JP3943505B2 - Extrusion molding method for thermoplastic elastomer composition, crosslinked foam and weather strip for automobile - Google Patents

Description

本発明のウェザストリップに用いられる熱可塑性エラストマー組成物は、上記ベースポリマー１００重量部に対して、無機系鉱物を０．０５〜５重量部の範囲で含有する熱可塑性エラストマー組成物がより好ましい。
【００６１】
無機系鉱物の含有量が０．０５重量部未満では得られるウェザストリップの発泡性が劣り、５重量部を超えて多くなると弾性が損なわれるとともに圧縮永久ひずみ性が劣り、共に不適である。
【００６２】
本発明に用いられる無機系鉱物としては、タルク、カオリン、炭酸カルシウム、クレー、マイカ、珪藻土、酸化チタン、ノイブルグ硅土を使用することができる。
【００６３】
その他の本発明に用いられる添加剤の具体例としては、充填剤、耐熱安定剤、老化防止剤、耐候安定剤、帯電防止剤、湿潤剤、金属セッケン、ワックス等の滑剤、顔料、染料、難燃剤、ブロッキング防止剤等の従来公知の添加剤が挙げられる。
〔架橋剤〕
本発明の熱可塑性エラストマー組成物に使用される架橋剤としては、上記α-オレフィン系共重合体（ハ）及びエチレン系共重合体（ニ）の融点以上の温度における押出発泡成形により、組成物中の少なくとも１種のエチレン−α−オレフィン系共重合体を架橋しうる化合物である。このような架橋剤としては、有機過酸化物、フェノール系架橋剤、硫黄、硫黄化合物、ｐ−キノン、ｐ−キノンジオキシムの誘導体、ビスマレイミド化合物、エポキシ化合物、シラン化合物、アミノ樹脂等を挙げることができ、特に有機過酸化物およびフェノール系架橋剤が好ましい。上記有機過酸化物としては、例えば１，３−ビス（ｔ−ブチルパーオキシイソプロピル）ベンゼン、２，５−ジメチル−２，５−ビス（ｔ−ブチルパーオキシ）ヘキシン−３、２，５−ジメチル−２，５−ビス（ｔ−ブチルパーオキシ）ヘキセン−３、２，５−ジメチル−２，５−ビス（ｔ−ブチルパーオキシ）ヘキサン、２，２’−ビス（ｔ−ブチルパーオキシ）−ｐ−イソプロピルベンゼン、ジクミルパーオキシド、ジ−ｔ−ブチルパーオキシド、ｔ−ブチルパーオキシド、ｐ−メンタンパーオキシド、１，１−ビス（ｔ−ブチルパーオキシ）−３，３，５−トリメチルシクロヘキサン、ジラウロイルパーオキシド、ジアセチルパーオキシド、ｔ−ブチルパーオキシベンゾエート、２，４−ジクロロベンゾイルパーオキシド、ｐ−クロロベンゾイルパーオキシド、ベンゾイルパーオキシド、ジ（ｔ−ブチルパーオキシ）パーベンゾエート、ｎ−ブチル−４，４−ビス（ｔ−ブチルパーオキシ）バレレート、ｔ−ブチルパーオキシイソプロピルカーボネート等を挙げることができる。これらの有機過酸化物のうち、１，３−ビス（ｔ−ブチルパーオキシイソプロピル）ベンゼン、２，５−ジメチル−２，５−ジ（ｔ−ブチルパーオキシ）ヘキシン−３、２，５−ジメチル−２，５−ジ（ｔ−ブチルパーオキシ）ヘキサン等の分解温度が比較的高い化合物が好ましい。
【００６４】
上記有機過酸化物は、単独でまたは２種以上を混合して使用することができる。本発明においては、上記有機過酸化物を適当な架橋助剤と併用することにより、均一かつ穏やかな架橋反応を行うことができる。このような架橋助剤としては、例えば粉末硫黄、コロイド硫黄、沈降硫黄、不溶性硫黄、表面処理硫黄、ジペンタメチレンチウラムテトラスルフィド等の硫黄あるいは硫黄化合物；ｐ−キノンオキシム、ｐ，ｐ’−ジベンゾイルキノンオキシム等のオキシム化合物；エチレングリコールジ（メタ）アクリレート、ジエチレングリコールジ（メタ）アクリレート、トリエチレングリコールジ（メタ）アクリレート、テトラエチレングリコールジ（メタ）アクリレート、ポリエチレングリコールジ（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレート、ジアリルフタレート、テトラアリルオキシエタン、トリアリルシアヌレート、Ｎ，Ｎ’−ｍ−フェニレンビスマレイミド、Ｎ，Ｎ’−トルイレンビスマレイミド、無水マレイン酸、ジビニルベンゼン、ジ（メタ）アクリル酸亜鉛等の多官能性モノマー類等を挙げることができる。これらの架橋助剤のうち、ｐ，ｐ’−ジベンゾイルキノンオキシム、Ｎ，Ｎ’−ｍ−フェニレンビスマレイミド、ジビニルベンゼンが好ましい。なお、Ｎ，Ｎ’−ｍ−フェニレンビスマレイミドは、単独でも架橋剤として作用しうるものである。上記架橋助剤は、単独でまたは２種以上を混合して使用することができる。また、上記フェノール系架橋剤としては、下記一般式（Ｉ）で表されるｐ−置換フェノール系化合物が好ましい。このｐ−置換フェノール系化合物は、米国特許第３２８７４４０号明細書および米国特許第３７０９８４０号明細書に記載されているように、従来からゴム用架橋剤として使用されているものである。
【００６５】
【化１】

【００６６】
尚、ｎは０〜１０の整数であり、Ｘはヒドロキシル基、ハロゲン化アルキル基及びハロゲン原子の少なくともいずれかであり、Ｒは炭素数１〜１５の飽和炭化水素基である。上記ｐ−置換フェノール系化合物は、アルカリ触媒の存在下におけるｐ−置換フェノールとアルデヒド（好ましくはホルムアルデヒド）との縮合反応により得られる。また、他のフェノール系架橋剤としては、例えばｏ−置換フェノール−アルデヒド縮合物、ｍ−置換フェノール−アルデヒド縮合物、臭素化アルキルフェノール−アルデヒド縮合物等を挙げることができる。
【００６７】
本発明において、上記フェノール系架橋剤は単独でも使用することができるが、架橋速度を調節するため、架橋促進剤と併用することもできる。このような架橋促進剤としては、金属ハロゲン化物（塩化第一すず、塩化第二鉄等）、等の有機ハロゲン化物（塩素化ポリプロピレン、臭化ブチルゴム、クロロプレンゴム等）等が挙げられる。また、架橋促進剤の他、更に、酸化亜鉛等の金属酸化物やステアリン酸等の分散剤を併用することがより望ましい。
【００６８】
これらの架橋剤使用量は、熱可塑性エラストマー組成物１００重量部に対して好ましくは０．０１〜１０重量部、より好ましくは０．０５〜５重量部とすることができる。有機過酸化物の使用量が０．０１重量部未満であると、架橋度が不足し最終的に得られる熱可塑性エラストマー組成物発泡体の圧縮永久歪みが低下する恐れがある。一方、１０重量部を超えると、架橋度が過度に高くなり、発泡成形加工性が悪化する傾向にある。
【００６９】
また、架橋剤として有機過酸化物を使用する場合の架橋助剤の使用量は、熱可塑性エラストマー組成物１００重量部に対して好ましくは１０重量部以下、より好ましくは０．２〜５重量部とすることができる。架橋助剤の使用量が１０重量部を超えると、架橋度が過度に高くなり、成形加工性が悪化したり、機械的物性が低下する傾向にある。
【００７０】
本発明の自動車用ウェザストリップには前記熱可塑性エラストマー組成物を化学発泡剤、水発泡剤、超臨界流体等の発泡剤を用いた架橋発泡体を具備することができるが、特に超臨界流体を用いて発泡させてなる架橋発泡体を具備してなることが好ましい。
【００７１】
超臨界流体を用いて発泡させることにより、セル径がより小さくなり外観意匠性に優れる。
【００７２】
本発明に使用される化学発泡剤としては、アゾジカルボンアミド、N,N'-ジニトロペンタメチレンテトラミン、4,4-オキシビス（ベンゼンスルホニルヒドラジド）、ヒドラゾジカルボンアミド、バリウムアゾジカルボキシレート等の有機系の群、あるいは炭酸水素ナトリウム等の無機系の群から一種又は二種以上の混合物が挙げられる。これらの発泡剤を前記熱可塑性エラストマー組成物１００重量部に対して０．３〜１．２重量部混入して、該熱可塑性エラストマー組成物を発泡させて所望する形状に押出成形した中空状シール部を得ることができる。
【００７３】
なお、前記発泡剤は、その分解温度（以下、単に「Ｔｄ」という）が例えば尿素やアルカリ性物質を助剤として１７０℃〜２１０℃の範囲内に調整したものが好ましく、１７０℃未満のものはセル径が大きくなって発泡が不均一になり、表面粗さも大きくなって外観上好ましくない。一方、２１０℃を超えると、オレフィン系熱可塑性エラストマーの軟化が著しく促進されて、発泡が生じない。
【００７４】
本発明に使用される超臨界流体としては、超臨界二酸化炭素と、超臨界窒素が挙げられる。
〔架橋剤を一部残存させて押出成形する方法〕
架橋剤を一部残存させるように押出発泡成形する方法としては下記の方法などが挙げられる。
（１）架橋反応が終了する前に押出機出口から熱可塑性エラストマー組成物が排出されるように押出発泡温度を調整する方法。
（２）反応速度の早い架橋剤と反応速度の遅い架橋剤を併用し、反応速度の早い架橋剤を押出機内部で架橋反応終了させ、押出発泡後の加熱架橋工程で反応速度の遅い架橋剤の架橋反応を終了させる方法。
（３）１分半減期温度の異なる有機過酸化物を２種以上併用し、１分半減期温度の低い有機過酸化物を押出機内部で架橋反応終了させ、押出発泡後の加熱架橋工程で１分半減期温度の高い有機過酸化物の架橋反応を終了させる方法。
【００７５】
（１）の押出発泡成形の場合は、熱可塑性エラストマー組成物の成形温度（以下、単に「Ｔｅ」という）は、用いる発泡剤、架橋剤により異なるが、押出発泡後に架橋剤の一部を残存するように押出発泡成形するため下記の条件を満たすことが好ましい。
【００７６】
Ｔｍ≦（Ｔｄ）≦Ｔｅ≦（Ｔｈ）
（１）熱可塑性エラストマー組成物の融点（以下、単に「Ｔｍ」という）以上、２８０℃以下で押出発泡成形することが好ましい。 Ｔｍ以下では熱可塑性エラストマーが溶融せず、発泡倍率が低下する恐れがある。一方、２８０℃以上では熱可塑性エラストマーが劣化し、機械的物性が低下する恐れがある。
（２）架橋剤として有機過酸化物を使用した場合は、熱可塑性エラストマー組成物のＴｍ以上、且つ有機過酸化物の１分半減期温度（以下、単に「Ｔｈ」という）以下で押出発泡成形することが好ましい。但し、有機過酸化物を２種以上併用する場合は、一番高い温度のＴｈ以下で押出発泡成形することが好ましい。Ｔｈ以上で押出発泡すると熱可塑性エラストマー組成物の架橋密度が向上し、発泡倍率が上がらない恐れがある。
（３）発泡剤が化学発泡剤の場合は、熱可塑性エラストマーのＴｍ以上の分解温度（以下、単に「Ｔｄ」という）を有する化学発泡剤を使用し、Ｔｄ以上の温度で押出発泡成形する。Ｔｄ以下の温度で押出発泡成形すると発泡倍率が上がらない恐れがある。
〔押出機滞留時間〕
本発明の押出発泡成形における熱可塑性エラストマー組成物の押出機滞留時間は、用いる発泡剤、架橋剤により異なるが、押出発泡後に架橋剤の一部を残存するように１０秒〜１０分で押出発泡成形することが好ましい。
〔発泡・成形後の加熱架橋工程〕
残存した架橋剤が反応する温度であれば何度でもよく、任意に設定できるが３００℃以下が好ましい。３００℃超えると熱可塑性エラストマー組成物が劣化し、機械的物性、圧縮永久ひずみが悪化する傾向にある。
【００７７】
押出発泡後の加熱架橋装置としては、オーブン、連続式架橋装置（例えば、熱風架橋（ＨＡＶ）、高周波架橋（ＵＨＦ））など任意に使用できる。
【００７８】
また、加熱架橋時間は何時間でもよく、任意に設定できる。
【００７９】
押出発泡成形に供する熱可塑性エラストマー組成物は、事前に架橋剤にて動的架橋処理した熱可塑性エラストマー組成物でもよいし、非架橋の熱可塑性エラストマーであってもよい。
【００８０】
本発明に基づくウェザストリップの一実施態様について、添付した図面を参照して以下に詳述する。図２は本発明に基づくウェザストリップ１０の要部を示す横断面図であり、図３および図４は実施例及び比較例で用いたウェザストリップの一部を構成する中空状シール部成形体の横断面図である。
【００８１】
先ず、図２に示したように、本発明に基づくウェザストリップ１０は、インサートメタルＩＭと共にその断面形状を略Ｕ字状に形成された基体部１１と、該基体部１１の外側面から突設した中空状シール部１３と、前記基体部１１のＵ字状の両内側面から対向して突設させた爪部１２とを具備して成る。
【００８２】
前記中空状シール部１３は、前記の各成分（イ）〜（ホ）を含有して成る熱可塑性エラストマー組成物に上記の発泡剤又は超臨界流体を混入させて、前記基体部１１と前記爪部１２と一体成形される。一方、前記基体部１１と前記爪部１２は、前記の各成分（イ）〜（ホ）を含有して成る前記熱可塑性エラストマー組成物を用いて前記インサートメタルＩＭと共に所望する形状に押出し成形されるのが好ましいが、前記中空状シール部１３と押出同時加硫成形ができ、かつ前記中空状シール部１３との界面接着力が十分である材質であれば、特に限定はしない。
【００８３】
なお、前記中空状シール部１３は、前記熱可塑性エラストマー組成物を上記工程に基づき、前記発泡剤又は超臨界流体を用い、発泡させて所望する形状に押出成形した前記中空状シール部１３を具備して成るので、該中空状シール部１３は、低圧縮永久ひずみ性と良発泡性の両立した特性を発現する。
【００８４】
【実施例】
以下に本発明の熱可塑性エラストマー組成物の成形方法及び自動車用ウェザストリップを実施例によって更に具体的に説明するが、勿論本発明の範囲は、これらによって限定されるものではない。
【００８５】
実施例及び比較例で用いた熱可塑性エラストマー組成物のベースポリマーは以下のものである。
（１）エチレン-α-オレフィン系共重合体（イ−１）
エチレン-プロピレン-エチリデンノルボルネン共重合体、エチレン含有量８０モル％、パラフィン系オイル７０重量部油展、ジェイエスアール（株）製、ＥＰ９８Ａ
（２）水添ジエン系共重合体（ロ−１）
G- H -G構造（Gは1,2-ビニル結合含量の少ないポリブタジエン、Hは1,2-ビニル結合含量の多いポリブタジエンで夫々のブタジエン部の二重結合が水添されている）を有し、Gにビニル結合含量が１５重量％で、Hのビニル結合含量が３５重量％で、全分子量が３００．０００の水添ブロック共重合体（水添率：９８％）
（３）炭素数３以上のα−オレフィンを主成分とする結晶性α−オレフィン系共重合体（ハ−１）
プロピレン-エチレンブロックポリマー（ｎ-デカン不溶分９３．５重量％）（日本ポリケム（株）製 ノバテックPP BC５ＣＷ）
（４）エチレン系共重合体（ニ−１）
線状低密度ポリエチレン（日本ポリケム（株）製 ノバテックLLDPE UF４２３）
（５）架橋剤
有機過酸化物（ホ−１）；日本油脂（株）製、パーブチルＰ−４０
有機過酸化物（ホ−２）；日本油脂（株）製、パーヘキシン２５Ｂ−４０
（６）その他添加剤
・架橋助剤（ヘ−１）；三共化成（株）製ジビニルベンゼン（純度５５％）、
・発泡剤マスターバッチ（ヘ−２）；永和化成工業（株）製ポリスレンＥＶ３０６Ｇ、発泡剤含有量３０ｗｔ％
・発泡剤、マスターバッチ（ヘ−３）；永和化成工業（株）製ポリスレンＥＥ２０６、発泡剤含有量２０ｗｔ％
・滑剤（ヘ−４）；エルカ酸アミド、日本精化（株）製 ニュートロンS
・老化防止剤（ヘ−５）；チバスペシャリティケミカルズ（株）製イルガノックス１０１０
・老化防止剤（へ−６）；旭電化工業（株）製ＰＥＰ−３６
・反応停止剤（ヘ−７）；N−ニトロソフェニルヒドロキシルアミン、和光純薬工業（株）製Ｑ−１３００
〔実施例１〜２、比較例１〜５〕
上記の熱可塑性エラストマー組成物のベースポリマーとして、下記表１に示す配合処方をヘンシェルミキサーにて３０秒混合した後、二軸押出機（池貝（株）製、型式「ＰＣＭ−４５」、同方向完全噛み合い型スクリューであり、スクリューフライト部の長さＬとスクリュー直径Ｄとの比であるＬ／Ｄが３３．５である）を用いて、２３０℃、３００ｒｐｍで２分間滞留する条件にて押出混練りして、ペレット状の熱可塑性エラストマー組成物を得た。次に下記表２に示す架橋剤、その他配合剤および熱可塑性エラストマー組成物をヘンシェルミキサーにて３０秒混合し、単軸押出機にて押出発泡成形、その後必要に応じて加熱処理（２４０℃、１分、東洋精機（株）製ギヤーオーブン）して実施例１〜２、比較例１〜５の処方のより、図３に準じた中空状シール部成形体１０aを成形したウェザストリップを作製した。
【００８６】
また、得られた実施例及び比較例の各試料の中空状シール部成形体の諸物性について測定した結果を表２に示した。
【００８７】
【表１】

【００８８】
【表２】

【００８９】
〔物性の評価法〕
表２に記載の物性の評価は、下記の方法によった。
（１）架橋密度
ゲル分率測定法による架橋密度として文中に示した。
（２）発泡倍率
比重測定値からの換算値とした。
（３）吸水率
予め重量を測定した成形体を、水面下５０ｍｍの位置で１２５ｍｍＨｇまで減圧し、３分間保持した。続いて、その成形体を大気圧に戻して３分経過後、吸水した成形体の重量を測定し、以下の計算式から吸水率を算出した。
【００９０】
吸水率（％）＝〔(Ｗ₂−Ｗ₁)/Ｗ₁〕×１００
Ｗ₁：浸漬前の成形体重量（ｇ）
Ｗ₂：浸漬後の成形体重量（ｇ）
（４）圧縮永久ひずみ性試験
ＪＩＳ Ｋ６２６２に準拠して測定（７０℃、２２ｈｒｓ、２５％圧縮）した。
【００９１】
表２から下記の事項が明らかである。
（１）比較例１は、疑似架橋だけからなり架橋処理をしていない本発明に用いる熱可塑性エラストマー組成物（以下、本ＴＰＥと称す）自体を発泡成形した場合で、発泡性・吸水率は良好だが、圧縮永久ひずみが著しく高いことを示す。
（２）比較例２は、本ＴＰＥを微架橋状態とし、その後に発泡成形した場合で、発泡性は良好だが、吸水率が高くなり、圧縮永久ひずみの改善も不十分であることを示す。
（３）比較例３は、本ＴＰＥを架橋反応終了した後に発泡成形した場合で、Ｃｓは向上しているが、発泡性が著しく損なわれている（発泡倍率1．1倍しか発泡せず）ことを示す。
（４）比較例４は、押出機内部で架橋反応の終了と発泡剤の分解が同時に起こるため、発泡性が著しく損なわれていることを示す。
（５）比較例５は、押出発泡後の加熱で架橋反応と発泡剤の分解反応が同時に起こるため、発泡性、吸水率、圧縮永久ひずみのバランスが悪化する傾向にある。
（６）実施例１は、発泡性、吸水率そして圧縮永久ひずみ全て良好な発泡体が得られ、「低圧縮永久ひずみと良発泡性の両立」が達成されていることを示す。
（７）実施例２は、本発明において実施例１よりもさらに成形後の架橋密度を高めた場合で、実施例１に比して、発泡性を損なわないまま、圧縮永久ひずみを向上させることができることを示す。
【００９２】
更に、本発明に基づく実施例の中空状シール部成形体は、低圧縮永久ひずみと良発泡性の両立した特性を発現し、満足すべき結果を得たが、比較例における中空状シール部成形体は、圧縮永久ひずみ又は発泡性において不満足なものであった。
【００９３】
【発明の効果】
以上説明したように、本発明の熱可塑性エラストマー組成物の押出成形方法、架橋発泡体及び自動車用ウェザストリップは、特定のエチレン-α-オレフィン系共重合体マトリックスにポリオレフィン系結晶相の擬似架橋点を分散させた熱可塑性エラストマー組成物に、発泡剤および架橋剤を添加し、架橋剤が一部残存するように発泡押出成形する工程、及び発泡押出成形後に成形品を加熱して架橋反応を終了させて架橋発泡体を得る工程からなり、該押出成形方法により低圧縮永久ひずみ性と良発泡性の両立した架橋発泡体のシール部を具備した優れた自動車用ウェザストリップを提供することができる。
【図面の簡単な説明】
【図１】本発明の熱可塑性エラストマー組成物の成形方法の工程概略図である。
【図２】本発明の熱可塑性エラストマー組成物の発泡成形体（中空状シール部）を具備するウェザストリップの横断面図である（ドアインナーウェザストリップ群）。
【図３】本発明の熱可塑性エラストマー組成物の発泡成形体（中空状シール部）を具備するウェザストリップの横断面図である（トランク・バックドアウェザストリップ群）。
【図４】本発明の熱可塑性エラストマー組成物の発泡成形体（中空状シール部）を具備するウェザストリップの横断面図である（フード・カウルシール群）。
【符号の説明】
１０ 本発明を適用するウェザストリップ（ドアインナーウェザストリップ群）
１１ 基体部
１２ 爪部
１３ 中空状シール部
ＩＭ インサートメタル
１０ａ 本発明を適用するウェザストリップ（トランク・バックドアウェザストリップ群）
１０ｂ 本発明を適用するウェザストリップ（フード・カウルシール群）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for extruding a thermoplastic elastomer composition, a cross-linked foam, and a weather strip for automobiles. More specifically, the present invention relates to a specific cross-linking point of a polyolefin crystal phase in a specific ethylene-α-olefin copolymer matrix. The present invention relates to an improved method of extrusion of a dispersed thermoplastic elastomer composition and a weather strip for an automobile for sealing a periphery of an automobile door panel or a door opening applied to the door panel using the same. The present invention relates to a weather strip which is low and has improved foamability.
[0002]
[Prior art]
A hollow portion or a lip shape that is fixed to a part of a base portion around a door panel of a vehicle or a flange portion of the door panel, protrudes from the base portion toward an object to be sealed, and is elastically deformable by contact with the target object. Conventionally, the sealing portion has been imparted with a desired sealing property by using a foam obtained by subjecting a thermoplastic elastomer composition to chemical foaming or water foaming.
[0003]
However, the conventional hollow seal portion has low surface smoothness and surface gloss, and is easy to bend and wrinkle when bent.
[0004]
As means for solving the problem of the hollow seal portion in this weather strip, a non-crosslinkable thermoplastic elastomer composition in which pseudo crosslink points of a polyolefin crystal phase are dispersed in an ethylene-α-olefin copolymer matrix is used. There has been proposed a weather strip that has a foamed foam and is excellent in appearance and sealing (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
JP 2002-187499 A
However, a drawback of a weather strip comprising a foam obtained by foaming the thermoplastic elastomer composition as a hollow seal portion is that it has a high compression set.
[0006]
As a measure for improving the compression set of a general thermoplastic elastomer composition, it is known to impart crosslinks by chemical bonds and increase the crosslink density.
[0007]
However, when a high crosslinking density is imparted to the thermoplastic elastomer composition, another problem arises that foamability is significantly impaired during molding, and the degree of compression set is not sufficiently improved with a degree of crosslinking that does not impair foamability. As a result, it was difficult to achieve both “low compression set and good foamability”. This “coexistence of low compression set and good foamability” was a problem.
[0008]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to solve the above-described problems of weather strips for automobiles, and an extrusion method using a thermoplastic elastomer composition capable of achieving both low compression set and good foamability, and An object of the present invention is to provide an excellent weather strip for automobiles that exhibits low compression set by the extrusion method.
[0009]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors have found an extrusion molding method for a thermoplastic elastomer composition having both low compression set and good foamability, and have reached the present invention. is there.
[0010]
That is, the method for extruding the thermoplastic elastomer composition of the present invention, the crosslinked foam and the weather strip for automobiles are as follows.
(1) (A) ethylene-α-olefin copolymer (ethylene content less than 90 mol%) 20-85 wt%,
(B) 5-50% by weight of hydrogenated diene copolymer,
(C) 1 to 10% by weight of a crystalline α-olefin copolymer mainly composed of an α-olefin having 3 or more carbon atoms,
(D) 5-30% by weight of an ethylene polymer (ethylene content of 90 mol% or more) [provided that (i) + (b) + (c) + (d) = 100% by weight], and
(E) the mineral oil softener contains 0 to 200 parts by weight with respect to 100 parts by weight of the component (b),
And when said (a) + (b) + (c) + (d) + (e) = 100 parts by weight, the sum of (a) and (e) is 61% by weight or more, A method for extruding and foaming a thermoplastic elastomer composition, wherein the weight ratio of the sum of (a) and (e) to the above (b) is 90/10 to 60/40,
(I) adding a foaming agent and a crosslinking agent to the thermoplastic elastomer composition, and performing foam extrusion so that at least a part of the crosslinking agent remains; and
(Ii) after foaming extrusion molding, heating the molded product to terminate the reaction of the crosslinking agent to obtain a crosslinked foam;
A method for extruding a thermoplastic elastomer composition, comprising:
(2) The (b) hydrogenated diene copolymer is at least one obtained from the following groups (b-1), (b-2), and (b-3): (1) A method for extruding the thermoplastic elastomer composition according to (1).
[0011]
(B-1) is a block copolymer (A)-(B), a block copolymer (A)-(B)-(C) or a block copolymer (A)-(B)-(A) (Wherein (A) is a vinyl aromatic compound polymer block, (B) is a conjugated diene polymer block or vinyl aromatic compound-conjugated diene random copolymer block, and (C) is a vinyl aromatic compound. Is a polymer showing a vinyl aromatic compound-conjugated diene tapered block in which the ratio of vinyl aromatic compound / conjugated diene is 5-60 / 95-40 by weight, and all monomers constituting the block copolymer The bond content of the vinyl aromatic compound in the polymer block (A) is 3% by weight or more, and the bond content of the total vinyl aromatic compound in the polymer blocks (A) and (C) is 3 to 50% by weight. %, The vinyl bond content of the conjugated diene moiety in the polymer block (B) is 20% by weight. Or a block copolymer unit in which the molecular chain of the block copolymer unit is extended or branched via a coupling agent residue. A hydrogenated diene copolymer or a modified hydrogenated diene copolymer having a number average molecular weight of 50,000 to 700,000 in which at least 80% of the heavy bonds are saturated.
[0012]
(B-2) is a polymer block copolymer having at least one polymer block (D), (E) and (F) in the molecule [wherein (D) represents a vinyl aromatic compound. Polymer block containing the main component, (E) is a polymer block containing a conjugated diene having a 1,2-vinyl bond content of 25 to 95% by weight, and (F) is a 1,2-vinyl bond content. Represents a polybutadiene polymer block of less than 25% by weight, and these block copolymers may have polymer molecular chains extended or branched via a coupling agent residue. The content of the polymer block (D) in the block copolymer is 5 to 60% by weight, the content of the polymer block (E) is 30 to 90% by weight, and the content of the polymer block (F) is 5 to 60% by weight, where [D) + (E) + (F) = 100% by weight] is hydrogenated to saturate at least 80% of the double bonds in the conjugated diene moiety The hydrogenated diene copolymer or modified hydrogenated diene copolymer having a number average molecular weight of 50,000 to 700,000.
[0013]
(B-3) is a block copolymer represented by (G)-(H)-(G) or (G)-(H) [wherein (G) is a 1,2-vinyl bond content. Is a polybutadiene polymer block having a conjugated diene polymer block or vinyl aromatic compound-conjugated diene polymer block, wherein the vinyl bond content of the conjugated diene moiety exceeds 25%. These block copolymers may have a polymer molecular chain extended or branched via a coupling agent residue. ] Is a hydrogenated diene copolymer or a modified hydrogenated diene copolymer having a number average molecular weight of 50,000 to 700,000 in which at least 80% of the double bonds of the conjugated diene moiety are saturated by hydrogenation. ]
[0014]
The molding method of the thermoplastic elastomer composition of the present invention can provide an excellent automotive weather strip having a cross-linked foam seal portion having both low compression set and good foamability.
[0015]
Moreover, the completely crosslinked foamed product by the molding method of the thermoplastic elastomer composition of the present invention can be used for other various automobile seal parts and building seal parts.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The thermoplastic elastomer composition extrusion molding method and automobile weather strip of the present invention will be described below.
[0017]
As mentioned above, (ii) ethylene-α-olefin copolymer (ethylene content is less than 90 mol%) 20-85 wt%,
(B) 5-50% by weight of hydrogenated diene copolymer,
(C) 1 to 10% by weight of a crystalline α-olefin copolymer mainly composed of an α-olefin having 3 or more carbon atoms,
(D) 5-30% by weight of an ethylene polymer (ethylene content of 90 mol% or more) [provided that (i) + (b) + (c) + (d) = 100% by weight] and
(E) the mineral oil softener contains 0 to 200 parts by weight with respect to 100 parts by weight of the component (b),
And when said (a) + (b) + (c) + (d) + (e) = 100 parts by weight, the sum of (a) and (e) is 61% by weight or more, A method for extruding a thermoplastic elastomer composition in which the weight ratio of the sum of (a) and (e) to the above (b) is 90/10 to 60/40,
(I) adding a foaming agent and, if necessary, a crosslinking agent for rubber to the thermoplastic elastomer composition, (step of foaming extrusion molding so that at least a part of the crosslinking agent for rubber remains, and
(Ii) After foam extrusion molding, the molded product is heated (the step of terminating the reaction of the rubber crosslinking agent to obtain a crosslinked foam,
A weather strip for automobiles comprising a seal portion of a cross-linked foam formed by foaming by an extrusion method of a thermoplastic elastomer composition characterized by comprising:
[0018]
A process schematic diagram of the extrusion molding method of the thermoplastic elastomer composition of the present invention is shown in FIG.
[Ethylene-α-olefin copolymer]
The component (a) needs to have an ethylene content of less than 90 mol%. This is because when the content of the ethylene component is 90 mol% or more and the content of the α-olefin component is 10 mol% or less, the flexibility of the ethylene-α-olefin copolymer is insufficient.
[0019]
Examples of the component ethylene-α-olefin copolymer (a) include ethylene / propylene copolymer rubber, ethylene / propylene / non-conjugated diene terpolymer rubber, ethylene / 1-butene copolymer rubber, ethylene / 1- An amorphous elastic copolymer containing olefin as a main component such as butene / non-conjugated diene terpolymer rubber is used.
[0020]
In these ethylene-α-olefin-based copolymers, it is desirable that the ethylene / α-olefin molar ratio is 50/50 to 90/10, and the non-conjugated dienes include ethylidene norbornone and diene. Cyclopentadiene and 1,4-hexadiene are preferred, and it is desirable that they be present in an amount that gives an iodine value of 40 or less.
[0021]
These ethylene-α-olefin copolymers have Mooney viscosity ML _{1 + 4} 100 degreeC is 10-500, Preferably it is 30-400. In the ethylene-α-olefin copolymer, it is not preferable that the ethylene content exceeds 50 mol% because the mechanical strength is insufficient. Mooney viscosity ML _{1 + 4} When 100 ° C. is less than 10, the mechanical strength is lowered, and when it is more than 500, poor dispersion with the polyolefin resin occurs, which is not preferable. The ethylene-α-olefin copolymer can be used alone or in combination of two or more.
[Hydrogenated diene copolymer]
Next, the hydrogenated diene copolymer of the component (b) will be described separately as components (b-1), (b-2), and (b-3). The component (b-1) is composed of the polymer block (A), the polymer block (B), and the polymer block (C), wherein the (A)-(B), (A)-(B )-(C) or (A)-(B)-(A), and obtained by hydrogenating a block copolymer arranged. Here, the vinyl aromatic compound used to obtain the component (b-1) is styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-difinylstyrene. N, N-dimethyl-p-aminoethylstyrene, vinylpyridine and the like are preferable, and styrene and α-methylstyrene are particularly preferable.
[0022]
The conjugated dienes used to obtain the component (b-1) are 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene. , 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene, etc., which can be used industrially and obtain a hydrogenated diene copolymer having excellent physical properties 1,3-butadiene, isoprene and 1,3-pentadiene are preferable, and 1,3-butadiene is more preferable.
[0023]
In the component (b-1), the polymer block (A) is a polymer block containing a vinyl aromatic compound as a main component, and other possible vinyl aromatics are preferably 10% by weight or less, more preferably You may copolymerize below 10weight%. In the block copolymer to be hydrogenated, the preferred weight ratio of vinyl aromatic compound / conjugated diene constituting the same is 5 to 60/95 to 40, and more preferably 7 to 50/93 to 50. .
[0024]
When the vinyl aromatic compound is less than 5% by weight (conjugated diene exceeds 95%), strength, workability, and heat resistance are inferior, and when the obtained hydrogenated diene copolymer is pelletized, it is easy to block. Become. When the vinyl aromatic content exceeds 60% by weight (conjugated diene is less than 40% by weight), it becomes resinous, resulting in poor impact resistance and low temperature characteristics. A preferable amount of the vinyl aromatic compound in the polymer block (A) or the polymer block (C) is 3 to 50% by weight, more preferably 5 to 40% by weight, desirably 5% by weight of the total monomers. ~ 30% by weight. When the amount of the vinyl aromatic compound in the polymer block (A) or the polymer block (C) is less than 3% by weight of the total monomers, the heat resistance and mechanical strength are poor, and the resulting hydrogenated diene is obtained. When the system copolymer is pelletized, it becomes easy to block, and when blended with other components, the processability is inferior. On the other hand, when it exceeds 50% by weight, the transparency, flexibility, processability, and low temperature characteristics are inferior.
[0025]
In addition, the preferable amount of the vinyl aromatic compound in the polymer block (A) is at least 3% by weight, more preferably 5 to 30% by weight, based on all monomers constituting the component (B-1). is there. When the bond content of the vinyl aromatic compound in the polymer block (A) is less than 3% by weight of the total monomers, the mechanical strength, heat resistance and processability are poor when blended with other components. Further, in the block copolymer to be hydrogenated, the vinyl bond content in the conjugated diene portion in the polymer block (B) is preferably 20% or more, more preferably 40% or more, and preferably 60% or more. When the vinyl bond content is 20% or less, even if blended with a resin component, the effect of improving flexibility is not sufficiently exhibited.
[0026]
The (A)-(B), (A)-(B)-(C) or (A)-(B)-(A) block copolymer is represented by the following formula via a coupling agent residue. It may be a block copolymer in which polymer molecular chains represented by (1) to (3) are extended or branched.
[0027]
▲ 1 ▼ [(A) − (B)] n−X
(2) [(A)-(B)-(C)] n-X
(3) [(A)-(B)-(A)] n-X
[Wherein (A), (B) and (C) are the above-mentioned block copolymers, n is an integer of 2 to 4, and X represents a coupling agent residue]
Coupling agents at this time are, for example, diethyl adipate, divinylbenzene, tetrachlorosilicon, tetrachlorogermanium, 1,2-dibroethane, 1,4-chloromethylbenzene, bis (tricrosssilyl) ethane, epoxidized linseed oil , Tolylene diisocyanate, 1,2,4-benzene triisocyanate and the like.
[0028]
Incidentally, the content of the polymer block (A), the polymer block (B) and the polymer block (C) in the block copolymer is usually 3 to 50% by weight of the polymer block (A). %, Preferably 4 to 40% by weight, the polymer block (B) is 30 to 97% by weight, preferably 35 to 94% by weight, and the polymer block (C) is 0 to 50% by weight, preferably 2 to 2%. 40% by weight [provided that (A) + (B) + (C) = 100% by weight]. The number average molecular weights of the polymer block (A) to the polymer block (C) are 0.150,000 to 350,000 for the polymer block (A), and 1.5 for the polymer block (B). The range is from 10,000 to 679,000, more preferably from 35,000 to 564,000, and the polymer block (C) is from 0 to 350,000, more preferably from 20,000 to 240,000.
[0029]
By hydrogenating the above block copolymer, the double bond of the conjugated diene portion of the block copolymer is saturated, and the component (B-1) that is a hydrogenated diene copolymer is obtained. . Here, the double bond of the conjugated diene portion needs to be saturated 80% or more, preferably 90% or more, more preferably 95 to 100%, and if less than 80%, the thermoplastic elastomer composition Thermal stability and durability are inferior.
[0030]
The number average molecular weight of the component (b-1) is 5 to 700,000, preferably 100,000 to 600,000. If it is less than 50,000, the heat resistance, strength, fluidity, and processability are lowered. When it exceeds 700,000, fluidity, workability, and flexibility are inferior. The component (b-1) used in the present invention can be obtained, for example, by the method disclosed in JP-A-3-72512.
[0031]
The vinyl aromatic compound and conjugated diene used for obtaining the component (b-2) are the same as those used for obtaining the component (b-1). The preferred polymer block (D) constituting the hydrogenated diene copolymer of the component (ro-2) is a polymer block mainly composed of a vinyl aromatic compound, and more specifically, a vinyl aromatic compound. A polymer block in which 80% by weight or more of the conjugated portion of a copolymer with a conjugated diene having 90% by weight or more of the homopolymer or vinyl aromatic compound in the polymer block (D) is hydrogenated. desirable.
[0032]
When the vinyl aromatic compound content in the polymer block (D) is less than 90% by weight, strength and weather resistance are lowered. The content of the polymer block (D) in the component (B-2) is preferably 5 to 60% by weight, more preferably 10 to 55% by weight. Moreover, the preferable number average molecular weights of the said polymer block (D) are 0.2-420,000. If it is less than 5% by weight, heat resistance and mechanical strength are inferior, whereas if it exceeds 60% by weight, workability and flexibility are inferior.
[0033]
The content of the polymer block (E) that constitutes the (b-2) hydrogenated diene copolymer is preferably 30 to 90% by weight, more preferably 35 to 80% by weight. When the content of the polymer block (E) is less than 30% by weight, the flexibility is lowered, while when it exceeds 90% by weight, the workability and the mechanical strength are lowered.
[0034]
The vinyl bond content of the conjugated diene moiety before hydrogenation contained in the polymer block (E) is preferably 25 to 95% by weight, more preferably 30 to 90% by weight. Among the conjugated diene blocks before hydrogenation to become the polymer block (E), for example, when the conjugated diene is butadiene, if the vinyl bond content is less than 25% by weight, a polyethylene chain is formed when hydrogenated and rubbery On the other hand, the properties are lost. On the other hand, if it exceeds 95% by weight, the glass transition temperature becomes high and the rubbery properties are lost, which is not preferable. The number average molecular weight of the polymer block (E) is preferably 15,000 to 630,000, more preferably 35,000 to 420,000, and the double bond of the conjugated diene moiety is hydrogenated by 80% or more. It is a conjugated diene polymer block.
[0035]
Further, the polymer block (F) constituting the block copolymer for obtaining the component (B-2) is a polybutadiene polymer block having a vinyl bond content of less than 25% by weight, preferably less than 20% by weight. is there. When the vinyl bond content is 25% by weight or more, mechanical strength is lost when hydrogenated, and the properties of the thermoplastic elastomer composition as a block copolymer are lost.
[0036]
Content of the said polymer block (F) in the said block copolymer is 5 to 60 weight%. If the content of the polymer block (F) is less than 5% by weight, the mechanical properties of the component (B-2) are inferior. On the other hand, if it exceeds 60% by weight, the rubbery properties are lost. The number average molecular weight of the polymer block (F) is preferably from 255,000 to 420,000, and is a copolymer block obtained by hydrogenating the double bond of the butadiene portion of the polybutadiene block by 80% or more.
[0037]
Further, the block copolymer constituting the component (b-2) comprises at least one polymer block (D), (E) or (F) via a coupling agent residue. It may be a block copolymer bonded to a single polymer and having a polymer molecular chain extended or branched as represented by the following formulas (4) to (5).
[0038]
(4) [(D)-(E)-(F)] n-X
(5) [(D)-(E)-(F)] X [(D)-(E)]
[In the formulas (4) to (5), n represents an integer of 2 to 4, X represents a coupling agent residue, and the coupling agent used is the same as that used in the component (b-1). It is. ]
By hydrogenating the above block copolymer, the double bond of the conjugated diene portion of the block copolymer is saturated, whereby a block copolymer which is a hydrogenated diene copolymer is obtained. Here, the double bond of the conjugated diene moiety needs to be saturated 80% or more, preferably 90% or more, more preferably 95 to 100%. When the saturation rate of the double bond of the conjugated diene moiety is less than 80%, the thermal stability and durability of the thermoplastic elastomer composition are inferior.
[0039]
The number average molecular weight of the component (B-2) is 50,000 to 700,000, preferably 100,000 to 600,000. If it is less than 50,000, heat resistance, mechanical strength, fluidity, and workability are lowered, and if it exceeds 700,000, fluidity, workability, and flexibility are inferior. The component (B-2) can be obtained, for example, by the method disclosed in JP-A-2-133406.
[0040]
In the component (b-3), the polymer block (G) and the polymer block (H) are arranged as (G)-(H)-(G) or (G)-(H). Further, 80% or more of the double bond portion of the linear or branched block copolymer was obtained by hydrogenation. Examples of the vinyl aromatic compound and the conjugated diene used for obtaining the component (b-3) include the compounds exemplified as those used for obtaining the component (b-1).
[0041]
The polymer block (G) in the component (b-3) is a crystalline polymer block having a structure similar to that of ordinary low density polyethylene (LDPE) by hydrogenation. The 1,2-vinyl bond content in the polymer block (G) is usually 25% by weight or less, preferably 20% by weight or less, more preferably 15% by weight or less. When the 1,2-vinyl bond content in the polymer block (a) exceeds 25% by weight, the crystal melting point drops significantly after hydrogenation and the mechanical strength is inferior.
[0042]
The polymer block (H) is a conjugated diene polymer block or a vinyl aromatic compound-conjugated diene copolymer block, and is a rubber-like ethylene-butene-1 copolymer block or a vinyl aromatic by hydrogenation. It becomes a polymer block having a structure similar to that of the group I compound-butene-1 copolymer block. The vinyl aromatic compound used in the polymer block (H) is used in an amount of 35% by weight or less, preferably 30% by weight or less, more preferably 25% by weight of the monomer constituting the polymer block (H). If it exceeds 35% by weight, the glass transition temperature of the polymer block (H) increases, and the low-temperature characteristics and flexibility are inferior.
[0043]
The vinyl bond content of the conjugated diene portion of the polymer block (H) is 25 to 95% by weight, preferably 25 to 75% by weight, more preferably 25 to 55% by weight, less than 25% by weight or 95% by weight. If it exceeds 50%, for example, when the conjugated diene is butadiene, a crystal structure derived from a polyethylene chain and a polybutene-1 chain is exhibited, resulting in a resinous property and poor flexibility. Moreover, in the block copolymer for obtaining the polymer block (H), the ratio of the polymer block (G) to the polymer block (H) is usually 5 to 5 for the polymer block (G). 90 wt%, preferably 10 to 80 wt%, and the polymer block (H) is 95 to 10 wt%, preferably 90 to 20 wt% [provided that the polymer block (G) + (H) = 100 wt% %].
[0044]
When the polymer block (G) is less than 5% by weight and the polymer block (H) exceeds 95% by weight, the crystalline polymer block is insufficient, and the dynamics of the component (b-3) This is not preferable because of poor mechanical properties. Moreover, when the said polymer block (G) exceeds 90 weight% and the said polymer block (H) is less than 10 weight%, the hardness of the said component (b-3) raises and is unpreferable.
[0045]
The preferred number average molecular weight of the polymer block (G) is from 0.25 to 630,000, more preferably from 10,000 to 480,000. Further, the number average molecular weight of the polymer block (H) is preferably from 50,000 to 650,000, more preferably from 20,000 to 540,000. The block copolymer for obtaining the component (b-3) is at least one polymer block of the polymer block (G) and the polymer block (H) via a coupling agent residue. It may be a block copolymer in which the polymer molecular chain is extended or branched as represented by the following formulas (6) to (7).
[0046]
▲ 6 ▼ [(G)-(H)] n-X
(7) [(G)-(H)-(G)] n-X
[In the formulas (6) to (7), n and X are the same as those in the formulas (4) to (5). ]
The coupling agent is also the same as that used for the component (b-1). The above block copolymer (B-3), which is a hydrogenated diene copolymer, is obtained by saturating the double bond of the conjugated diene portion of the block copolymer by hydrogenation.
[0047]
Here, the double bond of the conjugated diene portion needs to be saturated 80% or more, preferably 90% or more, and more preferably 95 to 100%. When the saturation rate of the double bond of the conjugated diene moiety is less than 80%, the thermal stability and durability of the thermoplastic elastomer composition are inferior. The number average molecular weight of the component (b-3) is 50,000 to 700,000, preferably 100,000 to 600,000. If it is less than 50,000, the heat resistance, mechanical strength, fluidity and workability are lowered, and if it exceeds 700,000, the fluidity, workability and flexibility are inferior. The component (b-3) can be obtained, for example, by the method disclosed in JP-A-3-128957.
[0048]
Each hydrogenated diene copolymer used as the component (b) in the present invention may be a modified hydrogenated block polymer modified with a functional group. Such a modified hydrogenated block polymer is at least one selected from the group of carboxyl groups, acid anhydride groups, hydroxyl groups, epoxy groups, halogen atoms, amino groups, isocyanate groups, sulfonyl groups and sulfonate groups. These functional groups are contained.
[0049]
As a method of containing this functional group,
(1) Using a conjugated diene or vinyl aromatic compound having a functional group, a copolymer is obtained with the functional group of the monomer protected to obtain a block copolymer, and polymerized by a method of deprotection after completion of the polymerization. How to add inside.
(2) A method of adding a radically polymerizable monomer having a functional group to a hydrogenated block copolymer by a known grafting reaction.
(3) Using a monomer having a functional group, the hydrogenated block polymer is kneaded using a kneader, a mixer, an extruder or the like in the presence or absence of an organic peroxide or an azo compound, And the like.
[0050]
Although any of these methods can be used to add a functional group efficiently, the methods (1) to (3) are industrially simple and effective. The amount of the functional group in this modified hydrogenated block copolymer is usually 0.01 to 10 mol%, preferably 0.1 to 8 mol%, more preferably relative to the molecules constituting the hydrogenated block polymer. 0.15 to 5 mol%. Preferred examples of the monomer for adding a functional group to the hydrogenated block polymer include acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and hydroxypropyl. Examples include methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, and dimethylaminoethyl methacrylate.
[Crystalline α-olefin copolymer mainly composed of α-olefin having 3 or more carbon atoms]
The crystalline α-olefin copolymer mainly containing an α-olefin having 3 or more carbon atoms used as the component (c) in the present invention is polypropylene, poly-1-butene, poly-4-methyl-1-pentene. , Poly-1-hexene, propylene-ethylene copolymer, propylene-1-butene copolymer and the like, and the content of olefin component having 3 or more carbon atoms is preferably 50 mol% or more.
[0051]
Of these, polypropylene, random or block ethylene-propylene copolymers are preferred. The component (c) is crystalline and has an n-decane insoluble content of 50% by weight or more, preferably 60% by weight or more, and more preferably 70% by weight or more. If the n-decane-insoluble component is less than 50% by weight, the mechanical strength and molding processability of the resulting thermoplastic elastomer composition may be impaired.
[Ethylene copolymer]
The component (d) used in the present invention has an ethylene content of 90 mol% or more, polyethylene produced by a known low pressure method or high pressure method, or ethylene and carbon having an ethylene content of 90 mol% or more. It may be a copolymer with an α-olefin such as propylene, butene-1,4-methyl, pentene-1, hexene-1, etc. having a number of 3 or more.
[0052]
The blending amount of the components (a) to (d) used in the present invention is 20 to 85% by weight, preferably 40 to 80% by weight, of the ethylene-α-olefin copolymer of the component (a). The hydrogenated diene copolymer of the component (b) is 5 to 50% by weight, preferably 7 to 20% by weight, and the component (c) is an α-olefin having 3 or more carbon atoms as a main component. The crystalline α-olefin copolymer is 1 to 10% by weight, preferably 2 to 7% by weight, and the ethylene copolymer of the component (d) is 5 to 30% by weight, preferably 7 to 20% by weight. %.
[0053]
When the amount of the ethylene-α-olefin copolymer of component (a) is less than 20% by weight, the rubber elasticity and flexibility of the resulting composition deteriorate, whereas when it exceeds 85% by weight, the resulting composition The moldability and mechanical strength of the steel deteriorate. If the amount of the component (b) is less than 5% by weight, the rubber elasticity and foaming properties are lowered, while if it exceeds 50 parts by weight, the heat resistance is deteriorated. When the component (c) is less than 1% by weight, the heat resistance of the resulting composition is deteriorated, whereas when it exceeds 10 parts by weight, rubber elasticity is deteriorated. When the component (d) is less than 5% by weight, the resulting mechanical strength is lowered, whereas when it exceeds 30 parts by weight, the flexibility is inferior.
[Mineral oil softener]
As the mineral oil-based softener of the component (e) used in the present invention, naphthenic oil and paraffin-based mineral oil can be used. Such an oil exhibition further improves processability and flexibility. In this case, the oil extended amount is 0 to 200 parts by weight, preferably 10 to 100 parts by weight, per 100 parts by weight of the ethylene-α-olefin copolymer (ii).
[0054]
Production of the thermoplastic elastomer composition according to the present invention is not particularly limited, and any method may be adopted as long as good dispersion of each component can be obtained. Usually, the target polymer is melt-kneaded by a closed kneader such as a roll mill, a Banbury mixer, a pressure kneader or the like used in the rubber / resin industry, a single screw extruder, a twin screw extruder, or the like. In the production of the composition of the present invention, the mixing temperature (kneading temperature) is a temperature at which at least the components (b), (c), and (d) melt, and is usually in the range of 120 to 280 ° C.
[0055]
In addition to the components (a) to (e), an antioxidant, an antistatic agent, a weathering agent, an ultraviolet absorber in an amount that does not impair the mechanical strength, flexibility, and moldability depending on the application. A lubricant, an antiblocking agent, a sealing property improving agent, a crystal nucleating agent, an antibacterial and antifungal agent, a tackifier, a softener, a plasticizer, a colorant, a filler and the like can be appropriately blended.
[0056]
As described above, the cross-linked foam used in the weather strip of the present invention has a cross-link density measured by gel fraction measurement in the range of 30 to 95, a melt temperature at a measurement temperature of 210 ° C., and a take-off speed of 0.5 m / min. Is in the range of 1 to 20 gf.
[0057]
If the gel fraction is 95% or more, the foamability of the weatherstrip may be reduced. If it is less than 30%, the compression set of the weather strip may decrease. In addition, the measuring method of the said gel fraction is as follows.
[0058]
Further, if the melt tension is 1 gf or less, the foamability of the weather strip may be lowered, and if it is 20 gf or more, the foamability of the weatherstrip may be lowered.
[Gel fraction measurement method]
About 200 mg of the thermoplastic elastomer composition or crosslinked foam is weighed and cut into pieces. The resulting strip is then immersed in 100 ml cyclohexane at 23 ° C. for 48 hours in a sealed container. Next, this sample is taken out on a filter paper, and dried under reduced pressure at 105 ° C. for 1 hour in a vacuum dryer. From the mass of this dry residue, (1) ethylene-α-olefin copolymer (a), hydrogenated diene copolymer (b), α-olefin copolymer (c) and ethylene copolymer Mass of cyclohexane insoluble component (filler, pigment, etc.) other than (d), and (2) hydrogenated diene copolymer (b) and α-olefin copolymer (c) in the sample before cyclohexane immersion The value obtained by subtracting the mass of the ethylene copolymer (d) is referred to as “corrected final mass (p)”.
[0059]
On the other hand, from the mass of the sample, (3) cyclohexane-soluble components other than ethylene-α-olefin copolymer (a), hydrogenated diene copolymer (b) and polyolefin resin (c) and (d) (E.g., mineral oil softener), (1) ethylene-α-olefin copolymer (a), hydrogenated diene copolymer (b), α-olefin copolymer (c) and ethylene The mass of cyclohexane insoluble components (fillers, pigments, etc.) other than copolymer (d), and (4) hydrogenated diene copolymer (b), α-olefin copolymer (c) and ethylene The value obtained by subtracting the mass of the copolymer (d) is defined as “corrected initial mass (q)”. Here, the gel fraction (cyclohexane insoluble matter) as the crosslinking density is determined by the following formula.
[0060]

The thermoplastic elastomer composition used in the weather strip of the present invention is more preferably a thermoplastic elastomer composition containing 0.05 to 5 parts by weight of an inorganic mineral with respect to 100 parts by weight of the base polymer.
[0061]
When the inorganic mineral content is less than 0.05 parts by weight, the foamability of the resulting weather strip is inferior, and when it exceeds 5 parts by weight, the elasticity is impaired and the compression set is inferior.
[0062]
As the inorganic mineral used in the present invention, talc, kaolin, calcium carbonate, clay, mica, diatomaceous earth, titanium oxide and Neuburg clay can be used.
[0063]
Specific examples of other additives used in the present invention include fillers, heat stabilizers, anti-aging agents, weathering stabilizers, antistatic agents, wetting agents, metal soaps, waxes and other lubricants, pigments, dyes, A conventionally well-known additive, such as a flame retardant and an antiblocking agent, is mentioned.
[Crosslinking agent]
The crosslinking agent used in the thermoplastic elastomer composition of the present invention is a composition obtained by extrusion foam molding at a temperature equal to or higher than the melting point of the α-olefin copolymer (c) and the ethylene copolymer (d). It is a compound capable of crosslinking at least one ethylene-α-olefin copolymer. Examples of such crosslinking agents include organic peroxides, phenolic crosslinking agents, sulfur, sulfur compounds, p-quinones, p-quinone dioxime derivatives, bismaleimide compounds, epoxy compounds, silane compounds, amino resins, and the like. In particular, organic peroxides and phenolic crosslinking agents are preferred. Examples of the organic peroxide include 1,3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, 2,5- Dimethyl-2,5-bis (t-butylperoxy) hexene-3, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, 2,2'-bis (t-butylperoxy) ) -P-isopropylbenzene, dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxide, p-menthane peroxide, 1,1-bis (t-butylperoxy) -3,3,5 -Trimethylcyclohexane, dilauroyl peroxide, diacetyl peroxide, t-butyl peroxybenzoate, 2,4-dichlorobenzoyl peroxide, p-chlorobe Nzoyl peroxide, benzoyl peroxide, di (t-butylperoxy) perbenzoate, n-butyl-4,4-bis (t-butylperoxy) valerate, t-butylperoxyisopropyl carbonate, etc. it can. Among these organic peroxides, 1,3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, 2,5- A compound having a relatively high decomposition temperature, such as dimethyl-2,5-di (t-butylperoxy) hexane, is preferred.
[0064]
The said organic peroxide can be used individually or in mixture of 2 or more types. In the present invention, a uniform and gentle crosslinking reaction can be performed by using the organic peroxide in combination with an appropriate crosslinking aid. Examples of such a crosslinking aid include sulfur or sulfur compounds such as powdered sulfur, colloidal sulfur, precipitated sulfur, insoluble sulfur, surface-treated sulfur, dipentamethylene thiuram tetrasulfide; p-quinone oxime, p, p′-di Oxime compounds such as benzoylquinone oxime; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tri Methylolpropane tri (meth) acrylate, diallyl phthalate, tetraallyloxyethane, triallyl cyanurate, N, N′-m-phenylene bismaleimide, N, N′-toluylene bismaleimide, maleic anhydride , Mention may be made of divinylbenzene, di (meth) polyfunctional monomers such as zinc acrylate and the like. Of these crosslinking aids, p, p′-dibenzoylquinone oxime, N, N′-m-phenylenebismaleimide, and divinylbenzene are preferred. N, N′-m-phenylenebismaleimide alone can act as a crosslinking agent. The crosslinking aids can be used alone or in admixture of two or more. Moreover, as said phenol type crosslinking agent, the p-substituted phenol type compound represented by the following general formula (I) is preferable. This p-substituted phenolic compound has been conventionally used as a crosslinking agent for rubber as described in US Pat. No. 3,287,440 and US Pat. No. 3,709,840.
[0065]
[Chemical 1]

[0066]
Note that n is an integer of 0 to 10, X is at least one of a hydroxyl group, a halogenated alkyl group, and a halogen atom, and R is a saturated hydrocarbon group having 1 to 15 carbon atoms. The p-substituted phenol compound is obtained by a condensation reaction between a p-substituted phenol and an aldehyde (preferably formaldehyde) in the presence of an alkali catalyst. Examples of other phenol-based crosslinking agents include o-substituted phenol-aldehyde condensates, m-substituted phenol-aldehyde condensates, brominated alkylphenol-aldehyde condensates.
[0067]
In the present invention, the above-mentioned phenolic crosslinking agent can be used alone, but can also be used in combination with a crosslinking accelerator in order to adjust the crosslinking rate. Examples of such a crosslinking accelerator include metal halides (such as stannous chloride and ferric chloride) and organic halides (such as chlorinated polypropylene, butyl bromide rubber, and chloroprene rubber). In addition to the crosslinking accelerator, it is more desirable to use a metal oxide such as zinc oxide or a dispersant such as stearic acid.
[0068]
The amount of these crosslinking agents used is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the thermoplastic elastomer composition. If the amount of the organic peroxide used is less than 0.01 parts by weight, the degree of crosslinking is insufficient, and the compression set of the finally obtained thermoplastic elastomer composition foam may be lowered. On the other hand, when it exceeds 10 parts by weight, the degree of crosslinking becomes excessively high and the foam molding processability tends to deteriorate.
[0069]
Further, the amount of the crosslinking aid used when the organic peroxide is used as the crosslinking agent is preferably 10 parts by weight or less, more preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the thermoplastic elastomer composition. It can be. When the amount of the crosslinking aid used exceeds 10 parts by weight, the degree of crosslinking becomes excessively high, and the moldability tends to deteriorate or the mechanical properties tend to decrease.
[0070]
The automobile weather strip of the present invention may comprise a crosslinked foam using the thermoplastic elastomer composition as a foaming agent such as a chemical foaming agent, a water foaming agent, and a supercritical fluid. It is preferable to comprise a cross-linked foam formed by foaming.
[0071]
By foaming using a supercritical fluid, the cell diameter becomes smaller and the appearance design is excellent.
[0072]
Examples of the chemical blowing agent used in the present invention include organic compounds such as azodicarbonamide, N, N′-dinitropentamethylenetetramine, 4,4-oxybis (benzenesulfonylhydrazide), hydrazodicarbonamide, and barium azodicarboxylate. One type or a mixture of two or more types may be mentioned from the group of systems or inorganic groups such as sodium hydrogen carbonate. A hollow seal in which 0.3 to 1.2 parts by weight of these foaming agents are mixed with 100 parts by weight of the thermoplastic elastomer composition, and the thermoplastic elastomer composition is foamed and extruded into a desired shape. Part can be obtained.
[0073]
The foaming agent preferably has a decomposition temperature (hereinafter simply referred to as “Td”) adjusted within the range of 170 ° C. to 210 ° C. with urea or an alkaline substance as an auxiliary, The cell diameter becomes large, foaming becomes uneven, the surface roughness becomes large, and this is not preferable in appearance. On the other hand, when it exceeds 210 ° C., the softening of the olefinic thermoplastic elastomer is remarkably promoted and foaming does not occur.
[0074]
Examples of the supercritical fluid used in the present invention include supercritical carbon dioxide and supercritical nitrogen.
[Method of extruding by partially leaving the cross-linking agent]
Examples of the method of extrusion foam molding so that a part of the crosslinking agent remains include the following methods.
(1) A method of adjusting the extrusion foaming temperature so that the thermoplastic elastomer composition is discharged from the exit of the extruder before the crosslinking reaction is completed.
(2) A cross-linking agent having a high reaction rate and a cross-linking agent having a low reaction rate are used in combination, the cross-linking agent having a high reaction rate is terminated inside the extruder, and the cross-linking agent having a low reaction rate in the heat-crosslinking step after extrusion foaming. To terminate the crosslinking reaction.
(3) Two or more organic peroxides having different one-minute half-life temperatures are used in combination, and the organic peroxide having a low one-minute half-life temperature is terminated inside the extruder, and in the heat-crosslinking step after extrusion foaming A method for terminating the crosslinking reaction of an organic peroxide having a high 1 minute half-life temperature.
[0075]
In the case of extrusion foam molding of (1), the molding temperature of the thermoplastic elastomer composition (hereinafter simply referred to as “Te”) varies depending on the foaming agent and crosslinking agent used, but a part of the crosslinking agent remains after extrusion foaming. In order to perform extrusion foam molding, the following conditions are preferably satisfied.
[0076]
Tm ≦ (Td) ≦ Te ≦ (Th)
(1) Extrusion foam molding is preferably performed at a melting point (hereinafter simply referred to as “Tm”) or higher and 280 ° C. or lower of the thermoplastic elastomer composition. If it is Tm or less, the thermoplastic elastomer does not melt, and the expansion ratio may decrease. On the other hand, if it is 280 ° C. or higher, the thermoplastic elastomer may be deteriorated and the mechanical properties may be lowered.
(2) When an organic peroxide is used as a crosslinking agent, extrusion foam molding is performed at a Tm of the thermoplastic elastomer composition or more and a 1 minute half-life temperature (hereinafter simply referred to as “Th”) of the organic peroxide. It is preferable to do. However, when two or more kinds of organic peroxides are used in combination, it is preferable to perform extrusion foam molding at a temperature equal to or lower than the highest temperature Th. When extrusion foaming is performed at Th or higher, the crosslinking density of the thermoplastic elastomer composition is improved, and the expansion ratio may not be increased.
(3) When the foaming agent is a chemical foaming agent, a chemical foaming agent having a decomposition temperature equal to or higher than Tm of the thermoplastic elastomer (hereinafter simply referred to as “Td”) is used, and extrusion foam molding is performed at a temperature equal to or higher than Td. If extrusion foaming is performed at a temperature of Td or less, the expansion ratio may not be increased.
[Extruder residence time]
The extruder residence time of the thermoplastic elastomer composition in the extrusion foam molding of the present invention varies depending on the foaming agent and the crosslinking agent used, but the extrusion foaming takes 10 seconds to 10 minutes so that a part of the crosslinking agent remains after the extrusion foaming. It is preferable to mold.
[Heat-crosslinking process after foaming and molding]
Any temperature can be used as long as it remains at the temperature at which the remaining cross-linking agent reacts. When it exceeds 300 ° C., the thermoplastic elastomer composition deteriorates, and mechanical properties and compression set tend to deteriorate.
[0077]
As the heat crosslinking apparatus after extrusion foaming, an oven, a continuous crosslinking apparatus (for example, hot-air crosslinking (HAV), high-frequency crosslinking (UHF)) or the like can be arbitrarily used.
[0078]
The heating crosslinking time may be any number and can be arbitrarily set.
[0079]
The thermoplastic elastomer composition to be subjected to extrusion foaming may be a thermoplastic elastomer composition that has been dynamically crosslinked in advance with a crosslinking agent, or may be a non-crosslinked thermoplastic elastomer.
[0080]
An embodiment of a weatherstrip according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 2 is a cross-sectional view showing a main part of a weather strip 10 according to the present invention, and FIGS. 3 and 4 show a hollow seal portion molded body constituting a part of the weather strip used in Examples and Comparative Examples. It is a cross-sectional view.
[0081]
First, as shown in FIG. 2, a weather strip 10 according to the present invention includes a base portion 11 having a substantially U-shaped cross section together with an insert metal IM, and a protruding portion from the outer surface of the base portion 11. The hollow sealing portion 13 and the claw portion 12 projecting from both U-shaped inner side surfaces of the base portion 11 are provided.
[0082]
The hollow seal portion 13 is formed by mixing the foaming agent or the supercritical fluid into the thermoplastic elastomer composition containing the components (A) to (E), and the base portion 11 and the nail. It is integrally formed with the part 12. On the other hand, the base portion 11 and the claw portion 12 are extruded into a desired shape together with the insert metal IM using the thermoplastic elastomer composition containing the components (A) to (E). However, the material is not particularly limited as long as it is a material that can be simultaneously extruded and vulcanized with the hollow seal portion 13 and has a sufficient interface adhesive force with the hollow seal portion 13.
[0083]
The hollow seal portion 13 includes the hollow seal portion 13 obtained by foaming the thermoplastic elastomer composition using the foaming agent or supercritical fluid and extruding the thermoplastic elastomer composition into a desired shape. As a result, the hollow seal portion 13 develops characteristics that are compatible with low compression set and good foamability.
[0084]
【Example】
Hereinafter, the method for molding a thermoplastic elastomer composition of the present invention and a weather strip for automobiles will be described more specifically with reference to examples, but of course the scope of the present invention is not limited thereto.
[0085]
The base polymers of the thermoplastic elastomer compositions used in the examples and comparative examples are as follows.
(1) Ethylene-α-olefin copolymer (I-1)
Ethylene-propylene-ethylidene norbornene copolymer, ethylene content 80 mol%, paraffinic oil 70 parts by weight oil exhibition, JSR Corporation, EP98A
(2) Hydrogenated diene copolymer (B-1)
G-H-G structure (G is polybutadiene with a low 1,2-vinyl bond content, H is a polybutadiene with a high 1,2-vinyl bond content, and the double bond of each butadiene part is hydrogenated) A hydrogenated block copolymer having a vinyl bond content of 15% by weight for G, a vinyl bond content of H of 35% by weight, and a total molecular weight of 300.000 (hydrogenation rate: 98%)
(3) Crystalline α-olefin copolymer mainly composed of α-olefin having 3 or more carbon atoms (C-1)
Propylene-ethylene block polymer (n-decane insoluble content: 93.5% by weight) (Novatech PP BC5CW manufactured by Nippon Polychem Co., Ltd.)
(4) Ethylene copolymer (d-1)
Linear low density polyethylene (Novatec LLDPE UF423, manufactured by Nippon Polychem Co., Ltd.)
(5) Crosslinking agent
Organic peroxide (e-1); manufactured by NOF Corporation, perbutyl P-40
Organic peroxide (E-2); manufactured by NOF Corporation, Perhexine 25B-40
(6) Other additives
・ Crosslinking aid (he-1); Sankyo Kasei Co., Ltd. divinylbenzene (purity 55%),
・ Foaming agent master batch (F-2); Polyslen EV306G manufactured by Eiwa Chemical Industry Co., Ltd., foaming agent content 30 wt%
-Foaming agent, masterbatch (F-3); Polyslen EE206 manufactured by Eiwa Chemical Industry Co., Ltd., foaming agent content 20 wt%
・ Lubricant (F-4); Erucamide, Nippon Seika Co., Ltd. Neutron S
Anti-aging agent (f-5); Irganox 1010 manufactured by Ciba Specialty Chemicals Co., Ltd.
Anti-aging agent (he-6); PEP-36 manufactured by Asahi Denka Kogyo Co., Ltd.
-Reaction terminator (f-7); N-nitrosophenylhydroxylamine, Q-1300 manufactured by Wako Pure Chemical Industries, Ltd.
[Examples 1-2, Comparative Examples 1-5]
As a base polymer of the above thermoplastic elastomer composition, the compounding formulation shown in Table 1 below was mixed for 30 seconds with a Henschel mixer, and then a twin screw extruder (Ikegai Co., Ltd., model “PCM-45”, in the same direction. Extrusion under the condition of retaining at 230 ° C. and 300 rpm for 2 minutes using a fully meshing screw and L / D, which is the ratio of the length L of the screw flight part to the screw diameter D (33.5) By kneading, a pellet-shaped thermoplastic elastomer composition was obtained. Next, the crosslinking agent, other compounding agents and thermoplastic elastomer composition shown in the following Table 2 were mixed for 30 seconds with a Henschel mixer, extruded and foamed with a single screw extruder, and then heat-treated (240 ° C, 1 minute, a gear oven manufactured by Toyo Seiki Co., Ltd.), and a weather strip in which a hollow seal portion molded body 10a according to FIG. .
[0086]
In addition, Table 2 shows the measurement results of various physical properties of the hollow seal portion moldings of the samples of the obtained Examples and Comparative Examples.
[0087]
[Table 1]

[0088]
[Table 2]

[0089]
[Evaluation method of physical properties]
The physical properties described in Table 2 were evaluated according to the following methods.
(1) Crosslink density
It was shown in the text as the crosslink density by the gel fraction measurement method.
(2) Foaming ratio
It was set as the converted value from the specific gravity measurement value.
(3) Water absorption rate
The molded body whose weight was measured in advance was depressurized to 125 mmHg at a position 50 mm below the water surface and held for 3 minutes. Subsequently, the molded body was returned to atmospheric pressure, and after 3 minutes, the weight of the water-absorbed molded body was measured, and the water absorption rate was calculated from the following formula.
[0090]
Water absorption rate (%) = [(W ₂ -W ₁ ) / W ₁ ] × 100
W ₁ : Molded body weight before immersion (g)
W ₂ : Molded body weight after immersion (g)
(4) Compression set test
Measurement was performed in accordance with JIS K6262 (70 ° C., 22 hrs, 25% compression).
[0091]
From Table 2, the following matters are clear.
(1) Comparative Example 1 is a case where the thermoplastic elastomer composition (hereinafter referred to as the present TPE) used in the present invention, which is composed only of pseudo-crosslinking and is not subjected to crosslinking treatment, is foam-molded. Good, but shows significantly higher compression set.
(2) Comparative Example 2 shows that the TPE is in a slightly cross-linked state and then subjected to foam molding, and the foamability is good, but the water absorption is high and the compression set is insufficiently improved.
(3) Comparative Example 3 is a case where the TPE is foam-molded after completion of the crosslinking reaction, and Cs is improved, but the foamability is remarkably impaired (foaming ratio is only 1.1 times). It shows that.
(4) Comparative Example 4 shows that the foaming property is remarkably impaired because the end of the crosslinking reaction and the decomposition of the foaming agent occur simultaneously in the extruder.
(5) In Comparative Example 5, since the crosslinking reaction and the decomposition reaction of the foaming agent occur simultaneously by heating after extrusion foaming, the balance of foamability, water absorption, and compression set tends to deteriorate.
(6) Example 1 shows that a foam having good foamability, water absorption, and compression set is obtained, and that “low compression set and good foamability” are achieved.
(7) Example 2 is a case where the crosslinking density after molding is further increased in Example 1 than in Example 1, and compared with Example 1, the compression set is improved without impairing foamability. Show that you can.
[0092]
Furthermore, the hollow seal part moldings of the examples based on the present invention exhibited the characteristics satisfying both low compression set and good foamability, and obtained satisfactory results. However, the hollow seal part moldings in the comparative examples were obtained. The body was unsatisfactory in compression set or foamability.
[0093]
【The invention's effect】
As described above, the method for extruding the thermoplastic elastomer composition of the present invention, the crosslinked foam, and the weather strip for automobiles include a pseudo-crosslinking point of a polyolefin crystal phase in a specific ethylene-α-olefin copolymer matrix. A foaming agent and a cross-linking agent are added to the thermoplastic elastomer composition in which is dispersed, and a foam extrusion process is performed so that a part of the cross-linking agent remains. It is possible to provide an excellent weather strip for an automobile having a cross-linked foam seal portion having both low compression set and good foamability by the extrusion molding method.
[Brief description of the drawings]
FIG. 1 is a process schematic diagram of a method for molding a thermoplastic elastomer composition of the present invention.
FIG. 2 is a cross-sectional view of a weather strip provided with a foamed molded article (hollow seal portion) of the thermoplastic elastomer composition of the present invention (door inner weather strip group).
FIG. 3 is a cross-sectional view of a weather strip provided with a foamed molded article (hollow seal part) of the thermoplastic elastomer composition of the present invention (trunk / back door weather strip group).
FIG. 4 is a cross-sectional view of a weather strip provided with a foamed molded article (hollow seal part) of the thermoplastic elastomer composition of the present invention (hood and cowl seal group).
[Explanation of symbols]
10. Weather strip to which the present invention is applied (door inner weather strip group)
11 Base part
12 nails
13 Hollow seal
IM insert metal
10a Weather strip to which the present invention is applied (trunk / back door weather strip group)
10b Weather strip to which the present invention is applied (hood and cowl seal group)

Claims (2)

(I) ethylene-α-olefin copolymer (ethylene content less than 90 mol%) 20-85 wt%,
(B) 5-50% by weight of hydrogenated diene copolymer,
(C) 1 to 10% by weight of a crystalline α-olefin copolymer mainly composed of an α-olefin having 3 or more carbon atoms,
(D) 5-30% by weight of ethylene-based polymer (ethylene content of 90 mol% or more) [provided that (b) + (b) + (c) + (d) = 100% by weight]] and (e ) Mineral oil-based softener contains 0 to 200 parts by weight per 100 parts by weight of component (a),
And when said (a) + (b) + (c) + (d) + (e) = 100 parts by weight, the sum of (a) and (e) is 61% by weight or more, A method for extruding and foaming a thermoplastic elastomer composition, wherein the weight ratio of the sum of (a) and (e) to the above (b) is 90/10 to 60/40,
(1) a step of adding a foaming agent and a crosslinking agent to the thermoplastic elastomer composition, and performing foam extrusion molding so that at least a part of the crosslinking agent remains; and (2) heating the molded product after foam extrusion molding. A step of terminating the reaction of the crosslinking agent to obtain a crosslinked foam,
A method for extruding a thermoplastic elastomer composition, comprising: The (b) hydrogenated diene copolymer is at least one kind obtained from the following groups (b-1), (b-2), and (b-3): A method for extruding a thermoplastic elastomer composition.
[(B-1) is a block copolymer (A)-(B), a block copolymer (A)-(B)-(C) or a block copolymer (A)-(B)-(A) Polymer [wherein (A) is a vinyl aromatic compound polymer block, (B) is a conjugated diene polymer block or a vinyl aromatic compound-conjugated diene random copolymer block, and (C) is a vinyl aromatic. A compound in which a compound gradually increases in a vinyl aromatic compound-conjugated diene taper block, wherein the ratio of vinyl aromatic compound / conjugated diene is 5 to 60/95 to 40 by weight, and all of the block copolymer The bond content of the vinyl aromatic compound in the polymer block (A) with respect to the monomer is 3% by weight or more, and the bond content of the total vinyl aromatic compound in the polymer blocks (A) and (C) is 3 to 50%. weight% A block copolymer in which the vinyl bond content of the conjugated diene moiety in the polymer block (B) exceeds 20% by weight, or the block copolymer unit extends a polymer molecular chain through a coupling agent residue. Or the branched block copolymer], and a hydrogenated diene copolymer having a number average molecular weight of 50,000 to 700,000 in which at least 80% of the vinyl double bond in the conjugated diene portion is saturated, or It is a modified hydrogenated diene copolymer.
(B-2) is a polymer block copolymer having one or more polymer blocks (D), (E) and (F) in the molecule [provided that (D) represents a vinyl aromatic compound. Polymer block containing main component, (E) is a polymer block mainly containing conjugated diene having a 1,2-vinyl bond content of 25 to 95% by weight, and (F) is 1,2-vinyl bond content. Represents a polybutadiene polymer block of less than 25% by weight, and these block copolymers may have polymer molecular chains extended or branched via a coupling agent residue. The content of the polymer block (D) in the block copolymer is 5 to 60% by weight, the content of the polymer block (E) is 30 to 90% by weight, and the content of the polymer block (F) is 5 to 60% by weight, where the block copolymer of (D) + (E) + (F) = 100% by weight is hydrogenated to saturate at least 80% of the double bonds in the conjugated diene moiety The hydrogenated diene copolymer or modified hydrogenated diene copolymer having a number average molecular weight of 50,000 to 700,000.
(B-3) is a block copolymer represented by (G)-(H)-(G) or (G)-(H) [wherein (G) is a 1,2-vinyl bond content. Is a polybutadiene polymer block having a conjugated diene polymer block or vinyl aromatic compound-conjugated diene polymer block, wherein the vinyl bond content of the conjugated diene moiety exceeds 25%. These block copolymers may have a polymer molecular chain extended or branched via a coupling agent residue. ] Is a hydrogenated diene copolymer or a modified hydrogenated diene copolymer having a number average molecular weight of 50,000 to 700,000 in which at least 80% of the double bonds of the conjugated diene moiety are saturated by hydrogenation. ]

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