JP3786775B2 - Heat-shrinkable tube and lithium ion secondary battery coated with the tube - Google Patents
Heat-shrinkable tube and lithium ion secondary battery coated with the tube Download PDFInfo
- Publication number
- JP3786775B2 JP3786775B2 JP34744497A JP34744497A JP3786775B2 JP 3786775 B2 JP3786775 B2 JP 3786775B2 JP 34744497 A JP34744497 A JP 34744497A JP 34744497 A JP34744497 A JP 34744497A JP 3786775 B2 JP3786775 B2 JP 3786775B2
- Authority
- JP
- Japan
- Prior art keywords
- heat
- tube
- shrinkable tube
- dyn
- ion secondary
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Secondary Cells (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
- Sealing Battery Cases Or Jackets (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、主に電池等の被覆用に好適に使用される耐熱性や自動機による被覆適性に優れた熱収縮性チューブ及び該チューブを被覆してなるリチウムイオン二次電池に関する。
【０００２】
【従来技術とその課題】
乾電池の亜鉛缶被覆用、あるいはキャップシールや各種物品の収縮被覆用の熱収縮性チューブとしては、ポリ塩化ビニル（ＰＶＣ）からなる熱収縮性ＰＶＣチューブが広く使用されている。このＰＶＣチューブは優れた実用特性と低コストの点で優れているが、廃棄物の焼却処理時に焼却炉を傷め易いこと等から、近年ＰＶＣ以外の材料が要望されるようになってきた。その原料の候補としては、ポリスチレン（ＰＳ）、ポリエチレンテレフタレート（ＰＥＴ）といったものが挙げられる。
【０００３】
これらの原料からなる熱収縮性チューブは、有機系溶剤に侵されることがあり、電解液に炭酸プロピレン等の有機系溶剤を用いるリチウムイオン二次電池の負極缶被覆の用途には不向きである。そこで耐有機系溶剤性に優れている樹脂としてオレフィン系樹脂が候補として挙げられる。
【０００４】
しかしながら、オレフィン系樹脂はＰＳ、ＰＥＴ等と異なり、通常、ガラス転移温度が室温以下にあるため、融点での延伸を行うことが一般的である。ここで、高融点（１００℃程度以上）の材料を用いた場合、それだけ延伸温度が高くなり、結局は熱収縮性チューブの被覆加工温度も高くなり作業性が劣るという問題があった。
【０００５】
一方、低融点（常温〜１００℃程度）の材料を用いれば低温での被覆加工が可能であるが、このような材料は一般的に熱収縮性チューブの長さ方向の腰が弱くなり、高速の自動被覆装置での被覆において、被覆物品の挿入トラブルやチューブ走行トラブルが生じてしまうという問題があった。
【０００６】
本発明は、前記の問題点を解決した常温での腰強さと、低温収縮性を共に満たす、オレフィン系熱収縮チューブ及び該チューブを被覆してなるリチウムイオン二次電池を提供することを目的とする。
【０００７】
【課題を解決するための手段】
前記の目的は以下の手段によって達成される。すなわち、本発明は、アイオノマー樹脂を主成分とする混合物（無機微粒子を含まず）からなる未延伸チューブを延伸してなる熱収縮性チューブであって、３０℃での貯蔵弾性率（Ｅ'）が６×１０９ｄｙｎ／ｃｍ２以上、３×１０１０ｄｙｎ／ｃｍ２以下、８０℃での貯蔵弾性率（Ｅ'）が７×１０８ｄｙｎ／ｃｍ２以下、１００℃での貯蔵弾性率（Ｅ'）が１×１０７ｄｙｎ／ｃｍ２以上であることを特徴とする熱収縮性チューブを提案するものであり、前記熱収縮性チューブは、電離放射線照射により架橋されたものであることを含んでいる。また、本発明は、上記いずれかの熱収縮性チューブを負極缶の外周面に収縮被覆したことを特徴とするリチウムイオン二次電池を提案するものである。
【０００８】
【発明の実施の形態】
以下、本発明をさらに詳細に説明する。
本発明で使用するアイオノマー樹脂は、エチレンとアクリル酸もしくはメタクリル酸との共重合体の分子間が亜鉛イオン、ナトリウムイオン、カリウムイオン等で架橋された樹脂であり、商業的には「ハイミラン」（三井・デュポンポリケミカル（株）製）として知られている。
【０００９】
また、金属イオンを含まないエチレンとアクリル酸もしくはメタクリル酸共重合体樹脂を原料に、アセチルアセトン金属錯体、酸化金属、脂肪酸金属塩等を必要量後添加してイオン架橋を導入し、成形加工時にアイオノマー樹脂を得てもよい。金属イオンを含まないエチレンとアクリル酸共重合体樹脂としては、商業的には「ユカロンＥＡＡ」（日本ポリケム（株）製）が代表的に知られている。さらに、エチレンとアクリル酸もしくはメタクリル酸共重合体にメチルメタクリレートやプロピレン等の第３、第４の共重合成分を入れることも可能である。
【００１０】
上記アイオノマー樹脂には貯蔵弾性率を調整するために原料を混合する必要があり、混合する原料としては、ポリアミド樹脂やエチレン−アクリル酸共重合体樹脂（ＥＡＡ）等のアイオノマー樹脂に相溶可能な樹脂、カオリン、クレー、タルク、マイカ、炭酸カルシウム、酸化ケイ素、テレフタル酸カルシウム、酸化アルミニウム、酸化チタン、リン酸カルシウム、フッ化リチウム等の無機微粒子等が挙げられる。コスト性の点からは無機微粒子の使用が好ましい。
【００１１】
上記のアイオノマー樹脂に相溶可能な樹脂や無機微粒子は、得られる熱収縮性チューブの主に低温側（３０℃）での貯蔵弾性率（Ｅ’）を高くする目的で添加する。一方、高温側（８０℃〜１００℃）でのＥ’を低下させるには低分子化合物の添加を行なえばよく、この低分子化合物としては、通常、ポリ塩化ビニル樹脂に対する可塑剤として知られているもの、例えばジブチルフタレート、ジ−２−エチルヘキシルフタレート、ジイソノニルフタレート等のフタル酸アルキルエステル；ジ−２−エチルヘキシルアジペート、ジイソノニルアジペート等のアジピン酸アルキルエステル；ジ−２−エチルヘキシルアゼレート等のアゼライン酸アルキルエステル；エポキシ化大豆油等のエポキシ化植物油等を挙げることができる。
【００１２】
また、ロジン、変性ロジン、重合ロジン、ロジングリセリンエステル等のロジン系樹脂；αピネン重合体、βピネン重合体、ジペンテン重合体、テルペン−フェノール共重合体等のポリテルペン系樹脂；Ｃ5 系石油樹脂、ジシクロペンタジエン系石油樹脂、Ｃ8 〜Ｃ10系のタール系石油樹脂等の石油樹脂；これらの部分水素化物又は、完全水素化物等も使用することができる。
【００１３】
さらに、液状ポリブテン、液状ポリブタジエン、液状ポリイソプレン、液状ポリイソブチレン、液状ブチルゴム等も使用することができる。
なお、ここで低分子とは、分子量が概略１００００以下、通常は５０００以下の範囲を持つ化合物をいう。
【００１４】
上記アイオノマー樹脂に混合する原料の添加量は各々異なるが、得られる熱収縮性チューブの３０℃での貯蔵弾性率Ｅ’が６×１０9 ｄｙｎ／ｃｍ2 以上、３×１０10ｄｙｎ／ｃｍ2 以下、８０℃でのＥ’が７×１０8 ｄｙｎ／ｃｍ2 以下、１００℃でのＥ’が１×１０7 ｄｙｎ／ｃｍ2 以上となるように調整することが重要である。つまり、一般にオレフィン系の樹脂を用いた場合、常温でのＥ’を高くすると８０℃〜１００℃でのＥ’も高くなってしまい、低温収縮性を付与できる温度域での延伸が困難となる。一方、８０℃〜１００℃でのＥ’を低くすると常温のＥ’も低くなってしまい、熱収縮性チューブの長さ方向の腰が弱くなり、高速の自動被覆装置での被覆において、被覆物品の挿入トラブルやチューブ走行トラブルが生じるという問題がある。
【００１５】
さらに、３０℃でのＥ’が６×１０9 ｄｙｎ／ｃｍ2 未満であると熱収縮性チューブの長さ方向の腰が弱くなり、高速の自動被覆装置での被覆において、被覆物品の挿入トラブルやチューブ走行トラブルが生じてしまう。
【００１６】
また、本来高分子材料においては、３０℃近辺でＥ’が３×１０10ｄｙｎ／ｃｍ2 を越えるものは見当たらないが、無機微粒子を大量に添加することにより実現できる。この場合、熱収縮性チューブの柔軟性に欠け、熱収縮性チューブにシワ入りが発生したり、破断強度の低下によりチューブ走行中に破断が生じ、チューブ走行トラブルが生じるという問題がある。８０℃でのＥ’が７×１０8 ｄｙｎ／ｃｍ2 を越えると低温収縮性を付与できる温度域で延伸しても延伸内圧が高くなり、チューブラー延伸が困難となる。
【００１７】
一方、１００℃でのＥ’が１×１０7 ｄｙｎ／ｃｍ2 未満であると延伸時の加熱によりチューブ内面密着を生じ、延伸ができ難いという問題がある。
これらアイオノマー樹脂に混合する原料は単独でも２種以上の混合物として添加しても良い。無機微粒子を使用する場合、全混合物を基準として１０〜５０重量％の範囲で配合することが好ましい。
【００１８】
本発明の熱収縮性チューブには成形加工性やチューブの物性を改良、調整する目的で、本発明の効果を阻害しない範囲で、他の高分子材料、あるいは酸化防止剤、滑剤、紫外線吸収剤、光安定剤、難燃材、顔料等の添加剤や改質剤を添加することも可能である。
【００１９】
以上説明した組成物は、通常の混練機で混合することができるが、操作の容易さから押出機、特に２軸押出機を用いるのが好ましい。また、ドライブレンドして直接押出成形しても良い。混合された組成物は押出機によって、環状ダイによりチューブ状に押出される。その未延伸チューブを長さ方向及び径方向にチューブラー延伸する。その際の延伸倍率は目的とする熱収縮率により決められるが、一般に長さ方向には１〜１．７倍、好ましくは１〜１．４倍とし、径方向には１．７〜４倍、好ましくは１．８〜３．５倍の範囲である。延伸温度は低温収縮性を考え７０〜１００℃の範囲から選ばれる。上記のようにして得られる熱収縮性チューブの厚さは特に限定されないが通常３０〜１５０μｍである。
【００２０】
以上の方法にて得られた熱収縮性チューブは、イオン架橋の効果により優れた耐熱性を有しているが、さらに高度の耐熱性を要求されるリチウムイオン二次電池被覆用にはチューブへの電離性放射線の照射による架橋が有効である。
電離性放射線としては紫外線、電子線、α線、γ線、β線、中性子線等が挙げられるが、工業的に好ましく採用できるのは電子線及びγ線である。
【００２１】
電離性放射線は未延伸チューブに照射した後、延伸しても良いし、延伸後、照射しても構わない。電離放射線量は、電離放射線の種類やチューブの厚み等によって適宜決められるが、３０〜３００ＫＧｒａｙの範囲が好ましい。かかる範囲を下回ると電離性放射による架橋効果が発現せず、上回ると未延伸チューブの延伸や収縮が困難になる。
【００２２】
本発明の熱収縮特性チューブの熱収縮特性は、主に延伸条件により決まるが、例えば乾電池や他の電池の内缶の被覆のようなスリーブ被覆用としては、１００℃熱水中、３０秒間での収縮率が長さ方向で４０％以下、好ましくは３０％以下、径方向には４０％以上、好ましくは４５％以上である。径方向の収縮率が４０％未満の時はスリーブ端部が密着せず、立ち上がった状態となり易い。また、径方向の収縮率が４０％以上でも長さ方向の収縮率が４０％を越えるものでは被覆位置がずれてしまったり、カット長さを長くしなければならずコスト上昇につながる。
【００２３】
本発明の熱収縮性チューブの好適な用途例としては、リチウムイオン二次電池の負極缶の被覆が挙げられる。絶縁等の目的で負極缶の外周面あるいは負極缶の外周面から正極蓋にかけて熱収縮性チューブが被覆される。リチウムイオン二次電池は、誤使用時に電池内部から電解液である炭酸プロピレン等の有機系溶剤が漏れる恐れがあり、その際熱収縮性チューブが電解液に侵され絶縁の機能を果たさなくなる恐れがある。本発明の熱収縮性チューブは耐熱性や耐電解液性に優れており、このようなリチウムイオン二次電池の負極缶の被覆用としての利用性が大きい。
【００２４】
【実施例】
以下に実施例を示すが、これらにより何ら制限を受けるものではない。
なお、実施例中に示す測定、評価は以下の方法で行った。
（１）貯蔵弾性率Ｅ’（ｄｙｎ／ｃｍ2 ）
岩本製作所（株）：粘弾性スペクトロメーター（ＶＥＳ−Ｆ３）を用い、振動周波数１０Ｈｚで測定した。
【００２５】
（２）自動機走行性
日本自動精機（株）製の電池用自動機（ＳＷ−１）を使い、自動機走行性を判断し、走行中チューブの引掛かり等の走行トラブルがないものを（○）、１０個中１〜５個の走行トラブルを起こしたものを（△）、１０個中６個以上の走行トラブルを起こしたものを（×）とした。
【００２６】
（３）仕上がり性
日本自動精機（株）製の電池用自動機（ＳＷ−１）を使い、折径２３ｍｍ、カット長さ５３ｍｍの熱収縮性チューブを単三電池に被覆後、２００℃×１０秒にて加熱収縮させた時、端部が密着せず立上がった状態となったり、被覆位置がずれて被覆されたものを（×）、これら不都合が極めて軽微なものを（△）、これらの不都合が全くなかったものを（○）とした。
【００２７】
（４）延伸性
延伸加熱時、問題なく延伸でき均一な熱収縮性チューブが得られたもの（○）、延伸加熱時、僅かにチューブ内面密着が生じ、均一な熱収縮性チューブが得られ難かったものを（△）、延伸加熱時、チューブ内面密着が生じ、均一な熱収縮性チューブが全く得られなかったものを（×）とした。
【００２８】
（５）耐熱性
（株）ナガノ化学機械製作所製の恒温熱風オープン（ＮＨ−４０２）を用い、折径３０ｍｍ、カット長さ７０ｍｍのチューブを直径１８ｍｍφのリチウムイオン二次電池に被覆した後、２００℃、３００℃で各５分間保持し、チューブにピンホール、裂け等の異常が生じなかったものを（○）、１０個中１〜５個の異常が生じたものを（△）、１０個中６個以上の異常が生じたものを（×）とした。
【００２９】
（参考例１）
エチレンとメタクリル酸との共重合体の分子間が亜鉛イオンで架橋されたアイオノマー樹脂（三井・デュポンポリケミカル（株）製、「ハイミラン１７０６」）と、無機微粒子であるタルクを表１に示す重量部で使用し同方向２軸押出機を用いて溶融混合し、組成物のペレットを得た。上記組成物をチューブラー押出しし、外径８．０ｍｍ 、厚さ０．２０ｍｍ の未延伸チューブを得た。
【００３０】
これを延伸温度９０℃で長さ方向に１．２倍、径方向に２．５倍チューブラー延伸し、熱収縮性チューブを得た。得られたチューブを評価し、その結果を表１に示した。
【００３１】
【表１】
表１に示す通り、３０℃におけるＥ’が６×１０9 ｄｙｎ／ｃｍ2 を下回る実験Ｎｏ．１は熱収縮性チューブの腰が弱く、自動機走行性に劣る。また、１００℃でのＥ’は１×１０7 ｄｙｎ／ｃｍ2 を下回るため、延伸加熱時、チューブ内面密着が生じ、延伸性に劣る。
【００３３】
一方、３０℃におけるＥ’が３×１０10ｄｙｎ／ｃｍ2 を越える実験Ｎｏ．５は自動機走行中に熱収縮性チューブにシワ入りが生じ、引っ掛かり等の走行トラブルが発生した。また、８０℃でのＥ’が７×１０8 ｄｙｎ／ｃｍ2 を越えるため、延伸温度が高くなり、低温収縮性が付与できず仕上がり性に劣る。
【００３４】
無機微粒子を４５重量部混合した実験Ｎｏ．６は８０℃でのＥ’が７×１０8 ｄｙｎ／ｃｍ2 をはるかに越えるため、安定した延伸ができず、仕上がり性も劣る。また、破断強度も低下するため、自動機走行時、チューブ破断が多発した。
【００３５】
（実施例２）
エチレンとメタクリル酸との共重合体の分子間が亜鉛イオンで架橋されたアイオノマー樹脂（三井・デュポンポリケミカル（株）製、「ハイミラン１７０５」）と６−ナイロン（三菱エンジニアリングプラスチック（株）製、「ノバミッド１０３０」）を表２に示す重量部で使用し、参考例１と同様にして熱収縮性チューブを得た。上記と同様の方法で得られたチューブを評価し、その結果を表２に示した。
【００３６】
【表２】
表２に示す通り、３０℃のＥ’が６×１０9 ｄｙｎ／ｃｍ2 を下回る実験Ｎｏ．７は自動機走行性に劣る。また、１００℃のＥ’が１×１０7 ｄｙｎ／ｃｍ2 を下回るため、延伸加熱時、チューブ内面密着を生じ、延伸性に劣る。一方、８０℃でのＥ’が７×１０8 ｄｙｎ／ｃｍ2 を越える実験Ｎｏ．１０は低温収縮性に劣る。
【００３８】
（実施例３）
エチレンとメタクリル酸との共重合体の分子間がナトリウムイオンで架橋されたアイオノマー樹脂（三井・デュポンポリケミカル（株）製、「ハイミラン１７０７」）に表３に示す原料を混合し、参考例１と同様の方法で実施、比較した。
【００３９】
【表３】
表３に示す通り、３０℃のＥ’が６×１０9 ｄｙｎ／ｃｍ2 を下回る実験Ｎｏ．１１は自動機走行性に劣る。また、石油樹脂５０重量部の実験Ｎｏ．１４は、１００℃でのＥ’が１×１０7 ｄｙｎ／ｃｍ2 を上回るものの石油樹脂自体の粘着性の為、延伸加熱時、チューブ内面密着が生じ易く、延伸性にやや劣る。
【００４１】
（参考例４）
エチレンとアクリル酸の共重合体樹脂（日本ポリケム（株）製、「ユカロンＥＡＡＡ２３１Ｋ」）７０重量部と無機微粒子である炭酸カルシウム３０重量部とアセチルアセトン亜鉛３重量部とジアリルイソシアネート３重量部を参考例１と同様の方法で未延伸チューブを得た。この未延伸チューブに加速電圧１ＭＶ の電子線を２００ＫＧｙ 照射後、参考例１と同様の方法で延伸し、熱収縮性チューブを得た。また、上記混合物を参考例１と同様の方法で延伸チューブを得た後、加速電圧１ＭＶ の電子線を１００ＫＧｙ 照射し、熱収縮性チューブを得た。その他、表４に示す熱収縮性チューブにて実施、比較した。
【００４２】
【表４】
表４に示す通り、電子線照射した実験Ｎｏ．１７、実験Ｎｏ．１８はより耐熱性が優れていることが判る。
【００４４】
【発明の効果】
上述したように、本発明の熱収縮性チューブにおいては、アイオノマー樹脂を主体とした混合物の貯蔵弾性率を調整することにより、従来のオレフィン系熱収縮性チューブの耐有機溶剤性には優れているが、腰強さと低温収縮性を共に満たすことが困難という弱点を改良できる。また、本発明の熱収縮性チューブは電解液に有機系溶剤を用い、自動被覆装置にて被覆、収縮加工を行うリチウムイオン二次電池の負極缶被覆等に好適に用いることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat-shrinkable tube that is preferably used for coating batteries and the like, and excellent in heat-shrinkability and coating suitability by an automatic machine, and a lithium ion secondary battery formed by coating the tube.
[0002]
[Prior art and its problems]
A heat-shrinkable PVC tube made of polyvinyl chloride (PVC) is widely used as a heat-shrinkable tube for covering a zinc can of a dry battery, or for covering a cap seal or various articles. This PVC tube is excellent in terms of excellent practical characteristics and low cost. However, in recent years, materials other than PVC have been demanded because the incinerator is easily damaged at the time of incineration of waste. Examples of the raw material candidates include polystyrene (PS) and polyethylene terephthalate (PET).
[0003]
The heat-shrinkable tube made of these raw materials may be attacked by an organic solvent, and is unsuitable for use as a negative electrode can coating of a lithium ion secondary battery using an organic solvent such as propylene carbonate as an electrolytic solution. Therefore, an olefin resin is listed as a candidate as a resin excellent in organic solvent resistance.
[0004]
However, unlike PS, PET, and the like, olefinic resins usually have a glass transition temperature of room temperature or lower, so that it is common to perform stretching at the melting point. Here, when a material having a high melting point (about 100 ° C. or higher) is used, there is a problem that the stretching temperature becomes higher and the coating temperature of the heat-shrinkable tube becomes higher, resulting in poor workability.
[0005]
On the other hand, if a material having a low melting point (from room temperature to about 100 ° C.) is used, it is possible to perform coating processing at a low temperature. In the coating with the automatic coating apparatus, there is a problem that a trouble of inserting a coated article and a trouble of tube running occur.
[0006]
An object of the present invention is to provide an olefin-based heat-shrinkable tube and a lithium-ion secondary battery that covers the tube that satisfy both the low-temperature shrinkage and low-temperature shrinkage properties that solve the above-mentioned problems. To do.
[0007]
[Means for Solving the Problems]
The above object is achieved by the following means. That is, the present invention is a heat-shrinkable tube obtained by stretching an unstretched tube made of a mixture (not including inorganic fine particles) mainly composed of an ionomer resin, and has a storage elastic modulus (E ′) at 30 ° C. Is 6 × 10 9 dyn / cm 2 or more, 3 × 10 10 dyn / cm 2 or less, storage elastic modulus (E ′) at 80 ° C. is 7 × 10 8 dyn / cm 2 or less, storage elastic modulus at 100 ° C. The present invention proposes a heat-shrinkable tube characterized in that (E ′) is 1 × 10 7 dyn / cm 2 or more, and the heat-shrinkable tube is cross-linked by ionizing radiation irradiation. Is included. The present invention also proposes a lithium ion secondary battery characterized in that any one of the above heat-shrinkable tubes is shrink-coated on the outer peripheral surface of the negative electrode can.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
The ionomer resin used in the present invention is a resin in which the intermolecular molecules of a copolymer of ethylene and acrylic acid or methacrylic acid are crosslinked with zinc ions, sodium ions, potassium ions, etc. It is known as Mitsui DuPont Polychemical Co., Ltd.
[0009]
In addition, ionic cross-linking is introduced by adding acetylacetone metal complex, metal oxide, fatty acid metal salt, etc. after using ethylene and acrylic acid or methacrylic acid copolymer resin, which do not contain metal ions, as necessary, and ionomers during molding processing. A resin may be obtained. As an ethylene / acrylic acid copolymer resin not containing metal ions, “Yukaron EAA” (manufactured by Nippon Polychem Co., Ltd.) is typically known commercially. Further, it is also possible to add third and fourth copolymer components such as methyl methacrylate and propylene to the ethylene and acrylic acid or methacrylic acid copolymer.
[0010]
In order to adjust the storage elastic modulus, it is necessary to mix raw materials with the ionomer resin, and the raw materials to be mixed are compatible with ionomer resins such as polyamide resin and ethylene-acrylic acid copolymer resin (EAA). Examples thereof include inorganic fine particles such as resin, kaolin, clay, talc, mica, calcium carbonate, silicon oxide, calcium terephthalate, aluminum oxide, titanium oxide, calcium phosphate, and lithium fluoride. From the viewpoint of cost, it is preferable to use inorganic fine particles.
[0011]
Resins and inorganic fine particles that are compatible with the above-mentioned ionomer resin are added for the purpose of increasing the storage elastic modulus (E ′) mainly on the low temperature side (30 ° C.) of the obtained heat-shrinkable tube. On the other hand, in order to reduce E ′ on the high temperature side (80 ° C. to 100 ° C.), a low molecular compound may be added, and this low molecular compound is usually known as a plasticizer for polyvinyl chloride resin. For example, phthalic acid alkyl esters such as dibutyl phthalate, di-2-ethylhexyl phthalate and diisononyl phthalate; adipic acid alkyl esters such as di-2-ethylhexyl adipate and diisononyl adipate; azelaic acid such as di-2-ethylhexyl azelate Alkyl ester; epoxidized vegetable oil such as epoxidized soybean oil and the like.
[0012]
In addition, rosin resins such as rosin, modified rosin, polymerized rosin, rosin glycerin ester; polyterpene resins such as α pinene polymer, β pinene polymer, dipentene polymer, terpene-phenol copolymer; C 5 petroleum resin , dicyclopentadiene-based petroleum resins, C 8 -C 10 tar petroleum resins and petroleum resins; these portions hydride or can also be used completely hydrides.
[0013]
Furthermore, liquid polybutene, liquid polybutadiene, liquid polyisoprene, liquid polyisobutylene, liquid butyl rubber and the like can also be used.
Here, the low molecule means a compound having a molecular weight of about 10,000 or less, usually 5000 or less.
[0014]
The addition amount of the raw material mixed with the ionomer resin is different, but the heat-shrinkable tube obtained has a storage elastic modulus E ′ at 30 ° C. of 6 × 10 9 dyn / cm 2 or more and 3 × 10 10 dyn / cm 2. Hereinafter, it is important to adjust so that E ′ at 80 ° C. is 7 × 10 8 dyn / cm 2 or less and E ′ at 100 ° C. is 1 × 10 7 dyn / cm 2 or more. That is, when an olefin-based resin is generally used, if E ′ at normal temperature is increased, E ′ at 80 ° C. to 100 ° C. is also increased, and it is difficult to stretch in a temperature range where low temperature shrinkage can be imparted. . On the other hand, when E ′ at 80 ° C. to 100 ° C. is lowered, E ′ at normal temperature also becomes low, and the heat shrinkable tube becomes weak in the length direction. Insertion trouble and tube running trouble occur.
[0015]
Furthermore, if E ′ at 30 ° C. is less than 6 × 10 9 dyn / cm 2 , the heat shrinkable tube becomes less elastic in the length direction, and troubles in inserting a coated article in coating with a high-speed automatic coating apparatus. And tube running troubles occur.
[0016]
In addition, in the case of polymer materials, there are essentially no materials where E ′ exceeds 3 × 10 10 dyn / cm 2 at around 30 ° C., but this can be realized by adding a large amount of inorganic fine particles. In this case, there is a problem in that the heat-shrinkable tube lacks flexibility, wrinkles are generated in the heat-shrinkable tube, and breakage occurs during tube running due to a decrease in breaking strength, resulting in tube running trouble. When E ′ at 80 ° C. exceeds 7 × 10 8 dyn / cm 2 , the stretching internal pressure becomes high even if stretching is performed in a temperature range where low temperature shrinkage can be imparted, and tubular stretching becomes difficult.
[0017]
On the other hand, when E ′ at 100 ° C. is less than 1 × 10 7 dyn / cm 2 , there is a problem that the inner surface of the tube is brought into close contact by heating during stretching, and stretching is difficult.
The raw materials to be mixed with these ionomer resins may be added singly or as a mixture of two or more. When using inorganic fine particles, it is preferable to blend in the range of 10 to 50% by weight based on the total mixture.
[0018]
In the heat-shrinkable tube of the present invention, other polymer materials, antioxidants, lubricants, ultraviolet absorbers are used for the purpose of improving and adjusting the molding processability and the physical properties of the tube, as long as the effects of the present invention are not impaired. It is also possible to add additives and modifiers such as light stabilizers, flame retardants, and pigments.
[0019]
Although the composition demonstrated above can be mixed with a normal kneading machine, it is preferable to use an extruder, especially a twin-screw extruder from the ease of operation. Alternatively, it may be dry blended and directly extruded. The mixed composition is extruded into a tube shape with an annular die by an extruder. The unstretched tube is tubular-stretched in the length direction and the radial direction. The draw ratio at that time is determined by the desired heat shrinkage rate, but is generally 1 to 1.7 times, preferably 1 to 1.4 times in the length direction, and 1.7 to 4 times in the radial direction. The range is preferably 1.8 to 3.5 times. The stretching temperature is selected from the range of 70 to 100 ° C. in consideration of low temperature shrinkage. The thickness of the heat-shrinkable tube obtained as described above is not particularly limited, but is usually 30 to 150 μm.
[0020]
The heat-shrinkable tube obtained by the above method has excellent heat resistance due to the effect of ion cross-linking, but for coating of lithium ion secondary batteries that require higher heat resistance, use the tube. Cross-linking by irradiation with ionizing radiation is effective.
Examples of the ionizing radiation include ultraviolet rays, electron beams, α rays, γ rays, β rays, neutron rays, and the like, and those that can be preferably employed industrially are electron rays and γ rays.
[0021]
The ionizing radiation may be stretched after irradiating the unstretched tube, or may be irradiated after stretching. The amount of ionizing radiation is appropriately determined depending on the type of ionizing radiation, the thickness of the tube, and the like, but is preferably in the range of 30 to 300 KGray. Below this range, the cross-linking effect due to ionizing radiation does not appear, and when it exceeds, it becomes difficult to stretch or shrink the unstretched tube.
[0022]
The heat shrink property of the tube of the present invention is mainly determined by the stretching conditions. For example, for sleeve coating such as the coating of an inner can of a dry battery or another battery, the tube is heated in 100 ° C. hot water for 30 seconds. The shrinkage ratio is 40% or less in the length direction, preferably 30% or less, and 40% or more, preferably 45% or more in the radial direction. When the contraction rate in the radial direction is less than 40%, the sleeve end portion is not in close contact and tends to stand up. Moreover, even if the shrinkage rate in the radial direction is 40% or more, if the shrinkage rate in the length direction exceeds 40%, the covering position is shifted or the cut length must be lengthened, leading to an increase in cost.
[0023]
As a suitable application example of the heat-shrinkable tube of the present invention, coating of a negative electrode can of a lithium ion secondary battery can be mentioned. For the purpose of insulation or the like, the heat shrinkable tube is covered from the outer peripheral surface of the negative electrode can or the outer peripheral surface of the negative electrode can to the positive electrode lid. Lithium ion secondary batteries may leak an organic solvent such as propylene carbonate, which is the electrolyte, from the inside of the battery when misused. At that time, the heat-shrinkable tube may be damaged by the electrolyte and not perform its insulating function. is there. The heat-shrinkable tube of the present invention is excellent in heat resistance and electrolytic solution resistance, and has great utility as a coating for a negative electrode can of such a lithium ion secondary battery.
[0024]
【Example】
Examples are shown below, but are not limited by these.
In addition, the measurement and evaluation shown in an Example were performed with the following method.
(1) Storage elastic modulus E ′ (dyn / cm 2 )
Iwamoto Seisakusho Co., Ltd .: Measured at a vibration frequency of 10 Hz using a viscoelastic spectrometer (VES-F3).
[0025]
(2) Automatic machine runnability The automatic machine for batteries (SW-1) manufactured by Nippon Auto Seiki Co., Ltd. is used to judge the automatic machine runnability, and there is no running trouble such as catching of the tube during running ( (Circle)) The thing which caused the driving | running | working trouble of 1-5 out of 10 was set as ((triangle | delta)), and the thing which caused the driving | running trouble of 6 or more out of 10 was set as (x).
[0026]
(3) Finishability Using a battery automatic machine (SW-1) manufactured by Nippon Automatic Seiki Co., Ltd., a heat-shrinkable tube having a folding diameter of 23 mm and a cut length of 53 mm is coated on an AA battery, and then 200 ° C. × 10 When heated and shrunk in seconds, the ends are not in close contact, or the coating position is shifted (×), and those inconveniences are very slight (△). (○) indicates that there was no inconvenience.
[0027]
(4) Stretchable heating with a uniform heat-shrinkable tube that can be stretched without any problems during stretching (○), and during stretching and heating, the inner surface of the tube slightly adheres, making it difficult to obtain a uniform heat-shrinkable tube. In the case of (Δ), when the tube was stretched and heated, close contact with the inner surface of the tube occurred, and no uniform heat-shrinkable tube was obtained (×).
[0028]
(5) Heat resistance After using a constant temperature hot air open (NH-402) manufactured by Nagano Chemical Machinery Co., Ltd., a tube having a folding diameter of 30 mm and a cut length of 70 mm was coated on a lithium ion secondary battery having a diameter of 18 mmφ, and then 200 Hold at 5 ° C. and 300 ° C. for 5 minutes each, no abnormalities such as pinholes, tears, etc. occur in the tube (◯), 1-5 out of 10 (Δ), 10 Those in which 6 or more abnormalities occurred were defined as (x).
[0029]
( Reference Example 1 )
Table 1 shows an ionomer resin (Mitsui / DuPont Polychemical Co., Ltd., “High Milan 1706”) in which the intermolecular molecules of a copolymer of ethylene and methacrylic acid are crosslinked with zinc ions, and talc as inorganic fine particles. The mixture was melt-mixed using the same-direction twin screw extruder to obtain pellets of the composition. The composition was extruded in a tubular manner to obtain an unstretched tube having an outer diameter of 8.0 mm and a thickness of 0.20 mm.
[0030]
This was stretched 1.2 times in the length direction and 2.5 times in the radial direction at a stretching temperature of 90 ° C. to obtain a heat-shrinkable tube. The obtained tubes were evaluated and the results are shown in Table 1.
[0031]
[Table 1]
As shown in Table 1, Experiment No. in which E ′ at 30 ° C. is less than 6 × 10 9 dyn / cm 2 is used. No. 1 is weak in heat shrinkable tube and inferior in automatic machine running. Moreover, since E ′ at 100 ° C. is less than 1 × 10 7 dyn / cm 2 , the tube inner surface adhesion occurs during stretching heating, and the stretchability is poor.
[0033]
On the other hand, in Experiment No. where E ′ at 30 ° C. exceeds 3 × 10 10 dyn / cm 2 . In No. 5, the heat shrinkable tube wrinkled during running of the automatic machine, and running troubles such as catching occurred. Further, since E ′ at 80 ° C. exceeds 7 × 10 8 dyn / cm 2 , the stretching temperature becomes high, and low temperature shrinkage cannot be imparted, resulting in poor finish.
[0034]
Experiment No. in which 45 parts by weight of inorganic fine particles were mixed. In No. 6, E ′ at 80 ° C. far exceeds 7 × 10 8 dyn / cm 2 , so that stable stretching cannot be achieved and the finish is inferior. In addition, since the breaking strength also decreased, tube breakage occurred frequently when the automatic machine was running.
[0035]
(Example 2)
Ionomer resin (Mitsui / DuPont Polychemical Co., Ltd., “Himiran 1705”) and 6-Nylon (Mitsubishi Engineering Plastics Co., Ltd.), in which the intermolecular molecules of the copolymer of ethylene and methacrylic acid are crosslinked with zinc ions “Novamid 1030”) was used in the parts by weight shown in Table 2, and a heat-shrinkable tube was obtained in the same manner as in Reference Example 1. The tubes obtained by the same method as described above were evaluated, and the results are shown in Table 2.
[0036]
[Table 2]
As shown in Table 2, the experiment No. in which E ′ at 30 ° C. is less than 6 × 10 9 dyn / cm 2 . 7 is inferior in automatic machine runnability. Moreover, since E 'of 100 degreeC is less than 1 * 10 < 7 > dyn / cm < 2 >, a tube inner surface contact | adherence is produced at the time of extending | stretching heating, and it is inferior to extensibility. On the other hand, in Experiment No. where E ′ at 80 ° C. exceeded 7 × 10 8 dyn / cm 2 . 10 is inferior in low temperature shrinkage.
[0038]
Example 3
Ionomer intermolecular copolymers of ethylene and methacrylic acid crosslinked with sodium ion resin (Du Pont-Mitsui Polychemicals Co., Ltd., "Himilan 1707") were mixed raw materials shown in Table 3 in Reference Example 1 The same method was used and compared.
[0039]
[Table 3]
As shown in Table 3, Experiment No. in which E ′ at 30 ° C. is less than 6 × 10 9 dyn / cm 2 is used. 11 is inferior to automatic machine runnability. In addition, in Experiment No. No. 14, E ′ at 100 ° C. exceeds 1 × 10 7 dyn / cm 2 , but due to the adhesiveness of the petroleum resin itself, the tube inner surface is likely to be closely contacted during stretching heating, and the stretchability is slightly inferior.
[0041]
( Reference Example 4 )
Copolymer resins of ethylene and acrylic acid (Nippon Polychem Co., Ltd., "Yukaron EAAA231K") 70 parts by weight of calcium carbonate 30 parts by weight of zinc acetylacetonate 3 parts by weight of diallyl isocyanate 3 parts by weight of inorganic fine particles Reference Example An unstretched tube was obtained in the same manner as in 1. The unstretched tube was irradiated with an electron beam with an acceleration voltage of 1 MV at 200 KGy, and then stretched in the same manner as in Reference Example 1 to obtain a heat-shrinkable tube. Moreover, after obtaining the extending | stretching tube by the method similar to the reference example 1 with the said mixture, the electron beam of acceleration voltage 1MV was irradiated with 100KGy, and the heat-shrinkable tube was obtained. In addition, the heat shrinkable tubes shown in Table 4 were used and compared.
[0042]
[Table 4]
As shown in Table 4, the experiment No. 17, Experiment No. It can be seen that 18 is more excellent in heat resistance.
[0044]
【The invention's effect】
As described above, in the heat-shrinkable tube of the present invention, the organic solvent resistance of the conventional olefin-based heat-shrinkable tube is excellent by adjusting the storage elastic modulus of the mixture mainly composed of ionomer resin. However, it is possible to improve the weak point that it is difficult to satisfy both waist strength and low temperature shrinkage. The heat-shrinkable tube of the present invention can be suitably used for covering a negative electrode can of a lithium ion secondary battery that uses an organic solvent as an electrolytic solution and is coated and contracted by an automatic coating apparatus.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34744497A JP3786775B2 (en) | 1997-12-17 | 1997-12-17 | Heat-shrinkable tube and lithium ion secondary battery coated with the tube |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34744497A JP3786775B2 (en) | 1997-12-17 | 1997-12-17 | Heat-shrinkable tube and lithium ion secondary battery coated with the tube |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2005111878A Division JP4287402B2 (en) | 2005-04-08 | 2005-04-08 | Heat-shrinkable tube and lithium ion secondary battery coated with the tube |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11170365A JPH11170365A (en) | 1999-06-29 |
| JP3786775B2 true JP3786775B2 (en) | 2006-06-14 |
Family
ID=18390284
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34744497A Expired - Lifetime JP3786775B2 (en) | 1997-12-17 | 1997-12-17 | Heat-shrinkable tube and lithium ion secondary battery coated with the tube |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3786775B2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6977343B2 (en) | 2000-05-18 | 2005-12-20 | Sony Corporation | Heat-sensitive material and heat-sensitive element |
| JP2002289158A (en) * | 2001-03-26 | 2002-10-04 | Honda Motor Co Ltd | Hermetically sealed cell |
| JP2002292737A (en) * | 2001-03-30 | 2002-10-09 | Mitsubishi Plastics Ind Ltd | Heat-shrinkable polyolefin tube |
| JP5194400B2 (en) * | 2006-01-05 | 2013-05-08 | 住友電気工業株式会社 | Ionomer resin composition and heat shrinkable tube using the same |
| JP2007302871A (en) * | 2006-04-10 | 2007-11-22 | Sumitomo Electric Ind Ltd | Resin composition, heat-shrinkable tube formed from the same resin composition and electric battery insulated and covered with the same heat-shrinkage tube |
| JP5182543B2 (en) * | 2007-04-27 | 2013-04-17 | 住友電気工業株式会社 | Ionomer resin composition and heat shrinkable tube using the same |
| JP7292139B2 (en) * | 2018-07-26 | 2023-06-16 | 三菱ケミカル株式会社 | Heat-shrinkable plastic parts, composite preforms and composite containers |
-
1997
- 1997-12-17 JP JP34744497A patent/JP3786775B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11170365A (en) | 1999-06-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4024323A (en) | Battery separator | |
| US8808925B2 (en) | Microporous polymer membrane modified by aqueous polymer, manufacturing method and use thereof | |
| JP5216327B2 (en) | Polyolefin microporous membrane | |
| JP3786775B2 (en) | Heat-shrinkable tube and lithium ion secondary battery coated with the tube | |
| CN111615422B (en) | Crosslinked polyolefin separator and method for producing same | |
| JP4287402B2 (en) | Heat-shrinkable tube and lithium ion secondary battery coated with the tube | |
| JP2010111095A (en) | Laminated porous film and separator for lithium cell and battery using the same | |
| KR20220094708A (en) | Film for packaging polymer cell | |
| JP3711305B2 (en) | Lithium secondary battery coated with heat-shrinkable tube | |
| JP2008066193A (en) | Crosslinked fine porous membrane | |
| JP2002292737A (en) | Heat-shrinkable polyolefin tube | |
| EP0135027B1 (en) | Polymer composition | |
| JP2009070620A (en) | Crosslinked fine porous membrane | |
| JP3629355B2 (en) | Heat shrinkable tube | |
| JPH09278974A (en) | Thermally shrinkable cyclic olefin-based polymer tube | |
| JP3628633B2 (en) | Heat-shrinkable polystyrene tube | |
| JP2007302871A (en) | Resin composition, heat-shrinkable tube formed from the same resin composition and electric battery insulated and covered with the same heat-shrinkage tube | |
| JP2000204174A (en) | Porous film and separator for battery or cell | |
| JPS6131446A (en) | Ethylene-propylene rubber composition having tracking resistance | |
| JP3506592B2 (en) | Heat-shrinkable aromatic polyester tube, production method thereof and use thereof | |
| KR20080090260A (en) | Ionomer resin composition and heat-shrinkable tube using the same | |
| JP3668456B2 (en) | Heat-shrinkable polystyrene tube for battery interior coating | |
| JPH09259840A (en) | Battery jar for sealed secondary battery | |
| JP6318997B2 (en) | Fluorine resin porous body | |
| JP2004189918A (en) | Porous film |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20041105 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A132 Effective date: 20041115 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20050114 Free format text: JAPANESE INTERMEDIATE CODE: A821 Effective date: 20050114 |
|
| RD02 | Notification of acceptance of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7422 Effective date: 20050114 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20050208 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20050408 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20060228 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20060322 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090331 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100331 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100331 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110331 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120331 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130331 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130331 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140331 Year of fee payment: 8 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| EXPY | Cancellation because of completion of term |