ｍｍになるときの温度をヒートシール温度と定義した。
（２）ヘイズ（％）
ＪＩＳ Ｋ−７１０５に準拠して求めた。
（３）フィルムインパクト（ｋＪ／ｍ）
ＡＳＴＭ−Ｄ３４２０に準拠し、東洋精機製作所製のフィルムインパクトテスターで測定した。衝撃頭の径は１インチに設定した。
また、共重合体の各物性は、前述した方法に従って求めた。
【００５０】
〔実施例１〕
（１）固体触媒成分〔Ｉ〕の調製
攪拌機付きのガラス製反応器（内容積６リットル）を窒素ガスで充分に置換した後、エタノール２４３０ｇ、ヨウ素１６ｇ、及び金属マグネシウム（顆粒状、平均粒度３５０μｍ）１６０ｇを入れ、攪拌しながら還流条件下で系内から水素ガスの発生がなくなるまで、加熱下で反応させ、固体状生成物を得た。この固体状生成物を含む反応溶液を減圧乾燥することにより固体生成物（Ａ）を得た。
【００５１】
窒素ガスで充分に置換したガラス製三つ口フラスコ（内容積３リットル）に上記で得られた固体生成物を８４ｇ、乾燥ｎ−ヘキサン７３８ｍｌを入れた。この系内温度を３０〜４０℃に保ち、攪拌しながらエチルアルミニウムジクロリドの５０重量％ヘキサン希釈液８７６ｍｌ（Ｂ）を１時間かけて滴下した。さらに、還流下、１時間反応させた。得られた固体成分を乾燥ｎ−ヘキサンで、原液残留率が０．１％以下になるまで充分に洗浄し、固体成分（Ａ＋Ｂ）を得た。これのアルミニウム含有量は１．３重量％であった。
【００５２】
ガラス製三つ口フラスコ（内容積３リットル）に前記固体成分（Ａ＋Ｂ）１５ｇ、乾燥ｎ−ヘキサン１４１０ｍｌを入れ、次にテトラブトキシチタン２．４ｇ（Ｃ）を加え、チタン原子濃度＝５ｍｍｏｌ／ｌ（チタン原子／マグネシウム原子＝０．０５ｍｏｌ／１ｍｏｌ）、系内温度３０℃で、２４時間反応させた。これを乾燥ｎ−ヘキサンで充分洗浄し、固体成分（Ａ＋Ｂ＋Ｃ）を得た。
【００５３】
次いで、前記フラスコ内の固体成分（Ａ＋Ｂ＋Ｃ）に、乾燥ｎ−ヘキサン、四塩化ケイ素１８ｍｌ（Ｄ）を加え、四塩化ケイ素の濃度＝０．１２ｍｏｌ／ｌ、還流下、２時間反応させた。この固体成分を精製ヘキサンで充分洗浄し、固体触媒成分を得た。この固体触媒成分中のアルミニウム含有量は０．４重量％であった。
【００５４】
（２）有機アルミニウム混合体〔II〕の調整
窒素ガスで充分に置換した攪拌機付ガラス製フラスコ（内容積５リットル）に乾燥ｎ−ヘキサン２３２０ｍｌ、ジエチルアルミニウムモノクロライド６７．５ｍｍｏｌ（アルミニウム原子当たり）を順次加え、それにイソプロピルクロラリド１５ｍｍｏｌ、ｎ−ブタノール１５ｍｍｏｌを同時に加えた。この溶液を室温にて、１時間攪拌し、有機アルミニウム混合体〔II〕を得た。
（３）重合
攪拌機付ステンレス製オートクレーブ（内容積１０リットル）に乾燥ｎ−ヘキサン４１００ｍｌ、乾燥１−オクテン７００ｍｌを投入した後、室温下、さらに水素ガスの導入を開始した（水素ガス分圧＝０．０２５ＭＰａ−Ｇ）。その後、攪拌しながら、系内を１８５℃まで昇温した。
触媒投入管に乾燥ｎ−ヘキサン２００ｍｌ、上記（２）有機アルミニウム混合体〔II〕２００ｍｌ、固体触媒成分〔Ｉ〕０．１２５ｍｍｏｌ（チタン原子当たり）を順次投入した。
【００５５】
次いで、アルゴンガスにより投入管内の触媒をオートクレーブ内に圧入すると同時にエチレンを導入し、重合を開始した。エチレンは全圧３．０ＭＰａ−Ｇ（エチレン分圧＝１．６ＭＰａ−Ｇ）で５分間導入した。５分後、イソプロピルアルコールを投入することで重合を停止した。これを冷却し、生成した重合体５５０ｇを回収した。得られた共重合体の特性の測定は前述の方法に従って行った。
【００５６】
また、その品質評価としては、以下のようにキャストフィルムを成形し、各特性について評価した。
まず、得られた共重合体に添加剤として、酸化防止剤（イルガノックス１０７６及びイルガノックス１０１０（いずれもチバガイギー社製））、中和剤（ステアリン酸カルシウム（日本油脂社製））アンチブロッキング剤（シルトンＡＭＴ（水沢化学社製））、スリップ剤（ニュトロンＳ（日本精化社製））を適量配合し、これを２０ｍｍφ単軸押出機で混練して造粒した。次いで、２０ｍｍφ押出成形機（塚田機械社製）で、以下の成形条件でキャストフィルムに成形した。
【００５７】
得られたフィルムの特性の測定は前述の方法に従って行った。
成形条件
スクリュー ：フルフライトタイプ（Ｌ／Ｄ＝２０）
スクリュー径：２０ｍｍ、 回転数：５０ｒｐｍ
ダイス ：コートハンガータイプ（幅１７０ｍｍ）
リップ幅 ：０．４ｍｍ、フィルム厚み：４０μｍ
樹脂温度 ：１７０℃
得られた共重合体の特性は第１表に、フィルム特性は第２表に示す。
【００５８】
〔実施例２〕
乾燥１−オクテンを６５０ｍｌ、室温下に導入を開始した水素ガスの分圧を０．１ＭＰａ−Ｇとした以外は、実施例１と同様にして重合体を得た。
実施例１と同様に、共重合体の特性及びフィルム特性の評価を行った。その結果は、第１表及び第２表に示す。
【００５９】
〔比較例１〕
有機アルミニウム混合体〔II〕の代わりにジエチルアルミニウムモノクロリドを単体にて使用した以外は、実施例１と同様にして重合体を得た。
実施例１と同様に、共重合体の特性及びフィルム特性の評価を行った。その結果は、第１表及び第２表に示す。
昇温分別９５℃以上溶出成分が多く、昇温分別平均溶出温度の標準偏差が大きい重合体が得られた。
【００６０】
〔比較例２〕
（１）固体触媒成分の調製
内容積２００ｍｌのステンレス製ポットに、直径１０ｍｍφのステンレス製ボール１００個を充填し、無水塩化マグネシウム（粉砕品）１４ｇ、四塩化チタン１．６ｍｌ、乾燥ｎ−ヘプタン４８ｍｌを、窒素ガス雰囲気下で封入した。
回転式ミルにのせ、６０時間粉砕した。得られた固体成分を、乾燥ｎ−ヘプタンで充分洗浄し、固体触媒成分を得た。
（２）有機アルミニウム混合体〔II〕
実施例１（２）と同様にして、有機アルミニウム混合体〔II〕を得た。
（３）重合
固体触媒成を（１）で得た固体触媒成に代えた以外は、実施例１と同様にして重合体を得た。
実施例１と同様に、共重合体の特性及びフィルム特性の評価を行った。その結果は、第１表及び第２表に示す。
昇温分別０℃溶出成分、９５℃以上溶出成分が多く、昇温分別平均溶出温度の標準偏差が大きい重合体が得られた。
【００６１】
〔比較例３〕
三井石油化学工業社製ウルトゼックス２０２１Ｌを実施例１と同様に評価した。その特性は第１表及び第２表に示す。
【００６２】
【表１】

【００６３】
【表２】

【００６４】
【発明の効果】
本発明は、特に透明性に優れ、ヒートシール性、機械的特性等が良好で、それらの特性バランスも良好であるフィルムを与えることができるエチレン系共重合体を得ることができる。従って、包装用フィルム、食品用フィルム、テープ用フィルムの用途に好ましく利用できる。また、好ましい特性を活かし、シート、容器、日用品等の用途にも利用できる。
【図面の簡単な説明】
【図１】第１図は、昇温分別法より得られるクロマトグラムを示す。（図にも示すように一定昇温であるから時間は溶出温度に相当する。）
【図２】第２図は、分析昇温分別装置の模式図を示す。
【図３】第３図は、ＧＰＣ・ＭＡＬＬＳ測定による９０°光散乱クロマトグラム示す。
【符号の説明】
１・・・ＴＲＥＦカラム
２・・・送液ポンプ
３・・・バルブオーブン
４・・・ＴＲＥＦオーブン
５・・・検出器
６・・・１０方バルブ
７・・・ループ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel ethylene copolymer. More specifically, the present invention relates to an ethylene copolymer composed of an ethylene unit and an olefin unit having 3 or more carbon atoms that are excellent in transparency, heat sealability, mechanical properties, and the like, and a film comprising the same.
[0002]
[Prior art]
Generally, linear low density polyethylene (hereinafter sometimes referred to as LLDPE), which is a copolymer of ethylene and α-olefin, has mechanical properties such as transparency, heat sealability, and impact resistance. Since it is excellent, it is widely used industrially as a raw material for films and sheets used in the packaging field and other film molded products.
[0003]
In recent years, further improvements in heat sealability, mechanical properties, and the like for LLDPE have been required due to improvements in packaging speed accompanying the development of automatic packaging technology. Moreover, the improvement of transparency is also required at the same time.
By the way, LLDPE is a method in which high temperature solution polymerization is performed in the presence of a catalyst obtained from a magnesium compound, a titanium compound, an organoaluminum compound, and an organohalogen compound, and various activators are applied to a catalyst comprising a magnesium compound, a titanium compound, and an organoaluminum compound. It has been manufactured by a method of adding and polymerizing, and the above-mentioned characteristics have been improved.
[0004]
However, an LLDPE that satisfies the transparency, heat sealability, and mechanical properties required as described above has not been obtained, and the design concept of what LLDPE structure should be used is not clarified.
[0005]
[Problems to be solved by the invention]
Under such circumstances, the present invention is an ethylene copolymer that can give a film that is particularly excellent in transparency, heat sealability, mechanical properties, etc., and that has a good balance of properties. And a film comprising the same.
[0006]
[Means for Solving the Problems]
As a result of earnest research to develop an ethylene copolymer that achieves the above object, it was found that an ethylene copolymer in a specific range as shown below can achieve the object, and the present invention was completed. did.
(1) An ethylene copolymer obtained from ethylene having the following characteristics (a) to (g) and an olefin having 3 or more carbon atoms.
(I) Density is 890-940kg / m^Three
(B) The intrinsic viscosity measured at a temperature of 135 ° C. in decalin is 0.5 to 5.0 deciliter / g.
(C) The chromatogram obtained by the temperature-raising fractionation method has a component that does not crystallize at 0 ° C. and is at a temperature higher than 0 ° C.TwoHaving a peak
(D) Elution component amount at 0 ° C in temperature rising fractionation is 5 wt% or less
(E) The amount of elution components above 95 ° C in temperature rising fractionation0.5-10% by weight
(F) The standard deviation of the average elution temperature excluding 0 ° C determined by the temperature rising fractionation method is 20 ° C or less
(G) In a 90 ° light scattering chromatogram measured by GPC / MALLS, a molecular weight of 10⁶The peak area of the ultra-high molecular weight component that appears above1.5% or more,Less than 5%
Moreover, the film formed by forming said ethylene-type copolymer into a film is provided.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The ethylene-based copolymer of the present invention is a copolymer of ethylene and an olefin having 3 or more carbon atoms, preferably ethylene and an olefin having 3 to 18 carbon atoms. Examples of the olefin having 3 or more carbon atoms used as a comonomer include linear, branched, and α-olefins substituted with aromatic nuclei having 3 to 18 carbon atoms.
[0008]
Specific examples of the α-olefin include linear monoolefins such as propylene, 1-butene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene and 1-dodecene, 3-methyl Branched chains such as -1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1,2-ethyl-1-hexene, 2,2,4-trimethyl-1-pentene Examples thereof include monoolefins and monoolefins substituted with aromatic nuclei such as styrene. These may be used alone to copolymerize with ethylene, or may be used in combination of two or more.
[0009]
The ethylene copolymer of the present invention has the following characteristics (a) to (g).
(I) Density
Density is 890-940kg / m^ThreeIt is in the range. This density is 890kg / m^ThreeLess than 940 kg / m.^ThreeIf it exceeds, transparency, impact resistance, and low-temperature heat sealing will deteriorate. The density is 900 to 935 kg / m from the viewpoint of the balance of characteristics of rigidity, transparency, impact resistance and low temperature heat sealability.^ThreeIs preferred, especially 905-930 kg / m^ThreeIs preferred. In addition, this density is the value calculated | required based on JISK-7112.
[0010]
(B) Intrinsic viscosity
The intrinsic viscosity is in the range of 0.5 to 5.0 deciliters / g in decalin at a temperature of 135 ° C. If the intrinsic viscosity is less than 0.5 deciliter / g, the moldability is inferior and the mechanical strength is insufficient, and if it exceeds 5.0 deciliter / g, the melt viscosity becomes high and the moldability decreases. From the viewpoint of moldability and mechanical strength, the intrinsic viscosity is preferably 0.90 to 4.80 deciliter / g, and particularly preferably 0.95 to 4.50 deciliter / g.
[0011]
(C) Chromatogram obtained by temperature-raising fractionation method
The short chain branching due to the LLDPE comonomer is not generated in the same number in every molecule, and there is a large and small distribution between the molecules (there is a composition distribution).
As a method for evaluating this, there is a temperature rising fractionation method using the fact that the smaller the short chain branching, the higher the melting point and the higher the elution temperature. For example, when o-dichlorobenzene is used as a solvent, a certain amount of LLDPE is dissolved therein, put into a predetermined column, cooled to 0 ° C., and then raised from 0 ° C. to about 135 ° C. The sequentially eluted components are collected and measured as the weight fraction of the LLDPE eluted components for each temperature.
[0012]
The known LLDPE has two or three peaks, and the recently developed metallocene-catalyzed LLDPE is known to have one peak, but the ethylene copolymer of the present invention is In the chromatogram obtained by this temperature rising fractionation method, it has a component that does not crystallize at 0 ° C. and is at a temperature higher than 0 ° C.2 piecesIt has a peak. When there is only one peak, there may be a case where a decrease in transparency, poor moldability, etc. occur, or there are many sticky components, resulting in a decrease in mechanical properties. The ethylene copolymer of the present invention has a component that does not crystallize at 0 ° C. and is at a temperature higher than 0 ° C.2 piecesThe desired characteristics can be obtained by having the following peak and being in the range defined by (d) to (f) below.
[0013]
(D) Amount of elution component at 0 ° C in temperature rising fractionation
The ethylene-based copolymer of the present invention has an elution component amount at 0 ° C. of 5% by weight or less in temperature rising fractionation. When this exceeds 5% by weight, the blocking resistance is inferior, and troubles due to bleeds occur. It is preferably 2% by weight or less mainly from the viewpoint of blocking resistance. In addition, the elution component amount at 0 ° C. in the temperature rising fractionation coincides with a component that does not crystallize at 0 ° C. as described later. (E) Elution component amount of 95 ° C. or higher in temperature rising fractionation The ethylene copolymer of the present invention has an elution component amount of 95 ° C. or higher in temperature rising fractionation.0.5It is in the range of -10 wt%.0.5If it is less than% by weight, the transparency is deteriorated, and if it exceeds 10% by weight, the haze is increased and the transparency is deteriorated. It is preferably in the range of 0.5 to 8% by weight mainly from the viewpoint of transparency.
[0014]
(F) Standard deviation of average elution temperature excluding 0 ° C. determined by temperature rising fractionation method The ethylene-based copolymer of the present invention has an average elution temperature excluding 0 ° C. determined by (f) temperature rising fractionation method. The standard deviation is 20 ° C. or less. Those exceeding 20 ° C. have a wide composition distribution and poor low temperature heat sealability and hot tackiness. From the viewpoint of low-temperature heat sealability, a temperature of 17 ° C. or lower is preferable. In the chromatogram obtained from the temperature rising fractionation method explained above2 piecesThe peak size, peak temperature, and standard deviation of the average elution temperature are extremely important.
[0015]
For example, in the case of having two peaks as shown in FIG. 1, the small peak on the high temperature side and the amount of the component that does not crystallize at 0 ° C. are correlated with each other in the normal manufacturing method. When trying to increase the small peak, the amount of components that did not crystallize at 0 ° C also increased, and it was not possible to control each individually, and it was also obvious how to control by focusing on each effect Was not.
Further, it is known that the smaller the standard deviation of the average elution temperature, the narrower the composition distribution, but it has not been clarified how much the composition should be in consideration of the required characteristics.
[0016]
The ethylene copolymer of the present invention has been found for the first time as a result of various investigations considering the required characteristics and the balance of peak size, peak temperature, standard deviation of average elution temperature, etc. It is meaningful to be within the range specified in (c) to (f), and can provide a film having an unprecedented balance of transparency, heat sealability and mechanical properties.
The above (c) to (f) are obtained by measuring under the following conditions using the temperature rising and sorting apparatus shown in FIG.

[0017]

Introduce the sample solution into the column at 135 ° C, slowly cool it at 5 ° C / hour to adsorb the polymer to the packing material, cool to 0 ° C, and then raise the column temperature under the above conditions Thus, the polymer concentration eluted at each temperature is detected with an infrared detector.
From the relationship between temperature and concentration, the amount of elution at each temperature can be determined.
The 0 ° C. elution component amount (%) is a component that did not crystallize upon cooling to 0 ° C., and corresponds to the weight percentage of the polymer amount in this component with respect to the polymer amount in the initial sample solution.
The amount of the component eluted at 95 ° C. or higher corresponds to the weight% of the amount of polymer in the component eluted at 95 ° C. or higher with respect to the amount of polymer in the initial sample solution.
[0018]
The standard deviation of the average elution temperature excluding 0 ° C is the temperature T_iAnd elution amount W_iFrom the above data, the average elution temperature (Tw) is first determined by the following equation, and then the standard deviation (σ) is determined. Since the temperature rises at a constant level, data on the amount of the eluted component can be obtained and obtained at a constant time interval.
[0019]
[Expression 1]

[0020]
[Expression 2]

[0021]
(G) 90 ° light scattering chromatogram by GPC / MALLS measurement The ethylene copolymer of the present invention is (g) all peaks in the chromatogram reflecting molecular weight distribution in the 90 ° light scattering chromatogram by GPC / MALLS measurement. Molecular weight with respect to area 10⁶The peak area of the ultra-high molecular weight component that appears above is1.5% or more,It is less than 5%. By making this less than 5%, the transparency of the film is excellent and the mechanical strength tends to be improved. From the viewpoint of transparency and haze, more preferably,1.5% or more,Less than 2%. FIG. 3 shows an example of a 90 ° light scattering chromatogram obtained by the GPC / MALLS measurement. As shown in the figure, the peak of the ultra-high molecular weight component tends to be prominently expressed, and the above definition is the molecular weight of 10 relative to the total peak area from the baseline.⁶The ratio of the peak (shaded part) area of the ultrahigh molecular weight component appearing above is shown.
[0022]
The GPC / MALLS measurement was performed using the following apparatus and conditions.

[0023]

[0024]
The ethylene-based copolymer of the present invention may be produced by any method as long as it has the above-mentioned characteristics, but the presence of a catalyst comprising the following [I] solid catalyst component and [II] organoaluminum mixture Under these conditions, ethylene and α-olefin can be efficiently produced by high-temperature solution polymerization.
[I] Solid catalyst component
The solid catalyst component is obtained by contacting and reacting the following (A) solid product, (B) organic aluminum halide, (C) titanium compound and (D) halogenating agent as shown below. The aluminum atom content is 5% by weight or less, preferably 3% by weight or less. If the aluminum atom content exceeds 5% by weight, the composition distribution of the ethylene copolymer polymerized using this solid catalyst component is expanded, and the desired effect cannot be obtained.
[0025]
(A) Solid product
The solid product is obtained by reacting (a) magnesium metal, (b) alcohol and (c) halogen and / or a halogen-containing compound.
(a) The shape of the metal magnesium is not particularly limited, and metal magnesium having an arbitrary particle size, for example, magnesium in the form of granules, ribbons, powders, etc. can be used. Moreover, although it does not specifically limit also to the surface state of metallic magnesium, The thing by which coating | covers, such as magnesium oxide, are not produced | generated on the surface is preferable.
[0026]
(b) Any alcohol can be used as the alcohol, but a lower alcohol having 1 to 6 carbon atoms is preferably used. In particular, ethanol is preferable. Further, the water content should be small, preferably 2000 ppm or less, and more preferably 200 ppm or less. If the water content is high, magnesium hydroxide may be formed on the metal magnesium surface.
Although it does not ask | require in particular about the quantity of alcohol, Preferably it is 2-100 mol with respect to 1 mol of metal magnesium, Most preferably, it is 5-50 mol. When there is too much alcohol, the yield of a solid substance with good morphology may be reduced, and when it is too little, stirring in the reaction vessel may not be performed smoothly.
[0027]
(c) Kinds of halogen and halogen-containing compounds are not particularly limited, but as halogen, chlorine, bromine and iodine are preferable, and iodine is particularly preferable. In addition, the halogen-containing compound may be a compound containing a halogen atom in the chemical formula, but a halogen-containing metal compound is preferable. Specific examples of this compound include MgCl₂, MgI₂Mg (OEt) I, Mg (OEt) Cl, MgBr₂, CaCl₂, NaCl, KBr and the like can be preferably mentioned.
The amount of halogen used is 0.0001 gram atom or more, preferably 0.0005 gram atom or more, more preferably 0.001 gram atom or more, per 1 gram atom of metal magnesium. The halogen-containing compound is used in an amount of 0.0001 gram atom or more, preferably 0.0005 gram atom or more, more preferably 0.001 per 1 gram atom of metal magnesium. More than gram atoms.
[0028]
Each of the halogen and the halogen-containing compound may be used alone or in combination of two or more. Further, a halogen and a halogen-containing compound may be used in combination. In this case, the amount of all halogen atoms is 0.0001 gram atom or more, preferably 0.0005 gram atom or more, more preferably 0.001 gram atom or more with respect to 1 gram atom of metal magnesium. The upper limit of the amount of halogen and / or halogen-containing compound used is not particularly defined and may be appropriately selected within the range in which the desired solid product can be obtained. Preferably less than 0.06 gram atoms relative to atoms.
[0029]
The reaction itself between magnesium metal, alcohol, halogen and / or halogen-containing compound can be carried out in the same manner as in a known method. For example, a solid material is obtained by reacting metallic magnesium, an alcohol, and a halogen and / or a halogen-containing compound under reflux until generation of hydrogen gas is not observed (usually 20 to 30 hours). Specifically, for example, when iodine is used as the halogen, a method in which solid iodine is introduced into an alcohol containing metal magnesium and then heated to reflux, and an alcohol solution of iodine is added dropwise to the alcohol containing metal magnesium. Examples thereof include a method of heating to reflux and a method of dropping an alcoholic solution of iodine while heating an alcohol containing metallic magnesium. In any method, it is preferable to carry out using an inert organic solvent (for example, saturated hydrocarbon such as n-hexane) in an inert gas (for example, nitrogen gas, argon gas) atmosphere.
[0030]
Regarding the charging of magnesium metal, alcohol, halogen, and / or halogen-containing compound, it is not necessary to add the entire amount to the reaction vessel from the beginning, and it may be divided and added. A particularly preferred form is a method in which the whole amount of alcohol is added from the beginning and metal magnesium is added in several portions. In such a case, a temporary mass generation of hydrogen gas can be prevented, which is very desirable from the viewpoint of safety. In addition, the reaction vessel can be reduced in size. Furthermore, it becomes possible to prevent entrainment of alcohol, halogen and / or halogen-containing compounds caused by temporary large-scale generation of hydrogen gas. The number of times of division may be determined in consideration of the scale of the reaction tank, and is not particularly limited. However, in view of the complexity of the operation, 5 to 10 times is usually preferable. The reaction itself may be either a batch type or a continuous type. Furthermore, as a modified method, an operation in which a small amount of magnesium metal is first charged into the alcohol that has been charged in its entirety from the beginning, the product produced by the reaction is separated and removed in a separate tank, and then a small amount of metal magnesium is charged again. It is also possible to repeat.
(B) Organic aluminum halide
[0031]
This organic aluminum halide has the general formula (1)
AlR¹ _nX¹ _3-n          (0 ≦ n <3) (1)
It is a compound represented by these.
R in general formula (1)¹Is a hydrocarbon group, and examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, and an aralkyl group. This R¹Specific examples of the methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group, octadecyl group , Allyl group, butenyl group, cyclopentyl group, cyclohexyl group, phenyl group, tolyl group, benzyl group, phenethyl group and the like.
X¹Is a halogen atom of a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and among these, a chlorine atom or a bromine atom is preferable, and a chlorine atom is particularly preferable.
[0032]
Representative examples of the organic aluminum halide represented by the general formula (1) include, for example, when n is 1, methylaluminum dichloride, ethylaluminum dichloride, n-propylaluminum dichloride, isopropylaluminum dichloride, n- When n is 2, butylaluminum dichloride, isobutylaluminum dichloride, etc., dimethylaluminum monochloride, diethylaluminum monochloride, di-n-propylaluminum monochloride, diisopropylaluminum monochloride, di-n-butylaluminum monochloride, Examples include diisobutylaluminum monochloride. These organic aluminum halides may be used alone or in combination of two or more.
[0033]
(C) Titanium compound
As the titanium compound, the general formula (2)
Ti (OR²)_mX² _4-m          (0 <m ≦ 4) (2)
It is a compound represented by these.
X in general formula (2)²Is a halogen atom of a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and among these, a chlorine atom or a bromine atom is preferable, and a chlorine atom is particularly preferable.
R²Is a hydrocarbon group, and examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, and an aralkyl group. This R²Specific examples of the methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group, octadecyl group , Allyl group, butenyl group, cyclopentyl group, cyclohexyl group, phenyl group, tolyl group, benzyl group, phenethyl group and the like.
[0034]
Representative examples of the titanium compound represented by the general formula (2) include, for example, when m is 1, ethoxytrichlorotitanium, n-butoxytrichlorotitanium, etc., and when m is 2, diethoxydichloro Titanium, di-n-butoxydichlorotitanium, etc., when m is 3, triethoxymonochlorotitanium, tri-n-butoxymonochlorotitanium, etc., when m is 4, tetraethoxytitanium, tetra-n-propoxy Titanium, tetraisopropoxy titanium, tetra-n-butoxy titanium and the like can be mentioned.
These titanium compounds may be used alone or in combination of two or more.
[0035]
(D) Halogenating agent
This halogenating agent is not a reducing organoaluminum halide, but a general formula (3)
MX^Three _kY¹ _4-k                    (0 <k ≦ 4) (3)
Is a compound having a relatively low reducing power.
[0036]
M in the general formula (3) represents a tetravalent element such as silicon or a transition metal element titanium.
X^ThreeIs a halogen atom of a chlorine atom, a bromine atom and an iodine atom, and among these, a chlorine atom or a bromine atom is preferable, and a chlorine atom is particularly preferable.
Y¹Is a hydrocarbon group, preferably an alkyl group having 1 to 8 carbon atoms, and specific examples include a methyl group, an ethyl group, and a propyl group.
As a typical halogenating agent represented by the general formula (3), SiCl_Four, SiMe₂Cl₂, SiMeCl_Three, SiMe_ThreeSilicon compounds such as Cl, TiCl_FourAnd halogen compounds of transition metals such as Preferably, SiCl_FourIt is. These halogenating agents may be used alone or in combination of two or more.
[0037]
The above (A), (B), (C), and (D) need to be contacted in this order, and will be described in detail below.
First, (A) and (B) are contacted and reacted according to a conventional method. The obtained solid component (A + B) may be sufficiently washed.
The aluminum content in the solid component is 0.1% by weight or more, preferably 0.5% by weight or more. This contact / reaction is preferably carried out in a hydrocarbon solvent such as hexane, heptane, cyclohexane, and toluene.
Next, the solid component (A + B) is contacted and reacted with (C) according to the following conditions. The amount of (C) used is 0.01 to 1 mol, preferably 0.01 to 0.5 mol, per 1 atom of titanium per mol of magnesium of the solid component (A + B). Good. If the amount used is 1 mol or more, a part of the solid component may be dissolved and lost. Moreover, if it is less than 0.01 mol, a desired titanium compound may not be hold | maintained at a solid component.
[0038]
When these contacts and reactions are carried out in the above hydrocarbon solvent, the concentration of (C) is 1 to 50 mmol / liter, preferably 1 to 30 mmol / liter, as the titanium atom concentration. When the concentration is 50 mmol / liter or more, a part of the solid component may be dissolved and lost. If it is less than 1 mmol / liter, the desired titanium compound may not be retained in the solid component.
[0039]
As the contact conditions, the contact temperature is usually in the range of 0 to 100 ° C., and the contact time is usually in the range of 1 minute to 48 hours, preferably in the range of 30 minutes to 24 hours. When the contact temperature exceeds 100 ° C., a part of the solid catalyst component is dissolved and lost, which may cause a decrease in catalyst activity. Further, when the contact time is less than 1 minute, the contact / reaction may not be sufficiently performed.
Further, (D) is contacted and reacted with the solid component (A + B + C) obtained above according to a conventional method to obtain the above-mentioned [I] solid catalyst component. The amount of (D) used is preferably 0.01 mol or more per halogen atom with respect to 1 mol of magnesium of the solid component (A + B + C). If the amount used is less than 0.01 mol, the desired halogenation may not be performed.
[0040]
[II] Organic aluminum mixture
This organoaluminum mixture is prepared from a mixture of (E) organoaluminum, (F) halogenated hydrocarbon, and (G) oxygen-containing compound.
(E) Organic aluminum
As this organoaluminum, the general formula (4)
AlR^Three _pX^Four _3-p      (0 ≦ p ≦ 3) (4)
It is a compound represented by these.
[0041]
R in general formula (4)^ThreeIs a hydrocarbon group such as an alkyl group having 1 to 10 carbon atoms, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, an aralkyl group, and the like.^FourIs a halogen atom such as a chlorine atom or a bromine atom.
Examples of such organoaluminum compounds include trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, diethylaluminum monochloride, diisobutylaluminum monochloride, diethylaluminum monomethoxide, diethylaluminum monoethoxide, diethylaluminum monomono Examples include butoxide, diethylaluminum monophenoxide, ethylaluminum dichloride, isopropylaluminum dichloride, methylaluminum sesquichloride, ethylaluminum sesquichloride and the like. These compounds may be used alone or in combination of two or more.
[0042]
(F) Halogenated hydrocarbon
Although arbitrary things can be used, a C1-C18 aliphatic halogenated hydrocarbon, a C6-C15 aromatic halogenated hydrocarbon, etc. are preferable. Preferable examples include 1,2-dichloroethane, 1,2-dichloropropane, isopropyl chloride, sec-butyl chloride and the like. These compounds may be used alone or in combination of two or more.
(G) Oxygenated compound
Although arbitrary things can be used, alcohols are preferable and especially a C1-C18 aliphatic alcohol is preferable. Preferable examples include n-butanol, isobutanol, tert-butanol, n-hexanol, 2-ethylhexanol and the like. These compounds may be used alone or in combination of two or more.
[0043]
The mixing ratio of (E) organoaluminum, (F) halogenated hydrocarbon, and (G) oxygen-containing compound is [(F) halogenated hydrocarbon + (G The oxygen-containing compound] is in the range of 0.01 to 10 mol, preferably 0.1 to 1 mol. If this exceeds 10 moles, the activity may be reduced.
[0044]
These contacts are preferably carried out in a hydrocarbon such as hexane, peptane, cyclohexane or toluene.
As these contact conditions, the contact temperature is usually in the range of 0 to 100 ° C., and the contact time is usually 1 minute or longer, preferably 5 minutes or longer.
The ethylene copolymer of the present invention can be efficiently produced by high-temperature solution polymerization of ethylene and α-olefin in the presence of a catalyst comprising the above-mentioned [I] solid catalyst component and [II] organoaluminum mixture. It is something that can be done. Specifically, the dispersion of the solid catalyst component and the organoaluminum mixture are added as a catalyst to the polymerization reaction system, and then ethylene and α-olefin are introduced. The α-olefin used for copolymerization with ethylene is as described above.
[0045]
In the catalyst comprising [I] solid catalyst component and [II] organoaluminum mixture, the ratio of [I] solid catalyst component and [II] organoaluminum mixture used is [II] per mole of titanium in [I]. The aluminum content is usually in the range of 1 to 1000 mol, preferably 10 to 100 mol.
As production conditions for high-temperature solution polymerization, polymerization is performed in an inert solvent such as an aliphatic hydrocarbon having 5 to 18 carbon atoms, an alicyclic hydrocarbon, and an aromatic hydrocarbon. Specific examples of the inert solvent include linear or branched hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, and tetradecane, cyclic hydrocarbons such as cyclohexane, and aromatics such as benzene, toluene, and xylene. A hydrocarbon is mentioned. A particularly preferable inert solvent is n-hexane.
[0046]
The reaction temperature is a temperature at which the produced copolymer is dissolved in the above-mentioned solvent, usually 140 ° C. or higher, and 170 to 220 ° C. is particularly preferable for the operation of the apparatus.
The reaction pressure is usually in the range of 1 to 15 MPa, and preferably in the range of 2 to 9 MPa.
The catalyst concentration is in the range of 0.001 to 10 mmol / liter as the titanium concentration, and preferably in the range of 0.001 to 0.1 mmol / liter.
[0047]
Furthermore, in the copolymerization, a known molecular weight regulator such as hydrogen can be used.
The produced copolymer is separated from the inert solvent by a known method, and it is used alone or in combination with additives as necessary, and is usually formed into pellets through an extruder. In addition, it may be used as a powder or a film or sheet molding machine.
The ethylene-based copolymer of the present invention obtained above is molded into a film, a sheet, or the like by a normal molding method alone or after blending an additive as necessary.
Examples of the additive include a lubricant, an antioxidant, a neutralizer, a stabilizer such as an ultraviolet absorber, an antistatic agent, an antiblocking agent, and a dye.
[0048]
Examples of the molding method include general extrusion molding methods, injection molding methods, blow molding methods, and rotational molding methods. For forming a film, a sheet or the like, a T-die molding method or an inflation molding method among extrusion molding methods is generally used.
[0049]
【Example】
EXAMPLES Next, the present invention will be specifically described by examples, but the present invention is not limited to the following examples. In addition, the characteristic of the film was calculated | required as shown below.
(1) Heat seal temperature (° C)
It calculated | required based on JISZ-1707. That is, using a thermal inclination tester manufactured by Toyo Seiki Seisakusho, at a set temperature, a pressure of 0.5 kg / cm²The heat sealing was performed with a sealing time of 1 second. The area of the seal part was MD (machine direction) 10 mm × TD (transverse direction) 15 mm, and the conditions of the tensile test method were a T-type peel of MD and a peel test speed of 200 mm / min. The temperature at which the peel strength was 0.3 kg / 15 mm was defined as the heat seal temperature.
(2) Haze (%)
It calculated | required based on JISK-7105.
(3) Film impact (kJ / m)
Based on ASTM-D3420, it was measured with a film impact tester manufactured by Toyo Seiki Seisakusho. The diameter of the impact head was set to 1 inch.
The physical properties of the copolymer were determined according to the method described above.
[0050]
[Example 1]
(1) Preparation of solid catalyst component [I]
A glass reactor (with an internal volume of 6 liters) equipped with a stirrer was sufficiently replaced with nitrogen gas, and then 2430 g of ethanol, 16 g of iodine, and 160 g of metallic magnesium (granular, average particle size 350 μm) were added and refluxed with stirring. The reaction was continued under heating until no hydrogen gas was generated from the system to obtain a solid product. The reaction solution containing this solid product was dried under reduced pressure to obtain a solid product (A).
[0051]
84 g of the solid product obtained above and 738 ml of dry n-hexane were placed in a glass three-necked flask (internal volume: 3 liters) sufficiently substituted with nitrogen gas. While maintaining the system temperature at 30 to 40 ° C., 876 ml (B) of 50% by weight hexane diluted with ethylaluminum dichloride was added dropwise over 1 hour with stirring. Furthermore, it was made to react under reflux for 1 hour. The obtained solid component was sufficiently washed with dry n-hexane until the residual ratio of the stock solution became 0.1% or less to obtain a solid component (A + B). The aluminum content of this was 1.3% by weight.
[0052]
A glass three-necked flask (internal volume: 3 liters) was charged with 15 g of the solid component (A + B) and 1410 ml of dry n-hexane, and then 2.4 g (C) of tetrabutoxytitanium was added. Titanium atom concentration = 5 mmol / l (Titanium atom / magnesium atom = 0.05 mol / 1 mol) The reaction was carried out at a system temperature of 30 ° C. for 24 hours. This was sufficiently washed with dry n-hexane to obtain a solid component (A + B + C).
[0053]
Next, dry n-hexane and 18 ml (D) of silicon tetrachloride were added to the solid component (A + B + C) in the flask, and the mixture was reacted for 2 hours under reflux at a concentration of silicon tetrachloride = 0.12 mol / l. This solid component was sufficiently washed with purified hexane to obtain a solid catalyst component. The aluminum content in the solid catalyst component was 0.4% by weight.
[0054]
(2) Preparation of organoaluminum mixture [II]
2320 ml of dry n-hexane and 67.5 mmol of diethylaluminum monochloride (per aluminum atom) were sequentially added to a glass flask with a stirrer (internal volume 5 liters) sufficiently substituted with nitrogen gas, followed by isopropyl chloride 15 mmol and n-butanol. 15 mmol was added simultaneously. This solution was stirred at room temperature for 1 hour to obtain an organoaluminum mixture [II].
(3) Polymerization
After introducing 4100 ml of dry n-hexane and 700 ml of dry 1-octene into a stainless steel autoclave (with an internal volume of 10 liters) with a stirrer, introduction of hydrogen gas was further started at room temperature (hydrogen gas partial pressure = 0.025 MPa-G). ). Thereafter, the temperature in the system was increased to 185 ° C. while stirring.
200 ml of dry n-hexane, 200 ml of the above (2) organoaluminum mixture [II], and 0.125 mmol (per titanium atom) of the solid catalyst component [I] were sequentially charged into the catalyst charging tube.
[0055]
Next, the catalyst in the charging tube was pressed into the autoclave with argon gas, and at the same time, ethylene was introduced to start polymerization. Ethylene was introduced at a total pressure of 3.0 MPa-G (ethylene partial pressure = 1.6 MPa-G) for 5 minutes. After 5 minutes, the polymerization was stopped by adding isopropyl alcohol. This was cooled and 550 g of the produced polymer was recovered. The properties of the obtained copolymer were measured according to the method described above.
[0056]
Moreover, as the quality evaluation, the cast film was shape | molded as follows and each characteristic was evaluated.
First, an antioxidant (Irganox 1076 and Irganox 1010 (both manufactured by Ciba Geigy)), a neutralizing agent (calcium stearate (manufactured by Nippon Oil & Fats)), an antiblocking agent (added to the obtained copolymer) An appropriate amount of SILTON AMT (manufactured by Mizusawa Chemical Co., Ltd.) and a slip agent (Nutron S (manufactured by Nippon Seika Co., Ltd.)) was blended and granulated by kneading with a 20 mmφ single screw extruder. Subsequently, it was formed into a cast film with a 20 mmφ extrusion molding machine (manufactured by Tsukada Kikai Co., Ltd.) under the following molding conditions.
[0057]
The properties of the obtained film were measured according to the method described above.
Molding condition
Screw: Full flight type (L / D = 20)
Screw diameter: 20mm, rotation speed: 50rpm
Dice: Coat hanger type (170mm width)
Lip width: 0.4 mm, film thickness: 40 μm
Resin temperature: 170 ° C
The properties of the copolymer obtained are shown in Table 1, and the film properties are shown in Table 2.
[0058]
[Example 2]
A polymer was obtained in the same manner as in Example 1, except that 650 ml of dry 1-octene and the partial pressure of hydrogen gas started to be introduced at room temperature were changed to 0.1 MPa-G.
As in Example 1, the copolymer properties and film properties were evaluated. The results are shown in Tables 1 and 2.
[0059]
[Comparative Example 1]
A polymer was obtained in the same manner as in Example 1 except that diethylaluminum monochloride was used alone instead of the organoaluminum mixture [II].
As in Example 1, the copolymer properties and film properties were evaluated. The results are shown in Tables 1 and 2.
A polymer with a large standard deviation of the temperature rising fractionation average elution temperature was obtained, with many elution components at 95 ° C. or higher.
[0060]
[Comparative Example 2]
(1) Preparation of solid catalyst component
A stainless steel pot with an internal volume of 200 ml is filled with 100 stainless steel balls with a diameter of 10 mmφ, and 14 g of anhydrous magnesium chloride (crushed), 1.6 ml of titanium tetrachloride, and 48 ml of dry n-heptane are sealed in a nitrogen gas atmosphere. did.
It was placed on a rotary mill and ground for 60 hours. The obtained solid component was sufficiently washed with dry n-heptane to obtain a solid catalyst component.
(2) Organoaluminum mixture [II]
In the same manner as in Example 1 (2), an organoaluminum mixture [II] was obtained.
(3) Polymerization
A polymer was obtained in the same manner as in Example 1 except that the solid catalyst composition was replaced with the solid catalyst composition obtained in (1).
As in Example 1, the copolymer properties and film properties were evaluated. The results are shown in Tables 1 and 2.
A polymer with a large standard deviation of the temperature rising fractionation average elution temperature was obtained, with many components eluted at 0 ° C. and 95 ° C. or higher.
[0061]
[Comparative Example 3]
Mitsui Petrochemical Co., Ltd.'s Ultzex 2021L was evaluated in the same manner as in Example 1. The characteristics are shown in Tables 1 and 2.
[0062]
[Table 1]

[0063]
[Table 2]

[0064]
【The invention's effect】
INDUSTRIAL APPLICABILITY The present invention can provide an ethylene copolymer that can provide a film that is particularly excellent in transparency, heat sealability, mechanical properties, etc., and that has a good balance of properties. Therefore, it can be preferably used for packaging films, food films, and tape films. Moreover, taking advantage of preferable characteristics, it can also be used for applications such as sheets, containers, and daily necessities.
[Brief description of the drawings]
FIG. 1 shows a chromatogram obtained by a temperature rising fractionation method. (The time corresponds to the elution temperature because the temperature is constant as shown in the figure.)
FIG. 2 shows a schematic diagram of an analytical temperature rising fractionation apparatus.
FIG. 3 shows a 90 ° light scattering chromatogram by GPC / MALLS measurement.
[Explanation of symbols]
1 ... TREF column
2 ... Liquid feeding pump
3 ... Valve oven
4 ... TREF oven
5 ... Detector
6 ... 10-way valve
7 ... Loop

Claims (2)

An ethylene copolymer obtained from ethylene having the following characteristics (a) to (g) and an olefin having 3 or more carbon atoms.
(I) Density is 890-940 kg / m ³
(B) The intrinsic viscosity measured at a temperature of 135 ° C. in decalin is 0.5 to 5.0 deciliter / g.
(C) In the chromatogram obtained from the temperature rising fractionation method, it has a component that does not crystallize at 0 ° C. and has two peaks at a temperature higher than 0 ° C. (d) Elution at 0 ° C. in the temperature rising fractionation 5% by weight or less of the component amount (e) The amount of the eluted component at 95 ° C. or more in the temperature rising fractionation is 0.5 to 10% by weight.
(F) Standard deviation of average elution temperature excluding 0 ° C determined by temperature rising fractionation method is 20 ° C or less. (G) Ultra high molecular weight appearing in molecular weight of 10 ⁶ or more in 90 ° light scattering chromatogram by GPC / MALLS measurement. Component peak area is 1.5% or more and less than 5% A film formed by forming the ethylene copolymer according to claim 1 into a film.

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