JP4652514B2 - Fuel container - Google Patents

Description

【００５９】
また水の存在下でボロン酸基に転化しうるホウ素含有基（以下単にホウ素含有基と略記する）としては、水の存在下で加水分解を受けて上記式（Ｉ）で示されるボロン酸基に転化しうるホウ素含有基であれば、どのようなものでもよいが、代表例として下記一般式（II）で示されるボロンエステル基、下記一般式（III）で示されるボロン酸無水物基、下記一般式（IV）で示されるボロン酸塩基が挙げられる。
【００６０】
【化２】

【００６１】
【化３】

【００６２】
【化４】

【００６３】
（式中、Ｘ，Ｙは水素原子、脂肪族炭化水素基（炭素数１〜２０の直鎖状、または分岐状アルキル基、またはアルケニル基など）、脂環式炭化水素基（シクロアルキル基、シクロアルケニル基など）、芳香族炭化水素基（フェニル基、ビフェニル基など）を表し、Ｘ，Ｙは同じ基でもよいし、異なっていてもよい。またＸとＹは結合していてもよい。ただしＸ，Ｙがともに水素原子である場合除かれる。またＲ¹，Ｒ²，Ｒ³は上記Ｘ，Ｙが同様の水素原子、脂肪族炭化水素基、脂環式炭化水素基、芳香族炭化水素基を表し、 Ｒ¹，Ｒ²，Ｒ³は同じ基でもよいし、異なっていてもよい。またＭはアルカリ金属またはアルカリ土類金属を表わす。また上記のＸ，Ｙ， Ｒ¹，Ｒ²，Ｒ³には他の基、たとえばカルボキシル基、ハロゲン原子などを有していてもよい。）
【００６４】
一般式（ＩＩ）〜（ＩＶ）で示されるボロン酸エステルの具体例としては、ボロン酸ジメチルエステル基、ボロン酸ジエチルエステル基、ボロン酸ジプロピルエステル基、ボロン酸ジイソプロピルエステル基、ボロン酸ジブチルエステル基、ボロン酸ジヘキシルエステル基、ボロン酸ジシクロヘキシル基、ボロン酸エチレングリコールエステル基、ボロン酸プロピレングリコールエステル基（ボロン酸１，２−プロパンジオールエステル基、ボロン酸１，３−プロパンジオールエステル基）、ボロン酸トリメチレングリコールエステル基、ボロン酸ネオペンチルグリコールエステル基、ボロン酸カテコールエステル基、ボロン酸グリセリンエステル基、ボロン酸トリメチロールエタンエステル基等のボロン酸エステル基；ボロン酸無水物基；ボロン酸のアルカリ金属塩基、ボロン酸のアルカリ土類金属塩基等が挙げられる。前記の官能基の中でもとくにボロン酸エチレングリコールエステル基などのボロン酸エステル基がＥＶＯＨとの相容性の点から好ましい。なお前記の水の存在下でボロン酸基またはボリン酸基に転化しうるホウ素含有基とは、ポリオレフィンを、水または水と有機溶媒（トルエン、キシレン、アセトンなど）との混合液体中で、反応時間１０分〜２時間、反応温度２５℃〜１５０℃の条件下に加水分解した場合に、ボロン酸基またはボリン酸基に転化しうる基を意味する。
【００６５】
前記官能基の含有量は特に制限はないが、０．０００１〜１ｍｅｑ／ｇ（ミリ当量／ｇ）が好ましく、特に、０．００１〜０．１ｍｅｑ／ｇが好ましい。この程度の少量の官能基の存在により、樹脂組成物の相容性等が著しく改善されることは驚くべきことである。
【００６６】
ホウ素含有基を有するポリオレフィンのベースポリマーとしてはエチレン、プロピレン、１−ブテン、イソブテン、３−メチルペンテン、１−ヘキセン、１−オクテン等のα−オレフィン類で代表されるオレフィン系単量体等が挙げられる。
【００６７】
ベースポリマーはこれらの単量体の一種または二種あるいは三種以上からなる重合体として使用される。これらのベースポリマーのうち、特にエチレン系重合体｛超低密度ポリエチレン、低密度ポリエチレン、中密度ポリエチレン、高密度ポリエチレン、直鎖状低密度ポリエチレン、エチレン−酢酸ビニル共重合体、エチレン−アクリル酸エステル共重合体、エチレン−アクリル酸共重合体の金属塩（Ｎａ，Ｋ，Ｚｎ系アイオノマー）、エチレン−プロピレン共重合体｝、が好適なものとして挙げられる。
【００６８】
次に本発明に用いるボロン酸基およびホウ素含有基を有するオレフィン系重合体の代表的製法について述べる。ボロン酸基あるいは水の存在によりボロン酸基に転化しうるホウ素含有基を有するオレフィン系重合体は、窒素雰囲気下で炭素−炭素二重結合を有するオレフィン系重合体にボラン錯体およびホウ酸トリアルキルエステルを反応させることによって、ボロン酸ジアルキルエステル基を有するオレフィン系重合体を得た後、水あるいはアルコール類を反応させることによって得られる。この製法において原料として末端に二重結合を有するオレフィン系重合体を使用すれば、末端にボロン酸基あるいは水の存在によりボロン酸基に転化しうるホウ素含有基を有するオレフィン系重合体が得られ、側鎖または主鎖に二重結合を有するオレフィン系重合体を原料として使用すれば、側鎖にボロン酸基あるいは水の存在によりボロン酸基に転化しうるホウ素含有基を有するオレフィン系重合体が得られる。
【００６９】
原料の二重結合を有するオレフィン系重合体の代表的製法としては、１）通常のオレフィン系重合体の末端に微量に存在する二重結合を利用する方法；２）通常のオレフィン系重合体を無酸素条件下、熱分解し、末端に二重結合を有するオレフィン系重合体を得る製法；３）オレフィン系単量体とジエン系重合体の共重合によりオレフィン系単量体とジエン系単量体との共重合体を得る製法；が挙げられる。１）については、公知のオレフィン系重合体の製法を用いることができるが、特に、連鎖移動剤として水素を用いず、重合触媒としてメタロセン系重合触媒を用いる製法（例えば、ＤＥ４０３０３９９）が好ましい。２）については、公知の方法（例えば、ＵＳＰ２８３５６５９，ＵＳＰ３０８７９２２）によりオレフィン系重合体を窒素雰囲気下や真空条件下等の無酸素条件下で３００℃〜５００℃の温度で熱分解することによって得られる。３）については公知のチーグラー系触媒を用いたオレフィン−ジエン系重合体の製法（例えば、特開昭５０−４４２８１、ＤＥ３０２１２７３）を用いることができる。
【００７０】
ボラン錯体としては、ボラン−テトラヒドロフラン錯体、ボラン−ジメチルスルフィド錯体、ボラン−ピリジン錯体、ボラン−トリメチルアミン錯体、ボラン−トリエチルアミン等が好ましい。これらのなかで、ボラン−トリエチルアミン錯体およびボラン−トリメチルアミン錯体がより好ましい。ボラン錯体の仕込み量はオレフィン系重合体の二重結合に対し、１／３当量から１０当量の範囲が好ましい。ホウ酸トリアルキルエステルとしては、トリメチルボレート、トリエチルボレート、トリプロピルボレート、トリブチルボレート等のホウ酸低級アルキルエステルが好ましい。ホウ酸トリアルキルエステルの仕込み量はオレフィン系重合体の二重結合に対し１から１００当量の範囲が好ましい。溶媒は特に使用する必要はないが、使用する場合は、ヘキサン、ヘプタン、オクタン、デカン、ドデカン、シクロヘキサン、エチルシクロヘキサン、デカリン等の飽和炭化水素系溶媒が好ましい。
【００７１】
導入する反応は、反応温度２５℃〜３００℃、好ましくは１００〜２５０℃、反応時間１分〜１０時間、好ましくは５分〜５時間行うのがよい。
【００７２】
水あるいはアルコール類を反応させる条件としては通常、トルエン、キシレン、アセトン、酢酸エチル等の有機溶媒を反応溶媒として用い、水またはメタノール、エタノール、ブタノール等のアルコール類；エチレングリコール、１，２−プロパンジオール、１．３−プロパンジオール、ネオペンテルグリコール、グリセリン、トリメチロールエタン、ペンタエリスリトール、ジペンタエリスリトール等の多価アルコール類をボロン酸基に対し、１から１００等量以上の大過剰量を用い、２５℃〜１５０℃の温度で１分〜１日程度反応を行うことによって得られる。なお、前記の官能基の中でボロン酸基に転化しうるホウ素含有基とは、水または水と有機溶媒（トルエン、キシレン、アセトンなど）との混合溶媒中で、反応時間１０分〜２時間、反応温度２５℃〜１５０℃の条件下に加水分解した場合に、ボロン酸基に転化しうる基を意味する。
【００７３】
本発明に用いられる熱可塑性樹脂（Ｂ）の好適なメルトフローレート（ＭＦＲ）（１９０℃−荷重２１６０ｇ）は、好ましくは０．０１〜１００ｇ／１０分、さらに好ましくは０．０３〜５０ｇ／１０分、最適には０．１〜３０ｇ／１０分である。但し、融点が１９０℃付近あるいは１９０℃を超えるものは２１６０ｇ荷重下、融点以上の複数の温度で測定し、片対数グラフで絶対温度の逆数を横軸、ＭＦＲの対数を縦軸にプロットし、１９０℃に外挿した値で表す。
【００７４】
上記熱可塑性樹脂（Ｂ）の中でも、密度０．９３ｇ／ｃｍ^３以上のポリエチレン、カルボン酸変性ポリオレフィン、およびボロン酸変性ポリオレフィンを用いることが好ましい。
【００７５】
熱可塑性樹脂（Ｂ）として密度０．９３ｇ／ｃｍ^３以上のポリエチレンを用いた場合、かかる構成の燃料容器用成形部品は従来品よりも耐衝撃性では劣るが、従来の高密度ポリエチレンのみからなる成形部品に比べ、ガソリンバリア性に大きな改善効果が見られる。ポリエチレンは密度が０．９３ｇ／ｃｍ^３以上であることが好適であり、密度が０．９３ｇ／ｃｍ^３未満では、得られる燃料容器用成形部品の耐衝撃性等の機械強度が不充分となる虞がある。
【００７６】
熱可塑性樹脂（Ｂ）としてカルボン酸変性ポリオレフィンを用いた場合、従来品と比べてガソリンバリア性に大きな改善効果が見られ、また、密度０．９３ｇ／ｃｍ^３以上のポリエチレンとバリア性樹脂（Ａ）をブレンドする系に比べ、得られる燃料容器用成形部品の耐衝撃性が優れている観点で更に好適である。
【００７７】
また、熱可塑性樹脂（Ｂ）としてボロン酸変性ポリオレフィンを用いた場合、バリア性樹脂（Ａ）との相容性が高く、特にバリア性樹脂（Ａ）としてＥＶＯＨを用いた場合にＥＶＯＨが非常に良好な分散性を示すため、耐衝撃性等の機械強度に優れるとともに、高いガソリンバリア性および耐有機溶剤性を燃料容器用成形部品に付与できる観点から特に好ましい。
【００７８】
（相容化剤（Ｃ））
本発明の燃料容器は、バリア性樹脂（Ａ）と熱可塑性樹脂（Ｂ）を配合してなる成形部品を燃料容器本体に装着してなる。この場合、熱可塑性樹脂（Ｂ）が相容化剤（Ｃ）および（Ｃ）以外の１１以下の溶解性パラメーター（Ｆｅｄｏｒｓの式から算出）を有する熱可塑性樹脂（Ｄ）からなり、かつ成分（Ａ）、（Ｃ）および（Ｄ）の配合割合が（Ａ）５〜７０重量％、（Ｃ）１〜８５重量％、（Ｄ）１０〜９４重量％であることが好ましい。かかる構成を採用することによりバリア性樹脂（Ａ）と熱可塑性樹脂（Ｄ）の相容性を向上させ、得られる樹脂組成物に安定したモルフォロジーを形成させることが可能となる。
【００７９】
相容化剤（Ｃ）としては特に限定されないが、好適な例として、エチレン含有量７０〜９９モル％、ケン化度４０％以上のエチレン−酢酸ビニル共重合体ケン化物（Ｃ１）、カルボン酸変性ポリオレフィン（Ｃ２）、ボロン酸変性ポリオレフィン（Ｃ３）などが挙げられる。これらの相容化剤（Ｃ）は単独で用いても良いし、２種以上を混合して用いてもよい。
【００８０】
また、バリア性樹脂（Ａ）、相容化剤（Ｃ）および熱可塑性樹脂（Ｄ）からなる樹脂組成物を用いるに際し、バリア性樹脂（Ａ）としてポリビニルアルコール系樹脂（Ａ１）、特に、ＥＶＯＨを用いる場合は、相容化剤（Ｃ）としてポリアミド２〜９８重量％、カルボン酸変性ポリオレフィン９８〜２重量％からなる樹脂組成物を使用することが好ましい。かかる相容化剤を用いることにより、バリア性樹脂（Ａ）と熱可塑性樹脂（Ｄ）の相容性が著しく改善され、成形部品の耐衝撃性を向上させることが可能な観点から好適である。
【００８１】
相容化剤（Ｃ）がポリアミド２〜９８重量％、カルボン酸変性ポリオレフィン９８〜２重量％からなる樹脂組成物である場合、ＥＶＯＨとの相容性の観点から、相容化剤（Ｃ）に用いられるポリアミド樹脂としては、ナイロン６成分を含むポリアミド樹脂（例えば、ナイロン−６、ナイロン−６，１２、ナイロン−６／１２、ナイロン−６／６，６等）が好ましい。ＥＶＯＨとポリアミド樹脂は高温での溶融過程で反応してゲル化する。そこで、ブレンド組成物の熱劣化を抑制する点から、ポリアミド樹脂の融点は２４０℃以下が好ましく、２３０℃以下であることが、より好ましい。
【００８２】
ＥＶＯＨとの相容化のために使用されるポリアミド樹脂の好適なメルトフローレート（ＭＦＲ）（２１０℃−荷重２１６０ｇ）は０．１〜５０ｇ／１０ｍｉｎ．、最適には０．５〜３０ｇ／１０ｍｉｎ．である。但し、融点が２１０℃付近あるいは２１０℃を超えるものは２１６０ｇ荷重下、融点以上の複数の温度で測定し、片対数グラフで絶対温度の逆数を横軸、ＭＦＲの対数を縦軸にプロットし、２１０℃に外挿した値で表す。
【００８３】
ポリアミドおよびカルボン酸変性ポリオレフィンからなる樹脂組成物を相容化剤（Ｃ）として用いる場合、使用されるカルボン酸変性ポリオレフィンとしては、ポリオレフィンと不飽和カルボン酸またはその無水物をランダム共重合して得られる重合体が好ましく、エチレンと不飽和カルボン酸またはその無水物がランダムに共重合していることがさらに望ましい。ランダム共重合体またはその金属塩がグラフト化合物よりも優れている理由は、グラフト化合物では、ポリアミドと配合した際に、バリア性樹脂（Ａ）と熱可塑性樹脂（Ｄ）との相容性を発揮するのに必要な高い酸含有量を得ることが難しいためである。さらに、不飽和カルボン酸、例えば無水マレイン酸のグラフト化合物の場合は、ＥＶＯＨ中の水酸基とグラフト共重合体中のカルボキシル基が反応して、ゲル・フィッシュアイの原因となるため、好ましくない場合がある。
【００８４】
不飽和カルボン酸の含有量は、好ましくは２〜１５モル％、さらに好ましくは３〜１２モル％である。不飽和カルボン酸としては、例えば、アクリル酸、メタアクリル酸、エタアクリル酸、マレイン酸、マレイン酸モノメチル、マレイン酸モノエチル、無水マレイン酸などが例示され、特にアクリル酸あるいはメタアクリル酸が好ましい。また、共重合体に含有されても良い他の単量体としては、酢酸ビニル、プロピオン酸ビニルのようなビニルエステル、アクリル酸メチル、アクリル酸エチル、アクリル酸イソプロピル、アクリル酸イソブチル、アクリル酸ｎ−ブチル、アクリル酸２−エチルヘキシル、メタアクリル酸メチル、メタアクリル酸イソブチル、マレイン酸ジエチルのような不飽和カルボン酸エステル、一酸炭素などが例示される。また、本発明の燃料容器に用いられる燃料容器用成形部品を製造するための樹脂組成物において、カルボン酸変性ポリオレフィンより、その金属塩がより好ましく用いられる。カルボン酸変性ポリオレフィンより、その金属塩を用いる方が優れている理由は明確でないが、金属塩の方が極性が高くなるために、ポリアミド樹脂に対する相容性が増すためと考えられる。
【００８５】
カルボン酸ポリオレフィンの金属塩における金属イオンとしては、リチウム、ナトリウム、カリウムなどのアルカリ金属、マグネシウム、カルシウムなどのアルカリ土類金属、亜鉛などの遷移金属が例示され、特に亜鉛を用いた場合がポリアミド樹脂に対する相容性の点で好ましい。カルボン酸ポリオレフィンの金属塩における中和度は、１００％以下、特に９０％以下、さらに７０％以下の範囲が望ましい。中和度の下限値については、通常５％以上、特に１０％以上、さらには３０％以上が望ましい。
【００８６】
（熱可塑性樹脂（Ｄ））
熱可塑性樹脂（Ｄ）としては、ポリオレフィン系樹脂、スチレン系樹脂、ポリ塩化ビニル系樹脂などが挙げられる。この中でも、ポリオレフィン系樹脂が成形部品の熱融着性や経済性等の観点から、特に好適である。熱可塑性樹脂（Ｄ）の溶解性パラメーターが１１を超える場合は、本発明の燃料容器用成形部品の燃料容器本体との熱融着性が不充分となる。
【００８７】
ポリオレフィン系樹脂としては、高密度もしくは低密度ポリエチレン、ポリプロピレン、ポリブテン−１などのα−オレフィンの単独重合体、エチレン、プロピレン、ブテン−１、ヘキセン−１などから選ばれたα−オレフィン同士の共重合体などが例示される。
【００８８】
この中でも、熱可塑性樹脂（Ｄ）として密度０．９３ｇ／ｃｍ^３以上のポリエチレンを用いた場合、耐衝撃性、熱融着性の改善効果が優れる観点で好適である。熱可塑性樹脂製の燃料容器本体の最外層は高密度ポリエチレンであることが多いため、かかる構成を採用することにより、特に熱融着性の改善効果が大きくなる。ポリエチレンは密度が０．９３ｇ／ｃｍ^３以上であることが好適であり、密度が０．９３ｇ／ｃｍ^３未満では、耐衝撃性等の機械強度の改善効果が不充分となる虞がある。
【００８９】
（樹脂添加物）
本発明に用いられる樹脂組成物中には、適切な添加剤（例えば、熱安定剤、可塑剤、酸化防止剤、紫外線吸収剤、着色剤など）が含まれてもよいが、これらの添加剤は、本発明の効果を阻害しない範囲で使用される。また、高級脂肪族カルボン酸の金属塩またはハイドロタルサイト化合物などを添加することは、バリア性樹脂（Ａ）がＥＶＯＨである場合に、ＥＶＯＨの熱による劣化を防ぐという観点から有効である。
【００９０】
ここで、ハイドロタルサイト化合物としては、特に、Ｍ_ｘＡｌ_ｙ（ＯＨ）_{２ｘ＋３ｙ−２ｚ}（Ａ）_ｚ・ａＨ_２Ｏ（ＭはＭｇ、ＣａまたはＺｎ、ＡはＣＯ_３またはＨＰＯ_４、ｘ、ｙ、ｚ、ａは正数）で示される複塩であるハイドロタルサイト化合物を挙げることができる。特に好適なものとして以下のハイドロタルサイト化合物が例示される。
Ｍｇ_６Ａｌ_２（ＯＨ）_１６ＣＯ_３・４Ｈ_２Ｏ
Ｍｇ_８Ａｌ_２（ＯＨ）_２０ＣＯ_３・５Ｈ_２Ｏ
Ｍｇ_５Ａｌ_２（ＯＨ）_１４ＣＯ_３・４Ｈ_２Ｏ
Ｍｇ_１０Ａｌ_２（ＯＨ）_２２（ＣＯ_３）_２・４Ｈ_２Ｏ
Ｍｇ_６Ａｌ_２（ＯＨ）_１６ＨＰＯ_４・４Ｈ_２Ｏ
Ｃａ_６Ａｌ_２（ＯＨ）_１６ＣＯ_３・４Ｈ_２Ｏ
Ｚｎ_６Ａｌ_６（ＯＨ）_１６ＣＯ_３・４Ｈ_２Ｏ
Ｍｇ_{４ . ５}Ａｌ_２（ＯＨ）_１３ＣＯ_３・３．５Ｈ_２Ｏ
【００９１】
また、ハイドロタルサイト化合物として、特開平１−３０８４３９号（ＵＳＰ４９５４５５７）に記載されているハイドロタルサイト系固溶体である、［Ｍｇ_０．７５Ｚｎ_０．２５］_０．６７Ａｌ_０．３３（ＯＨ）_２（ＣＯ_３）_{０．１６７}・０．４５Ｈ_２Ｏのようなものも用いることができる。
【００９２】
高級脂肪族カルボン酸の金属塩とは、炭素数８〜２２の高級脂肪酸の金属塩をいう。炭素数８〜２２の高級脂肪酸としては、ラウリン酸、ステアリン酸、ミリスチン酸などが挙げられる。金属としては、ナトリウム、カリウム、マグネシウム、カルシウム、亜鉛、バリウム、アルミニウムなどがあげられる。このうちマグネシウム、カルシウム、バリウム等のアルカリ土類金属が好適である。
【００９３】
これらの高級脂肪族カルボン酸の金属塩、またはハイドロタルサイト化合物の含有量は、樹脂組成物の合計重量に対して０．０１〜３重量部が好ましく、より好適には０．０５〜２．５重量部である。
【００９４】
（無機フィラーの添加）
上記バリア性樹脂（Ａ）、熱可塑性樹脂（Ｂ）のいずれかに無機フィラーを添加してから混錬してもよく、混錬時に無機フィラーを添加しても良い。無機フィラーを添加した場合、ガソリンバリア性の向上、機械強度の向上、ガソリンによる膨潤の低減に代表される耐有機溶剤性の向上などの改善効果を得ることができる。
【００９５】
本発明で用いられる無機フィラーの好ましい例としては、マイカ、セリサイト、ガラスフレークおよびタルクなどが挙げられ、特に限定されるものではない。これらの無機フィラーは単独で用いることもできるし、また複数の混合物としても用いることが出来る。
【００９６】
本発明における無機フィラーの含有量は１〜５０重量％であることが好適であり、含有量の下限はより好ましくは５重量％以上、さらに好ましくは１０重量％以上であり、最適には１５重量％以上である。また、含有量の上限はより好ましくは４５重量％以下であり、更に好ましくは４０重量％以下である。１重量％未満の場合、機械強度やガソリンバリア性の向上などの改善効果が不満足なものとなる虞がある。一方、５０重量％を超える場合は成形時に流動異常が生じ易くなり、ヒケ、ウェルドライン等の原因となり、外観良好な成形品を得ることが出来ない虞がある。
【００９７】
本発明の燃料容器は、上記バリア性樹脂（Ａ）および熱可塑性樹脂（Ｂ）、あるいは、バリア性樹脂（Ａ）、相容化剤（Ｃ）、および熱可塑性樹脂（Ｄ）を適宜組合せて配合してなる成形部品が燃料容器本体に装着されている。以下、まず、燃料容器に装着する成形部品について説明する。
【００９８】
（成形部品）
燃料容器に装着する成形部品は、上記バリア性樹脂（Ａ）５〜７０重量％および熱可塑性樹脂（Ｂ）３０〜９５重量％からなる樹脂組成物を成形して得られる。より好適にはバリア性樹脂（Ａ）１０〜６０重量％および熱可塑性樹脂（Ｂ）４０〜９０重量％であり、さらに好適にはバリア性樹脂（Ａ）２０〜５０重量％および熱可塑性樹脂（Ｂ）５０〜８０重量％である。
【００９９】
このような成形部品を用いることにより、ガソリンバリア性、機械強度、および燃料容器本体との熱融着性において優れる燃料容器が得られる。
【０１００】
バリア性樹脂（Ａ）が５重量％未満の場合および熱可塑性樹脂（Ｂ）が９５重量％を超える場合は、成形部品のガソリンバリア性の改善効果が不充分となる虞がある。また、バリア性樹脂（Ａ）が７０重量％を超える場合および熱可塑性樹脂（Ｂ）が３０重量％未満の場合、成形部品の耐衝撃性、耐疲労性および熱融着性などが不満足となる虞がある。
【０１０１】
本発明に用いられる成形部品においては、バリア性樹脂（Ａ）が連続相、熱可塑性樹脂（Ｂ）が分散相となる樹脂組成物を用いる場合、燃料容器本体との熱融着性、耐衝撃性および耐疲労性などの改善効果が不充分となる虞がある。本発明に用いられる燃料容器用成形部品は、バリア性樹脂（Ａ）と熱可塑性樹脂（Ｂ）の双方が連続相を形成している樹脂組成物、あるいはバリア性樹脂（Ａ）が分散相、熱可塑性樹脂（Ｂ）が連続相となる樹脂組成物を用いることが好適であり、バリア性樹脂（Ａ）が分散相、熱可塑性樹脂（Ｂ）が連続相となる樹脂組成物を用いることが、バリア性と機械強度を両立させる観点から、特に好ましい。
【０１０２】
成形部品が、バリア性樹脂（Ａ）と熱可塑性樹脂（Ｂ）を配合してなる樹脂組成物からなる場合、熱可塑性樹脂（Ｂ）が相容化剤（Ｃ）および（Ｃ）以外の１１以下の溶解性パラメーター（Ｆｅｄｏｒｓの式から算出）を有する熱可塑性樹脂（Ｄ）からなり、かつ成分（Ａ）、（Ｃ）および（Ｄ）の配合割合が（Ａ）５〜７０重量％、（Ｃ）１〜８５重量％、（Ｄ）１０〜９４重量％であることが好ましい。かかる構成を採用することによりバリア性樹脂（Ａ）層と熱可塑性樹脂（Ｄ）の相容性を向上させ、得られる樹脂組成物に安定したモルフォロジーを形成させることが可能となる。
【０１０３】
バリア性樹脂（Ａ）が５重量％未満の場合は、成形部品のガソリンバリア性の改善効果が不充分なものとなる虞がある。また、バリア性樹脂（Ａ）が７０重量％を超える場合、成形部品の耐衝撃性、耐疲労性および熱融着性などが不充分なものとなる虞がある。
【０１０４】
相容化剤（Ｃ）が１重量％に満たない場合、バリア性樹脂（Ａ）と熱可塑性樹脂（Ｄ）の相容化効果が不満足なものになる虞がある。相容化剤（Ｃ）が８５重量％を超える場合は、樹脂組成物全体量のうち、バリア性樹脂（Ａ）と熱可塑性樹脂（Ｄ）の比率が低下するため、本来バリア性樹脂の有するバリア性や熱可塑性樹脂（Ｄ）の有する溶融成形性、機械強度、熱融着性等の性能が低下する虞がある。
【０１０５】
熱可塑性樹脂（Ｄ）が１０重量％に満たない場合、溶融成形性、機械強度、熱融着性等の改善効果が不満足となる虞がある。熱可塑性樹脂（Ｄ）としてはポリオレフィンである場合が好ましい。ポリオレフィンが１０重量％に満たない場合は、ポリオレフィンが有する力学特性、熱融着性が不充分である他、経済性の観点から見た優位性を充分に享受できない虞がある。また、熱可塑性樹脂（Ｄ）が９４重量％を超える場合は、成形部品のガソリンバリア性の改善効果が不充分なものとなる虞がある。
【０１０６】
本発明の燃料容器用成形部品においては、バリア性樹脂（Ａ）が連続相、相容化剤（Ｃ）および熱可塑性樹脂（Ｄ）が分散相となる樹脂組成物を用いる場合、燃料容器本体との熱融着性、耐衝撃性および耐疲労性などの改善効果が不充分となる虞がある。本発明の燃料容器用成形部品は、バリア性樹脂（Ａ）と相容化剤（Ｃ）および／または熱可塑性樹脂（Ｄ）のいずれもが連続相を形成している樹脂組成物、あるいはバリア性樹脂（Ａ）が分散相、相容化剤（Ｃ）および／または熱可塑性樹脂（Ｄ）が連続相となる樹脂組成物を用いることが好適であり、バリア性樹脂（Ａ）が分散相、相容化剤（Ｃ）および／または熱可塑性樹脂（Ｄ）が連続相となる樹脂組成物を用いることが、バリア性と機械強度を両立させる観点から、特に好ましい。
【０１０７】
また、バリア性樹脂（Ａ）としてＥＶＯＨを、相容化剤（Ｃ）としてポリアミド樹脂（Ｃ４）およびカルボン酸変性ポリオレフィン（好適にはその金属塩）（Ｃ２）を用いる場合は、バリア性樹脂（Ａ）、相容化剤（Ｃ）および熱可塑性樹脂（Ｄ）の配合重量比は下記式（１）〜（４）を満足するものである。
０．６≦Ｗ（Ａ＋Ｄ）／Ｗ（Ｔ）≦０．９９５ （１）
０．００５≦Ｗ（Ｃ４＋Ｃ２）／Ｗ（Ｔ）≦０．４ （２）
０．５≦Ｗ（Ｄ）／Ｗ（Ａ＋Ｄ）≦０．９９ （３）
０．０２≦Ｗ（Ｃ４）／Ｗ（Ｃ４＋Ｃ２）≦０．９８ （４）
（但し、Ｗ（Ａ＋Ｄ）；組成物中の（Ａ）と（Ｄ）との合計重量
Ｗ（Ｃ４）；組成物中のポリアミド（Ｃ４）の重量
Ｗ（Ｃ４＋Ｃ２）；組成物中のポリアミド（Ｃ４）とカルボン酸変性ポリオレフィン（Ｃ２）との合計重量
Ｗ（Ｄ）；組成物中の（Ｄ）の重量
Ｗ（Ｔ）；組成物の合計重量）。
好適には、
０．６５≦Ｗ（Ａ＋Ｄ）／Ｗ（Ｔ）≦０．９９ （１’）
０．０１≦Ｗ（Ｃ４＋Ｃ２）／Ｗ（Ｔ）≦０．３５ （２’）
０．５５≦Ｗ（Ｄ）／Ｗ（Ａ＋Ｄ）≦０．９８ （３’）
０．０４≦Ｗ（Ｃ４）／Ｗ（Ｃ４＋Ｃ２）≦０．９６ （４’）
であり、より好適には、
０．７０≦Ｗ（Ａ＋Ｄ）／Ｗ（Ｔ）≦０．９８５ （１”）
０．０１５≦Ｗ（Ｃ４＋Ｃ２）／Ｗ（Ｔ）≦０．３０ （２”）
０．６≦Ｗ（Ｄ）／Ｗ（Ａ＋Ｄ）≦０．９７ （３”）
０．０５≦Ｗ（Ｃ４）／Ｗ（Ｃ４＋Ｃ２）≦０．９５ （４”）
である。
【０１０８】
Ｗ（Ａ＋Ｄ）／Ｗ（Ｔ）が０．９９５を超える場合あるいはＷ（Ｃ４＋Ｃ２）／Ｗ（Ｔ）が０．００５未満の場合には、ＥＶＯＨ（Ａ）と熱可塑性樹脂（Ｄ）との相容性が低下し、本発明の効果が得られない。また、 Ｗ（Ａ＋Ｄ）／Ｗ（Ｔ）が０．６未満の場合、あるいはＷ（Ｃ４＋Ｃ２）／Ｗ（Ｔ）が０．４を超える場合には、組成物全体の量のうちＥＶＯＨ（Ａ）と熱可塑性樹脂（Ｄ）の比率が低下するため、本来ＥＶＯＨ（Ａ）の有するバリア性や熱可塑性樹脂（Ｄ）の有する溶融成形性等の性能が低下する虞がある。
【０１０９】
また、 Ｗ（Ｃ４）／Ｗ（Ｃ４＋Ｃ２）が０．０２未満の場合、ＥＶＯＨ（Ａ）とポリアミド樹脂（Ｃ４）の相容性が低下し、 Ｗ（Ｃ４）／Ｗ（Ｃ４＋Ｃ２）が０．９８を超える場合、カルボン酸変性ポリオレフィン（Ｃ２）と熱可塑性樹脂（Ｄ）との相容性が低下する。各成分間の相容性の低下は、樹脂組成物自身の機械強度、あるいはバリア性の低下につながる。
【０１１０】
また、ポリアミド樹脂（Ｃ４）とカルボン酸変性ポリオレフィン（Ｃ２）との配合重量比Ｗ（Ｃ４）／Ｗ（Ｃ４＋Ｃ２）が、０．５以下であることが、熱安定性の観点から好ましく、より好適には０．４５以下であり、最適には０．４以下である。配合重量比Ｗ（Ｃ４）／Ｗ（Ｃ４＋Ｃ２）がかかる範囲にあることで、樹脂組成物の溶融安定性が改善され、長時間におよぶ溶融成形においても良好な外観の成形物を得ることができ、生産性が向上する。この理由は明らかではないが、ＥＶＯＨとポリアミド樹脂との反応が溶融安定性に悪影響を与えているものと考えられる。
【０１１１】
本発明に用いられる燃料容器用成形部品は、 熱可塑性樹脂（Ｄ）が連続相、 ＥＶＯＨ（Ａ）が分散相となる樹脂組成物を用いることが好ましい。このような樹脂組成物を成形することにより機械強度、耐衝撃性を保持しながら、ガソリンバリア性が改善された燃料容器用成形部品が得られる。このような分散形態を得るためには、Ｗ（Ｄ）／Ｗ（Ａ＋Ｄ）の値を大きくするか、あるいは（Ａ）／（Ｄ）の溶融粘度比を大きくすればよい。Ｗ（Ｄ）／Ｗ（Ａ＋Ｄ） の値は０．５以上、０．９９以下の範囲、好ましくは０．５５以上、０．９８以下、更に好ましくは、０．６以上０．９７以下である。 Ｗ（Ｄ）／Ｗ（Ａ＋Ｄ） の値が０．５未満の場合には、 熱可塑性樹脂（Ｄ）が連続相を形成しにくくなり、耐衝撃性が不足する虞がある。Ｗ（Ｄ）／Ｗ（Ａ＋Ｄ） の値が０．９９を超える場合は、ガソリンバリア性が不足する虞がある。
【０１１２】
（樹脂組成物の混錬方法）
本発明に用いられる樹脂組成物は、通常の溶融混錬装置により各成分を溶融混合することにより容易に得ることができる。各成分をブレンドする方法は特に限定されるものではないが、バリア性樹脂（Ａ）、熱可塑性樹脂（Ｂ）、相容化剤（Ｃ）、熱可塑性樹脂（Ｄ）を適宜組合せて、単軸または二軸スクリュー押出機などで溶融混錬し、ペレット化し乾燥する方法等が挙げられる。また、バリア性樹脂（Ａ）のペレットと熱可塑性樹脂（Ｂ）のペレットを成形機に投入し、成形機内で混練することも可能である。溶融配合操作においては、ブレンドが不均一になったり、ゲル、ブツが発生、混入したりする可能性があるので、ブレンドペレット化はなるべく混練度の高い押出機を使用し、ホッパー口を窒素ガスでシールし、低温で押出しすることが望ましい。
【０１１３】
本発明に用いる成形部品を得る方法としては、例えば、一般のポリオレフィンの分野における適切な成形方法を用いることができるが、特に限定されない。しかし、コネクター、キャップ、バルブなどに例示される燃料容器用成形部品は、一般に形状が複雑であるため、燃料容器用成形部品の一部もしくは全部が射出成形法で成形されてなることが特に好ましい。
【０１１４】
（成形部品および成形部品が装着された燃料容器本体）
本発明の燃料容器は、ガソリンのみならず、アルコール含有ガソリン、ＭＴＢＥ含有ガソリンなどの、いわゆる含酸素ガソリンを好適に収納できる容器であり、燃料容器本体とこの燃料容器本体に装着された成形部品からなる。
【０１１５】
燃料容器本体は、好ましくは熱可塑性樹脂製であり、通常、中間層にバリア性樹脂層を有する多層構造の樹脂からなり、最外層にはポリオレフィン層が配置されていることが、燃料容器の機械強度などの点から好ましい。バリア性樹脂層としては、好適にはＥＶＯＨが用いられ、エチレン含有量５〜６０モル％、ケン化度９０％以上であるＥＶＯＨが好ましい。最外層のポリオレフィンとしては、高密度ポリエチレンであることが好ましい。
【０１１６】
本発明に用いられる成形部品は、燃料容器本体に装着されて用いられる成形部品をいい、具体的には、燃料容器用コネクター、燃料容器用キャップ、燃料容器用バルブなどが挙げられるが、これに限定されない。好ましくは、燃料容器用コネクター、燃料容器用バルブである。
【０１１７】
これらの成形部品を燃料容器本体に装着する方法は特に限定されず、ねじ込み式、填め込み式による装着、および熱融着による装着が例示されるが、熱融着による装着が組み付け工数の減少および装着部分からの燃料漏れの抑制という観点から、特に好ましい。熱融着には一般的な手法が用いられ、ヒーターなどにより燃料容器本体および／または燃料容器用成形部品の融着面を加熱した後、融着を行う方法、燃料容器本体と当該成形部品を高周波融着する方法、および燃料容器本体と当該成形部品を超音波融着する方法などが例示されるが、これらに限定されない。
【０１１８】
コネクターとしての成型部品の使用態様としては、燃料容器本体に装着された燃料容器用コネクターとして使用する態様、さらにフレキシブルな燃料輸送用のパイプが装着される態様などが挙げられるが、これらに限定されない。このコネクターを燃料容器本体に装着する方法としては、ねじ込み式、填め込み式、熱融着による接合などが例示されるが、組み付け工数の減少および接合部分からの燃料漏れの抑制という観点から、熱融着により装着されることが好ましい。そのため、このコネクターは燃料容器本体との熱融着性に優れていることが特に好ましい。また、燃料容器本体とこのコネクターの装着部分からの燃料漏れを抑制するために、コネクターはガソリンバリア性に優れていることが特に好適である。さらに、コネクターは耐ストレスクラック特性、耐有機溶剤性に優れていることが、燃料容器用成形部品の長期連続使用性、すなわち製品寿命の観点から好適である。
【０１１９】
また、燃料容器用コネクターとしての好適な実施態様としては、燃料容器本体に接合された燃料容器用コネクターに、さらにフレキシブルな燃料輸送用のパイプが接合される。このため、車両走行時や、燃料容器からエンジンへの燃料の供給時、あるいは燃料供給口から燃料容器への燃料の受け入れ時など、燃料容器そのものの振動あるいは輸送パイプの振動によるコネクターへの連続的負荷が発生する。これらの観点から、燃料容器用コネクターは、耐衝撃性、耐ストレスクラック性、耐有機溶剤性に優れていることが望ましい。
【０１２０】
燃料容器用キャップは、給油口の閉蓋具として用いられる。その接合方法は特に限定されないが、ねじ込み式、填め込み式などが例示され、好ましくはねじ込み式である。現在、多くの燃料容器用キャップは金属製であるが、軽量化、リサイクルなどの観点から熱可塑性樹脂製のキャップが近年注目を集めている。また、給油口は給油管、燃料容器用コネクターを経て燃料容器本体と繋がっているが、従来、金属製の燃料容器用キャップから発生する錆による金属酸化物の燃料容器への混入が問題となっている。かかる観点からも、熱可塑性樹脂からなるキャップの存在意義は大きい。かかる燃料容器用キャップはガソリンバリア性、耐有機溶剤性、耐ストレスクラック特性に優れていることが好ましく、開閉を繰り返すことから、耐摩耗性等の機械強度にも優れていることがさらに好ましい。
【０１２１】
また、熱硬化性樹脂（Ｅ）からなる部品が、成形部品が装着された燃料容器本体に、成形部品を介して装着されてなる燃料容器も、本発明の実施態様として好適である。上記構成の燃料容器は、熱硬化性樹脂（Ｅ）からなる部品が機械強度および優れたガソリンバリア性を有し、かつ熱硬化性樹脂（Ｅ）からなる部品と燃料容器本体との装着部分に本発明の樹脂組成物からなる成形部品を介在させることにより、高いガソリンバリア性を付与することが出来る点で好適である。熱硬化性樹脂（Ｅ）としては、機械強度、ガソリンバリア性などの観点からポリメチレンオキサイド系樹脂を用いることが特に好適である。かかる構成によって燃料容器に装着される燃料容器用成形部品は特に限定されないが、燃料容器用圧抜きバルブが好適である。
【０１２２】
熱硬化性樹脂（Ｅ）からなる部品が、成形部品を介して燃料容器に装着される方法は特に限定されない。まず、燃料容器本体に成形部品を装着し、次にこの成形部品に熱硬化性樹脂（Ｅ）からなる燃料容器用部品をねじ込み式あるいは填め込み式などの方法で装着する方法、または、まず、熱硬化性樹脂（Ｅ）からなる部品に上記成形部品を装着し、ついで、これを燃料容器本体に装着する方法などが例示されるが、特に限定されない。
【０１２３】
成形部品を燃料容器本体に装着する方法は特に限定されない。ねじ込み式、填め込み式による装着、および熱融着による装着が例示されるが、熱融着による装着が組み付け工数の減少および装着部分からの燃料漏れの抑制という観点から、特に好ましい。
【０１２４】
熱硬化性樹脂（Ｅ）からなる部品に、成形部品を装着する方法は特に限定されない。ねじ込み式、填め込み式による方法が好適である。また、熱硬化性樹脂（Ｅ）からなる部品と燃料容器との接合面を本発明に用いる樹脂組成物で被覆する方法も好適である。熱硬化性樹脂（Ｅ）と本発明で用いられる樹脂組成物は一般的に接着性が小さいことから、熱硬化性樹脂（Ｅ）からなる部品の表面を、成形部品の機能を阻害しない範囲内で出来るだけ本発明に用いる樹脂組成物で被覆することが特に好適である。かかる構成を採用することにより、熱硬化性樹脂（Ｅ）からなる成形部品本体と、本発明の樹脂組成物との界面の剥離を抑制することが可能である。
【０１２５】
また、成形部品本体を、本発明に用いる樹脂組成物で被覆する方法は特に限定されないが、先に射出成形法などで作成した熱硬化性樹脂（Ｅ）からなる部品本体を金型内に設置し、これに射出成形機にて本発明の樹脂組成物を射出して被覆する方法（インサートインジェクション法）、あるいは熱硬化性樹脂（Ｅ）および本発明に用いる樹脂組成物を共射出成形する方法などが好適なものとして挙げられるが、インサートインジェクション法が特に好適である。
【０１２６】
【実施例】
以下、実施例により本発明を更に詳細に説明するが、本発明はこの実施例に限定されるものではない。
【０１２７】
（使用材料）
参考例１〜４、実施例５〜１１および比較例１〜１０の成形部品の製造に用いた樹脂成分を以下の表１に示す。
【０１２８】
【表１】

【０１２９】
（本発明に使用する樹脂の合成）
（合成例１）
表１のボロン酸変性ポリエチレン（b-3）（末端にボロン酸エチレングリコールエステル基を有するポリエチレン）は、以下のように調製した。
【０１３０】
冷却器、撹拌機および滴下ロート付きセパラブルフラスコにポリエチレン｛ＭＦＲ０．３ｇ／１０分（２１０℃−荷重２１６０ｇ）密度０．９０ｇ／ｃｍ^３、末端二重結合量０．０４８ｍｅｑ／ｇ｝１０００ｇ、デカリン２５００ｇを仕込み、室温で減圧することにより脱気を行った後、窒素置換を行った。これにホウ酸トリメチル７８ｇ、ボラン−トリエチルアミン錯体５．８ｇを添加し、２００℃で４時間反応後、蒸留器具を取り付け、さらにメタノール１００ｍｌをゆっくり滴下した。メタノール滴下終了後、減圧蒸留により、メタノール、ホウ酸トリメチル、トリエチルアミン等の低沸点の不純物を留去した。さらにエチレングリコール３１ｇを添加し、１０分間撹拌後、アセトンに再沈し、乾燥することにより、ボロン酸エチレングリコールエステル基量０．０２７ｍｅｑ／ｇ、ＭＦＲ０．２ｇ／１０分のボロン酸変性ポリエチレン（b-3）を得た。
【０１３１】
（合成例２）
表１のボロン酸変性超低密度ポリエチレン（c-3）（末端にボロン酸エチレングリコールエステル基を有する超低密度ポリエチレン）は、以下のように調製した。
【０１３２】
冷却器、撹拌機および滴下ロート付きセパラブルフラスコに超低密度ポリエチレン｛ＭＦＲ７ｇ／１０分（２１０℃−荷重２１６０ｇ）密度０．８９ｇ／ｃｍ^３、末端二重結合量０．０４８ｍｅｑ／ｇ｝１０００ｇ、デカリン２５００ｇを仕込み、室温で減圧することにより脱気を行った後、窒素置換を行った。これにホウ酸トリメチル７８ｇ、ボラン−トリエチルアミン錯体５．８ｇを添加し、２００℃で４時間反応後、蒸留器具を取り付けさらにメタノール１００ｍｌをゆっくり滴下した。メタノール滴下終了後、減圧蒸留により、メタノール、ホウ酸トリメチル、トリエチルアミン等の低沸点の不純物を留去した。さらにエチレングリコール３１ｇを添加し、１０分間撹拌後、アセトンに再沈し、乾燥することにより、ボロン酸エチレングリコールエステル基量０．０２７ｍｅｑ／ｇ、ＭＦＲ５ｇ／１０分（２１０℃−荷重２１６０ｇ）のボロン酸変性超低密度ポリエチレン（c-3）を得た。
【０１３３】
（使用樹脂の燃料透過量の測定）
バリア性樹脂（Ａ）の燃料透過量の測定は、以下の（１）〜（５）の工程で行った。
（１）高密度ポリエチレン（ＨＤＰＥ）としてＰａｘｏｎ製ＢＡ−０５５（密度０．９７０ｇ／ｃｍ^３、１９０℃−荷重２１６０ｇにおけるＭＦＲ＝０．０３ｇ／１０分）を、接着性樹脂（Ｔｉｅ）として三井化学製ＡＤＭＥＲ ＧＴ−６ＡＭＦＲ０．９４ｇ／１０分（１９０℃−荷重２１６０ｇ）を用い、高密度ポリエチレン、バリア性樹脂（Ａ）、接着性樹脂を別々の押出機に仕込み、高密度ポリエチレン／接着性樹脂／バリア性樹脂（Ａ）／接着性樹脂／高密度ポリエチレン（膜厚み５０μｍ／５μｍ／１０μｍ／５μｍ／５０μｍ）の構成を有する全層厚み１２０μｍの共押出シートを成形装置により得た。押出成形は高密度ポリエチレンが直径６５ｍｍ、Ｌ／Ｄ＝２４の一軸スクリューを備えた押出機を１７０〜２１０℃の温度とし、接着性樹脂は直径４０ｍｍ、Ｌ／Ｄ＝２２ｍｍの一軸スクリューを備えた押出機を１６０〜２１０℃の温度とし、バリア性樹脂（Ａ）は直径４０ｍｍ、Ｌ／Ｄ＝２２の一軸スクリューを備えた押出機を１７０〜２１０℃の温度とし、フィードブロック型ダイ（幅６００ｍｍ）を２１０℃で運転し、共押出シート（ａ１）を得た。
（２）該共押出シート（ａ１）の片面をアルミテープ（エフピー化工株式会社製、商品名アルミシール：ガソリンバリア性＝０ｇ・２０μｍ／ｍ^２・ｄａｙ）を用いて被覆した。
（３）該共押出シート（ａ１）およびアルミテープで被覆した共押出シート（ｂ１）をそれぞれ２１０ｍｍ×３００ｍｍの大きさにカットした。
（４）カットしたそれぞれのシートを中央で折り曲げ、二辺を、富士インパルス製ヒートシーラーＴ−２３０を使用し、ダイヤル６にてシール幅１０ｍｍになるようにヒートシールし、パウチを作製した。
（５）それぞれのパウチにモデルガソリンとしてＲｅｆ．Ｃ（トルエン／イソオクタン＝１／１）をシールされていない辺より２００ｍｌ充填し、投入辺を上述した方法と同様にシール幅１０ｍｍとなるようにヒートシールした。
【０１３４】
該燃料投入パウチを防爆型恒温恒湿槽（４０℃−６５％ＲＨ）に放置し、７日おきに３ヶ月間パウチの重量を測定した。かかる試験を、アルミ箔なしの共押出パウチ（ａ２）およびアルミテープで被覆した共押出パウチ（ｂ２）それぞれ５個のパウチについて行い、放置前と各放置時間後の該パウチの重量変化を読みとり、放置時間とパウチの重量変化量の傾きから燃料透過量を算出した。
【０１３５】
アルミテープなしの共押出パウチ（ａ２）の燃料透過量はパウチ表面とヒートシール部の双方からの燃料透過量の和を示し、アルミテープで被覆した共押出パウチ（ｂ２）の燃料透過量はヒートシール部分からの燃料透過量を示す。
【０１３６】
｛（ａ２）からの透過量｝−｛（ｂ２）からの透過量｝をバリア性樹脂（Ａ）の燃料透過量とし、バリア性樹脂（Ａ）層２０μｍあたりの透過量に厚み換算をしてバリア性樹脂（Ａ）の燃料透過量（ｇ・２０μｍ／ｍ^２・ｄａｙ）を求めた。
【０１３７】
Ａ．単層成形部品の製造例１
（参考例１〜４、比較例１〜４）
参考例１
エチレン含量４４モル％、ＭＦＲ１．３ｇ／１０分（１９０℃−荷重２１６０ｇ）のＥＶＯＨ（a-1）４０重量部、ＭＦＲ１．１ｇ／１０分（１９０℃−荷重２１６０ｇ）、密度０．９５４ｇ／ｃｍ^３のポリエチレン（b-1）６０重量部からなるブレンド物を以下の方法で得た。即ち、ＥＶＯＨ（a-1）と密度０．９５４ｇ／ｃｍ^３のポリエチレン（b-1）を二軸スクリュータイプのベント式押出機に入れ、窒素の存在下２２０℃で押出しペレット化を行い樹脂組成物のペレットを得た。
【０１３８】
得られたペレットを射出成形機に仕込み、図１の形状を有する、内径６３ｍｍ、外径７０ｍｍ、高さ４０ｍｍの円筒状単層射出成形品を作製した。この成形品は燃料容器用コネクター類似の形状（以下、コネクター様成形品という）を有し、図２に示されるように、コネクター様成形品１は、容器本体２に取り付けられ、コネクター様成形品１の口部にパイプ３が取り付けられる。一方、高密度ポリエチレン（ＨＤＰＥ：三井化学製ＨＺ８２００Ｂ）を内外層とし、更に接着性樹脂（無水マレイン酸変性ＬＤＰＥ、三井化学製アドマーＧＴ５Ａ）を用い、３種５層のダイレクトブロー成形機にて容量３５リットル、表面積０．８５ｍ^２のＥＶＯＨ系多層燃料容器を作製した。本燃料容器の層構成は、（外）ＨＤＰＥ／接着性樹脂／ＥＶＯＨ（a-1）／接着性樹脂／ＨＤＰＥ（内）＝２５００／１００／１５０／１００／２５００（μｍ）であった。また機械強度などの性能を評価するため、上記ペレットを用いて縦１０ｃｍ、横１０ｃｍ、厚み５ｍｍの平板および各種試験用射出片を成形した。
【０１３９】
本燃料容器にコネクター装着のための直径５５ｍｍの孔を二箇所あけた後、その部分および上記作製した図１の単層射出成形品の双方を２５０℃の鉄板で４０秒融解させた後に圧着して熱融着させて、多層燃料容器を得た。得られた本単層射出成形品を２個融着させた多層燃料容器を用いて、以下の方法でガソリンバリア性および接着強度を評価した。また上記ペレットを用いて成形した平板および試験用射出片を用いて、以下の方法で耐衝撃性、耐ストレスクラッキング性、耐有機溶剤性を評価した。結果を表２に示す。
【０１４０】
（１）ガソリンバリア性
上記の方法で得られた、開口部を有する本単層射出成形品を２個融着させた多層燃料容器に、２５リッターのモデルガソリン（トルエン：イソオクタン＝５０／５０体積％）を充填した。次いで、本単層射出成形品の片側に直径８０ｍｍ、厚さ０．５ｍｍのアルミ板をエポキシ系接着剤にて強固に接着させた後、防爆型恒温恒湿槽（４０℃−６５％ＲＨ）にて４週間後の重量減少量（ｎ＝５）を測定し、本単層射出成形品を２個融着させた多層燃料容器からの燃料透過量（ｇ／ｐｋｇ・４ｗｅｅｋｓ）を求めた。
【０１４１】
（２）接着強度
燃料容器に溶着したコネクターに太さ２ｍｍの鉤型の針金をとりつけ、コネクターが下側になるように燃料容器を逆さまにして針金を下方に垂らし、針金の先に重さ２０ｋｇの錘をゆっくりと取り付けて、接着部の破壊が起きるかどうかを観察し、以下の基準にて判定した。

【０１４２】
（３）耐衝撃性
樹脂組成物を射出成形して得られた平板サンプル（ｎ＝５）を２０℃−６５％ＲＨに２週間放置した後、アイゾット試験機を用いてＪＩＳ Ｋ７１１０に準じて衝撃強度を求めた。
【０１４３】
（４）耐ストレスクラック特性
樹脂組成物を射出成形して得られた規定の試験片（ｎ＝１０）を２０℃−６５％ＲＨに２週間放置した後、水中にてＪＩＳ Ｚ１７０３に準じてストレスクラッキング特性（時間）を測定した。
【０１４４】
（５）耐有機溶剤性
樹脂組成物を射出成形して得られた円板サンプル（ｎ＝５）を２０℃−６５％ＲＨに２週間放置した後、モデルガソリン（トルエン：イソオクタン＝５０／５０体積％）中にてＪＩＳ Ｋ７１１４に従い膨潤度を測定し、外観を観察した。
外観は、以下の基準で判定した。

【０１４５】
参考例２〜４、比較例１〜４
表１に記載のバリア性樹脂（Ａ）(a-1)、(a-2)と熱可塑性樹脂（Ｂ）（b-1）、（b-2）および(b-3)とを、表２に記載の配合割合で含有する樹脂組成物を作製し、参考例１と同様にコネクター様成形品を作製し、参考例１と同様に評価した。結果を表２に示す。
【０１４６】
【表２】

【０１４７】
参考例１〜４で得られた本発明の燃料容器用成形部品は、ガソリンバリア性および耐衝撃性に優れ、熱融着性、耐ストレスクラック性、耐有機溶剤性も充分であった。中でも、熱可塑性樹脂（Ｂ）として、カルボン酸変性ポリオレフィンあるいはボロン酸変性ポリオレフィンを用いた場合は、優れた耐衝撃性と耐ストレスクラック性を備え、かつ、ガソリンバリア性と耐有機溶剤性が顕著に改善されている点から、特に好適であった。
【０１４８】
バリア性樹脂（Ａ）が５重量％未満の比較例３およびバリア性樹脂（Ａ）を含まない熱可塑性樹脂（Ｂ）のみの比較例２は、ガソリンバリア性が極端に悪かった。また、バリア性樹脂（Ａ）のみからなる比較例１および熱可塑性樹脂（Ｂ）が３０重量％に満たない比較例４では、熱融着性が不合格であった。
Ｂ．単層成形部品の製造例２
【０１４９】
（実施例５〜８、比較例５〜９）
この実施例５〜８は、熱可塑性樹脂（Ｂ）として相容化剤（Ｃ）と熱可塑性樹脂（Ｄ）とを用いる、単層の成形部品の製造を示す実施例である。
【０１５０】
バリア性樹脂（Ａ）の燃料透過量の測定は、前記と同様に行った。
【０１５１】
熱可塑性樹脂（Ｄ）のガソリンバリア性の測定は、以下の方法で行った。
（１）東洋精機製ラボプラストミル（直径２０ｍｍ、Ｌ／Ｄ＝２２）を使用し、３００ｍｍ幅のコートハンガーダイを用い、熱可塑性樹脂（Ｃ）の融点＋２０℃にて押し出し、１００μｍシートを作製し、該シートを２１０ｍｍ×３００ｍｍの大きさにカットした。
（２）カットしたシートを中央で折り曲げ、二辺を、富士インパルス製ヒートシーラーＴ−２３０を使用し、ダイヤル６にてシール幅１０ｍｍになるようにヒートシールし、パウチを作製した。
（３）該パウチにモデルガソリンとしてＲｅｆ．Ｃ（トルエン／イソオクタン＝１／１）をシールされていない辺より２００ｍｌ充填し、投入辺を上述した方法と同様にシール幅１０ｍｍとなるようにヒートシールした。
（４）該燃料投入パウチを防爆型恒温恒湿槽（４０℃−６５％ＲＨ）に放置し、６時間置きに３日間パウチの重量を測定した。かかる試験を５個のパウチについて行い、放置前と各放置時間後の該パウチの重量変化を読みとり、放置時間とパウチの重量変化量の傾きから該パウチの燃料透過量を求め、厚み換算により熱可塑性樹脂（Ｃ）の燃料透過量（ｇ・２０μｍ／ｍ^２・ｄａｙ）を算出した。
【０１５２】
実施例５
エチレン含量４４モル％、ケン化度９９．５％、ＭＦＲ１．３ｇ／１０分（１９０℃−２１６０ｇ）のＥＶＯＨ（a-1）３０重量部、エチレン含量８９モル％、ケン化度９７％、ＭＦＲ５ｇ／１０分（１９０℃−荷重２１６０ｇ）のエチレン−酢酸ビニル共重合体ケン化物（c-1）１５重量部およびＭＦＲ１．１ｇ／１０分（１９０℃−荷重２１６０ｇ）の密度０．９５４ｇ／ｃｍ^３のポリエチレン（ｄ-1）５５重量部からなる樹脂組成物を以下の方法で得た。即ち、ＥＶＯＨ（a-1）とエチレン含量８９モル％、ケン化度９７モル％のエチレン−酢酸ビニル共重合体ケン化物（c-1）および密度０．９５４ｇ／ｃｍ^３のポリエチレン（ｄ-1）を二軸スクリュータイプのベント式押出機に入れ、窒素の存在下２２０℃で押出しペレット化を行い樹脂組成物のペレットを得た。
【０１５３】
得られた樹脂ペレットを参考例１と同様にして、平板、各種試験用射出片、および図１に示す形状のコネクター様の円筒状単層射出成形品を装着した燃料容器（図２）を作製し、ガソリンバリア性、接着強度、耐衝撃性、耐ストレスクラック性、耐有機溶剤性を測定した。結果を表３に示す。
【０１５４】
実施例６〜８、比較例５〜８
表１に記載のバリア性樹脂（Ａ）(a-1)、（a-2)、相容化剤（C）（c-1）、（c-2）、（c-3）と熱可塑性樹脂（Ｄ）（d-1）を、表３に記載の配合割合で含有する樹脂組成物を作製し、参考例１と同様にコネクター様成形品を作製し、参考例４と同様に評価した。結果を表３に示す。
【０１５５】
【表３】

【０１５６】
実施例５〜８で得られた燃料容器用成形部品は、ガソリンバリア性及び耐衝撃性に優れ、熱融着性、耐ストレスクラック特性、耐有機溶剤性も充分であった。中でも、相容化剤（Ｃ）としてカルボン酸変性ポリオレフィン（Ｃ２）としてエチレン−メタクリル酸ランダム共重合体（c-2)あるいはボロン酸変性ポリオレフィン（c-3）を用いた場合は、優れた耐衝撃性と耐ストレスクラック性を備え、かつ、ガソリンバリア性と耐有機溶剤性が顕著に改善されている点から、特に好適であった。バリア性樹脂（Ａ）が５重量％未満の比較例８およびバリア性樹脂（Ａ）を含まない熱可塑性樹脂（Ｄ）のみの比較例６は、ガソリンバリア性が極端に悪かった。また、バリア性樹脂（Ａ）のみからなる比較例５およびバリア性樹脂（Ａ）が７０重量％を越える比較例７では、熱融着性が不合格であった。
【０１５７】
Ｃ．単層成形部品の製造例３
この実施例は、相容化剤（Ｃ）としてポリアミド樹脂とカルボン酸変性ポリオレフィンとからなる樹脂組成物を用いた、単層成形部品の製造例である。
【０１５８】
実施例９
ＥＶＯＨ（a-2）３０重量部、ポリアミド樹脂（f-1）５重量部、エチレン−メタクリル酸ランダム共重合体（ＥＭＡＡ；c-4）１０重量部および高密度ポリエチレン（ＨＤＰＥ；d-2）５５重量部からなるブレンド物を以下の方法で得た。すなわち、まずポリアミド樹脂（f-1）とＥＭＡＡ（c-4）を二軸スクリュータイプのベント式押出機に入れ、窒素の存在下２２０℃で押出しペレット化を行い、得られたブレンドペレットと残りのＥＶＯＨ（a-2）およびＨＤＰＥ（d-2）を再度同様の方法でブレンドし、樹脂組成物のペレットを得た。
【０１５９】
得られたペレットを参考例１と同様にして、コネクター様の円筒状単層射出成形品（図１）を装着した燃料容器（図２）を作製し、ガソリンバリア性を測定した。また、耐衝撃性については、上記ブレンドペレットを射出成形機にて射出成形し、試料片を作製し、この試料片（ｎ＝５）を２０℃−６５％ＲＨに１週間放置した後、アイゾット試験機を用いてＡＳＴＭ−Ｄ２５６に準じて衝撃強度を求めた。評価結果を表４に示す。
【０１６０】
実施例１０〜１１、比較例９〜１０
表１に記載のガスバリアー性樹脂（Ａ）（a-2）、（a-3）、ポリアミド樹脂（f-1）、相容化剤（C）（c-4）、（c-5）、熱可塑性樹脂（Ｄ）（d-2）を、表４に記載の配合比率で用いた以外は、実施例９と同様にしてコネクター様の円筒状単層射出成形品（図１）を装着した燃料容器（図２）を作製し、実施例９と同様に評価した。なお、樹脂組成物が３成分からなる場合には１回の混練操作でブレンドを行い、１成分からなる場合には、混練操作を行わなかった。結果を表４に示す。
【０１６１】
【表４】

【０１６２】
相容化剤（Ｃ）としてポリアミドとカルボン酸変性ポリオレフィンとからなる樹脂組成物を用いた単層成形部品を装着された燃料容器は、外観に優れ、ガソリンバリア性、耐衝撃性に優れた性能を有していた。
【０１６３】
【発明の効果】
１１を超える溶解性パラメーター（Ｆｅｄｏｒｓの式から算出）を有するバリア性樹脂（Ａ）と１１以下の溶解性パラメーター（Ｆｅｄｏｒｓの式から算出）を有する熱可塑性樹脂（Ｂ）とを配合してなる成形部品は、ガソリンバリア性に優れ、かつガスバリア性、耐衝撃性、熱融着性、機械強度、耐ストレスクラック特性、耐有機溶剤性においても優れた性能を発揮する。このような成形部品が装着された燃料容器は、当該成形部品部分からの燃料の漏れが大幅に改善される。
【図面の簡単な説明】
【図１】 円筒状単層射出成形品（コネクター様成形品）を示す図である。
【図２】 コネクター様成形品の使用形態を示す図である。
【符号の説明】
１：コネクター様成形品
２：容器本体
３：パイプ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel container in which a molded part for a fuel container excellent in gasoline barrier properties, heat-fusibility, and mechanical strength is mounted on a fuel container body.
[0002]
[Prior art]
In recent years, fuel containers typified by automobiles have been actively put into practical use from metal to thermoplastic resin fuel containers in terms of weight reduction, rust prevention, easy moldability, and recyclability. It has been.
[0003]
However, when a thermoplastic resin fuel container is used, the permeation and volatilization of gasoline components from the fuel container body becomes a problem. Thus, a multilayer fuel container containing an ethylene-vinyl alcohol copolymer (hereinafter abbreviated as EVOH) having high gas barrier properties has been developed (Japanese Patent Laid-Open No. 9-29904). Thus, by making EVOH contain in a fuel container, the permeation | transmission and volatilization of the gasoline component from a fuel container main body are improved significantly.
[0004]
On the other hand, the molded parts attached to the fuel container (for example, fuel tube, gas vent line of the fuel filler port, pressure relief valve, connector to these container bodies, etc.) are generally made of high-density polyethylene. Has been. For this reason, fuel permeates and volatilizes. Therefore, even if the fuel container body is excellent in gas barrier properties, the fuel permeates and volatilizes from the molded parts to be connected, and the amount is not negligible.
[0005]
For this reason, it is conceivable to use a barrier resin (for example, EVOH) instead of high-density polyethylene. However, when only barrier resin is used as a molded part for a fuel container, the problem of gasoline permeation and volatilization can be solved, but the thermal fusion with the fuel container body, mechanical strength, impact resistance, etc. It will be unsatisfactory.
[0006]
[Problems to be solved by the invention]
Therefore, a molded part for a fuel container that exhibits excellent performance in gasoline barrier properties, heat fusion properties, and mechanical strength is desired. In the fuel container equipped with such a molded part, fuel leakage from the molded part is greatly improved.
[0007]
[Means for Solving the Problems]
The present invention relates to a thermoplastic resin having 5 to 70% by weight of a barrier resin (A) having a solubility parameter (calculated from the Fedors equation) exceeding 11 and a solubility parameter (calculated from the Fedors equation) of 11 or less. B) The molded part formed by blending 30 to 95% by weight relates to a fuel container mounted on the fuel container body.
[0008]
In a preferred embodiment, the barrier resin (A) has a gasoline permeation rate of 100 g · 20 μm / m.²-It is below day (value measured at 40 ° C.-65% RH).
[0009]
In a preferred embodiment, the barrier resin (A) is at least one selected from the group consisting of polyvinyl alcohol resins, polyamides and aliphatic polyketones.
[0010]
In a more preferred embodiment, the barrier resin (A) is an ethylene-vinyl alcohol copolymer having an ethylene content of 5 to 60 mol% and a saponification degree of 85% or more.
[0011]
In another preferred embodiment, the thermoplastic resin (B) is a polyolefin resin.
[0012]
In a preferred embodiment, the thermoplastic resin (B) has an ethylene content of 70 to 99 mol%, a saponified ethylene-vinyl acetate copolymer having a saponification degree of 40% or more, a carboxylic acid-modified polyolefin, and a boronic acid-modified product. Selected from the group consisting of polyolefins.
[0013]
In another preferred embodiment, the thermoplastic resin (B) has 11 or less solubility parameters (calculated from the Fedors equation) other than the compatibilizers (C) and (C). And the blending ratio of components (A), (C) and (D) is (A) 5 to 70% by weight, (C) 1 to 85% by weight and (D) 10 to 94% by weight.
[0014]
In a more preferred embodiment, the compatibilizer (C) is an ethylene-vinyl acetate copolymer saponified product having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, a carboxylic acid-modified polyolefin, and a boronic acid-modified. Selected from the group consisting of polyolefins.
[0015]
In a preferred embodiment, the compatibilizer (C) is a resin composition comprising 2 to 98% by weight of polyamide and 2 to 98% by weight of carboxylic acid-modified polyolefin.
[0016]
In another preferred embodiment, the thermoplastic resin (D) has a density of 0.93 g / cm.³The above polyethylene.
[0017]
In a more preferred embodiment, all or part of the molded part is a molded part formed by an injection molding method.
[0018]
In a more preferred embodiment, the molded part is a fuel container connector, a fuel container cap or a fuel container valve.
[0019]
In a preferred embodiment, the fuel container of the present invention has the molded part attached to the fuel container body by heat fusion.
[0020]
The present invention also relates to a fuel container in which a part made of a thermosetting resin (E) is attached to the fuel container to which the molded part is attached via the molded part.
[0021]
In a preferred embodiment, the thermosetting resin (E) is polymethylene oxide.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
The present invention comprises a barrier resin (A) having a solubility parameter (calculated from the Fedors equation) exceeding 11 and a thermoplastic resin (B) having a solubility parameter (calculated from the Fedors equation) of 11 or less. The present invention relates to a fuel container in which the formed part is mounted on the fuel container body.
[0023]
The “fuel” in the fuel container of the present invention includes not only gasoline but also so-called oxygen-containing gasoline such as alcohol-containing gasoline (containing alcohol such as methanol) and MTBE (methyl tertiary butyl ether) -containing gasoline.
[0024]
(Barrier resin (A))
The barrier resin (A) used in the present invention has a solubility parameter (calculated from the equation of Fedors) exceeding 11 and has a barrier property against the fuel filled in the fuel container of the present invention. It is. As such a barrier resin (A), the gasoline permeation amount is 100 g · 20 μm / m.²-It is preferable that it is below day (value measured by 40 degreeC-65% RH). The upper limit of the gasoline permeation amount is more preferably 10 g · 20 μm / m²· Day or less, more preferably 1g · 20μm / m²・ Day or less, particularly preferably 0.5 g · 20 μm / m²・ Day or less, optimally 0.1g ・ 20μm / m²-Day or less. Here, the gasoline used for measuring the gasoline permeation amount is Ref. It is a model gasoline called C that is mixed at a volume fraction of toluene / isooctane = 1/1.
[0025]
Examples of the barrier resin (A) used in the present invention include polyvinyl alcohol resin (A1), polyamide (A2), and aliphatic polyketone (A3). These resins may be used alone or in combination. Among these resins, from the viewpoint of gasoline barrier properties, polyvinyl alcohol resins (A1) and polyamides (A2) are suitable as the barrier resin (A) used in the present invention, and in particular, polyvinyl alcohol resins ( A1) is preferred.
[0026]
In the present invention, the “polyvinyl alcohol resin” refers to a resin obtained by saponifying a vinyl ester polymer or a copolymer of a vinyl ester and another monomer using an alkali catalyst or the like.
[0027]
The saponification degree of the vinyl ester component of the polyvinyl alcohol resin (A1) used in the present invention is preferably 90% or more, more preferably 95% or more, and further preferably 99% or more. If the saponification degree is less than 90 mol%, the gas barrier property under high humidity may be lowered, and the gasoline barrier property may be insufficient. The polyvinyl alcohol resin (A1) may be a blend of two or more types of polyvinyl alcohol resins having different saponification degrees. In such a case, the average value calculated from the blending weight ratio is defined as the degree of saponification. The degree of saponification of the polyvinyl alcohol resin (A1) can be determined by a nuclear magnetic resonance (NMR) method.
[0028]
The polyvinyl alcohol-based resin (A1) used in the present invention is capable of melt molding, has a good gas barrier property under high humidity, and has an excellent gasoline barrier property. Combined (EVOH) is preferred.
[0029]
EVOH is preferably obtained by saponifying an ethylene-vinyl ester copolymer. Among them, an ethylene-vinyl alcohol copolymer having an ethylene content of 5 to 60 mol% and a saponification degree of 85% or more is preferable. The lower limit of the ethylene content of EVOH is preferably 15 mol% or more, more preferably 20 mol% or more, and further preferably 25 mol% or more. Moreover, the upper limit of ethylene content becomes like this. Preferably it is 55 mol% or less, More preferably, it is 50 mol% or less. If the ethylene content is less than 5 mol%, melt moldability may be deteriorated, and water resistance and hot water resistance may be deteriorated. On the other hand, when it exceeds 60 mol%, there is a possibility that the barrier property is insufficient. The saponification degree of the vinyl ester component is preferably 85% or more, more preferably 90% or more, and still more preferably 99% or more. If the degree of saponification is less than 85%, the gasoline barrier property and thermal stability may be insufficient.
[0030]
A typical vinyl ester used in the production of EVOH is vinyl acetate, but other fatty acid vinyl esters (vinyl propionate, vinyl pivalate, etc.) can also be used. Moreover, EVOH can contain 0.0002-0.2 mol% of vinyl silane compounds as a copolymerization component. Here, examples of the vinylsilane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxy-ethoxy) silane, and γ-methacryloxypropylmethoxysilane. Of these, vinyltrimethoxysilane and vinyltriethoxysilane are preferably used. Furthermore, other comonomer such as propylene, butylene, or unsaturated such as (meth) acrylic acid, methyl (meth) acrylate or ethyl (meth) acrylate as long as the object of the present invention is not inhibited. Carboxylic acid or an ester thereof and vinylpyrrolidone such as N-vinylpyrrolidone can also be copolymerized.
[0031]
Furthermore, a boron compound can be blended with EVOH as long as the object of the present invention is not impaired. Examples of the boron compound include boric acids, boric acid esters, borates, borohydrides, and the like. Specific examples of boric acids include orthoboric acid, metaboric acid, and tetraboric acid. Examples of boric acid esters include triethyl borate and trimethyl borate. Examples include alkali metal salts of acids, alkaline earth metal salts, and borax. Among these compounds, orthoboric acid (hereinafter sometimes simply referred to as boric acid) is preferable.
[0032]
When blending a boron compound, the content of the boron compound is preferably 20 to 2000 ppm, more preferably 50 to 1000 ppm in terms of boron element. By being in this range, EVOH in which torque fluctuation during heating and melting is suppressed can be obtained. If it is less than 20 ppm, such an effect is small, and if it exceeds 2000 ppm, gelation tends to occur and moldability may be deteriorated.
[0033]
In addition, it is preferable to contain an alkali metal salt in an amount of 5 to 5000 ppm in terms of an alkali metal element with respect to EVOH used in the present invention, in order to improve the compatibility.
[0034]
A more preferable content of the alkali metal salt is 20 to 1000 ppm, further 30 to 500 ppm in terms of alkali metal element. Here, examples of the alkali metal include lithium, sodium, and potassium, and examples of the alkali metal salt include an aliphatic carboxylate, an aromatic carboxylate, and a metal complex of a monovalent metal. Examples thereof include sodium acetate, potassium acetate, sodium stearate, potassium stearate, sodium salt of ethylenediaminetetraacetic acid, and the like. Of these, sodium acetate and potassium acetate are preferred.
[0035]
Moreover, it is also preferable to contain 2 to 200 ppm, more preferably 3 to 150 ppm, and most preferably 5 to 100 ppm of phosphorus compound in terms of phosphorus element with respect to EVOH used in the present invention. When the phosphorus concentration in EVOH is less than 2 ppm or more than 200 ppm, there may be a problem in melt moldability and thermal stability. In particular, the occurrence of gel-like spots and coloring problems during melt molding over a long time tends to occur.
[0036]
The kind of phosphorus compound mix | blended in EVOH is not specifically limited. Various acids such as phosphoric acid and phosphorous acid and salts thereof can be used. The phosphate may be contained in any form of primary phosphate, secondary phosphate, and tertiary phosphate, and the cation species is not particularly limited, but alkali metal salts An alkaline earth metal salt is preferred. Among them, it is preferable to add a phosphorus compound in the form of sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, particularly preferably sodium dihydrogen phosphate, dipotassium hydrogen phosphate. It is.
[0037]
In addition, a heat stabilizer, an ultraviolet absorber, an antioxidant, a colorant, other resins (polyamide, polyolefin, etc.), and a plasticizer such as glycerin or glycerin monostearate are blended with EVOH as long as the object of the present invention is not impaired. You can also. Further, the addition of a metal salt of a higher aliphatic carboxylic acid or a hydrotalcite compound is effective from the viewpoint of preventing EVOH from being deteriorated by heat.
[0038]
A suitable melt flow rate (MFR) (190 ° C.-load 2160 g) of EVOH used in the present invention is 0.1 to 50 g / 10 minutes, more preferably 0.3 to 40 g / 10 minutes, and further preferably. Is 0.5-30 g / 10 min. However, those having a melting point near 190 ° C. or exceeding 190 ° C. were measured under a load of 2160 g and at a plurality of temperatures higher than the melting point. The value is extrapolated to 190 ° C. These EVOH resins can be used alone or in combination of two or more.
[0039]
The polyamide (A2) used as the barrier resin (A) of the present invention is a polymer having an amide bond, such as polycaproamide (nylon-6), polyundecanamide (nylon-11), polylauryl. Homopolymers such as lactam (nylon-12), polyhexamethylene adipamide (nylon-6,6), polyhexamethylene sebacamide (nylon-6,12), caprolactam / lauryl lactam copolymer (nylon- 6/12), caprolactam / aminoundecanoic acid polymer (nylon-6 / 11), caprolactam / ω-aminononanoic acid polymer (nylon-6,9), caprolactam / hexamethylenediammonium adipate copolymer (nylon-6) / 6,6), caprolactam / hexamethylenediammonium adip / Hexamethylenediammonium sebacate copolymer (nylon-6 / 6,6 / 6,12), polymer of adipic acid and metaxylylenediamine, or hexamethylenediamine and m, p-phthalic acid Aromatic nylon which is a polymer is exemplified. These polyamides can be used alone or in combination of two or more. Among these polyamides, nylon-6 is preferred from the viewpoint of gasoline barrier properties.
[0040]
The aliphatic polyketone (A3) used as the barrier resin (A) of the present invention is a carbon monoxide-ethylene copolymer, and the carbon monoxide-ethylene copolymer includes carbon monoxide and ethylene. And those obtained by copolymerizing an unsaturated compound other than ethylene, mainly composed of carbon monoxide and ethylene. Here, examples of unsaturated compounds other than ethylene include α-olefins having 3 or more carbon atoms, styrene, dienes, vinyl esters, and aliphatic unsaturated carboxylic acid esters. Examples of the copolymer include a random copolymer, an alternating copolymer, and the like, but an alternating copolymer with high crystallinity is preferable in terms of barrier properties.
[0041]
Among the alternating copolymers, copolymerization with a third component other than carbon monoxide or ethylene is preferable from the viewpoint of melt stability because the melting point is lowered. Among the monomers to be copolymerized, α-olefin is preferable. Propylene, butene-1, isobutene, pentene-1, 4-methylpentene-1, hexene-1, octene-1, dodecene-1 Among them, α-olefins having 3 to 8 carbon atoms are preferable, and propylene is particularly preferable. The copolymerization amount of these α-olefins is preferably 0.5 to 7% by weight based on the polyketone from the viewpoint of ensuring appropriate crystallinity and melt stability.
[0042]
The diene to be copolymerized preferably has 4 to 12 carbon atoms, and examples thereof include butadiene, isoprene, 1,5-hexadiene, 1,7-octadiene, 1,9-decadiene and the like. Examples of the vinyl ester include vinyl acetate, vinyl propionate, vinyl pivalate, and the like. Aliphatic unsaturated carboxylic acids, salts and esters thereof include acrylic acid, methacrylic acid, maleic anhydride, maleic acid, itaconic acid, acrylic ester, methacrylic ester, maleic monoester, maleic diester, fumaric acid Monoesters, fumaric acid diesters, itaconic acid monoesters, itaconic acid diesters (these esters include methyl esters, alkyl esters such as ethyl esters), acrylates, maleates, itaconates (as these salts) Monovalent or divalent metal salts). These comonomer may be used alone or in combination of two or more.
[0043]
As the production method of the aliphatic polyketone (A3), known methods, for example, U.S. Pat. No. 2,495,286, JP-A-53-128690, JP-A-59-197427, JP-A-61-91226 are known. JP, 62-232434, JP 62-53332, JP 63-3025, JP 63-105031, JP 63-154737, JP 1-149829, Examples thereof include, but are not limited to, the methods described in Kaihei 1-201333 and JP-A-2-67319.
[0044]
The suitable melt flow rate (MFR) of the aliphatic polyketone used in the present invention is 0.01 to 50 g / 10 min (230 ° C.-load 2160 g), and optimally 0.1 to 10 g / 10 min. When the MFR is in the above range, the fluidity of the resin is excellent, and the molding processability is also excellent.
[0045]
(Thermoplastic resin (B))
Examples of the thermoplastic resin (B) having a solubility parameter of 11 or less (calculated from the Fedors equation) used in the present invention include polyolefin resins, styrene resins, and polyvinyl chloride resins. When a molded component for a fuel container is mounted on a fuel container made of a thermoplastic resin, it is often mounted by thermal fusion from the viewpoint of simplifying the work process. In general, a polyolefin-based resin, preferably high-density polyethylene is used for the outermost layer of the fuel container body made of a thermoplastic resin in order to obtain sufficient mechanical strength. Since the solubility parameter of such a polyolefin resin is 11 or less, if the solubility parameter of the thermoplastic resin (B) exceeds 11, the heat fusion property between the fuel container body and the molded part for the fuel container becomes insufficient. Therefore, the performance of the fuel container of the present invention cannot be sufficiently exhibited. These thermoplastic resins (B) can be used alone or in combination of two or more.
[0046]
Among these thermoplastic resins (B), it is preferable to use a polyolefin-based resin from the viewpoint of thermal fusion with the fuel container body.
[0047]
Examples of the polyolefin-based resin include high-density, low-density or ultra-low-density polyethylene, carboxylic acid-modified polyolefin, boronic acid-modified polyolefin, polypropylene, polybutene-1, and other homopolymers of ethylene, propylene, butene-1, Examples thereof include copolymers of α-olefins selected from hexene-1 and the like. Moreover, what copolymerized the following components: Vinyl compounds, such as a diolefin, vinyl chloride, and vinyl acetate, unsaturated carboxylic acid esters, such as acrylic acid ester and methacrylic acid ester, etc. are included. Examples of styrene resins include polystyrene, acrylonitrile-butadiene-styrene copolymer resin (ABS), acrylonitrile-styrene copolymer resin (AS), block copolymers with styrene-isobutylene, and copolymers with styrene-butadiene. Or the block copolymer with styrene-isoprene etc. are mentioned.
[0048]
Among the polyolefin-based resins, the density is 0.93 g / cm.³The above polyethylene, ethylene-vinyl acetate copolymer saponified product having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, a carboxylic acid-modified polyolefin, and a boronic acid-modified polyolefin are preferred.
[0049]
The saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a vinyl acetate component saponification degree of 40% or more used in the present invention has an ethylene content from the viewpoint of improving compatibility. Is more preferably 72 to 96 mol%, still more preferably 72 to 94 mol%. The saponification degree of the vinyl acetate component is preferably 45% or more. The upper limit of the saponification degree is not particularly limited, and those having a saponification degree of 100% can be used.
[0050]
The ethylene-vinyl acetate copolymer saponified product having an ethylene content of 70 to 99 mol% and a vinyl acetate component having a saponification degree of 40% or more is preferably a barrier resin (A), particularly preferably EVOH. Used in combination. When the degree of saponification of the vinyl acetate component is less than 40% or the ethylene content exceeds 99 mol%, the compatibility with EVOH is lowered, and the moldability may be deteriorated. Further, when the ethylene content is less than 70 mol%, the heat-fusibility between the fuel container molded part and the fuel container body is insufficient.
[0051]
Melt flow rate (MFR) of saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a vinyl acetate component saponification degree of 40% or more used in the present invention (210 ° C.-load 2160 g) Is preferably 0.1 g / 10 min or more, preferably 0.5 g / 10 min or more, 100 g / 10 min or less, more preferably 50 g / 10 min or less, and most preferably 30 g / 10 min. The following is desirable.
[0052]
The carboxylic acid-modified polyolefin used in the present invention refers to a copolymer comprising an olefin, particularly an α-olefin, and an unsaturated carboxylic acid or an anhydride thereof. In the polyolefin and polyolefin having a carboxyl group in the molecule. Those in which all or part of the contained carboxyl groups are present in the form of metal salts are also included. Examples of the polyolefin used as the base of the carboxylic acid-modified polyolefin include polyethylene (for example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE), etc.), polypropylene, copolymer polypropylene, and ethylene. -Various polyolefins, such as a vinyl acetate copolymer and an ethylene- (meth) acrylic acid ester copolymer, are mentioned.
[0053]
Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, monomethyl maleate, monoethyl maleate, and itaconic acid. Acrylic acid or methacrylic acid is particularly preferable. Content of unsaturated carboxylic acid becomes like this. Preferably it is 0.5-20 mol%, More preferably, it is 2-15 mol%, More preferably, it is 3-12 mol%. Examples of the unsaturated carboxylic acid anhydride include itaconic anhydride and maleic anhydride, and maleic anhydride is particularly preferable. As content of unsaturated carboxylic acid anhydride, Preferably it is 0.0001-5 mol%, More preferably, it is 0.0005-3 mol%, More preferably, it is 0.001-1 mol%. Other monomers that may be contained in the copolymer include vinyl esters such as vinyl acetate and vinyl propionate, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, and acrylic acid n. Examples thereof include unsaturated carboxylic acid esters such as butyl, 2-ethylhexyl acrylate, methyl methacrylate, isobutyl methacrylate and diethyl maleate, and carbon monoxide.
[0054]
Examples of the metal ion in the metal salt of the carboxylic acid-modified polyolefin include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium and calcium, and transition metals such as zinc. It is preferable in terms of tolerability. The degree of neutralization of the metal salt of the carboxylic acid-modified polyolefin is desirably 100% or less, particularly 90% or less, and more preferably 70% or less. The lower limit of the degree of neutralization is usually preferably 5% or more, particularly 10% or more, and more preferably 30% or more.
[0055]
The melt flow rate (MFR) (190 ° C.-load 2160 g) of the carboxylic acid-modified polyolefin used in the present invention is preferably 0.01 to 50 g / 10 minutes, more preferably 0.05 to 30 g / 10 minutes, still more preferably. Is 0.1 to 10 g / 10 min. These carboxylic acid-modified polyolefins can be used alone or in combination of two or more.
[0056]
The boronic acid-modified polyolefin used in the present invention is a polyolefin having at least one functional group selected from a boronic acid group, a borinic acid group, and a boron-containing group that can be converted to a boronic acid group or a borinic acid group in the presence of water. It is.
[0057]
The polyolefin having at least one functional group selected from a boronic acid group, a boronic acid group and a boron-containing group that can be converted to a boronic acid group in the presence of water in the presence of a boronic acid group, a boronic acid group, At least one functional group selected from the group consisting of a boronic acid group or a boron-containing group that can be converted to a boronic acid group in the presence of water is bonded to the main chain, side chain, or terminal by a boron-carbon bond. Polyolefin. Of these, polyolefins in which the functional group is bonded to the side chain or terminal are preferred, and polyolefins bonded to the terminal are optimal. Here, the term “end” means one end or both ends. The carbon of the boron-carbon bond is derived from a polyolefin base polymer described later, or derived from a boron compound to be reacted with the base polymer. Preferable examples of the boron-carbon bond include a bond between boron and a main chain or a terminal or side chain alkylene group. In the present invention, since a polyolefin having a boronic acid group is suitable, this point will be described below. In the present invention, the boronic acid group is represented by the following formula (I).
[0058]
[Chemical 1]

[0059]
A boron-containing group that can be converted to a boronic acid group in the presence of water (hereinafter simply referred to as a boron-containing group) is a boronic acid group represented by the above formula (I) by hydrolysis in the presence of water. Any boron-containing group can be used as long as it can be converted into a boron ester group represented by the following general formula (II) as a representative example, a boronic acid anhydride group represented by the following general formula (III), Examples thereof include boronate groups represented by the following general formula (IV).
[0060]
[Chemical formula 2]

[0061]
[Chemical 3]

[0062]
[Formula 4]

[0063]
(Wherein X and Y are a hydrogen atom, an aliphatic hydrocarbon group (such as a linear or branched alkyl group or alkenyl group having 1 to 20 carbon atoms), an alicyclic hydrocarbon group (a cycloalkyl group, A cycloalkenyl group, etc.) and an aromatic hydrocarbon group (phenyl group, biphenyl group, etc.), X and Y may be the same or different, and X and Y may be bonded. However, it excludes when both X and Y are hydrogen atoms.¹, R², R^ThreeWherein X and Y represent the same hydrogen atom, aliphatic hydrocarbon group, alicyclic hydrocarbon group, and aromatic hydrocarbon group, R¹, R², R^ThreeMay be the same group or different. M represents an alkali metal or an alkaline earth metal. Also, the above X, Y, R¹, R², R^ThreeMay have other groups such as a carboxyl group and a halogen atom. )
[0064]
Specific examples of the boronic acid ester represented by the general formulas (II) to (IV) include a boronic acid dimethyl ester group, a boronic acid diethyl ester group, a boronic acid dipropyl ester group, a boronic acid diisopropyl ester group, and a boronic acid dibutyl ester. Group, boronic acid dihexyl ester group, boronic acid dicyclohexyl group, boronic acid ethylene glycol ester group, boronic acid propylene glycol ester group (boronic acid 1,2-propanediol ester group, boronic acid 1,3-propanediol ester group), Boronic acid ester groups such as boronic acid trimethylene glycol ester group, boronic acid neopentyl glycol ester group, boronic acid catechol ester group, boronic acid glycerin ester group, boronic acid trimethylolethane ester group; boronic acid anhydride group; Alkali metal base Ron acid, alkaline earth metal base such as boronic acid. Among the above functional groups, boronic acid ester groups such as boronic acid ethylene glycol ester groups are particularly preferred from the viewpoint of compatibility with EVOH. The boron-containing group that can be converted to a boronic acid group or a borinic acid group in the presence of water is a reaction of polyolefin in water or a mixed liquid of water and an organic solvent (toluene, xylene, acetone, etc.). This means a group that can be converted to a boronic acid group or a borinic acid group when hydrolyzed under the conditions of a reaction temperature of 25 ° C. to 150 ° C. for 10 minutes to 2 hours.
[0065]
Although there is no restriction | limiting in particular in content of the said functional group, 0.0001-1 meq / g (milli equivalent / g) is preferable, and 0.001-0.1 meq / g is especially preferable. It is surprising that the compatibility of the resin composition is remarkably improved by the presence of such a small amount of functional groups.
[0066]
Examples of the base polymer of the polyolefin having a boron-containing group include olefin monomers represented by α-olefins such as ethylene, propylene, 1-butene, isobutene, 3-methylpentene, 1-hexene, and 1-octene. Can be mentioned.
[0067]
The base polymer is used as a polymer composed of one, two or three or more of these monomers. Among these base polymers, particularly ethylene-based polymers {ultra low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester Preferred examples include copolymers, metal salts of ethylene-acrylic acid copolymers (Na, K, Zn ionomers, ethylene-propylene copolymers).
[0068]
Next, a typical process for producing an olefin polymer having a boronic acid group and a boron-containing group used in the present invention will be described. An olefin polymer having a boron-containing group that can be converted to a boronic acid group in the presence of a boronic acid group or water is obtained by adding a borane complex and a trialkyl borate to an olefin polymer having a carbon-carbon double bond under a nitrogen atmosphere. By obtaining an olefin polymer having a boronic acid dialkyl ester group by reacting with an ester, it is obtained by reacting with water or alcohol. If an olefin polymer having a double bond at the terminal is used as a raw material in this production method, an olefin polymer having a boron-containing group that can be converted into a boronic acid group by the presence of a boronic acid group or water at the terminal can be obtained. If an olefin polymer having a double bond in the side chain or main chain is used as a raw material, the olefin polymer having a boron-containing group that can be converted into a boronic acid group in the presence of a boronic acid group or water in the side chain Is obtained.
[0069]
The typical production method of the olefin polymer having a double bond as a raw material is as follows: 1) a method using a double bond existing in a trace amount at the end of a normal olefin polymer; 2) a normal olefin polymer. A process for obtaining an olefin polymer having a double bond at the end by thermal decomposition under anoxic conditions; 3) Olefin monomer and diene monomer by copolymerization of olefin monomer and diene polymer And a production method for obtaining a copolymer with the body. As for 1), a known method for producing an olefin polymer can be used, but a method using a metallocene polymerization catalyst as a polymerization catalyst without using hydrogen as a chain transfer agent (for example, DE 4030399) is particularly preferable. 2) can be obtained by thermally decomposing an olefin polymer at a temperature of 300 ° C. to 500 ° C. under anoxic conditions such as a nitrogen atmosphere or a vacuum under a known method (for example, USP 2835659, USP 3087922). . As for 3), a method for producing an olefin-diene polymer using a known Ziegler-based catalyst (for example, JP-A-50-44281, DE3021273) can be used.
[0070]
As the borane complex, borane-tetrahydrofuran complex, borane-dimethyl sulfide complex, borane-pyridine complex, borane-trimethylamine complex, borane-triethylamine and the like are preferable. Of these, borane-triethylamine complex and borane-trimethylamine complex are more preferred. The amount of the borane complex charged is preferably in the range of 1/3 equivalent to 10 equivalents relative to the double bond of the olefin polymer. As the boric acid trialkyl ester, boric acid lower alkyl esters such as trimethyl borate, triethyl borate, tripropyl borate, tributyl borate and the like are preferable. The amount of the trialkyl borate charged is preferably in the range of 1 to 100 equivalents relative to the double bond of the olefin polymer. Although it is not necessary to use a solvent in particular, saturated hydrocarbon solvents such as hexane, heptane, octane, decane, dodecane, cyclohexane, ethylcyclohexane and decalin are preferred.
[0071]
The reaction to be introduced is carried out at a reaction temperature of 25 ° C. to 300 ° C., preferably 100 to 250 ° C., a reaction time of 1 minute to 10 hours, preferably 5 minutes to 5 hours.
[0072]
Water or alcohols are usually reacted with an organic solvent such as toluene, xylene, acetone or ethyl acetate as a reaction solvent. Water or alcohols such as methanol, ethanol or butanol; ethylene glycol, 1,2-propane A large excess of 1 to 100 equivalents or more of polyhydric alcohols such as diol, 1.3-propanediol, neopenterglycol, glycerin, trimethylolethane, pentaerythritol and dipentaerythritol is used with respect to the boronic acid group. The reaction is carried out at a temperature of 25 ° C. to 150 ° C. for about 1 minute to 1 day. The boron-containing group that can be converted to a boronic acid group among the functional groups is a reaction time of 10 minutes to 2 hours in water or a mixed solvent of water and an organic solvent (toluene, xylene, acetone, etc.). Means a group that can be converted into a boronic acid group when hydrolyzed under the reaction temperature of 25 ° C. to 150 ° C.
[0073]
The suitable melt flow rate (MFR) (190 ° C.-load 2160 g) of the thermoplastic resin (B) used in the present invention is preferably 0.01 to 100 g / 10 minutes, more preferably 0.03 to 50 g / 10. Min, optimally 0.1-30 g / 10 min. However, those having a melting point near 190 ° C. or exceeding 190 ° C. were measured under a load of 2160 g and at a plurality of temperatures higher than the melting point. The value is extrapolated to 190 ° C.
[0074]
Among the thermoplastic resins (B), the density is 0.93 g / cm.³It is preferable to use the above polyethylene, carboxylic acid-modified polyolefin, and boronic acid-modified polyolefin.
[0075]
Density 0.93g / cm as thermoplastic resin (B)³When the above polyethylene is used, the molded part for fuel containers with such a configuration is inferior in impact resistance to the conventional product. However, it has a significant improvement effect on gasoline barrier properties compared to the conventional molded part consisting only of high-density polyethylene. It is done. Polyethylene has a density of 0.93 g / cm³It is preferable that the density is 0.93 g / cm.³If it is less than this, the mechanical strength such as impact resistance of the molded part for a fuel container obtained may be insufficient.
[0076]
When the carboxylic acid-modified polyolefin is used as the thermoplastic resin (B), a large improvement effect on the gasoline barrier property is seen as compared with the conventional product, and the density is 0.93 g / cm.³Compared to the system in which the above polyethylene and barrier resin (A) are blended, the molded article for a fuel container obtained is more suitable from the viewpoint of excellent impact resistance.
[0077]
Further, when boronic acid-modified polyolefin is used as the thermoplastic resin (B), the compatibility with the barrier resin (A) is high, and particularly when EVOH is used as the barrier resin (A), the EVOH is very high. In order to exhibit good dispersibility, it is particularly preferable from the viewpoint of excellent mechanical strength such as impact resistance and the like, and high gasoline barrier properties and organic solvent resistance can be imparted to molded parts for fuel containers.
[0078]
(Compatibilizer (C))
The fuel container of the present invention is formed by mounting a molded part formed by blending a barrier resin (A) and a thermoplastic resin (B) on a fuel container body. In this case, the thermoplastic resin (B) comprises a thermoplastic resin (D) having 11 or less solubility parameters (calculated from the Fedors equation) other than the compatibilizers (C) and (C), and the component ( The blending ratio of A), (C) and (D) is preferably (A) 5 to 70% by weight, (C) 1 to 85% by weight, and (D) 10 to 94% by weight. By adopting such a configuration, it is possible to improve the compatibility of the barrier resin (A) and the thermoplastic resin (D) and to form a stable morphology in the resulting resin composition.
[0079]
Although it does not specifically limit as a compatibilizing agent (C), As a suitable example, ethylene-vinyl acetate copolymer saponified product (C1) of ethylene content 70-99 mol% and saponification degree 40% or more, carboxylic acid Examples thereof include modified polyolefin (C2) and boronic acid modified polyolefin (C3). These compatibilizers (C) may be used alone or in combination of two or more.
[0080]
Further, when using a resin composition comprising a barrier resin (A), a compatibilizer (C) and a thermoplastic resin (D), a polyvinyl alcohol resin (A1), particularly EVOH, is used as the barrier resin (A). Is preferably used as the compatibilizer (C), a resin composition comprising 2 to 98% by weight of polyamide and 98 to 2% by weight of carboxylic acid-modified polyolefin. By using such a compatibilizing agent, the compatibility between the barrier resin (A) and the thermoplastic resin (D) is remarkably improved, which is preferable from the viewpoint that the impact resistance of the molded part can be improved. .
[0081]
When the compatibilizer (C) is a resin composition comprising 2 to 98% by weight of polyamide and 98 to 2% by weight of carboxylic acid-modified polyolefin, from the viewpoint of compatibility with EVOH, the compatibilizer (C) As the polyamide resin used in the above, a polyamide resin containing a nylon 6 component (for example, nylon-6, nylon-6, 12, nylon-6 / 12, nylon-6 / 6, 6, etc.) is preferable. EVOH and polyamide resin react and gel in the melting process at high temperature. Therefore, from the viewpoint of suppressing thermal deterioration of the blend composition, the melting point of the polyamide resin is preferably 240 ° C. or less, and more preferably 230 ° C. or less.
[0082]
A suitable melt flow rate (MFR) (210 ° C.-load 2160 g) of the polyamide resin used for compatibilization with EVOH is 0.1 to 50 g / 10 min. , Optimally 0.5-30 g / 10 min. It is. However, those having a melting point near 210 ° C or exceeding 210 ° C were measured under a load of 2160 g at a plurality of temperatures higher than the melting point, and the reciprocal absolute temperature was plotted on the horizontal axis and the logarithm of MFR on the vertical axis in a semilogarithmic graph The value is extrapolated to 210 ° C.
[0083]
When a resin composition comprising a polyamide and a carboxylic acid-modified polyolefin is used as the compatibilizer (C), the carboxylic acid-modified polyolefin used is obtained by random copolymerization of a polyolefin and an unsaturated carboxylic acid or its anhydride. The polymer is preferably a copolymer of ethylene and an unsaturated carboxylic acid or anhydride thereof, which is desirably copolymerized randomly. The reason why the random copolymer or its metal salt is superior to the graft compound is that the graft compound exhibits compatibility between the barrier resin (A) and the thermoplastic resin (D) when blended with polyamide. This is because it is difficult to obtain a high acid content necessary for the production. Furthermore, in the case of a graft compound of an unsaturated carboxylic acid, such as maleic anhydride, the hydroxyl group in EVOH reacts with the carboxyl group in the graft copolymer to cause gel and fish eyes, which may be undesirable. is there.
[0084]
The content of unsaturated carboxylic acid is preferably 2 to 15 mol%, more preferably 3 to 12 mol%. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, monomethyl maleate, monoethyl maleate, and maleic anhydride, and acrylic acid or methacrylic acid is particularly preferable. Other monomers that may be contained in the copolymer include vinyl esters such as vinyl acetate and vinyl propionate, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, and acrylic acid n. Examples include -butyl, 2-ethylhexyl acrylate, methyl methacrylate, isobutyl methacrylate, unsaturated carboxylic acid esters such as diethyl maleate, carbon monoxide, and the like. In the resin composition for producing a molded part for a fuel container used in the fuel container of the present invention, the metal salt is more preferably used than the carboxylic acid-modified polyolefin. The reason why the metal salt is superior to the carboxylic acid-modified polyolefin is not clear, but it is considered that the metal salt has higher polarity and therefore the compatibility with the polyamide resin is increased.
[0085]
Examples of the metal ion in the metal salt of the carboxylic acid polyolefin include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium and calcium, and transition metals such as zinc. Polyamide resins are particularly used when zinc is used. It is preferable in terms of compatibility. The degree of neutralization in the metal salt of the carboxylic acid polyolefin is preferably 100% or less, particularly 90% or less, and more preferably 70% or less. The lower limit of the degree of neutralization is usually preferably 5% or more, particularly 10% or more, and more preferably 30% or more.
[0086]
(Thermoplastic resin (D))
Examples of the thermoplastic resin (D) include polyolefin resins, styrene resins, and polyvinyl chloride resins. Among these, polyolefin resins are particularly preferable from the viewpoints of heat-fusibility and economical efficiency of molded parts. When the solubility parameter of the thermoplastic resin (D) exceeds 11, the heat-fusibility between the molded part for a fuel container of the present invention and the fuel container body becomes insufficient.
[0087]
Examples of the polyolefin-based resin include α-olefin homopolymers such as high-density or low-density polyethylene, polypropylene, and polybutene-1, and copolymers of α-olefins selected from ethylene, propylene, butene-1, hexene-1, and the like. A polymer etc. are illustrated.
[0088]
Among these, a density of 0.93 g / cm as the thermoplastic resin (D)³When the above polyethylene is used, it is suitable from the viewpoint of excellent impact resistance and heat-fusibility improvement effects. Since the outermost layer of the thermoplastic resin fuel container body is often made of high-density polyethylene, the effect of improving the heat-sealing property is particularly increased by adopting such a configuration. Polyethylene has a density of 0.93 g / cm³It is preferable that the density is 0.93 g / cm.³If it is less than 1, the effect of improving the mechanical strength such as impact resistance may be insufficient.
[0089]
(Resin additive)
The resin composition used in the present invention may contain appropriate additives (for example, heat stabilizers, plasticizers, antioxidants, ultraviolet absorbers, colorants, etc.). Is used as long as the effects of the present invention are not impaired. Addition of a metal salt of a higher aliphatic carboxylic acid or a hydrotalcite compound is effective from the viewpoint of preventing deterioration of EVOH due to heat when the barrier resin (A) is EVOH.
[0090]
Here, as the hydrotalcite compound, in particular, M_xAl_y(OH)_{2x + 3y-2z}(A)_z・ AH₂O (M is Mg, Ca or Zn, A is CO₃Or HPO₄, X, y, z, and a are positive numbers). Particularly preferred are the following hydrotalcite compounds.
Mg₆Al₂(OH)₁₆CO₃・ 4H₂O
Mg₈Al₂(OH)₂₀CO₃・ 5H₂O
Mg₅Al₂(OH)₁₄CO₃・ 4H₂O
Mg₁₀Al₂(OH)₂₂(CO₃)₂・ 4H₂O
Mg₆Al₂(OH)₁₆HPO₄・ 4H₂O
Ca₆Al₂(OH)₁₆CO₃・ 4H₂O
Zn₆Al₆(OH)₁₆CO₃・ 4H₂O
Mg_{4 . 5}Al₂(OH)₁₃CO₃・ 3.5H₂O
[0091]
Further, as the hydrotalcite compound, [Mg] is a hydrotalcite-based solid solution described in JP-A-1-308439 (USP 4945557)._0.75Zn_0.25]_0.67Al_0.33(OH)₂(CO₃)_0.167・ 0.45H₂Things like O can also be used.
[0092]
The metal salt of a higher aliphatic carboxylic acid refers to a metal salt of a higher fatty acid having 8 to 22 carbon atoms. Examples of higher fatty acids having 8 to 22 carbon atoms include lauric acid, stearic acid, and myristic acid. Examples of the metal include sodium, potassium, magnesium, calcium, zinc, barium, and aluminum. Of these, alkaline earth metals such as magnesium, calcium and barium are preferred.
[0093]
The content of the metal salt of the higher aliphatic carboxylic acid or the hydrotalcite compound is preferably 0.01 to 3 parts by weight, more preferably 0.05 to 2 parts by weight based on the total weight of the resin composition. 5 parts by weight.
[0094]
(Addition of inorganic filler)
The inorganic filler may be added to either the barrier resin (A) or the thermoplastic resin (B) and then kneaded, or the inorganic filler may be added during kneading. When an inorganic filler is added, improvement effects such as improvement in gasoline barrier properties, improvement in mechanical strength, and improvement in organic solvent resistance typified by reduction in swelling due to gasoline can be obtained.
[0095]
Preferable examples of the inorganic filler used in the present invention include mica, sericite, glass flakes and talc, and are not particularly limited. These inorganic fillers can be used alone or as a mixture.
[0096]
The content of the inorganic filler in the present invention is preferably 1 to 50% by weight, and the lower limit of the content is more preferably 5% by weight or more, further preferably 10% by weight or more, and optimally 15% by weight. % Or more. The upper limit of the content is more preferably 45% by weight or less, and still more preferably 40% by weight or less. If it is less than 1% by weight, the improvement effects such as improvement in mechanical strength and gasoline barrier property may be unsatisfactory. On the other hand, if it exceeds 50% by weight, abnormal flow tends to occur during molding, which may cause sink marks, weld lines, and the like, and there is a possibility that a molded product with a good appearance cannot be obtained.
[0097]
In the fuel container of the present invention, the barrier resin (A) and the thermoplastic resin (B), or the barrier resin (A), the compatibilizer (C), and the thermoplastic resin (D) are appropriately combined. A molded molded part is mounted on the fuel container body. Hereinafter, first, a molded part to be mounted on the fuel container will be described.
[0098]
(Molded parts)
A molded part to be attached to the fuel container is obtained by molding a resin composition comprising 5 to 70% by weight of the barrier resin (A) and 30 to 95% by weight of the thermoplastic resin (B). More preferably, the barrier resin (A) is 10 to 60% by weight and the thermoplastic resin (B) is 40 to 90% by weight, and further preferably the barrier resin (A) is 20 to 50% by weight and the thermoplastic resin ( B) 50 to 80% by weight.
[0099]
By using such a molded part, a fuel container excellent in gasoline barrier properties, mechanical strength, and heat fusion property with the fuel container main body can be obtained.
[0100]
When the barrier resin (A) is less than 5% by weight and when the thermoplastic resin (B) exceeds 95% by weight, the effect of improving the gasoline barrier property of the molded part may be insufficient. Further, when the barrier resin (A) exceeds 70% by weight and when the thermoplastic resin (B) is less than 30% by weight, the impact resistance, fatigue resistance, heat fusion property, etc. of the molded part are unsatisfactory. There is a fear.
[0101]
In the molded part used in the present invention, in the case of using a resin composition in which the barrier resin (A) is a continuous phase and the thermoplastic resin (B) is a dispersed phase, the thermal fusion with the fuel container main body, impact resistance There is a risk that the improvement effect such as property and fatigue resistance may be insufficient. The molded part for a fuel container used in the present invention is a resin composition in which both the barrier resin (A) and the thermoplastic resin (B) form a continuous phase, or the barrier resin (A) is a dispersed phase. It is preferable to use a resin composition in which the thermoplastic resin (B) is a continuous phase, and to use a resin composition in which the barrier resin (A) is a dispersed phase and the thermoplastic resin (B) is a continuous phase. From the viewpoint of achieving both barrier properties and mechanical strength, it is particularly preferable.
[0102]
When the molded part is made of a resin composition obtained by blending the barrier resin (A) and the thermoplastic resin (B), the thermoplastic resin (B) is 11 other than the compatibilizers (C) and (C). It consists of a thermoplastic resin (D) having the following solubility parameter (calculated from the equation of Fedors), and the blending ratio of components (A), (C) and (D) is (A) 5 to 70% by weight, ( C) 1 to 85% by weight and (D) 10 to 94% by weight are preferable. By adopting such a configuration, it is possible to improve the compatibility of the barrier resin (A) layer and the thermoplastic resin (D) and to form a stable morphology in the resulting resin composition.
[0103]
When barrier resin (A) is less than 5 weight%, there exists a possibility that the improvement effect of the gasoline barrier property of a molded part may become inadequate. On the other hand, when the barrier resin (A) exceeds 70% by weight, there is a risk that the impact resistance, fatigue resistance, heat fusion property, etc. of the molded part will be insufficient.
[0104]
If the compatibilizer (C) is less than 1% by weight, the compatibilizing effect of the barrier resin (A) and the thermoplastic resin (D) may be unsatisfactory. When the compatibilizer (C) exceeds 85% by weight, the ratio of the barrier resin (A) to the thermoplastic resin (D) in the total amount of the resin composition is lowered, so that the inherently possessed by the barrier resin. There exists a possibility that performance, such as the melt-formability which a barrier property and a thermoplastic resin (D) have, mechanical strength, heat-fusion property, may fall.
[0105]
When the thermoplastic resin (D) is less than 10% by weight, the improvement effects such as melt moldability, mechanical strength, and heat-fusibility may be unsatisfactory. The thermoplastic resin (D) is preferably a polyolefin. When the polyolefin content is less than 10% by weight, the mechanical properties and heat-fusibility of the polyolefin are insufficient, and there is a possibility that the advantages from the viewpoint of economy cannot be fully enjoyed. Moreover, when a thermoplastic resin (D) exceeds 94 weight%, there exists a possibility that the improvement effect of the gasoline barrier property of a molded component may become inadequate.
[0106]
In the molded part for a fuel container of the present invention, when a resin composition in which the barrier resin (A) is a continuous phase and the compatibilizer (C) and the thermoplastic resin (D) are a dispersed phase is used, There is a possibility that the improvement effect such as heat fusion property, impact resistance, and fatigue resistance will be insufficient. The molded component for a fuel container of the present invention is a resin composition in which a barrier resin (A) and a compatibilizer (C) and / or a thermoplastic resin (D) all form a continuous phase, or a barrier It is preferable to use a resin composition in which the conductive resin (A) is a dispersed phase and the compatibilizer (C) and / or the thermoplastic resin (D) is a continuous phase, and the barrier resin (A) is a dispersed phase. It is particularly preferable to use a resin composition in which the compatibilizer (C) and / or the thermoplastic resin (D) is a continuous phase from the viewpoint of achieving both barrier properties and mechanical strength.
[0107]
Further, when EVOH is used as the barrier resin (A), and the polyamide resin (C4) and the carboxylic acid-modified polyolefin (preferably a metal salt thereof) (C2) are used as the compatibilizing agent (C), the barrier resin ( The blending weight ratio of A), compatibilizer (C) and thermoplastic resin (D) satisfies the following formulas (1) to (4).
0.6 ≦ W (A + D) / W (T) ≦ 0.995 (1)
0.005 ≦ W (C4 + C2) / W (T) ≦ 0.4 (2)
0.5 ≦ W (D) / W (A + D) ≦ 0.99 (3)
0.02 ≦ W (C4) / W (C4 + C2) ≦ 0.98 (4)
(W (A + D); total weight of (A) and (D) in the composition)
W (C4); weight of polyamide (C4) in the composition
W (C4 + C2); total weight of polyamide (C4) and carboxylic acid-modified polyolefin (C2) in the composition
W (D); weight of (D) in the composition
W (T); total weight of the composition).
Preferably,
0.65 ≦ W (A + D) / W (T) ≦ 0.99 (1 ′)
0.01 ≦ W (C4 + C2) / W (T) ≦ 0.35 (2 ′)
0.55 ≦ W (D) / W (A + D) ≦ 0.98 (3 ′)
0.04 ≦ W (C4) / W (C4 + C2) ≦ 0.96 (4 ′)
And more preferably
0.70 ≦ W (A + D) / W (T) ≦ 0.985 (1 ″)
0.015 ≦ W (C4 + C2) / W (T) ≦ 0.30 (2 ″)
0.6 ≦ W (D) / W (A + D) ≦ 0.97 (3 ″)
0.05 ≦ W (C4) / W (C4 + C2) ≦ 0.95 (4 ″)
It is.
[0108]
When W (A + D) / W (T) exceeds 0.995 or W (C4 + C2) / W (T) is less than 0.005, the phase of EVOH (A) and the thermoplastic resin (D) The capacity is lowered and the effect of the present invention cannot be obtained. When W (A + D) / W (T) is less than 0.6 or when W (C4 + C2) / W (T) exceeds 0.4, EVOH (A) of the total amount of the composition The ratio between the thermoplastic resin (D) and the thermoplastic resin (D) is lowered, so that there is a possibility that the performance such as the barrier property originally possessed by the EVOH (A) and the melt moldability possessed by the thermoplastic resin (D) may be lowered.
[0109]
Moreover, when W (C4) / W (C4 + C2) is less than 0.02, the compatibility between EVOH (A) and the polyamide resin (C4) is lowered, and W (C4) / W (C4 + C2) is 0.98. In the case of exceeding, the compatibility between the carboxylic acid-modified polyolefin (C2) and the thermoplastic resin (D) is lowered. A decrease in compatibility between the components leads to a decrease in mechanical strength or barrier property of the resin composition itself.
[0110]
Further, the blending weight ratio W (C4) / W (C4 + C2) of the polyamide resin (C4) and the carboxylic acid-modified polyolefin (C2) is preferably 0.5 or less from the viewpoint of thermal stability, and more preferable. Is 0.45 or less, and optimally is 0.4 or less. When the blending weight ratio W (C4) / W (C4 + C2) is in such a range, the melt stability of the resin composition is improved, and a molded article having a good appearance can be obtained even in a long-time melt molding. , Improve productivity. The reason for this is not clear, but it is thought that the reaction between EVOH and the polyamide resin has an adverse effect on the melt stability.
[0111]
The molded part for a fuel container used in the present invention preferably uses a resin composition in which a thermoplastic resin (D) is a continuous phase and EVOH (A) is a dispersed phase. By molding such a resin composition, a molded part for a fuel container having improved gasoline barrier properties while maintaining mechanical strength and impact resistance can be obtained. In order to obtain such a dispersed form, the value of W (D) / W (A + D) may be increased, or the melt viscosity ratio of (A) / (D) may be increased. The value of W (D) / W (A + D) is in the range of 0.5 to 0.99, preferably 0.55 to 0.98, and more preferably 0.6 to 0.97. . When the value of W (D) / W (A + D) is less than 0.5, it becomes difficult for the thermoplastic resin (D) to form a continuous phase and the impact resistance may be insufficient. If the value of W (D) / W (A + D) exceeds 0.99, the gasoline barrier property may be insufficient.
[0112]
(Method of kneading resin composition)
The resin composition used for this invention can be easily obtained by melt-mixing each component with a normal melt kneading apparatus. The method of blending each component is not particularly limited, but a simple combination of barrier resin (A), thermoplastic resin (B), compatibilizer (C), and thermoplastic resin (D) can be used. Examples thereof include a method of melt-kneading with a screw or twin screw extruder, pelletizing and drying. It is also possible to put the pellets of the barrier resin (A) and the pellets of the thermoplastic resin (B) into a molding machine and knead them in the molding machine. In the melt blending operation, blending may become non-uniform, and gels and blisters may be generated or mixed. For blend pelletization, an extruder with a high degree of kneading should be used, and the hopper port should be filled with nitrogen gas. It is desirable to seal with and extrude at a low temperature.
[0113]
As a method for obtaining a molded part used in the present invention, for example, an appropriate molding method in the field of general polyolefin can be used, but it is not particularly limited. However, the molded parts for fuel containers exemplified by connectors, caps, valves and the like are generally complicated in shape, and it is particularly preferable that part or all of the molded parts for fuel containers are molded by an injection molding method. .
[0114]
(Molded parts and fuel container body with molded parts attached)
The fuel container of the present invention is a container that can suitably store not only gasoline but also so-called oxygen-containing gasoline such as alcohol-containing gasoline and MTBE-containing gasoline. From the fuel container body and the molded parts attached to the fuel container body Become.
[0115]
The fuel container body is preferably made of a thermoplastic resin, and is usually made of a multilayer resin having a barrier resin layer as an intermediate layer, and a polyolefin layer is disposed as the outermost layer. It is preferable in terms of strength. As the barrier resin layer, EVOH is preferably used, and EVOH having an ethylene content of 5 to 60 mol% and a saponification degree of 90% or more is preferable. The outermost polyolefin is preferably high density polyethylene.
[0116]
The molded part used in the present invention refers to a molded part used by being attached to the fuel container body, and specifically includes a fuel container connector, a fuel container cap, a fuel container valve, and the like. It is not limited. Preferred are a fuel container connector and a fuel container valve.
[0117]
The method of attaching these molded parts to the fuel container main body is not particularly limited, and examples include screw-in, plug-in, and heat-fusion attachment, but heat-fusion attachment reduces the assembly man-hours and This is particularly preferable from the viewpoint of suppressing fuel leakage from the mounting portion. A general technique is used for heat fusion. A method of performing fusion after heating the fusion surface of a fuel container body and / or a molded part for a fuel container with a heater or the like, and the fuel container body and the molded part Examples include, but are not limited to, a method of high-frequency fusion and a method of ultrasonic fusion of the fuel container body and the molded part.
[0118]
Examples of usage of the molded part as a connector include, but are not limited to, an embodiment in which the molded component is used as a connector for a fuel container mounted on a fuel container body, and a mode in which a flexible fuel transport pipe is mounted. . Examples of the method of mounting this connector on the fuel container body include screw-in type, plug-in type, and joining by heat fusion, etc., but from the viewpoint of reducing assembly man-hours and suppressing fuel leakage from the joining part, It is preferable to attach by fusion. Therefore, it is particularly preferable that this connector is excellent in heat fusion with the fuel container body. In order to suppress fuel leakage from the fuel container body and the connector mounting portion, it is particularly preferable that the connector is excellent in gasoline barrier properties. Furthermore, it is preferable that the connector is excellent in stress crack resistance and organic solvent resistance from the viewpoint of long-term continuous use of molded parts for fuel containers, that is, product life.
[0119]
As a preferred embodiment of the fuel container connector, a flexible fuel transport pipe is joined to the fuel container connector joined to the fuel container body. For this reason, when the vehicle travels, when fuel is supplied from the fuel container to the engine, or when fuel is received from the fuel supply port to the fuel container, the fuel container itself or the transportation pipe vibrates continuously. A load is generated. From these viewpoints, it is desirable that the fuel container connector is excellent in impact resistance, stress crack resistance, and organic solvent resistance.
[0120]
The fuel container cap is used as a lid for a fuel filler opening. The joining method is not particularly limited, and examples thereof include a screwing type and a fitting type, and a screwing type is preferable. Currently, many caps for fuel containers are made of metal, but in recent years, caps made of thermoplastic resin have attracted attention from the viewpoints of weight reduction and recycling. In addition, the fuel filler port is connected to the fuel container main body via a fuel pipe and a fuel container connector. Conventionally, mixing of metal oxide into the fuel container due to rust generated from a metal fuel container cap has become a problem. ing. From this viewpoint, the presence of a cap made of a thermoplastic resin is significant. Such a fuel container cap is preferably excellent in gasoline barrier properties, organic solvent resistance, and stress crack resistance properties, and more preferably in mechanical strength such as wear resistance because it repeatedly opens and closes.
[0121]
A fuel container in which a part made of a thermosetting resin (E) is attached to a fuel container body to which a molded part is attached via a molded part is also suitable as an embodiment of the present invention. In the fuel container having the above structure, the part made of the thermosetting resin (E) has mechanical strength and excellent gasoline barrier property, and the part made of the thermosetting resin (E) and the fuel container main body are attached to the mounting portion. By interposing a molded part made of the resin composition of the present invention, it is preferable in that a high gasoline barrier property can be imparted. As the thermosetting resin (E), it is particularly preferable to use a polymethylene oxide resin from the viewpoints of mechanical strength, gasoline barrier properties, and the like. The fuel container molded part attached to the fuel container with this configuration is not particularly limited, but a fuel container pressure relief valve is suitable.
[0122]
There is no particular limitation on the method in which the part made of the thermosetting resin (E) is attached to the fuel container via the molded part. First, a molded part is attached to the fuel container body, and then a fuel container part made of a thermosetting resin (E) is attached to the molded part by a method such as a screwing type or a fitting type, or first, A method of attaching the molded part to a part made of the thermosetting resin (E) and then attaching it to the fuel container main body is exemplified, but it is not particularly limited.
[0123]
The method for attaching the molded part to the fuel container body is not particularly limited. The screw-type mounting, the fitting-type mounting, and the thermal fusion mounting are exemplified, but the thermal fusion mounting is particularly preferable from the viewpoint of reducing the number of assembly steps and suppressing fuel leakage from the mounting portion.
[0124]
The method for attaching the molded part to the part made of the thermosetting resin (E) is not particularly limited. A screwing type or a filling type method is preferred. Further, a method of coating the joint surface between the component made of the thermosetting resin (E) and the fuel container with the resin composition used in the present invention is also suitable. Since the thermosetting resin (E) and the resin composition used in the present invention generally have low adhesion, the surface of the part made of the thermosetting resin (E) is within a range that does not hinder the function of the molded part. It is particularly preferable to coat the resin composition used in the present invention as much as possible. By employ | adopting this structure, it is possible to suppress peeling of the interface between the molded part body made of the thermosetting resin (E) and the resin composition of the present invention.
[0125]
The method of coating the molded part body with the resin composition used in the present invention is not particularly limited, but the part body made of the thermosetting resin (E) previously prepared by an injection molding method or the like is placed in the mold. A method of injecting and coating the resin composition of the present invention on an injection molding machine (insert injection method), or a method of co-injecting the thermosetting resin (E) and the resin composition used in the present invention The insert injection method is particularly suitable.
[0126]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this Example.
[0127]
  (Materials used)
  referenceExample 1-4, Example 5Table 1 below shows the resin components used in the production of the molded parts of -11 and Comparative Examples 1-10.
[0128]
[Table 1]

[0129]
(Synthesis of resin used in the present invention)
(Synthesis Example 1)
The boronic acid-modified polyethylene (b-3) in Table 1 (polyethylene having a boronic acid ethylene glycol ester group at the terminal) was prepared as follows.
[0130]
Polyethylene {MFR 0.3 g / 10 min (210 ° C.-load 2160 g) density 0.90 g / cm in a separable flask equipped with a condenser, stirrer and dropping funnel³, Terminal double bond amount 0.048 meq / g} 1000 g and decalin 2500 g were charged, deaerated by reducing the pressure at room temperature, and then purged with nitrogen. To this were added 78 g of trimethyl borate and 5.8 g of borane-triethylamine complex. After reacting at 200 ° C. for 4 hours, a distillation apparatus was attached, and 100 ml of methanol was slowly added dropwise. After completion of the dropwise addition of methanol, low-boiling impurities such as methanol, trimethyl borate and triethylamine were distilled off by distillation under reduced pressure. Further, 31 g of ethylene glycol was added, stirred for 10 minutes, reprecipitated in acetone, and dried to obtain a boronic acid-modified polyethylene (b) having a boronic acid ethylene glycol ester group amount of 0.027 meq / g and an MFR of 0.2 g / 10 minutes. -3) was obtained.
[0131]
(Synthesis Example 2)
The boronic acid-modified ultra-low density polyethylene (c-3) in Table 1 (ultra-low density polyethylene having a boronic acid ethylene glycol ester group at the terminal) was prepared as follows.
[0132]
Super low density polyethylene {MFR 7 g / 10 min (210 ° C-load 2160 g) density 0.89 g / cm in a separable flask equipped with a condenser, stirrer and dropping funnel³, Terminal double bond amount 0.048 meq / g} 1000 g and decalin 2500 g were charged, deaerated by reducing the pressure at room temperature, and then purged with nitrogen. To this were added 78 g of trimethyl borate and 5.8 g of borane-triethylamine complex. After reacting at 200 ° C. for 4 hours, a distillation apparatus was attached and 100 ml of methanol was slowly added dropwise. After completion of the dropwise addition of methanol, low-boiling impurities such as methanol, trimethyl borate and triethylamine were distilled off by distillation under reduced pressure. Further, 31 g of ethylene glycol was added, stirred for 10 minutes, reprecipitated in acetone, and dried, so that boron having an ethylene glycol ester group content of 0.027 meq / g and MFR of 5 g / 10 minutes (210 ° C.—load of 2160 g) was obtained. An acid-modified ultra-low density polyethylene (c-3) was obtained.
[0133]
(Measurement of fuel permeation of resin used)
The fuel permeation amount of the barrier resin (A) was measured by the following steps (1) to (5).
(1) BA-055 manufactured by Paxon (density 0.970 g / cm) as high density polyethylene (HDPE)³MFR = 0.03 g / 10 min at 190 ° C.-load 2160 g) using ADMER GT-6AMFR 0.94 g / 10 min (190 ° C.-load 2160 g) manufactured by Mitsui Chemicals as the adhesive resin (Tie) , Barrier resin (A) and adhesive resin were charged into separate extruders, and high density polyethylene / adhesive resin / barrier resin (A) / adhesive resin / high density polyethylene (film thickness 50 μm / 5 μm / 10 μm / A coextruded sheet having a total thickness of 120 μm having a configuration of 5 μm / 50 μm was obtained by a molding apparatus. Extrusion molding was carried out with a high-density polyethylene having a diameter of 65 mm and an extruder equipped with a uniaxial screw of L / D = 24 at a temperature of 170 to 210 ° C., and the adhesive resin having a uniaxial screw of 40 mm in diameter and L / D = 22 mm. The extruder is set to a temperature of 160 to 210 ° C., the barrier resin (A) has a diameter of 40 mm, and the extruder provided with a single screw of L / D = 22 is set to a temperature of 170 to 210 ° C. ) Was operated at 210 ° C. to obtain a coextruded sheet (a1).
(2) One side of the co-extruded sheet (a1) is aluminum tape (manufactured by FP Kako Co., Ltd., trade name: aluminum seal: gasoline barrier property = 0 g · 20 μm / m²-Coated with day).
(3) The coextruded sheet (a1) and the coextruded sheet (b1) covered with aluminum tape were each cut into a size of 210 mm × 300 mm.
(4) Each cut sheet was bent at the center, and two sides were heat-sealed with a dial 6 to a seal width of 10 mm using a heat sealer T-230 manufactured by Fuji Impulse to produce a pouch.
(5) Each pouch has Ref. 200 ml of C (toluene / isooctane = 1/1) was filled from the unsealed side, and the sealed side was heat-sealed so as to have a seal width of 10 mm in the same manner as described above.
[0134]
The fuel input pouch was left in an explosion-proof constant temperature and humidity chamber (40 ° C.-65% RH), and the weight of the pouch was measured every 7 days for 3 months. Such a test was performed on each of five coextruded pouches (a2) without aluminum foil and coextruded pouches (b2) coated with aluminum tape, and the weight change of the pouch before and after each standing time was read. The fuel permeation amount was calculated from the slope of the standing time and the weight change amount of the pouch.
[0135]
The fuel permeation amount of the coextrusion pouch (a2) without the aluminum tape represents the sum of the fuel permeation amounts from both the pouch surface and the heat seal part, and the fuel permeation amount of the coextrusion pouch (b2) covered with the aluminum tape is the heat. The fuel permeation amount from the seal portion is shown.
[0136]
{Transmission amount from (a2)}-{Transmission amount from (b2)} is defined as the fuel transmission amount of the barrier resin (A), and the thickness is converted into the transmission amount per 20 μm of the barrier resin (A) layer. Fuel permeation rate of barrier resin (A) (g · 20μm / m²-Day) was obtained.
[0137]
  A. Production example 1 of single-layer molded parts
  (referenceExamples 1-4, Comparative Examples 1-4)
  referenceExample 1
  40 parts by weight of EVOH (a-1) having an ethylene content of 44 mol%, MFR 1.3 g / 10 min (190 ° C.-load 2160 g), MFR 1.1 g / 10 min (190 ° C.-load 2160 g), density 0.954 g / cm³A blend comprising 60 parts by weight of polyethylene (b-1) was obtained by the following method. That is, EVOH (a-1) and a density of 0.954 g / cm³The polyethylene (b-1) was put into a twin screw type vent type extruder and extruded and pelletized at 220 ° C. in the presence of nitrogen to obtain pellets of a resin composition.
[0138]
The obtained pellets were charged into an injection molding machine to produce a cylindrical single-layer injection-molded product having the shape of FIG. 1 and having an inner diameter of 63 mm, an outer diameter of 70 mm, and a height of 40 mm. This molded article has a shape similar to a connector for a fuel container (hereinafter referred to as a connector-like molded article). As shown in FIG. 2, the connector-like molded article 1 is attached to the container body 2 and is connected to the connector-like molded article. A pipe 3 is attached to the mouth of 1. On the other hand, high density polyethylene (HDPE: HZ8200B manufactured by Mitsui Chemicals) is used as the inner and outer layers, and adhesive resin (maleic anhydride-modified LDPE, Admer GT5A manufactured by Mitsui Chemicals) is used, and the volume is measured by a three-type five-layer direct blow molding machine. 35 liters, surface area 0.85m²An EVOH multilayer fuel container was prepared. The layer configuration of this fuel container was (outside) HDPE / adhesive resin / EVOH (a-1) / adhesive resin / HDPE (inside) = 2500/100/150/100/2500 (μm). Further, in order to evaluate performance such as mechanical strength, a flat plate having a length of 10 cm, a width of 10 cm, and a thickness of 5 mm and various test injection pieces were molded using the pellets.
[0139]
After drilling two holes with a diameter of 55 mm for mounting the connector on the fuel container, both the part and the single-layer injection-molded product of FIG. 1 produced above were melted with an iron plate at 250 ° C. for 40 seconds and then crimped. And a multi-layer fuel container was obtained. Gasoline barrier properties and adhesive strength were evaluated by the following methods using a multilayer fuel container in which two obtained single-layer injection molded articles were fused. Further, impact resistance, stress cracking resistance, and organic solvent resistance were evaluated by the following methods using a flat plate formed from the above pellets and a test injection piece. The results are shown in Table 2.
[0140]
(1) Gasoline barrier properties
A 25-liter model gasoline (toluene: isooctane = 50/50 vol%) was filled in a multilayer fuel container obtained by fusing two single-layer injection molded articles having openings, obtained by the above method. Next, an aluminum plate having a diameter of 80 mm and a thickness of 0.5 mm is firmly bonded to one side of the single-layer injection molded product with an epoxy adhesive, and then an explosion-proof constant temperature and humidity chamber (40 ° C.-65% RH) The weight loss after 4 weeks (n = 5) was measured at 4 to determine the amount of fuel permeation (g / pg · 4weeks) from a multilayer fuel container in which two single-layer injection molded products were fused.
[0141]
(2) Adhesive strength
Attach a 2 mm thick saddle-shaped wire to the connector welded to the fuel container, hang the fuel container upside down so that the connector is on the bottom, and slowly place a weight of 20 kg on the tip of the wire It was attached and observed whether or not the bonded portion was broken, and judged according to the following criteria.

[0142]
(3) Impact resistance
A flat plate sample (n = 5) obtained by injection molding of the resin composition was allowed to stand at 20 ° C.-65% RH for 2 weeks, and the impact strength was determined according to JIS K7110 using an Izod tester.
[0143]
(4) Stress crack resistance
Specified test pieces (n = 10) obtained by injection molding of the resin composition were allowed to stand at 20 ° C.-65% RH for 2 weeks, and then stress cracking characteristics (time) were measured in water according to JIS Z1703. did.
[0144]
(5) Organic solvent resistance
A disk sample (n = 5) obtained by injection molding of the resin composition was allowed to stand at 20 ° C.-65% RH for 2 weeks, and then JIS in model gasoline (toluene: isooctane = 50/50 vol%). The degree of swelling was measured according to K7114, and the appearance was observed.
The appearance was judged according to the following criteria.

[0145]
  referenceExamples 2-4, Comparative Examples 1-4
  Table 1 shows the barrier resins (A) (a-1) and (a-2) and thermoplastic resins (B) (b-1), (b-2) and (b-3) listed in Table 1. 2 to prepare a resin composition containing at a blending ratio described in 2,referenceA connector-like molded product was prepared in the same manner as in Example 1.referenceEvaluation was performed in the same manner as in Example 1. The results are shown in Table 2.
[0146]
[Table 2]

[0147]
  referenceThe molded parts for fuel containers of the present invention obtained in Examples 1 to 4 were excellent in gasoline barrier properties and impact resistance, and had sufficient heat fusion properties, stress crack resistance properties, and organic solvent resistance properties. In particular, when a carboxylic acid-modified polyolefin or boronic acid-modified polyolefin is used as the thermoplastic resin (B), it has excellent impact resistance and stress crack resistance, and has excellent gasoline barrier properties and organic solvent resistance. It was particularly suitable because it was improved.
[0148]
In Comparative Example 3 in which the barrier resin (A) was less than 5% by weight and Comparative Example 2 in which only the thermoplastic resin (B) containing no barrier resin (A) was used, the gasoline barrier property was extremely poor. Moreover, in the comparative example 1 which consists only of barrier resin (A), and the comparative example 4 in which a thermoplastic resin (B) is less than 30 weight%, heat-fusibility was unacceptable.
B. Production example 2 of single-layer molded parts
[0149]
(Examples 5-8, Comparative Examples 5-9)
Examples 5 to 8 are examples showing the production of a single-layer molded part using the compatibilizer (C) and the thermoplastic resin (D) as the thermoplastic resin (B).
[0150]
The fuel permeation amount of the barrier resin (A) was measured in the same manner as described above.
[0151]
The gasoline barrier property of the thermoplastic resin (D) was measured by the following method.
(1) Using a Toyo Seiki lab plast mill (diameter 20 mm, L / D = 22), using a coat hanger die with a width of 300 mm, extruding at a melting point of the thermoplastic resin (C) + 20 ° C. to produce a 100 μm sheet The sheet was cut into a size of 210 mm × 300 mm.
(2) The cut sheet was bent at the center, and two sides were heat-sealed to a seal width of 10 mm with a dial 6 using a heat sealer T-230 manufactured by Fuji Impulse, and a pouch was produced.
(3) The ref. 200 ml of C (toluene / isooctane = 1/1) was filled from the unsealed side, and the sealed side was heat-sealed so as to have a seal width of 10 mm in the same manner as described above.
(4) The fuel input pouch was left in an explosion-proof thermostatic chamber (40 ° C.-65% RH), and the weight of the pouch was measured every 6 hours for 3 days. This test was carried out on five pouches, the weight change of the pouch before and after each standing time was read, the fuel permeation amount of the pouch was obtained from the slope of the standing time and the weight change amount of the pouch, and the heat was converted by thickness conversion. Fuel permeation amount of plastic resin (C) (g · 20μm / m²-Day) was calculated.
[0152]
Example 5
Ethylene content 44 mol%, saponification degree 99.5%, MFR 1.3 g / 10 min (190 ° C.-2160 g) EVOH (a-1) 30 parts by weight, ethylene content 89 mol%, saponification degree 97%, MFR 5 g / 10 minutes (190 ° C.-load 2160 g) of ethylene-vinyl acetate copolymer saponified product (c-1) and MFR 1.1 g / 10 minutes (190 ° C.-load 2160 g) density 0.954 g / cm³A resin composition comprising 55 parts by weight of polyethylene (d-1) was obtained by the following method. That is, EVOH (a-1), saponified ethylene-vinyl acetate copolymer (c-1) having an ethylene content of 89 mol% and a saponification degree of 97 mol%, and a density of 0.954 g / cm³The polyethylene (d-1) was put into a twin screw type vent type extruder and extruded and pelletized at 220 ° C. in the presence of nitrogen to obtain resin composition pellets.
[0153]
  The resulting resin pelletreferenceIn the same manner as in Example 1, a fuel container (FIG. 2) equipped with a flat plate, various test injection pieces, and a connector-like cylindrical single-layer injection molded product having the shape shown in FIG. The strength, impact resistance, stress crack resistance, and organic solvent resistance were measured. The results are shown in Table 3.
[0154]
  Examples 6-8, Comparative Examples 5-8
  Barrier resins (A) (a-1) and (a-2), compatibilizers (C) (c-1), (c-2) and (c-3) listed in Table 1 and thermoplasticity A resin composition containing the resin (D) (d-1) at a blending ratio shown in Table 3 was prepared,referenceA connector-like molded product was prepared in the same manner as in Example 1.referenceEvaluation was performed in the same manner as in Example 4. The results are shown in Table 3.
[0155]
[Table 3]

[0156]
The molded parts for fuel containers obtained in Examples 5 to 8 were excellent in gasoline barrier properties and impact resistance, and had sufficient heat fusion properties, stress crack resistance properties, and organic solvent resistance. In particular, when ethylene-methacrylic acid random copolymer (c-2) or boronic acid-modified polyolefin (c-3) is used as the carboxylic acid-modified polyolefin (C2) as the compatibilizer (C), excellent resistance It was particularly suitable because it had impact resistance and stress crack resistance, and the gasoline barrier properties and organic solvent resistance were remarkably improved. In Comparative Example 8 in which the barrier resin (A) was less than 5% by weight and Comparative Example 6 in which only the thermoplastic resin (D) containing no barrier resin (A) was used, the gasoline barrier property was extremely poor. Moreover, in Comparative Example 5 consisting only of the barrier resin (A) and Comparative Example 7 in which the barrier resin (A) exceeds 70% by weight, the heat-fusibility was unacceptable.
[0157]
C. Production example 3 of single-layer molded parts
This example is a production example of a single-layer molded part using a resin composition comprising a polyamide resin and a carboxylic acid-modified polyolefin as a compatibilizer (C).
[0158]
Example 9
EVOH (a-2) 30 parts by weight, polyamide resin (f-1) 5 parts by weight, ethylene-methacrylic acid random copolymer (EMAA; c-4) 10 parts by weight and high density polyethylene (HDPE; d-2) A blend consisting of 55 parts by weight was obtained by the following method. That is, first, the polyamide resin (f-1) and EMAA (c-4) were put into a twin screw type vent type extruder and extruded and pelletized at 220 ° C. in the presence of nitrogen. EVOH (a-2) and HDPE (d-2) were blended again in the same manner to obtain pellets of the resin composition.
[0159]
  The resulting pelletreferenceIn the same manner as in Example 1, a fuel container (FIG. 2) equipped with a connector-like cylindrical single-layer injection molded product (FIG. 1) was prepared, and the gasoline barrier property was measured. For impact resistance, the blended pellet was injection molded with an injection molding machine to prepare a sample piece, and this sample piece (n = 5) was left at 20 ° C.-65% RH for 1 week, and then Izod The impact strength was determined according to ASTM-D256 using a testing machine. The evaluation results are shown in Table 4.
[0160]
Examples 10-11, Comparative Examples 9-10
Gas barrier resins (A) (a-2), (a-3), polyamide resins (f-1), compatibilizers (C) (c-4), (c-5) listed in Table 1 A connector-like cylindrical single-layer injection-molded product (FIG. 1) was mounted in the same manner as in Example 9, except that the thermoplastic resin (D) (d-2) was used at the blending ratio shown in Table 4. A fuel container (FIG. 2) was prepared and evaluated in the same manner as in Example 9. In addition, when the resin composition was composed of three components, blending was performed by one kneading operation, and when the resin composition was composed of one component, the kneading operation was not performed. The results are shown in Table 4.
[0161]
[Table 4]

[0162]
A fuel container equipped with a single-layer molded part using a resin composition comprising a polyamide and a carboxylic acid-modified polyolefin as a compatibilizer (C) has excellent appearance, performance with excellent gasoline barrier properties, and impact resistance. Had.
[0163]
【The invention's effect】
A molding comprising a barrier resin (A) having a solubility parameter (calculated from the Fedors equation) exceeding 11 and a thermoplastic resin (B) having a solubility parameter (calculated from the Fedors equation) of 11 or less. The parts are excellent in gasoline barrier properties, and exhibit excellent performance in gas barrier properties, impact resistance, heat fusion properties, mechanical strength, stress crack resistance properties, and organic solvent resistance. In a fuel container equipped with such a molded part, fuel leakage from the molded part is greatly improved.
[Brief description of the drawings]
FIG. 1 is a view showing a cylindrical single-layer injection molded product (connector-like molded product).
FIG. 2 is a view showing a usage form of a connector-like molded product.
[Explanation of symbols]
1: Connector-like molded product
2: Container body
3: Pipe

Claims (3)

A single resin composition comprising a barrier resin (A) 5 to 70% by weight, a compatibilizer (C) 1 to 85% by weight, and a thermoplastic resin (D) 10 to 94% by weight. The layer molded component is a fuel container attached to the fuel container body,
The barrier resin (A) is an ethylene- vinyl alcohol copolymer having an ethylene content of 5 to 60 mol% and a saponification degree of 85% or more ,
The compatibilizer (C) is an ethylene-vinyl acetate copolymer saponified product having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, a carboxylic acid-modified polyolefin, a boronic acid-modified polyolefin, and a polyamide 2 And at least one selected from the group consisting of a resin composition consisting of 98% by weight and 2 to 98% by weight of a carboxylic acid-modified polyolefin,
The fuel container, wherein the thermoplastic resin (D) is polyethylene having a density of 0.93 g / cm ³ or more, and the single-layer molded part is a fuel container connector, a fuel container cap or a fuel container valve. The fuel container according to claim 1, wherein all or part of the molded part is a molded part formed by an injection molding method. The molded part is mounted on the fuel container body by thermal fusion, the fuel container according to claim 1 or 2.

Images