JP4543538B2 - Oxygen absorbing package - Google Patents

Description

式中、Ｒは直鎖或いは分岐鎖のアルキル基であり、
ｎはゼロを含む正の整数である、
で表される反復単位、例えば、
乳酸ラクトン［Ｒ＝ＣＨ_３、ｎ＝０、ＬＬＡ］、
３−ヒドロキシブチレート［Ｒ＝ＣＨ_３、ｎ＝１、３ＨＢ］、
３−ヒドロキシバリレート［Ｒ＝ＣＨ_２ＣＨ_３、ｎ＝１、３ＨＶ］、
３−ヒドロキシカプロエート［Ｒ＝（ＣＨ_２）_２ＣＨ_３、ｎ＝１、３ＨＣ］、
３−ヒドロキシヘプタノエート［Ｒ＝（ＣＨ_２）_３ＣＨ_３、ｎ＝１、３ＨＨ］、
３−ヒドロキシオクタノエート［Ｒ＝（ＣＨ_２）_４ＣＨ_３ｎ＝１、３ＨＯ］、
３−ヒドロキシノナノエート［Ｒ＝（ＣＨ_２）_５ＣＨ_３ 、ｎ＝１、３ＨＮ］、
３−ヒドロキシデカノエート［Ｒ＝（ＣＨ_２）_６ＣＨ_３ 、ｎ＝１、３ＨＤ］、
等の１種或いは２種以上からなる重合体が挙げられる。
【００４５】
このポリヒドロキシアルカノエートは、ポリ乳酸のような単独重合体であってもよく、また３−ヒドロキシブチレートと、他の３−ヒドロキシアルカノエート、特に３−ヒドロキシバリレートとを共重合させた共重合体であってもよい。
【００４６】
この脂肪族ポリエステル樹脂は、少なくともフィルムを形成し得る分子量を有するべきであり、一般にその数平均分子量は、５００００乃至２５００００、特に６００００乃至２０００００の範囲にあるのがよい。
脂肪族ポリエステルは、ガラス転移点（Ｔｇ）が−６０℃以上、特に−３０℃以上のものが好ましい。
【００４７】
これらの脂肪族ポリエステルの内でも、工業的に生産されて入手が容易であり、環境にも優しい脂肪族ポリエステルとして、ポリ乳酸が挙げられる。
ポリ乳酸（ＰＬＬＡ）は、トウモロコシなどの穀物デンプンを原料とする樹脂であり、デンプンの乳酸発酵物、Ｌ−乳酸をモノマーとする重合体であり、一般にそのダイマーであるラクタイドの開環重合により製造される。この重合体は、自然界に存在する微生物により、水と炭酸ガスにより分解され、完全リサイクルシステム型の樹脂として着目されている。
また、そのガラス転移点（Ｔｇ）も約５８℃とＰＥＴのそれに近いという利点を有している。
【００４８】
（ハ）分岐鎖含有熱可塑性ポリアミド：
酸化性樹脂として使用可能なポリアミドは、このポリアミドを構成する脂肪族ジカルボン酸、脂肪族ジアミン、脂肪族アミノカルボン酸或いはそのラクタムの少なくとも一部が、炭素分岐鎖を有するものである。
一般にこのポリアミドは、分岐鎖を有する脂肪族ジアミンとジカルボン酸成分とから誘導されたポリアミドであることが好ましい。
【００４９】
分岐鎖を有するジアミン成分としては、炭素数４〜２５とくに６〜１８の直鎖状アルキレンジアミンが適当であり、その具体例としては、1,4-ジアミノ-1-メチルブタン、1,4-ジアミノ-2-メチルブタン、1,4-ジアミノ-1-エチルブタン、1,4-ジアミノ-1,2-ジメチルブタン、1,4-ジアミノ-1,3-ジメチルブタン、1,4-ジアミノ-1,4-ジメチルブタン、1,4-ジアミノ-2,3-ジメチルブタン、1,5-ジアミノ- 2-メチルペンテン、1,2-ジアミノ-1-ブチルエタン、1,6-ジアミノ-2-メチルヘキサン、1,6-ジアミノ-2,5-ジメチルヘキサン、1,6-ジアミノ-2,4-ジメチルヘキサン、1,6-ジアミノ-3,3-ジメチルヘキサン、1,6-ジアミノ-2,2-ジメチルヘキサン、1,6-ジアミノ-2,2,4-トリメチルヘキサン、1,6-ジアミノ-2,4,4-トリメチルヘキサン、1,7-ジアミノ-2-メチルヘプタン、1,7-ジアミノ-2,4-ジメチルヘプタン、1,7-ジアミノ-2,3-ジメチルヘプタン、1,7-ジアミノ-2,4-ジメチルヘプタン、1,7-ジアミノ-2,5-ジメチルヘプタン、1,7-ジアミノ-2,2-ジメチルヘプタン、1,8-ジアミノ-2-メチルオクタン、1,8-ジアミノ-1,3-ジメチルオクタン、1,8-ジアミノ-1,4-ジメチルオクタン、1,8-ジアミノ-2,4-ジメチルオクタン、1,8-ジアミノ-3,4-ジメチルオクタン、1,8-ジアミノ-4,5-ジメチルオクタン、1,8-ジアミノ-2,2-ジメチルオクタン、1,8-ジアミノ-3,3-ジメチルオクタン、1,8-ジアミノ-4,4-ジメチルオクタン、1,6-ジアミノ-2,4-ジエチルヘキサン、1,9-ジアミノ-5-メチルノナンなどが挙げられる。
【００５０】
これらの分岐鎖ジアミンは、単独でも２種以上の組合せでも使用され、更に他のジアミン成分、例えば 1,6- ジアミノヘキサン、1,8-ジアミノオクタン、1,10- ジアミノデカン、1,12- ジアミノドデカン等の炭素数４〜２５とくに６〜１８の直鎖状アルキレンジアミンや、ビス（アミノメチル）シクロヘキサン、ビス（4-アミノシクロヘキシル）メタン、4, 4′- ジアミノ-3,3′- ジメチルジシクロヘキシルメタン、特にビス（4-アミノシクロヘキシル）メタン、1,3-ビス（アミノシクロヘキシル）メタン、1,3-ビス（アミノメチル）シクロヘキサン等の脂環族ジアミン、ｍ−キシリレンジアミン及び／又はｐ−キシリレンジアミン等の芳香脂肪族ジアミンとの組合せでも用いられる。
【００５１】
一方、ジカルボン酸成分としては、例えばコハク酸、アジピン酸、セバチン酸、デカンジカルボン酸、ウンデカンジカルボン酸、ドデカンジカルボン酸等の炭素数４乃至１５の脂肪族ジカルボン酸やテレフタール酸やイソフタール酸等の芳香族ジカルボン酸が挙げられる。
【００５２】
このポリアミドには、アミノカルボン酸成分が共重合されていてもよく、このアミノカルボン酸成分としては、脂肪族アミノカルボン酸、例えばω−アミノカプロン酸、ω−アミノオクタン酸、ω−アミノウンデカン酸、ω−アミノドデカン酸や、例えばパラ−アミノメチル安息香酸、パラ−アミノフェニル酢酸等の芳香脂肪族アミノカルボン酸等を挙げることができる。
【００５３】
これらのポリアミド樹脂も、容器の機械的特性及び加工の容易さから、９８％硫酸中、1.0 g/dlの濃度及び２０℃の温度で測定した相対粘度（ηrel ）が１．３乃至４．２、特に１．５乃至３．８の範囲内にあることが望ましい。
【００５４】
（ii）ポリアミド樹脂：
ポリアミド樹脂、特にキシリレンジアミンを主体とするジアミン成分とジカルボン酸成分とから誘導されたポリアミドが、遷移金属触媒との組合せで酸化性を有することが知られており、本発明の目的にも、勿論使用することができる。
遷移金属系触媒によるポリアミド樹脂のメチレン鎖（特にアリーレン基に隣接するメチレン鎖）からの水素原子の引き抜きによるラジカルが発生し、前述したのと同様の反応機構で酸化が進行する。
【００５５】
ポリアミド樹脂としては、キシリレン基含有ポリアミドが好ましく、具体的には、ポリメタキシリレンアジパミド、ポリメタキシリレンセバカミド、ポリメタキシリレンスベラミド、ポリパラキシリレンピメラミド、ポリメタキシリレンアゼラミド等の単独重合体、及びメタキシリレン／パラキシリレンアジパミド共重合体、メタキシリレン／パラキシリレンピメラミド共重合体、メタキシリレン／パラキシリレンセバカミド共重合体、メタキシリレン／パラキシリレンアゼラミド共重合体等の共重合体、或いはこれらの単独重合体または共重合体の成分とヘキサメチレンジアミンの如き脂肪族ジアミン、ピペラジンの如き脂環式ジアミン、パラ−ビス（２アミノエチル）ベンゼンの如き芳香族ジアミン、テレフタル酸の如き芳香族ジカルボン酸、ε−カプロラクタムの如きラクタム、７−アミノヘプタン酸の如きω−アミノカルボン酸、パラ−アミノメチル安息香酸の如き芳香族アミノカルボン酸等を共重合した共重合体が挙げられるが、ｍ−キシリレンジアミン及び／又はｐ−キシリレンジアミンを主成分とするジアミン成分と、脂肪族ジカルボン酸及び／又は芳香族ジカルボン酸とから得られるポリアミドが特に好適に用いることができる。
これらのキシリレン基含有ポリアミドでは、ベンゼン環の隣接メチレン鎖の部分にラジカルの生成と酸素の吸収（パーオキサイドの生成）が効率よく起きるので酸素吸収性の点で好ましいものである。
【００５６】
本発明に用いるポリアミド樹脂は、末端アミノ基濃度が１０〜５０ｅｑ／１０^６ｇであることが好ましく、末端アミノ基濃度が上記範囲をこえると、酸素吸収速度が低下するので好ましくなく、一方末端アミノ基濃度があまり低くても酸素吸収速度の向上には限度がある。
また、本発明に用いるポリアミド樹脂は、末端カルボキシル基濃度／末端アミノ基濃度の比が、１〜１２、好ましくは２乃至１１の範囲にあるのがよい。
末端カルボキシル基濃度／末端アミノ基濃度の比が上記範囲をこえると、酸素吸収速度が低下するので好ましくなく、一方この比があまり低くても酸素吸収速度の向上には限度がある。
【００５７】
末端アミノ基濃度或いは末端カルボキシル基濃度／末端アミノ基濃度の比が前記範囲内にあるポリアミド樹脂は、市販のポリアミド樹脂の樹脂から選択して用いることができる。
一般に固相重合法で製造されたポリアミド樹脂は、他の重合法で製造されたポリアミド樹脂に比して、末端アミノ基濃度が低い範囲内にある。
また、末端アミノ基濃度が本発明で規定した範囲を上回るポリアミド樹脂でも、末端アミノ基濃度を低下させる手段を講じることにより、所定の末端アミノ基濃度とすることができる。
例えば、ポリアミドの製造工程中で、或いは製造後に、末端アミノ基にこれを封鎖するアシル化を行うことにより、末端アミノ基の低減処理を行うことができる。この目的に使用するアシル化剤としては、無水酢酸、塩化アセチル、塩化ベンゾイル、トルエンスルホン酸等の酸、酸無水物、酸ハライドなどを挙げることができるが、これらの例に限定されない。
【００５８】
これらのポリアミド樹脂は、容器の機械的特性及び加工の容易さから、９８％硫酸中、1.0 g/dlの濃度及び２０℃の温度で測定した相対粘度（ηrel ）が１．３乃至４．２、特に１．５乃至３．８の範囲内にあることが望ましい。
【００５９】
（iii） エチレン系不飽和基含有重合体：
ブタジエン、イソプレン等の共役ジエン；1,4-ヘキサジエン、3-メチル-1,4- ヘキサジエン、4-メチル-1,4- ヘキサジエン、5-メチル-1,4- ヘキサジエン、4,5-ジメチル-1,4- ヘキサジエン、7-メチル-1,6- オクタジエン等の鎖状非共役ジエン；メチルテトラヒドロインデン、5-エチリデン-2- ノルボルネン、5-メチレン-2- ノルボルネン、5-イソプロピリデン-2- ノルボルネン、5-ビニリデン-2- ノルボルネン、6-クロロメチル-5- イソプロペニル-2- ノルボルネン、ジシクロペンタジエン等の環状非共役ジエン；2,3-ジイソプロピリデン-5- ノルボルネン、2-エチリデン-3- イソプロピリデン-5- ノルボルネン、2-プロペニル-2,2- ノルボルナジエン等のトリエン等を単独重合させた重合体や、これらのポリエンを他の単量体と共重合させた共重合体は、主鎖或いは側鎖にエチレン系不飽和結合を含んでおり、酸素の吸収により酸化することが知られている。本発明においても、これらのエチレン系不飽和基含有重合体を酸化性樹脂として用いることができる。
【００６０】
（iv）遷移金属触媒：
遷移金属触媒（Ｂ）は、上記酸化性熱可塑性樹脂（Ａ）の酸化反応の触媒となるもので、遷移金属の有機酸塩或いは有機錯塩等が好適に使用される。
用いる遷移金属系触媒としては、鉄、コバルト、ニッケル等の周期律表第VIII族金属成分が好ましいが、他に銅、銀等の第Ｉ族金属：錫、チタン、ジルコニウム等の第IV族金属、バナジウムの第V族、クロム等VI族、マンガン等のVII族の金属成分を挙げることができる。これらの金属成分の内でもコバルト成分は、酸素吸収速度が大きく、特に好適なものである。
【００６１】
遷移金属系触媒は、上記遷移金属の低価数の無機酸塩或いは有機酸塩或いは錯塩の形で一般に使用される。
無機酸塩としては、塩化物などのハライド、硫酸塩等のイオウのオキシ酸塩、硝酸塩などの窒素のオキシ酸塩、リン酸塩などのリンオキシ酸塩、ケイ酸塩等が挙げられる。
一方有機酸塩としては、カルボン酸塩、スルホン酸塩、ホスホン酸塩などが挙げられるが、カルボン酸塩が本発明の目的に好適であり、その具体例としては、酢酸、プロピオン酸、イソプロピオン酸、ブタン酸、イソブタン酸、ペンタン酸、イソペンタン酸、ヘキサン酸、ヘプタン酸、イソヘプタン酸、オクタン酸、２−エチルヘキサン酸、ノナン酸、３，５，５−トリメチルヘキサン酸、デカン酸、ネオデカン酸、ウンデカン酸、ラウリン酸、ミリスチン酸、パルミチン酸、マーガリン酸、ステアリン酸、アラキン酸、リンデル酸、ツズ酸、ペトロセリン酸、オレイン酸、リノール酸、リノレン酸、アラキドン酸、ギ酸、シュウ酸、スルファミン酸、ナフテン酸等の遷移金属塩が挙げられる。
一方、遷移金属の錯体としては、β−ジケトンまたはβ−ケト酸エステルとの錯体が使用され、β−ジケトンまたはβ−ケト酸エステルとしては、例えば、アセチルアセトン、アセト酢酸エチル、１，３−シクロヘキサジオン、メチレンビス−１，３ーシクロヘキサジオン、２−ベンジル−１，３−シクロヘキサジオン、アセチルテトラロン、パルミトイルテトラロン、ステアロイルテトラロン、ベンゾイルテトラロン、２−アセチルシクロヘキサノン、２−ベンゾイルシクロヘキサノン、２−アセチル−１，３−シクロヘキサンジオン、ベンゾイル−ｐ−クロルベンゾイルメタン、ビス（４−メチルベンゾイル）メタン、ビス（２−ヒドロキシベンゾイル）メタン、ベンゾイルアセトン、トリベンゾイルメタン、ジアセチルベンゾイルメタン、ステアロイルベンゾイルメタン、パルミトイルベンゾイルメタン、ラウロイルベンゾイルメタン、ジベンゾイルメタン、ビス（４−クロルベンゾイル）メタン、ビス（メチレン−３，４−ジオキシベンゾイル）メタン、ベンゾイルアセチルフェニルメタン、ステアロイル（４−メトキシベンゾイル）メタン、ブタノイルアセトン、ジステアロイルメタン、アセチルアセトン、ステアロイルアセトン、ビス（シクロヘキサノイル）−メタン及びジピバロイルメタン等を用いることが出来る。
【００６２】
本発明に用いる酸素吸収性樹脂組成物（１）においては、遷移金属触媒（Ｂ）が金属として熱可塑性樹脂（Ａ）当たり１０乃至６０００ｐｐｍ、特に５０乃至５０００ｐｐｍの量で含有されることが望ましい。
樹脂（Ａ）に遷移金属触媒（Ｂ）を配合するには、種々の手段を用いることができる。例えば、遷移金属触媒（Ｂ）を樹脂に単に乾式でブレンドすることもでき、高濃度の遷移金属触媒（Ｂ）を含有するマスターバッチを用いた希釈法でもよい。又、遷移金属触媒（Ｂ）が樹脂に比して少量であるので、ブレンドを均質に行うために、一般に遷移金属触媒（Ｂ）を有機溶媒に溶解し、この溶液と粉末或いは粒状の樹脂とを混合し、必要によりこの混合物を不活性雰囲気下に乾燥するのがよい。
【００６３】
（２）熱可塑性樹脂と酸素吸収剤との樹脂組成物：
本発明において、酸素吸収性樹脂層としては、酸素吸収剤と熱可塑性樹脂との組成物を用いることもできる。
酸素吸収剤としては、従来この種の用途に使用されている酸素吸収剤は全て使用できるが、一般には還元性でしかも実質上水に不溶なものが好ましく、その適当な例としては、還元性を有する金属粉、例えば還元性鉄、還元性亜鉛、還元性錫粉；金属低位酸化物、例えば酸化第一鉄、四三酸化鉄、更に還元性金属化合物、例えば炭化鉄、ケイ素鉄、鉄カルボニル、水酸化鉄；などの一種又は組合せたものを主成分としたものが挙げられ、これらは必要に応じてアルカリ金属、アルカリ土類金属の水酸化物、炭酸塩、亜硫酸塩、チオ硫酸塩、第三リン酸塩、第二リン酸塩、有機酸塩、ハロゲン化物、更に活性炭、活性アルミナ、活性白土のような助剤とも組合せて使用することが出来る。
また多価フェノールを骨格内に有する高分子化合物、例えば多価フェノール含有フェノール・アルデヒド樹脂等が挙げられる。
これらの酸素吸収剤は、一般に平均１００μm 以下、特に５０μm 以下の粒径を有することが好ましい。
【００６４】
上記酸素吸収剤は吸水材と組み合わせて用いるのが好ましく、吸水剤としては、潮解性無機塩、潮解性有機化合物或いは高吸水性樹脂等が使用され、潮解性物質の例としては、塩化ナトリウム、塩化カルシウム、塩化亜鉛、塩化アンモニウム、硫酸アンモニウム、硫酸ナトリウム、硫酸マグネシウム、リン酸水素二ナトリウム、二リン酸ナトリウム、炭酸カリウム、硝酸ナトリウム等の無機塩類；グルコース、果糖、ショトウ、ゼラチン、変性カゼイン、変性デンプン、トラガントゴム等の有機化合物等が挙げられる。
また、吸水材としては高吸水性樹脂を用いることもでき、ここで高吸水性樹脂としては、本質的に水不溶性でしかも自重の数十倍から数百倍に達する水を吸水し得る能力を有する樹脂として定義される。この高吸水性樹脂は、一般に吸水性に寄与する電離性基を有すると共に、この樹脂を水不溶性にするための網状乃至架橋構造或いはゲル状構造を有している。
この高吸水性樹脂としては、アクリル酸（塩）グラフト化澱粉、澱粉のアクリロニトリルグラフト化加水分解物、アクリル酸（塩）グラフト化セルローズ等の澱粉乃至セルローズ系のグラフト誘導体や、架橋ポリアクリル酸（塩）、特にアクリル酸（塩）とジビニルベンゼン等の多官能モノマー或いは更にスチレン、アクリルエステル類等の疎水性モノマーとの共重合体；酢酸ビニルとアクリル酸エステルとの共重合体のケン化で製造されるビニルアルコール−アクリル酸（塩）ブロック共重合体；ポリビニルアルコールやポリビニルアルコールに無水マレイン酸、無水フタル酸等の酸無水物を反応させ、側鎖にカルボキシル基と架橋構造を同時に導入た変性ポリビニルアルコール等が知られている。これらの樹脂において、澱粉、セルロース或いはポリビニルアルコール成分は、ポリアクリル酸成分を不溶化してゲル状に保つ作用を有する。これらの高吸水性樹脂を全て使用できるが、就中架橋ポリアクリル酸（塩）が好ましく、このものはアクアキーブ４Ｓ、アクアキーブ１０ＳＨの商品名で製鉄化学（株）から市販されている。他の好適な例は、ビニルアルコールアクリル酸（塩）ブロック共重合体であり、住友化学（株）からスミカゲル５Ｓの商品名で市販されている。
これらの他に、吸水剤としては、シリカゲル、アルミナゲル、シリカ−アルミナゲル、各種ゼオライト等を用いることもできる。
【００６５】
熱可塑性樹脂としては、既に例示したオレフィン系樹脂や酸素バリアー性樹脂、ポリスチレン、アクリロニトリル・スチレン共重合体、ＡＢＳ、α−メチルスチレン・スチレン共重合体等のスチレン系樹脂、ポリ塩化ビニル、ポリ塩化ビニリデン、塩化ビニル・塩化ビニリデン共重合体、ポリアクリル酸メチル、ポリメタクリル酸メチル等のポリビニル化合物、ナイロン６、ナイロン６−６、ナイロン６−１０、ナイロン１１、ナイロン１２等のポリアミド、ポリエチレンテレフタレート、ポリブチレンテレフタレート等の熱可塑性ポリエステル、ポリカーボネート、ポリフエニレンオキサイド等あるいはそれらの混合物のいずれかの樹脂が使用される。
これらの内でも、オレフィン系樹脂が好適である。
【００６６】
酸素吸収剤は、熱可塑性樹脂１００重量部当たり酸素吸収剤が１乃至２００重量部、特に１０乃至１００重量部となる量で配合するのがよい。
【００６７】
［積層体］
本発明に用いる積層体は、前述した積層構造を有するが、オレフィン系樹脂内面層が３０乃至２００μｍの厚み、酸素バリアー性樹脂の第一の層が２乃至１００μｍの厚み、酸素吸収性樹脂層が２乃至３００μｍの厚み、環状オレフィン系共重合体層２乃至１００μｍの厚み、酸素バリアー性樹脂の第二の層２乃至１００μｍの厚み、オレフィン系樹脂外面層５０乃至２５００μｍの厚みをそれぞれ有することが好ましい。
オレフィン系樹脂内面層の厚みが上記範囲を下回ると衛生的特性やフレーバー保持性が低下する傾向があり、この厚みが上記範囲を上回ると包装内の酸素吸収性が低下する傾向がある。
酸素バリアー樹脂の第一の層の厚みが上記範囲を下回ると、酸素吸収性樹脂層の活性化が不十分となる傾向があり、一方この厚みが上記範囲を上回ると包装内の酸素吸収性が低下する傾向があると共に、包装体のコストも増加するので好ましくない。
酸素吸収性樹脂層の厚みが上記範囲を下回ると、包装内の酸素の吸収性も、器壁透過酸素の吸収性も低下するので好ましくなく、またこの厚みが上記範囲よりも厚くても格別の酸素吸収性の増大は望めなく、経済的には不利となるので好ましくない。
環状オレフィン系共重合体の厚みが上記範囲を下回ると、包装内水分による酸素バリアー樹脂の第二の層へのバリアー性の悪影響がでるので好ましくなく、上記範囲よりも厚くても格別の利点は望めなく、経済的には不利となるので好ましくない。
酸素バリアー樹脂の第二層の厚みが上記範囲を下回ると、器壁透過酸素に対するバリアー性が低下するので好ましくなく、またこの厚みが上記範囲よりも厚くても格別の酸素バリアー性の増大は望めなく、経済的には不利となるので好ましくない。
ポリオレフィン外面材の厚みが上記範囲を下回るとオレフィン系樹脂による保護効果が低下する傾向があり、一方厚みが上記範囲を上回ると容器の柔軟性や可撓性が低下する傾向がある。
【００６８】
上記積層体の製造に当たって、各樹脂層間に必要により接着剤樹脂を介在させることもできる。

を主鎖又は側鎖に、１乃至７００ミリイクイバレント（meq)／１００ｇ樹脂、特に１０乃至５００meq／１００ｇ樹脂の濃度で含有する熱可塑性樹脂が挙げられる。
接着剤樹脂の適当な例は、エチレン−アクリル酸共重合体、イオン架橋オレフイン共重合体、無水マレイン酸グラフトポリエチレン、無水マレイン酸グラフトポリプロピレン、アクリル酸グラフトポリオレフイン、エチレン−酢酸ビニル共重合体、共重合ポリエステル、共重合ポリアミド等の１種又は２種以上の組合せである。これらの樹脂は、同時押出或いはサンドイッチラミネーション等による積層に有用である。
また、予じめ形成された酸素バリアー性樹脂フイルムとオレフィン系樹脂フイルムとの接着積層には、イソシアネート系或いはエポキシ系等の熱硬化型接着剤樹脂も使用される。
これらの接着剤層は、一般に２乃至２０μｍの厚さで用いることが好ましい。
【００６９】
本発明の多層の包装材料及び包装容器において、全体の厚みは、用途によっても相違するが、一般に１００乃至３４００μｍ、特に４００乃至９００μｍのあるのがよい。
【００７０】
本発明に用いる包装材料及び包装容器は、前述した積層構成を用いる点を除けば、それ自体公知の方法で製造が可能である。
例えば、フィルム、シート或いはチューブの成形は、前記樹脂組成物を押出機で溶融混練した後、Ｔ−ダイ、サーキュラーダイ（リングダイ）等を通して所定の形状に押出すことにより行われ、Ｔ−ダイ法フィルム、ブローウンフィルム等が得られる。Ｔダイフィルムはこれを二軸延伸することにより、二軸延伸フィルムが形成される。
また、前記樹脂組成物を射出機で溶融混練した後、射出金型中に射出することにより、容器や容器製造用のプリフォーム、更には容器蓋殻体を製造する。
更に、前記樹脂組成物を押出機を通して、一定の溶融樹脂塊に押し出し、これを金型で圧縮成形することにより、容器や容器製造用のプリフォーム、更には容器蓋殻体を製造する。
成形物は、フイルム、シート、ボトル、カップ、キャップ、チューブ形成用パリソン乃至はパイプ、ボトル乃至チューブ成形用プリフォーム等の形をとり得る。
パリソン、パイプ或いはプリフォームからのボトルの形成は、押出物を一対の割型でピンチオフし、その内部に流体を吹込むことにより容易に行われる。
また、パイプ乃至はプリフォームを冷却した後、延伸温度に加熱し、軸方向に延伸すると共に、流体圧によって周方向にブロー延伸することにより、延伸ブローボトル等が得られる。
更に、また、フイルム乃至シートを、真空成形、圧空成形、張出成形、プラグアシスト成形等の手段に付することにより、カップ状、トレイ状等の包装容器が得られる。
【００７１】
フィルム等の包装材料は、種々の形態の包装袋として用いることができ、その製袋は、それ自体公知の製袋法で行うことができ、三方或いは四方シールの通常のパウチ類、ガセット付パウチ類、スタンディングパウチ類、ピロー包装袋などが挙げられるが、この例に限定されない。
【００７２】
多層押出成形体の製造には、それ自体公知の共押出成形法を用いることができ、例えば樹脂の種類に応じた数の押出機を用いて、多層多重ダイを用いる以外は上記と同様にして押し出し成形を行えばよい。
また、多層射出成形体の製造には、樹脂の種類に応じた数の射出成形機を用いて、共射出法や逐次射出法により多層射出成形体を製造することができる。
更に、多層フィルムや多層シートの製造には、押出コート法や、サンドイッチラミネーションを用いることができ、また、予め形成されたフィルムのドライラミネーションによって多層フィルムあるいはシートを製造することもできる。
【００７３】
本発明の包装体は、酸素による内容物の香味低下を防止し、シェルフライフを向上させる容器として有用である。
充填できる内容物としては、飲料ではビール、ワイン、フルーツジュース、炭酸ソフトドリンク等、食品では果物、ナッツ、野菜、肉製品、幼児食品、コーヒー、ジャム、マヨネーズ、ケチャップ、食用油、ドレッシング、ソース類、佃煮類、乳製品類等、その他では医薬品、化粧品、ガソリン等、酸素存在下で劣化を起こしやすい内容品などが挙げられるが、これらの例に限定されない。
【００７４】
【実施例】
本発明を次の例により更に説明するが、本発明はこれらの実施例に制限されるものでない。
【００７５】
［実施例１］
α−オレフィンが１−ブテンであるα−オレフィン共重合体の酸変性低密度ポリエチレンに、二軸押出し機を用いて、コバルト濃度が５０００ｐｐｍになるよう、有機金属触媒ステアリン酸コバルトをメルトブレンドした。押出し温度１６０℃〜２２０℃。次に、溶融混合樹脂をストランド状に引き取り、ペレタイザーにてペレット成形した。これを試験樹脂組成物として用い、更に、５本の押出し機からなる多層押出し成形機を用い、押出し温度１７０℃〜２２０℃の温度範囲で、内層から外層に至る層構成が、ＬＤＰＥ／接着層／エチレンビニルアルコール共重合層／試験樹脂層／環状オレフィン樹脂層／接着層／エチレンビニルアルコール共重合体層／接着層／ＬＤＰＥからなるパリソンをブロー成形にて、内層から外層に至る各層の肉厚が、１００μｍ／２０μｍ／３０μｍ／３０μｍ／３０μｍ／２０μｍ／３０μｍ／２０μｍ／１７０μｍの総肉厚４５０μｍの５種９層チューブを成形した。
【００７６】
（評価）
作成したチューブの口部をアルミラミネートフィルムにてヒートシールした後、真空チャンバーに入れ、脱気、窒素置換操作を３回繰り返した。次に、窒素気体中で、チューブに脱気水を２ｍｌ充填後、底部をヒートシールした。以後、温度４０℃−相対湿度７５％の保存条件下、３週間保存後、ガスタイトシリンジを用い、チューブ内空気を１ｍｌ捕集し、島津製作所社製ＴＣＤ検知器付きＧＣ−９ＡＭガスクロマトグラフィーにて、チューブ内酸素濃度を測定し、結果を表１に示した。
【００７７】
［比較例１］
α−オレフィンが１−ブテンであるα−オレフィン共重合体の酸変性低密度ポリエチレンに、二軸押出し機を用いて、コバルト濃度が５０００ｐｐｍになるよう、有機金属塩：ステアリン酸コバルトをメルトブレンドした。押出し温度１６０℃〜２２０℃。次に、溶融混合樹脂をストランド状に引き取り、ペレタイザーにてペレット成形した。これを試験樹脂組成物として、更に、５本の押出し機からなる多層押出し成形機を用い、押出し温度１７０℃〜２２０℃の温度範囲で、内層から外層に至る層構成が、ＬＤＰＥ／接着層／試験樹脂層／環状オレフィン樹脂層／接着層／エチレンビニルアルコール共重合層／接着層／ＬＤＰＥとなるパリソンをブロー成形し、各層の肉厚が、１００μｍ／２０μｍ／３０μｍ／３０μｍ／２０μｍ／３０μｍ／２０μｍ／２００μｍの総肉厚４５０μｍの５種８層チューブを成形した。
（評価）
サンプル作成、保存条件、チューブ内酸素濃度測定は実施例１と同様の方法で行った。結果は表１に示す。
【００７８】
［実施例２］
低密度ポリエチレンに酸化促進材（塩化ナトリウム）が２部含有及び３０部の鉄粉からなる組成物を、二軸押出し機を用い、押出し温度１６０℃〜２２０℃にてメルトブレンドした。これを試験樹脂組成物として、更に、５本の押出し機からなる多層押出し成形機を用い、押出し温度１７０℃〜２２０℃の温度範囲で、内層から外層に至る層構成が、ＬＤＰＥ／接着層／エチレンビニルアルコール共重合層／試験樹脂層／環状オレフィン樹脂層／接着層／エチレンビニルアルコール共重合層／接着層／ＬＤＰＥからなるパリソンをブロー成形し、各層の肉厚が、１００μｍ／２０μｍ／３０μｍ／３０μｍ／３０μｍ／２０μｍ／３０μｍ／２０μｍ／１７０μｍの総肉厚が４５０μｍの５種９層チューブを成形した。
【００７９】
（評価）
作成したチューブの口部をアルミラミネートフィルムにてヒートシールした後、大気条件下、リン酸系緩衝剤を含有する、過酸化水素濃度４ｗｔ％の過酸化水溶液を４０ｇ充填し、底部をヒートシールした。次に、温度４０℃−相対湿度７５％の保存条件下、２ヶ月保存後、ガスタイトシリンジを用い、チューブ内空気を１ｍｌ捕集し、島津製作所社製ＴＣＤ検知器付きＧＣ−９ＡＭガスクロマトグラフィーにて、チューブ内酸素濃度を測定し、結果を表２に示した。
【００８０】
［比較例２］
低密度ポリエチレンに酸化促進材（塩化ナトリウム）が２部含有及び３０部の鉄粉からなる組成物を、二軸押出し機を用い、押出し温度１６０℃〜２２０℃にてメルトブレンドした。次に、溶融混合樹脂をストランド状に引き取り、ペレタイザーにてペレット成形した。これを試験樹脂組成物とし、更に、５本の押出し機からなる多層押出し成形機を用い、押出し温度１７０℃〜２２０℃の温度範囲で、内層から外層に至る層構成が、ＬＤＰＥ／接着層／試験樹脂層／環状オレフィン樹脂層／接着層／エチレンビニルアルコール共重合体層／接着層／ＬＤＰＥからなるパリソンをブロー成形にて、各層の肉厚が、１００μｍ／２０μｍ／３０μｍ／３０μｍ／２０μｍ／３０μｍ／２０μｍ／２００μｍである総肉厚４５０μｍの５種８層チューブを成形した。
（評価）
サンプル作成、保存条件、チューブ内酸素濃度測定は実施例２と同様に行った。結果は表２に示す。
【００８１】
【表１】

【００８２】
【表２】

【００８３】
【発明の効果】
本発明によれば、酸素吸収性樹脂層４の内面側に、酸素バリアー性樹脂の第一の層３を設け、酸素吸収性樹脂層４の外面側に環状オレフィン系共重合体層５を設け、この共重合体層５の外面側に酸素バリアー性樹脂の第二の層６を設けることにより、包装内の酸素濃度を低いレベルに抑制することができる。
酸素バリアー性樹脂の第一の層３及び酸素バリアー性樹脂の第二の層６は共に、器壁を通しての酸素透過を抑制する酸素バリアーとして役立つが、酸素バリアー性樹脂の第一の層３は、包装内水分により、酸素吸収性樹脂層４を活性化して、包装内酸素及び器壁を透過して内部に浸透しようとする酸素の吸収にも有効に寄与する。
即ち、酸素バリアー性樹脂は、一般に強い水素結合を有するものであり、水分を吸収し、吸着する傾向が大きい。本発明は、酸素バリアー性樹脂の第一の層３が吸収乃至吸着し内容品側から器壁外部方向への酸素の透過速度を高めるとともに酸素吸収性樹脂層４の活性化に利用するものである。
また、酸素バリアー性樹脂の第二の層６と酸素吸収性樹脂層４との間に環状オレフィン系共重合体層５を設けることにより、包装内水分による酸素バリアー性樹脂の第二の層６の酸素バリアー低下を抑制し、酸素バリアー性樹脂の第二の層６の酸素バリアー性能を高めることができる。
【図面の簡単な説明】
【図１】本発明の包装材に用いる積層体の断面構造の一例を示す断面図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oxygen-absorbing package, and more particularly to an oxygen-absorbing package having a specific multilayer structure and capable of reducing the oxygen concentration in the package.
[0002]
[Prior art]
Conventionally, metal cans, glass bottles, various plastic containers, and the like are used as packaging containers, but plastic containers are used for various applications in terms of light weight, impact resistance, and cost.
[0003]
However, in the case of metal cans and glass bottles, oxygen permeation through the container wall is zero, whereas in the case of plastic containers, oxygen permeation through the container wall occurs in an order that cannot be ignored. It is a problem.
[0004]
In order to prevent this, a plastic container has a multi-layered container wall, and an oxygen-permeable resin such as an ethylene-vinyl alcohol copolymer is used as at least one layer.
[0005]
In order to remove oxygen in the container, an oxygen absorbent has been used for a long time. As an example of applying this to a container wall, there is an invention of Japanese Patent Publication No. 62-1824, A multilayer structure for packaging is formed by laminating a layer formed by blending an oxygen-permeable resin with an oxygen absorbent containing a reducing substance as a main component and a layer having an oxygen gas barrier property.
[0006]
In JP-A-8-118552, when the oxygen permeation amount at 20 ° C. and 65% RH is 20 μm, 20 cc / m.²A gas barrier resin layer is formed from a resin composition in which a gas barrier resin having a capacity of 24 h · atm is mixed with an oxygen scavenger, and protective layers made of a moisture-resistant thermoplastic resin are formed on both sides of the gas barrier resin layer. There is described a gas barrier laminate characterized in that it is provided and has a layer structure in which the gas barrier resin layer and the protective layer are not melt bonded.
[0007]
In JP-A-8-197692, a laminated material comprising two or more gas barrier layers and one or more of each of an adhesive layer, an intermediate layer, and a protective layer, the adhesive layer, the intermediate layer, and the protective layer A gas barrier laminate is described in which an oxygen scavenger and / or a hygroscopic agent is contained in at least one layer.
[0008]
In JP-A-9-40024, at least a part of a container has a heat-sealable thermoplastic resin inner layer, an oxygen absorbent-containing thermoplastic resin layer, and a thermoplastic resin having a thickness of 10 μm or more from the inner surface side to the outer surface side. A sealed container excellent in storage stability, characterized by comprising a laminate container material of a cushion layer, an oxygen barrier layer and a heat resistant resin outer layer is described.
[0009]
Japanese Patent Application Laid-Open No. 9-11416 includes an inner and outer layer containing an olefin resin and an intermediate layer containing an amorphous or low crystalline copolymer of an olefin and a cyclic olefin. A scent-retaining multi-layer container is described.
[0010]
[Problems to be solved by the invention]
Oxygen in the packaging container has an important effect on the storage stability and flavor retention of the contents of the container.
The oxygen in the package is classified into two types, oxygen existing from the beginning of sealing in the head space or the like in the packaging container and oxygen penetrating through the packaging wall after packaging and entering the interior. A laminated packaging material including an absorbent resin layer and an oxygen barrier resin layer is not yet sufficient for the purpose of absorbing these oxygens or preventing their permeation.
[0011]
Therefore, the object of the present invention is excellent in both the ability to absorb oxygen and the ability to prevent permeation of oxygen as compared with the conventional laminated package, and as a result, the oxygen concentration in the package is lowered. It is in providing the oxygen absorptive package which can be suppressed.
[0012]
[Means for Solving the Problems]
  According to the present invention, from the inside of the package toward the outside of the package,Made of ethylene-vinyl alcohol copolymerFirst layer of oxygen barrier resin / oxygen-absorbing resin layer / cyclic olefin copolymer layer /Made of ethylene-vinyl alcohol copolymerAn oxygen-absorbing package having a laminated structure of a second layer of an oxygen barrier resin / an outer surface layer of an olefin resin is provided.
[0013]
  In the package of the present invention, the olefin-based resin inner layer is 30 to 200 μm thick, the oxygen barrier resin first layer is 2 to 100 μm thick, the oxygen-absorbing resin layer is 5 to 300 μm thick, cyclic olefin It is preferable that the copolymer layer has a thickness of 2 to 100 μm, a second layer 2 to 100 μm of the oxygen barrier resin, and a thickness of 50 to 2500 μm of the olefin resin outer surface layer.Yes.
  As the oxygen-absorbing resin layer, a resin composition of an oxidizing resin and a transition metal catalyst, or a resin composition of a thermoplastic resin and an oxygen absorbent is preferably used.
  The package of the present invention is preferably in the form of a tube container or a blow molded container, but of course is not limited to this form.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
[Multilayer structure and function of package]
In FIG. 1 showing an example of the oxygen-absorbing package of the present invention, this oxygen-absorbing package 1 is an olefin-based resin inner surface layer 2 / first layer of oxygen barrier resin from the inside of the package to the outside of the package. 3 / Oxygen-absorbing resin layer 4 / cyclic olefin copolymer layer 5 / oxygen barrier resin second layer 6 / olefin resin outer layer 7
[0015]
In the oxygen-absorbing package of the present invention, an oxygen-barrier resin first layer 3 is provided on the inner surface side of the oxygen-absorbing resin layer 4, and a cyclic olefin copolymer is provided on the outer surface side of the oxygen-absorbing resin layer 4. It is important to provide the layer 5 and to provide the second layer 6 of the oxygen barrier resin on the outer surface side of the copolymer layer 5.
[0016]
The first layer 3 of oxygen barrier resin and the second layer 6 of oxygen barrier resin both serve as oxygen barriers that suppress oxygen permeation through the vessel wall, but the first layer 3 of oxygen barrier resin is The oxygen-absorbing resin layer 4 is activated by the moisture in the package, and effectively contributes to absorption of oxygen in the package and oxygen that permeates through the vessel wall and penetrates into the vessel wall.
That is, the oxygen barrier resin generally has a strong hydrogen bond, and has a large tendency to absorb and adsorb moisture. When moisture is adsorbed, the oxygen barrier property is lowered and oxygen easily permeates. In the present invention, the moisture absorbed or adsorbed by the first layer 3 of the oxygen barrier resin is used to activate the oxygen absorbing resin layer 4.
[0017]
Further, by providing the cyclic olefin copolymer layer 5 between the oxygen barrier resin second layer 6 and the oxygen absorbing resin layer 4, the second oxygen barrier resin layer 6 due to moisture in the package is provided. An oxygen barrier fall can be suppressed and the oxygen barrier performance of the 2nd oxygen barrier resin layer 6 can be improved.
[0018]
According to the present invention, the above can be integrated and the oxygen concentration in the package can be suppressed to a low level.
In the package of the present invention, the olefin-based resin inner surface layer 2 and the olefin-based resin outer surface layer 7 are used because they are a resin excellent in hygienic properties and also excellent in moisture resistance to some extent. This is because it is possible.
[0019]
The above layer structure shows a basic layer structure, and it is natural that an adhesive layer can be provided between the respective layers when there is no thermal adhesiveness between the respective layers.
Hereinafter, the constituent material of the present invention will be described.
[0020]
[Olefin resin]
In the present invention, an olefin resin is used for the inner and outer surfaces of the laminate.
Examples of the polyolefin include low-, medium- or high-density polyethylene, linear low density polyethylene, isotactic polypropylene, syndiotactic polypropylene, linear low density polyethylene, ethylene-propylene copolymer, polybutene-1, Poly-4-methyl-1-pentene, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ion-crosslinked olefin copolymer Examples thereof include polymers (ionomers) and ethylene-acrylic acid ester copolymers. These can be used alone or in the form of a blend of two or more.
[0021]
From the viewpoint of heat resistance against retort sterilization, crystalline propylene polymers are suitable. Under the condition that they are homopolypropylene or crystalline, propylene-based random copolymers and block copolymers are used. used.
The propylene polymer to be used preferably has a melt flow rate (JIS K6758) of 0.8 to 12 g / 10 min.
[0022]
When the oxygen absorbing layer is colored, the polyolefin inner surface material and outer surface material are desirably blended with a white pigment, particularly titanium dioxide, for the purpose of concealing the oxygen absorbing layer. The blending amount of titanium dioxide is not particularly limited, but a range of 5 to 25 parts by weight per 100 parts by weight of polyolefin is appropriate.
[0023]
[Oxygen barrier resin]
As the oxygen barrier resin, the above-described thermoplastic resin having the oxygen permeability coefficient and the hygroscopic property and capable of being thermoformed is used.
The most suitable example of the oxygen barrier resin is an ethylene-vinyl alcohol copolymer, for example, an ethylene-vinyl acetate copolymer having an ethylene content of 20 to 60 mol%, particularly 25 to 50 mol%. A saponified copolymer obtained by saponifying the polymer so that the saponification degree is 96 mol% or more, particularly 99 mol% or more is used. The saponified ethylene-vinyl alcohol copolymer should have a molecular weight sufficient to form a film and is generally 0.01 dl measured at 30 ° C. in a 85:15 weight ratio of phenol: water in a mixed solvent. It is desirable to have a viscosity of not less than / g, especially not less than 0.05 dl / g.
[0024]
Other examples of the oxygen barrier resin having the above characteristics include polyamides having 5 to 50, especially 6 to 20, amide groups per 100 carbon atoms; for example, nylon 6, nylon 6,6, nylon 6 / 6,6 copolymer, metaxylylene asiamid, nylon 6,10, nylon 11, nylon 12, nylon 13, etc. are used.
These polyamides should also have a molecular weight sufficient to form a film, and the relative viscosity (ηrel) measured at a concentration of 1.0 g / dl in concentrated sulfuric acid and at a temperature of 30 ° C. is 1.1 or more, particularly 1.5 or more. Is desirable.
[0025]
[Cyclic olefin copolymer]
Examples of the cyclic olefin copolymer include an amorphous or low crystalline copolymer (COC) of an olefin and a cyclic olefin. As the olefin of this copolymer, ethylene is preferable, but in addition, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methyl 1-pentene, 1-decene and the like having 3 to 3 carbon atoms. Twenty α-olefins are used alone or in combination with ethylene.
[0026]
The cyclic olefin is basically an alicyclic hydrocarbon compound having an ethylenically unsaturated bond and a bicyclo ring, particularly a hydrocarbon compound having a bicyclo [2,2,1] hept-2-ene skeleton. Specific examples include the following, but of course not limited thereto.
[0027]
Bicyclo [2.2.1] hept-2-ene and its derivatives;
Tricyclo [4.3.0.1^2.5] -3-decene and its derivatives;
Tricyclo [4.3.0.1^2.5] -3-decene and its derivatives;
Tricyclo [4.4.0.1^2.5] -3-Undecene and its derivatives;
Tricyclo [4.4.0.1^2.5] -3-Undecene and its derivatives;
Tetracyclo [4.4.0.1^2.5 . 1^7.10] -3-dodecene and its derivatives;
Pentacyclo [6.5.1.1^3.6 . 0^2.7 . 0^9.13] -4-pentadecene and its derivatives;
Pentacyclo [7.4.0.1^2.5 . 1^9.12. 0^8.13] -3-Pentadecene and its derivatives;
Pentacyclo [7.4.0.1^2.5 . 1^9.12. 0^8.13] -3-Pentadecene and its derivatives;
Pentacyclo [6.5.1.1^3.6. 0^2.7 . 0^9.13] -4,10-pentadecadiene and its derivatives;
Pentacyclo [6.5.1.1^3.6 . 0^2.7 . 0^9.13] -4,10-pentadecadiene derivative;
Pentacyclo [8.4.0.1^2.5 . 1^9.12. 0^8.13] -3-hexadecene and its derivatives;
Pentacyclo [6.6.1.1^3.6 . 0^2.7. 0^9.14] -4-hexadecene and its derivatives;
Hexacyclo [6.6.1.1^3.6 . 1^10.13 . 0^2.7 . 0^9.14] -4-heptadecene and its derivatives;
Heptacyclo [8.7.0.1^2.9 . 1^4.7 . 1^11.17 . 0^3.8 . 0^12.16 ] -5-eicosene and its derivatives;
Heptacyclo [8.7.0.1^3.6 . 1^10.17. 1^12.15 . 0^2.7. 0^11.16 ] -4-eicosene and its derivatives;
Heptacyclo [8.8.0.1^2.9 . 1^4.7. 1^11.18 . 0^3.8. 0^12.17 ] -5-Heneicosene and its derivatives;
Heptacyclo [8.8.0.1^4.7. 1^11.18 . 1^13.16. 0^3.8 . 0^12.17 ] -5-Heneicosene and its derivatives;
Octacyclo [8.8.0.1^2.9. 1^4.7. 1^11.18. 1^13.16. 0^3.8 . 0^12.17 ] -5-docosene and its derivatives;
Nonacyclo [10.9.1.1^4.7 . 1^13.20 . 1^15.18 . 0^2.10 . 0^3.8. 0^12.21 . 0^14.19 ] -5-pentacosene and derivatives thereof;
Nonacyclo [10.10.1.1.1^5.8. 1^14.21 . 1^16.19. 0^2.11. 0^4.9 . 0^13.22 . 0^15.20 ] -6-Hexacocene and its derivatives;
5-Phenyl-bicyclo [2.2.1] hept-2-ene
5-Methyl-5-phenyl [2.2.1] hept-2-ene
5-Benzyl-bicyclo [2.2.1] hept-2-ene
5-Tolyl-bicyclo [2.2.1] hept-2-ene
5- (Ethylphenyl) -bicyclo [2.2.1] hept-2-ene
5- (Isopropylphenyl) -bicyclo [2.2.1] hept-2-ene
5- (biphenyl) -bicyclo [2.2.1] hept-2-ene
5- (β-Naphtyl) -bicyclo [2.2.1] hept-2-ene
5- (α-Naphtyl) -bicyclo [2.2.1] hept-2-ene
5- (Anthracenyl) -bicyclo [2.2.1] hept-2-ene
5,6-Diphenyl-bicyclo [2.2.1] hept-2-ene
Cyclopentadiene-acenaphthylene adduct
1,4-methano-1,4,4a, 9a-tetrahydrofluorene
1,4-methano-1,4,4a, 5,10,10a-hexahydroanthracene 8-phenyl-tetracyclo [4.4.0.1^2.5 . 1^7.10  ] -3-Dodecene
8-Methyl-8-phenyl-tetracyclo [4.4.0.1^2.5 . 1^7.10 ] -3-Dodecene
8-Benzyl-tetracyclo [4.4.0.1^2.5 . 1^7.10 ] -3-Dodecene
8-Tolyl-tetracyclo [4.4.0.1^2.5 . 1^7.10 ] -3-Dodecene
8- (Ethylphenyl) -tetracyclo [4.4.0.1^2.5 . 1^7.10 ] -3-Dodecene
8- (Isopropylphenyl) -tetracyclo [4.4.0.1^2.5 . 1^7.10] -3-Dodecene
8,9-diphenyl-tetracyclo [4.4.0.1^2.5 . 1^7.10 ] -3-Dodecene
8- (biphenyl) tetracyclo [4.4.0.1^2.5. 1^7.10] -3-Dodecene
8- (β-naphthyl) tetracyclo [4.4.0.1^2.5 . 1^7.10 ] -3-Dodecene
8- (α-naphthyl) -tetracyclo [4.4.0.1^2.5 . 1^7.10 ] -3-Dodecene
8- (anthracenyl) -tetracyclo [4.4.0.1^2.5. 1^7.10] -3-Dodecene
Compound in which cyclopentadiene is further added to (cyclopentadiene-acenaphthylene adduct)
11,12-benzo-pentacyclo [6.5.1.1^3.6 . 0^2.7 . 0^9.13 ] -4-Pentadecene
11,12-benzo-pentacyclo [6.6.1.1^3.6 . 0^2.7. 0^9.14] -4-Hexadecene
11-phenyl-hexacyclo [6.6.1.1^3.6 . 1^10.13 . 0^2.7 . 0^9.14] -4-Heptadecene
14,15-Benzo-heptacyclo [8.7.0.1^2.9 . 1^4.7 . 1^11.17. 0^3.8. 0^12.16 -5-eikosen]
[0028]
This copolymer (COC) is derived from 10 to 50 mol%, in particular 12 to 48 mol% of cyclic olefin and the remaining ethylene and has a glass transition point of 5 to 200 ° C., in particular 40 to 190 ° C. Is good.
[0029]
The molecular weight of this copolymer is not particularly limited, but it should have an intrinsic viscosity [η] of 0.1 to 5 dl / g measured in decalin at 135 ° C., and its crystallinity is It is generally 10% or less, particularly 5% or less, as measured by X-ray diffraction.
[0030]
The copolymer (COC) can be obtained by random polymerization of an olefin and a cyclic olefin in the presence of a vanadium catalyst or a metallocene catalyst known per se.
[0031]
A suitable copolymer (COC) is available from Mitsui Chemicals, Inc. under the trade name APEL.
[0032]
[Oxygen-absorbing resin layer]
As the oxygen-absorbing resin layer, a resin composition of an oxidizing resin and a transition metal catalyst, or a resin composition of a thermoplastic resin and an iron-based oxygen absorber is used.
[0033]
(1) Resin composition of oxidizing resin and transition metal catalyst:
The oxidizing resin is a resin that is oxidized by oxygen in the air by the action of a catalyst of a transition metal catalyst, and includes (i) a carbon side chain (a) and a carboxylic acid group in the main chain or side chain. A resin containing at least one functional group (b) selected from the group consisting of a carboxylic acid anhydride group, a carboxylic acid ester group, a carboxylic acid amide group, and a carbonyl group, (ii) a polyamide resin, and (iii) an ethylene-based resin An unsaturated group-containing polymer is used.
This example will be described below.
[0034]
Resin (i):
As a specific example of such a thermoplastic resin,
(A) at least selected from the group consisting of a unit derived from an α-olefin or polyene having 3 or more carbon atoms, a carboxylic acid group, a carboxylic acid anhydride group, a carboxylic acid ester group, a carboxylic acid amide group, and a carbonyl group A branched chain-containing modified olefin resin comprising a unit derived from an unsaturated monomer having one functional group,
(B) a branched chain-containing thermoplastic polyester derived from an aliphatic dicarboxylic acid, an aliphatic diol, an aliphatic oxycarboxylic acid or a lactone thereof having a branched chain, particularly an aliphatic polyester,
(C) Branched chain-containing thermoplastic polyamides derived from aliphatic dicarboxylic acids, aliphatic diamines, aliphatic aminocarboxylic acids or lactams having branched chains, particularly aliphatic polyamides.
[0035]
In the carbon-carbon main chain of the resin, hydrogen atoms are easily extracted, and the position where radicals are easily generated is considered to be the position of the tertiary carbon atom or methine group to which the carbon side chain is bonded. Oxygen absorption in the composition containing the transition metal catalyst and the resin is carried out through oxidation of the resin. (1) This oxidation is performed from the tertiary carbon atom by the transition metal catalyst. It is believed to occur through the elementary reactions of radical generation by abstraction of hydrogen atoms, (2) generation of peroxy radicals by addition of oxygen molecules to the radicals, and (3) abstraction of hydrogen atoms by peroxy radicals.
However, under the coexistence of a small amount of a transition metal catalyst that does not cause deterioration of the resin even under normal conditions, there is an induction period in the generation of the above radicals and addition of oxygen, and these elementary reactions are not necessarily effectively performed. Conceivable.
On the other hand, the thermoplastic resin (i) is a group consisting of a carboxylic acid group, a carboxylic acid anhydride group, a carboxylic acid ester group, a carboxylic acid amide group, and a carbonyl group in addition to the carbon side chain (a). It is believed that it has at least one functional group (b) selected more effectively and is useful for shortening the induction period.
That is, each of the functional groups (b) is an electron-withdrawing group and activates the tertiary carbon atom, and / or the functional group (b) is an adsorption site for the transition metal catalyst component. The reason is that.
[0036]
(A) Modified olefin resin:
The α-olefin used for introducing a branched chain into the olefin resin is suitably an α-olefin having 3 to 20 carbon atoms, specifically, propylene, 1-butene, 4-methyl-1 -Pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene 1-nonadecene, 1-eicosene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, and the like.
[0037]
Polyene can also be used to introduce a branched chain into an olefin resin, and as such polyene, a resin containing a unit derived from a polyene having 4 to 20 carbon atoms, a chain or cyclic conjugated or nonconjugated polyene. Are preferably used. Examples of these monomers include conjugated dienes such as butadiene and isoprene; 1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4 -Chain non-conjugated dienes such as hexadiene, 4,5-dimethyl-1,4-hexadiene, 7-methyl-1,6-octadiene; methyltetrahydroindene, 5-ethylidene-2-norbornene, 5-methylene-2- Cyclic non-conjugated dienes such as norbornene, 5-isopropylidene-2-norbornene, 5-vinylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, dicyclopentadiene; 2,3-diisopropylidene Examples include trienes such as -5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, and 2-propenyl-2,2-norbornadiene.
[0038]
These α-olefins and polyenes can be used alone or in combination of two or more for polymerization of olefinic resins, and can be used for polymerization of olefinic resins in combination with other olefins such as ethylene. .
[0039]
In addition, at least one functional group (b) selected from the group consisting of a carboxylic acid group, a carboxylic acid anhydride group, a carboxylic acid ester group, a carboxylic acid amide group and a carbonyl group is introduced into the olefin resin. Examples of the monomer used include ethylenically unsaturated monomers having the functional group (b) and carbon monoxide.
[0040]
As these monomers, it is desirable to use unsaturated carboxylic acids or derivatives thereof, and specifically, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, etc. α, β-unsaturated carboxylic acid, unsaturated carboxylic acid such as bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydroanhydride Α, β unsaturated carboxylic acid anhydrides such as phthalic acid, anhydrides of unsaturated carboxylic acids such as bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid anhydride, methyl acrylate, Methyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconic acid, tetrahydroanhydride Dimethyl, bicyclo [2,2,1] hept-2-ene-5,6-esters of unsaturated carboxylic acids dicarboxylic acids such as dimethyl and the like can be exemplified. Among these, maleic acid, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid or anhydrides thereof are preferable.
[0041]
The modification of the olefinic resin is produced by using an olefinic resin having a carbon branched chain as a base polymer and graft copolymerizing an unsaturated carboxylic acid or a derivative thereof to the base polymer by a method known per se. It can also be produced by random copolymerization of an α-olefin or polyene with an unsaturated carboxylic acid or derivative thereof.
[0042]
A preferred modified olefin resin is a modified olefin resin having an α-olefin having 4 or more carbon atoms as a structural unit, specifically, maleic anhydride-modified polybutene-1, maleic anhydride-modified butene-1, and ethylene. Examples of the polymer include a maleic anhydride-modified butene-1 / propylene copolymer and a maleic anhydride-modified butene-1 / propylene / ethylene copolymer.
The modified olefin resin preferably has a melt flow rate (MFR, JIS K6760) in the range of 0.1 to 50 g / 10 min, particularly 0.2 to 30 g / 10 min in view of workability and mechanical properties.
[0043]
(B) Branched chain-containing thermoplastic polyester:
Any thermoplastic polyester derived from an acid component having a carbon branched chain, a diol component, a hydroxycarboxylic acid component, or a lactone component can be used as an oxygen-absorbing agent.
Suitable aliphatic polyester resins include biodegradable aliphatic polyester resins mainly composed of branched chain-containing hydroxyalkanoate units.
[0044]
Examples of the branched chain-containing polyhydroxyalkanoate include the following formula (I)

In the formula, R is a linear or branched alkyl group,
n is a positive integer including zero,
A repeating unit represented by
Lactic acid lactone [R = CH₃, N = 0, LLA],
3-hydroxybutyrate [R = CH₃, N = 1, 3HB],
3-hydroxyvalerate [R = CH₂CH₃, N = 1, 3HV],
3-hydroxycaproate [R = (CH₂)₂CH₃, N = 1, 3HC],
3-hydroxyheptanoate [R = (CH₂)₃CH₃, N = 1, 3HH],
3-hydroxyoctanoate [R = (CH₂)₄CH₃n = 1, 3HO],
3-hydroxynonanoate [R = (CH₂)₅CH₃, N = 1, 3HN],
3-hydroxydecanoate [R = (CH₂)₆CH₃, N = 1, 3HD],
The polymer which consists of 1 type, or 2 or more types, etc. is mentioned.
[0045]
The polyhydroxyalkanoate may be a homopolymer such as polylactic acid, and is a copolymer obtained by copolymerizing 3-hydroxybutyrate with another 3-hydroxyalkanoate, particularly 3-hydroxyvalerate. It may be a polymer.
[0046]
The aliphatic polyester resin should have at least a molecular weight capable of forming a film, and generally its number average molecular weight should be in the range of 50,000 to 250,000, especially 60000 to 200,000.
The aliphatic polyester preferably has a glass transition point (Tg) of -60 ° C or higher, particularly -30 ° C or higher.
[0047]
Among these aliphatic polyesters, polylactic acid is mentioned as an aliphatic polyester that is industrially produced and easily available and is also environmentally friendly.
Polylactic acid (PLLA) is a resin made from cereal starches such as corn, and is a lactic acid fermentation product of starch and a polymer using L-lactic acid as a monomer, and is generally produced by ring-opening polymerization of lactide, a dimer thereof. Is done. This polymer is decomposed by water and carbon dioxide by microorganisms that exist in nature, and has attracted attention as a completely recycle system type resin.
In addition, the glass transition point (Tg) has an advantage of about 58 ° C., which is close to that of PET.
[0048]
(C) Branched chain-containing thermoplastic polyamide:
The polyamide that can be used as the oxidizable resin is one in which at least a part of the aliphatic dicarboxylic acid, aliphatic diamine, aliphatic aminocarboxylic acid or lactam constituting the polyamide has a carbon branched chain.
Generally, this polyamide is preferably a polyamide derived from a branched aliphatic diamine and a dicarboxylic acid component.
[0049]
As the diamine component having a branched chain, a linear alkylenediamine having 4 to 25 carbon atoms, particularly 6 to 18 carbon atoms is suitable. Specific examples thereof include 1,4-diamino-1-methylbutane and 1,4-diamino. -2-methylbutane, 1,4-diamino-1-ethylbutane, 1,4-diamino-1,2-dimethylbutane, 1,4-diamino-1,3-dimethylbutane, 1,4-diamino-1,4 -Dimethylbutane, 1,4-diamino-2,3-dimethylbutane, 1,5-diamino-2-methylpentene, 1,2-diamino-1-butylethane, 1,6-diamino-2-methylhexane, 1 , 6-Diamino-2,5-dimethylhexane, 1,6-diamino-2,4-dimethylhexane, 1,6-diamino-3,3-dimethylhexane, 1,6-diamino-2,2-dimethylhexane 1,6-diamino-2,2,4-trimethylhexane, 1,6-diamino-2,4,4-trimethylhexane, 1,7-diamino-2-methylheptane, 1,7-diamino-2, 4-dimethylheptane 1,7-diamino-2,3-dimethylheptane, 1,7-diamino-2,4-dimethylheptane, 1,7-diamino-2,5-dimethylheptane, 1,7-diamino-2,2-dimethyl Heptane, 1,8-diamino-2-methyloctane, 1,8-diamino-1,3-dimethyloctane, 1,8-diamino-1,4-dimethyloctane, 1,8-diamino-2,4-dimethyl Octane, 1,8-diamino-3,4-dimethyloctane, 1,8-diamino-4,5-dimethyloctane, 1,8-diamino-2,2-dimethyloctane, 1,8-diamino-3,3 -Dimethyloctane, 1,8-diamino-4,4-dimethyloctane, 1,6-diamino-2,4-diethylhexane, 1,9-diamino-5-methylnonane and the like.
[0050]
These branched diamines may be used alone or in combination of two or more, and further diamine components such as 1,6-diaminohexane, 1,8-diaminooctane, 1,10-diaminodecane, 1,12- Linear alkylenediamines having 4 to 25 carbon atoms, especially 6 to 18 carbon atoms such as diaminododecane, bis (aminomethyl) cyclohexane, bis (4-aminocyclohexyl) methane, 4,4'-diamino-3,3'-dimethyl Dicyclohexylmethane, especially alicyclic diamines such as bis (4-aminocyclohexyl) methane, 1,3-bis (aminocyclohexyl) methane, 1,3-bis (aminomethyl) cyclohexane, m-xylylenediamine and / or p -Also used in combination with araliphatic diamines such as xylylenediamine.
[0051]
On the other hand, examples of the dicarboxylic acid component include aromatic dicarboxylic acids having 4 to 15 carbon atoms such as succinic acid, adipic acid, sebacic acid, decanedicarboxylic acid, undecanedicarboxylic acid, and dodecanedicarboxylic acid, and aromatics such as terephthalic acid and isophthalic acid. Group dicarboxylic acids.
[0052]
The polyamide may be copolymerized with an aminocarboxylic acid component. Examples of the aminocarboxylic acid component include aliphatic aminocarboxylic acids such as ω-aminocaproic acid, ω-aminooctanoic acid, ω-aminoundecanoic acid, Examples thereof include ω-aminododecanoic acid and aromatic aliphatic aminocarboxylic acids such as para-aminomethylbenzoic acid and para-aminophenylacetic acid.
[0053]
These polyamide resins also have a relative viscosity (η rel) of 1.3 to 4.2 measured in 98% sulfuric acid at a concentration of 1.0 g / dl and a temperature of 20 ° C. due to the mechanical properties of the container and ease of processing. In particular, it is desirable to be in the range of 1.5 to 3.8.
[0054]
(Ii) Polyamide resin:
Polyamide resins, particularly polyamides derived from a diamine component mainly composed of xylylenediamine and a dicarboxylic acid component, are known to have oxidizing properties in combination with a transition metal catalyst, and for the purposes of the present invention, Of course, it can be used.
Radicals are generated by the extraction of hydrogen atoms from the methylene chain (especially the methylene chain adjacent to the arylene group) of the polyamide resin by the transition metal catalyst, and oxidation proceeds by the same reaction mechanism as described above.
[0055]
The polyamide resin is preferably a xylylene group-containing polyamide, specifically, polymetaxylylene adipamide, polymetaxylylene sebacamide, polymetaxylylene veramide, polyparaxylylene pimeramide, polymetaxylylene azease. Homopolymers such as ramids, and metaxylylene / paraxylylene adipamide copolymers, metaxylylene / paraxylylene pimeramide copolymers, metaxylylene / paraxylylene sebacamide copolymers, metaxylylene / paraxylylene azease A copolymer such as a ramid copolymer, or a homopolymer or copolymer component thereof, an aliphatic diamine such as hexamethylenediamine, an alicyclic diamine such as piperazine, and para-bis (2aminoethyl) benzene. Aromatic diamines such as terephthalic acid A copolymer obtained by copolymerizing an acid, a lactam such as ε-caprolactam, an ω-aminocarboxylic acid such as 7-aminoheptanoic acid, an aromatic aminocarboxylic acid such as para-aminomethylbenzoic acid, and the like. A polyamide obtained from a diamine component mainly composed of xylylenediamine and / or p-xylylenediamine and an aliphatic dicarboxylic acid and / or an aromatic dicarboxylic acid can be particularly preferably used.
These xylylene group-containing polyamides are preferable in terms of oxygen absorption because radical generation and oxygen absorption (peroxide generation) occur efficiently in the adjacent methylene chain portion of the benzene ring.
[0056]
The polyamide resin used in the present invention has a terminal amino group concentration of 10 to 50 eq / 10.⁶When the terminal amino group concentration exceeds the above range, it is not preferable because the oxygen absorption rate decreases. On the other hand, even if the terminal amino group concentration is too low, there is a limit to the improvement of the oxygen absorption rate.
The polyamide resin used in the present invention may have a terminal carboxyl group concentration / terminal amino group concentration ratio in the range of 1 to 12, preferably 2 to 11.
If the ratio of the terminal carboxyl group concentration / terminal amino group concentration exceeds the above range, the oxygen absorption rate is lowered, which is not preferable.
[0057]
A polyamide resin having a terminal amino group concentration or a terminal carboxyl group concentration / terminal amino group concentration ratio within the above range can be selected from commercially available polyamide resins.
Generally, a polyamide resin produced by a solid phase polymerization method has a lower terminal amino group concentration than a polyamide resin produced by another polymerization method.
Even with a polyamide resin having a terminal amino group concentration exceeding the range specified in the present invention, a predetermined terminal amino group concentration can be obtained by taking a means for reducing the terminal amino group concentration.
For example, the terminal amino group can be reduced by acylating the terminal amino group during or after the production process of the polyamide. Examples of the acylating agent used for this purpose include acids such as acetic anhydride, acetyl chloride, benzoyl chloride, and toluenesulfonic acid, acid anhydrides, and acid halides, but are not limited to these examples.
[0058]
These polyamide resins have a relative viscosity (ηrel) of 1.3 to 4.2 measured in 98% sulfuric acid at a concentration of 1.0 g / dl and a temperature of 20 ° C. due to the mechanical properties of the container and ease of processing. In particular, it is desirable to be in the range of 1.5 to 3.8.
[0059]
(Iii) Ethylenically unsaturated group-containing polymer:
Conjugated dienes such as butadiene and isoprene; 1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4,5-dimethyl- Chain non-conjugated dienes such as 1,4-hexadiene, 7-methyl-1,6-octadiene; methyltetrahydroindene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2- Cyclic non-conjugated dienes such as norbornene, 5-vinylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, dicyclopentadiene; 2,3-diisopropylidene-5-norbornene, 2-ethylidene- Polymers obtained by homopolymerizing trienes such as 3-isopropylidene-5-norbornene and 2-propenyl-2,2-norbornadiene, and copolymers obtained by copolymerizing these polyenes with other monomers are: Eth on main chain or side chain It contains a lenic unsaturated bond and is known to oxidize by absorption of oxygen. Also in the present invention, these ethylenically unsaturated group-containing polymers can be used as oxidizing resins.
[0060]
(Iv) Transition metal catalyst:
The transition metal catalyst (B) serves as a catalyst for the oxidation reaction of the oxidizable thermoplastic resin (A), and an organic acid salt or an organic complex salt of a transition metal is preferably used.
The transition metal catalyst used is preferably a group VIII metal component of the periodic table such as iron, cobalt, nickel, etc., but also a group I metal such as copper, silver, etc .: a group IV metal such as tin, titanium, zirconium, etc. And V group of vanadium, Group VI such as chromium, and Group VII metal components such as manganese. Among these metal components, the cobalt component is particularly suitable because of its high oxygen absorption rate.
[0061]
The transition metal catalyst is generally used in the form of a low-valent inorganic acid salt, organic acid salt or complex salt of the transition metal.
Examples of inorganic acid salts include halides such as chlorides, sulfur oxyacid salts such as sulfates, nitrogen oxyacid salts such as nitrates, phosphorus oxyacid salts such as phosphates, and silicates.
On the other hand, examples of the organic acid salt include a carboxylate, a sulfonate, and a phosphonate. The carboxylate is suitable for the purpose of the present invention, and specific examples thereof include acetic acid, propionic acid, and isopropion. Acid, butanoic acid, isobutanoic acid, pentanoic acid, isopentanoic acid, hexanoic acid, heptanoic acid, isoheptanoic acid, octanoic acid, 2-ethylhexanoic acid, nonanoic acid, 3,5,5-trimethylhexanoic acid, decanoic acid, neodecanoic acid , Undecanoic acid, Lauric acid, Myristic acid, Palmitic acid, Margaric acid, Stearic acid, Arachic acid, Linderic acid, Tuzic acid, Petroceric acid, Oleic acid, Linoleic acid, Linolenic acid, Arachidonic acid, Formic acid, Oxalic acid, Sulfamine Examples thereof include transition metal salts such as acid and naphthenic acid.
On the other hand, as the transition metal complex, a complex with β-diketone or β-keto acid ester is used, and examples of β-diketone or β-keto acid ester include acetylacetone, ethyl acetoacetate, 1,3-cyclohexane. Sadione, methylenebis-1,3-cyclohexadione, 2-benzyl-1,3-cyclohexadione, acetyltetralone, palmitoyltetralone, stearoyltetralone, benzoyltetralone, 2-acetylcyclohexanone, 2-benzoylcyclohexanone 2-acetyl-1,3-cyclohexanedione, benzoyl-p-chlorobenzoylmethane, bis (4-methylbenzoyl) methane, bis (2-hydroxybenzoyl) methane, benzoylacetone, tribenzoylmethane, diacetylbenzoylmethane Stearoylbenzoylmethane, palmitoylbenzoylmethane, lauroylbenzoylmethane, dibenzoylmethane, bis (4-chlorobenzoyl) methane, bis (methylene-3,4-dioxybenzoyl) methane, benzoylacetylphenylmethane, stearoyl (4-methoxybenzoyl) ) Methane, butanoylacetone, distearoylmethane, acetylacetone, stearoylacetone, bis (cyclohexanoyl) -methane, dipivaloylmethane, and the like can be used.
[0062]
In the oxygen-absorbing resin composition (1) used in the present invention, the transition metal catalyst (B) is preferably contained as a metal in an amount of 10 to 6000 ppm, particularly 50 to 5000 ppm, per thermoplastic resin (A).
Various means can be used for blending the transition metal catalyst (B) with the resin (A). For example, the transition metal catalyst (B) can be simply blended with the resin in a dry manner, or a dilution method using a masterbatch containing a high concentration of the transition metal catalyst (B) may be used. In addition, since the transition metal catalyst (B) is a small amount compared to the resin, the transition metal catalyst (B) is generally dissolved in an organic solvent in order to carry out the blending homogeneously. And, if necessary, the mixture may be dried under an inert atmosphere.
[0063]
(2) Resin composition of thermoplastic resin and oxygen absorbent:
In the present invention, as the oxygen-absorbing resin layer, a composition of an oxygen absorbent and a thermoplastic resin can also be used.
As the oxygen absorbent, all the oxygen absorbents conventionally used for this kind of application can be used, but in general, those which are reducible and substantially insoluble in water are preferable. Metal powders containing, for example, reducing iron, reducing zinc, reducing tin powders; metal lower oxides such as ferrous oxide, iron tetroxide, and reducing metal compounds such as iron carbide, silicon iron, iron carbonyl , Iron hydroxide; and the like based on one or a combination thereof, such as alkali metal, alkaline earth metal hydroxide, carbonate, sulfite, thiosulfate, It can be used in combination with auxiliary agents such as tertiary phosphate, secondary phosphate, organic acid salt, halide, and activated carbon, activated alumina, activated clay.
Moreover, the high molecular compound which has polyhydric phenol in frame | skeleton, for example, polyhydric phenol containing phenol aldehyde resin, etc. are mentioned.
These oxygen absorbents generally have an average particle size of 100 μm or less, particularly 50 μm or less.
[0064]
The oxygen absorbent is preferably used in combination with a water-absorbing material. As the water-absorbing agent, a deliquescent inorganic salt, a deliquescent organic compound, a superabsorbent resin, or the like is used. Examples of the deliquescent substance include sodium chloride, Inorganic salts such as calcium chloride, zinc chloride, ammonium chloride, ammonium sulfate, sodium sulfate, magnesium sulfate, disodium hydrogen phosphate, sodium diphosphate, potassium carbonate, sodium nitrate; glucose, fructose, shot, gelatin, modified casein, modified Examples include organic compounds such as starch and tragacanth gum.
In addition, a highly water-absorbing resin can also be used as the water-absorbing material, and the highly water-absorbing resin has an ability to absorb water that is essentially insoluble in water and reaches several tens to several hundred times its own weight. Defined as having resin. This highly water-absorbing resin generally has an ionizing group that contributes to water absorption, and also has a network or cross-linked structure or a gel-like structure for making the resin water-insoluble.
Examples of the highly water-absorbing resin include starch or cellulose-based graft derivatives such as acrylic acid (salt) grafted starch, acrylonitrile grafted hydrolyzate of starch, acrylic acid (salt) grafted cellulose, and crosslinked polyacrylic acid ( Salt), especially a copolymer of acrylic acid (salt) and a polyfunctional monomer such as divinylbenzene or a hydrophobic monomer such as styrene or acrylic ester; a saponification of a copolymer of vinyl acetate and acrylic ester Manufactured vinyl alcohol-acrylic acid (salt) block copolymer; polyvinyl alcohol and polyvinyl alcohol were reacted with acid anhydrides such as maleic anhydride and phthalic anhydride, and a carboxyl group and a crosslinked structure were simultaneously introduced into the side chain. Modified polyvinyl alcohol and the like are known. In these resins, the starch, cellulose or polyvinyl alcohol component has the action of insolubilizing the polyacrylic acid component and keeping it in a gel state. Although all of these superabsorbent resins can be used, cross-linked polyacrylic acid (salt) is particularly preferred, and these are commercially available from Steel Manufacturing Chemical Co., Ltd. under the trade names of Aquakive 4S and Aquakive 10SH. Another suitable example is a vinyl alcohol acrylic acid (salt) block copolymer, which is commercially available from Sumitomo Chemical Co., Ltd. under the trade name Sumikagel 5S.
In addition to these, silica gel, alumina gel, silica-alumina gel, various zeolites and the like can also be used as the water absorbing agent.
[0065]
Examples of the thermoplastic resin include olefin resins and oxygen barrier resins already exemplified, polystyrene, styrene resins such as acrylonitrile / styrene copolymer, ABS, α-methylstyrene / styrene copolymer, polyvinyl chloride, and polychlorinated chloride. Polyvinylidene chloride, vinyl chloride / vinylidene chloride copolymer, polyvinyl compounds such as polymethyl acrylate and polymethyl methacrylate, polyamides such as nylon 6, nylon 6-6, nylon 6-10, nylon 11 and nylon 12, polyethylene terephthalate, A resin such as thermoplastic polyester such as polybutylene terephthalate, polycarbonate, polyphenylene oxide, or a mixture thereof is used.
Of these, olefin-based resins are preferred.
[0066]
The oxygen absorbent is preferably blended in an amount of 1 to 200 parts by weight, particularly 10 to 100 parts by weight, per 100 parts by weight of the thermoplastic resin.
[0067]
[Laminate]
The laminate used in the present invention has the above-described laminate structure, but the olefin-based resin inner layer has a thickness of 30 to 200 μm, the oxygen barrier resin first layer has a thickness of 2 to 100 μm, and the oxygen-absorbing resin layer has It is preferable to have a thickness of 2 to 300 μm, a thickness of the cyclic olefin copolymer layer 2 to 100 μm, a thickness of the second layer 2 to 100 μm of the oxygen barrier resin, and a thickness of 50 to 2500 μm of the olefin resin outer surface layer. .
When the thickness of the olefin-based resin inner surface layer is below the above range, hygienic characteristics and flavor retention tend to be reduced, and when the thickness exceeds the above range, oxygen absorption in the package tends to be reduced.
If the thickness of the first layer of the oxygen barrier resin is less than the above range, the activation of the oxygen absorbing resin layer tends to be insufficient, while if the thickness exceeds the above range, the oxygen absorbability in the package is reduced. This tends to decrease and increases the cost of the package, which is not preferable.
If the thickness of the oxygen-absorbing resin layer is less than the above range, the oxygen absorbability in the package and the absorbability of oxygen transmitted through the vessel wall are also not preferable, and even if this thickness is larger than the above range, it is exceptional. An increase in oxygen absorbability cannot be expected, which is not preferable because it is economically disadvantageous.
If the thickness of the cyclic olefin copolymer is less than the above range, it is not preferable because the barrier property to the second layer of the oxygen barrier resin due to moisture in the package is undesirable, and even if it is thicker than the above range, the special advantage is This is not preferable because it cannot be expected and is economically disadvantageous.
If the thickness of the second layer of the oxygen barrier resin is less than the above range, the barrier property against oxygen transmitted through the vessel wall is lowered, which is not preferable, and even if the thickness is larger than the above range, a significant increase in oxygen barrier property can be expected. This is not preferable because it is economically disadvantageous.
When the thickness of the polyolefin outer surface material is less than the above range, the protective effect by the olefin resin tends to be reduced. On the other hand, when the thickness exceeds the above range, the flexibility and flexibility of the container tend to be reduced.
[0068]
In manufacturing the laminate, an adhesive resin may be interposed between the resin layers as necessary.

Is a thermoplastic resin containing 1 to 700 milliquivalent (meq) / 100 g resin, particularly 10 to 500 meq / 100 g resin in the main chain or side chain.
Suitable examples of the adhesive resin include ethylene-acrylic acid copolymer, ion-crosslinked olefin copolymer, maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, acrylic acid grafted polyolefin, ethylene-vinyl acetate copolymer, copolymer. One type or a combination of two or more types such as polymerized polyester and copolymerized polyamide. These resins are useful for lamination by coextrusion or sandwich lamination.
In addition, an isocyanate-based or epoxy-based thermosetting adhesive resin is also used for adhesive lamination of the oxygen barrier resin film and the olefin resin film that are formed in advance.
These adhesive layers are generally preferably used in a thickness of 2 to 20 μm.
[0069]
In the multilayer packaging material and packaging container of the present invention, the overall thickness varies depending on the application, but it is generally 100 to 3400 μm, particularly 400 to 900 μm.
[0070]
The packaging material and packaging container used in the present invention can be produced by a method known per se, except that the above-described laminated structure is used.
For example, the film, sheet, or tube is formed by melt-kneading the resin composition with an extruder and then extruding it into a predetermined shape through a T-die, a circular die (ring die), etc. Method film, blown film, etc. are obtained. The T-die film is biaxially stretched to form a biaxially stretched film.
Moreover, after melt-kneading the said resin composition with an injection machine, it injects into an injection die, and manufactures the container, the preform for container manufacture, and also the container lid shell.
Further, the resin composition is extruded into a certain molten resin mass through an extruder and compression molded with a mold to produce a container, a preform for producing the container, and further a container lid shell.
The molded product may take the form of a film, a sheet, a bottle, a cup, a cap, a tube forming parison or pipe, a bottle or tube forming preform, and the like.
Formation of a bottle from a parison, a pipe or a preform is easily performed by pinching off the extrudate with a pair of split molds and blowing a fluid into the inside.
Further, after cooling the pipe or the preform, it is heated to a stretching temperature, stretched in the axial direction, and blow-stretched in the circumferential direction by a fluid pressure to obtain a stretch blow bottle or the like.
Furthermore, a cup or tray-like packaging container can be obtained by subjecting the film or sheet to means such as vacuum forming, pressure forming, bulging forming, or plug assist forming.
[0071]
Packaging materials such as film can be used as packaging bags of various forms, and the bags can be produced by a known bag making method. Ordinary pouches with three- or four-side seals, pouches with gussets. , Standing pouches, pillow packaging bags, and the like, but are not limited to this example.
[0072]
For the production of a multilayer extrusion molded body, a known coextrusion molding method can be used. For example, the number of extruders corresponding to the type of resin is used, and a multilayer multiple die is used in the same manner as described above. Extrusion molding may be performed.
Further, in the production of a multilayer injection molded article, a multilayer injection molded article can be produced by a co-injection method or a sequential injection method using a number of injection molding machines corresponding to the type of resin.
Furthermore, for the production of a multilayer film or a multilayer sheet, an extrusion coating method or sandwich lamination can be used, and the multilayer film or sheet can also be produced by dry lamination of a film formed in advance.
[0073]
The package of this invention is useful as a container which prevents the fall of the flavor of the content by oxygen and improves shelf life.
Contents that can be filled include beer, wine, fruit juice, carbonated soft drink for beverages, fruit, nuts, vegetables, meat products, infant food, coffee, jam, mayonnaise, ketchup, cooking oil, dressing, sauces for food , Boiled foods, dairy products, etc., and other items such as pharmaceuticals, cosmetics, gasoline, etc., which are susceptible to deterioration in the presence of oxygen, but are not limited to these examples.
[0074]
【Example】
The invention is further illustrated by the following examples, but the invention is not limited to these examples.
[0075]
[Example 1]
The acid-modified low density polyethylene of the α-olefin copolymer in which the α-olefin is 1-butene was melt blended with an organometallic catalyst cobalt stearate using a twin screw extruder so that the cobalt concentration was 5000 ppm. Extrusion temperature 160 to 220 ° C. Next, the molten mixed resin was taken up into a strand shape, and pelletized with a pelletizer. Using this as a test resin composition, and using a multi-layer extruder comprising 5 extruders, the layer structure from the inner layer to the outer layer at an extrusion temperature of 170 ° C. to 220 ° C. is an LDPE / adhesive layer Thickness of each layer from the inner layer to the outer layer by blow molding a parison consisting of / ethylene vinyl alcohol copolymer layer / test resin layer / cyclic olefin resin layer / adhesive layer / ethylene vinyl alcohol copolymer layer / adhesive layer / LDPE However, five types and nine-layer tubes with a total thickness of 450 μm of 100 μm / 20 μm / 30 μm / 30 μm / 30 μm / 20 μm / 30 μm / 20 μm / 170 μm were formed.
[0076]
(Evaluation)
After the mouth of the prepared tube was heat-sealed with an aluminum laminate film, it was placed in a vacuum chamber, and degassing and nitrogen replacement operations were repeated three times. Next, 2 ml of degassed water was filled into the tube in nitrogen gas, and then the bottom was heat sealed. Thereafter, after storage for 3 weeks under a storage condition of a temperature of 40 ° C. and a relative humidity of 75%, 1 ml of air in the tube was collected using a gas tight syringe and subjected to GC-9AM gas chromatography with a TCD detector manufactured by Shimadzu Corporation. The oxygen concentration in the tube was measured, and the results are shown in Table 1.
[0077]
[Comparative Example 1]
The acid-modified low density polyethylene of the α-olefin copolymer in which the α-olefin is 1-butene was melt blended with an organic metal salt: cobalt stearate so that the cobalt concentration was 5000 ppm using a twin screw extruder. . Extrusion temperature 160 to 220 ° C. Next, the molten mixed resin was taken up into a strand shape, and pelletized with a pelletizer. Using this as a test resin composition, a multilayer extrusion molding machine comprising 5 extruders was used, and the layer structure from the inner layer to the outer layer at an extrusion temperature of 170 ° C. to 220 ° C. was LDPE / adhesive layer / A parison to be a test resin layer / cyclic olefin resin layer / adhesive layer / ethylene vinyl alcohol copolymer layer / adhesive layer / LDPE is blow molded, and the thickness of each layer is 100 μm / 20 μm / 30 μm / 30 μm / 20 μm / 30 μm / 20 μm. 5 types of 8 layer tubes having a total wall thickness of 450 μm / 200 μm were formed.
(Evaluation)
Sample preparation, storage conditions, and measurement of oxygen concentration in the tube were performed in the same manner as in Example 1. The results are shown in Table 1.
[0078]
[Example 2]
A composition comprising 2 parts of an oxidation promoter (sodium chloride) and 30 parts of iron powder in low density polyethylene was melt blended at an extrusion temperature of 160 ° C. to 220 ° C. using a twin screw extruder. Using this as a test resin composition, a multilayer extrusion molding machine comprising 5 extruders was used, and the layer structure from the inner layer to the outer layer at an extrusion temperature of 170 ° C. to 220 ° C. was LDPE / adhesive layer / A parison consisting of ethylene vinyl alcohol copolymer layer / test resin layer / cyclic olefin resin layer / adhesive layer / ethylene vinyl alcohol copolymer layer / adhesive layer / LDPE was blow molded, and the thickness of each layer was 100 μm / 20 μm / 30 μm / Five types of 9-layer tubes having a total thickness of 450 μm of 30 μm / 30 μm / 20 μm / 30 μm / 20 μm / 170 μm were formed.
[0079]
(Evaluation)
After the mouth of the prepared tube was heat sealed with an aluminum laminate film, 40 g of a hydrogen peroxide concentration 4 wt% aqueous peroxide solution containing a phosphate buffer was filled under atmospheric conditions, and the bottom was heat sealed. . Next, after storage for 2 months under a storage condition of a temperature of 40 ° C. and a relative humidity of 75%, 1 ml of air in the tube was collected using a gas tight syringe, and GC-9AM gas chromatography with a TCD detector manufactured by Shimadzu Corporation The oxygen concentration in the tube was measured and the results are shown in Table 2.
[0080]
[Comparative Example 2]
A composition comprising 2 parts of an oxidation promoter (sodium chloride) and 30 parts of iron powder in low density polyethylene was melt blended at an extrusion temperature of 160 ° C. to 220 ° C. using a twin screw extruder. Next, the molten mixed resin was taken up into a strand shape, and pelletized with a pelletizer. Using this as a test resin composition, and using a multi-layer extrusion molding machine comprising 5 extruders, the layer structure from the inner layer to the outer layer at an extrusion temperature of 170 ° C. to 220 ° C. is LDPE / adhesive layer / Parison consisting of test resin layer / cyclic olefin resin layer / adhesive layer / ethylene vinyl alcohol copolymer layer / adhesive layer / LDPE is blow molded, and the thickness of each layer is 100 μm / 20 μm / 30 μm / 30 μm / 20 μm / 30 μm. Five types of eight-layer tubes having a total thickness of 450 μm, which were / 20 μm / 200 μm, were formed.
(Evaluation)
Sample preparation, storage conditions, and measurement of oxygen concentration in the tube were performed in the same manner as in Example 2. The results are shown in Table 2.
[0081]
[Table 1]

[0082]
[Table 2]

[0083]
【The invention's effect】
According to the present invention, the oxygen barrier resin first layer 3 is provided on the inner surface side of the oxygen absorbing resin layer 4, and the cyclic olefin copolymer layer 5 is provided on the outer surface side of the oxygen absorbing resin layer 4. By providing the second layer 6 of the oxygen barrier resin on the outer surface side of the copolymer layer 5, the oxygen concentration in the package can be suppressed to a low level.
The first layer 3 of oxygen barrier resin and the second layer 6 of oxygen barrier resin both serve as oxygen barriers that suppress oxygen permeation through the vessel wall, but the first layer 3 of oxygen barrier resin is The oxygen-absorbing resin layer 4 is activated by moisture in the package, and effectively contributes to absorption of oxygen in the package and oxygen that permeates the inside of the container wall.
That is, the oxygen barrier resin generally has a strong hydrogen bond and has a large tendency to absorb and adsorb moisture. The present invention is used for the activation of the oxygen-absorbing resin layer 4 while the first layer 3 of the oxygen-barrier resin is absorbed or adsorbed to increase the oxygen transmission rate from the contents side to the outside of the vessel wall. is there.
Further, by providing the cyclic olefin copolymer layer 5 between the second layer 6 of oxygen barrier resin and the oxygen absorbing resin layer 4, the second layer 6 of oxygen barrier resin due to moisture in the package. The oxygen barrier performance of the second layer 6 of the oxygen barrier resin can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a cross-sectional structure of a laminate used for a packaging material of the present invention.

Claims (6)

From the inside of the package to the outside of the package, the inner surface layer of the olefin resin / the first layer of the oxygen barrier resin composed of an ethylene-vinyl alcohol copolymer / the oxygen-absorbing resin layer / the cyclic olefin copolymer layer / ethylene- An oxygen-absorbing package having a laminated structure of a second layer of an oxygen-barrier resin comprising a vinyl alcohol copolymer / an outer surface layer of an olefin-based resin.   The olefin resin inner surface layer has a thickness of 30 to 200 μm, the oxygen barrier resin first layer has a thickness of 2 to 100 μm, the oxygen absorbing resin layer has a thickness of 5 to 300 μm, and the cyclic olefin copolymer layer 2 to 100 μm. 2. The oxygen-absorbing package according to claim 1, having a thickness of 2 to 100 μm, a thickness of 2 to 100 μm of an oxygen barrier resin, and a thickness of 50 to 2500 μm of an olefin-based resin outer surface layer. The oxygen-absorbing package according to claim 1 or 2 , wherein the oxygen-absorbing resin layer comprises a resin composition of an oxidizing resin and a transition metal catalyst. The oxygen-absorbing package according to claim 1 or 2 , wherein the oxygen-absorbing resin layer comprises a resin composition of a thermoplastic resin and an oxygen absorbent. The oxygen-absorbing package according to any one of claims 1 to 4 , which is in the form of a tube container. The oxygen-absorbing package according to any one of claims 1 to 4 , which is in the form of a blow molded container.

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