JPH0428737B2 - - Google Patents
Info
- Publication number
- JPH0428737B2 JPH0428737B2 JP57161283A JP16128382A JPH0428737B2 JP H0428737 B2 JPH0428737 B2 JP H0428737B2 JP 57161283 A JP57161283 A JP 57161283A JP 16128382 A JP16128382 A JP 16128382A JP H0428737 B2 JPH0428737 B2 JP H0428737B2
- Authority
- JP
- Japan
- Prior art keywords
- ethylene
- weight
- film
- stretching
- vinyl acetate
- 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
- 229920001577 copolymer Polymers 0.000 claims description 17
- 239000004604 Blowing Agent Substances 0.000 claims description 14
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 12
- 239000005977 Ethylene Substances 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 10
- 239000005038 ethylene vinyl acetate Substances 0.000 claims description 9
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 claims description 9
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 claims description 8
- 239000006261 foam material Substances 0.000 claims description 7
- 229920000642 polymer Polymers 0.000 claims description 4
- VXNZUUAINFGPBY-UHFFFAOYSA-N ethyl ethylene Natural products CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 claims description 2
- 239000000463 material Substances 0.000 description 18
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 12
- 230000000694 effects Effects 0.000 description 12
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 238000005187 foaming Methods 0.000 description 7
- 238000001125 extrusion Methods 0.000 description 5
- 239000006260 foam Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 230000000704 physical effect Effects 0.000 description 4
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 4
- 235000017557 sodium bicarbonate Nutrition 0.000 description 4
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 3
- 239000004793 Polystyrene Substances 0.000 description 3
- 210000000497 foam cell Anatomy 0.000 description 3
- 239000004088 foaming agent Substances 0.000 description 3
- 229920002223 polystyrene Polymers 0.000 description 3
- OZAIFHULBGXAKX-UHFFFAOYSA-N 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile Chemical compound N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 description 2
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 2
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 2
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 210000004027 cell Anatomy 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 229920005674 ethylene-propylene random copolymer Polymers 0.000 description 2
- 239000005022 packaging material Substances 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- -1 polypropylene Polymers 0.000 description 2
- 229920005604 random copolymer Polymers 0.000 description 2
- 239000004156 Azodicarbonamide Substances 0.000 description 1
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000001099 ammonium carbonate Substances 0.000 description 1
- 235000012501 ammonium carbonate Nutrition 0.000 description 1
- 239000002216 antistatic agent Substances 0.000 description 1
- XOZUGNYVDXMRKW-AATRIKPKSA-N azodicarbonamide Chemical compound NC(=O)\N=N\C(N)=O XOZUGNYVDXMRKW-AATRIKPKSA-N 0.000 description 1
- 235000019399 azodicarbonamide Nutrition 0.000 description 1
- 230000009172 bursting Effects 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 206010061592 cardiac fibrillation Diseases 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000002600 fibrillogenic effect Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000005429 filling process Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000002654 heat shrinkable material Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- SQDFHQJTAWCFIB-UHFFFAOYSA-N n-methylidenehydroxylamine Chemical compound ON=C SQDFHQJTAWCFIB-UHFFFAOYSA-N 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 235000002906 tartaric acid Nutrition 0.000 description 1
- 239000011975 tartaric acid Substances 0.000 description 1
Landscapes
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
- Details Of Rigid Or Semi-Rigid Containers (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Description
本発明は緩衝効果等の優れた縦方向に熱収縮性
を有する発泡材料に関する。
従来、熱収縮性を有する例えば発泡シート、フ
イルム等の発泡材料は、その原料をポリスチレン
を使用したものが主流をしめ、特にこれがビン等
の容器類の外装に用いることにより、破ビン防止
効果と緩衝効果を発揮するので有用な包装材料と
して周知である。
ところが、前記ポリスチレンからなる熱収縮性
を有する発泡材料は、その原料の特性から衝撃に
弱く脆いものであり、例えばビン等の破ビン防止
効果、緩衝効果等を有するラベル用として装着し
ても、その洗浄工程や充填工程、更には輸送中に
発泡材料が破損するという欠点があり、又、同材
料表面に印刷を施しても鮮明に表出できず、その
上発泡材料が端縁から層状になつて、部分的に剥
離する等の現象がみられ問題となつていた。
この発明は、前記した問題点を解決するために
なされたものであり、縦方向に熱収縮性を有する
発泡材料として、エチレン含有量が１〜10モル％
のエチレン−プロピレン共重合体と、酢酸ビニル
含有量３〜40重量％のエチレン−酢酸ビニル共重
合体及び／または結晶化度３〜20％のエチレン−
１−ブテン共重合体、及び発泡剤と配合した組成
物を製膜し、しかる後縦方向に３〜８倍の範囲で
一軸延伸してなることを、この発明の要旨とする
ものである。以下本発明について詳述する。
本発明で使用するエチレン−プロピレン共重合
体は、通常エチレン含有量１〜10モル％、好まし
くは２〜６モル％のもので、このさい10モル％を
越えると製造された発泡材料がべたついてブロツ
キングを起し易くなつて好ましくなく、また１モ
ル％未満ではその性質がポリプロピレンに近づ
き、従つて延伸しても収縮率が小さく、熱収縮性
部材として不満足である上に、発泡セルが破れて
毛羽立ち現象を起し易くなる。なお前記共重合体
中にはエチレンがランダムに入つているものが好
ましい。この際、前記共重合体の使用量は効果の
表われる量を適宜に加えれば良いが、好ましくは
全重合体量に対し50〜90重量％程度でよい。
次に本発明で使用する酢酸ビニル含有量３〜40
重量％のエチレン−酢酸ビニル共重合体及び／ま
たは結晶化度３〜20％のエチレン−１−ブテン共
重合体は、発泡材料の発泡セルに弾性を付与する
ために添加するもので、このエチレン−酢酸ビニ
ル共重合体及び／またはエチレン−１−ブテン共
重合体を添加しない場合は発泡の際の内部圧力に
耐えられず、発泡セルが膨脹し易くなるので微細
な発泡構造のものが得られない。
このエチレン−酢酸ビニル共重合体及び／また
はエチレン−１−ブテン共重合体は発泡時のセル
に弾性を付与する性質を有するもので酢酸ビニル
含有量３〜40重量％のエチレン−酢酸ビニル共重
合体及び／またはエチレン含有量85〜95モル％
（密度0.86〜0.91ｇ／cm3、結晶化度３〜20％）の
エチレン−１−ブテンランダム共重合体等を例示
できる。なおこの酢酸ビニル含有量３〜40重量％
のエチレン−酢酸ビニル共重合体及び／または結
晶化度３〜20％のエチレン−１−ブテン共重合体
の使用量は少なくともその効果が表われる量を加
えれば良く、好ましくは全重合体量に対し10〜50
重量％程度でよい。
又、本発明で使用する発泡剤は公知のものであ
れば如何なるものでもよく、適応可能な発泡剤と
してその種類を例示すると、揮発性のものとして
ペンタン、ブタン等、有機系のものとしてヒドラ
ジン系、ニトロン系、アゾ系等が、又無機系のも
のとして重炭酸ソーダ、炭酸アンモニア等があ
る。
この際、より好ましい例としては前記アゾ系発
泡剤ではアゾジカルボンアミド、アゾビスイソブ
チロニトリル等、無機系発泡剤では重炭酸ナトリ
ウム、炭酸アンモン等の炭酸塩とクエン酸、酒石
酸等の有機酸とからなるものをあげることができ
る。なお、この発泡剤の使用量は少なくともその
効果が表われる量を加えればよいが、エチレン含
有量１〜10モル％のエチレン−プロピレン共重合
体と、酢酸ビニル含有量３〜40重量％のエチレン
−酢酸ビニル共重合体及び／または結晶化度３〜
20％のエチレン−１−ブテン共重合体との合計量
全重合体量100重量部に対し、0.2〜５重量部、更
に好ましくは0.5〜２重量部程度を例示できる。
上記発泡剤は本発明に係るエチレン−プロピレン
共重合体に直接ブレンドしたり、濃度の高い発泡
剤を含むマスターペレツトを加えてブレンドした
り、予じめ前記共重合体中に発泡剤を適宜量練り
込んで用いたりすればよく、その用法には特に制
限はない。
なお、本発明では上記３者からなる成分の他に
適宜の添加剤や充填剤等を加えることもあり、例
えば滑剤、帯電防止剤等を必要に応じ加えて物性
の改善を図ることも適宜行い得、必要ならば顔料
を添加することにより希望する着色も可能であ
る。
本発明に係る発泡材料とは、フイルム、シート
状のもの等を例示でき、特にその形状を限定する
ものでないが、フイルムやシート状のものは延伸
操作が容易に出来るので好適な一例である。
本発明は上記各成分を配合した組成物を製膜し
しかる後、縦方向に延伸が行なわれる。こゝで、
縦方向に延伸を行うのは縦方向に熱収縮性を付与
するためであり、これは発泡材料を製造する方向
即ち、縦方向に延伸を行うことにより達成され、
この縦延伸を行うためには、組成物を製膜し発泡
後、もしくは発泡し製膜後（場合によつては延伸
中に発泡させてもよい）に行えばよいが、フラツ
トシート状発泡材料を速度の異なるロール間を通
して行う、いわゆるロール延伸により行えば最も
好ましい結果が得られる。
この際、ロール延伸の具体例としては数個の等
速の予熱ロールを通して延伸可能な温度に予熱
し、しかる後、所定の延伸比に設定された延伸ロ
ールにより所望の倍率に延伸される方法を例示で
きる。
斯る予熱ロール温度は適宜でよいが好ましくは
90〜130℃に設定するとよい。高過ぎると低温収
縮性が損われ、収縮時に高い温度が必要になつ
て、エネルギーの損出が起こり、また部分的にシ
ートが溶融するという問題を生じたり、低過ぎる
と延伸時に大きな応力が生じ、機械負荷が増大し
たり、破れが生ずることもあり、好ましいとは言
い難いが実施は可能である。前記した延伸ロール
温度は適宜でよいが、一般に予熱ロールより低く
例えば60℃以下に設定されており、次いで延伸さ
れたシートは数本の冷却ロールにより段階的に降
下せしめ、常温として自然収縮が起こりにくいよ
うにすることも一方法である。
以上はフラツト状発泡材料を例にとつて説明し
たが、チユーブラー状発泡材料、例えばフイル
ム、シートを作成することも随時行われる。この
場合は環状ダイスにより押出し、内部に加圧エア
ーを入れ適当なバルーン比でチユーブラー状の発
泡シートもしくはフイルムを製膜すればよい。次
いで速度の異なるニツプロール間を通して縦方向
に延伸すればよく、要すれば内部に加圧エアーを
入れて通常の方法で行うことも可能である。この
際、押出時や延伸時の加圧エアーのために、横方
向にも多少配向が起ることも考えられるが、これ
らは全て本発明の範囲であり、フラツト状のもの
も同様である。
尚、縦方向の延伸手段は前記のものに限定され
るものではない。次に延伸温度（予熱温度も含
め）であるが、これは適宜選択できるが例えば90
〜130℃が好ましい。また延伸倍率は必要に応じ
その大きさを選定するが３〜８倍程度でよく、上
記の各数値条件で延伸を行えば好ましい縦方向の
熱収縮性を有する発泡材料が得られることにな
る。
本発明に係る発泡材料を作成する１例として、
押出機によりフイルムもしくはシート状に製膜し
後延伸する方法を以下に述べる。
先ず、エチレン含有量１〜10モル％のエチレン
−プロピレン共重合体と、酢酸ビニル含有量３〜
40重量％のエチレン−酢酸ビニル共重合体及び／
または結晶化度３〜20％のエチレン−１−ブテン
共重合体及び発泡剤を配合した組成物をダイス内
で発泡しない程度に押出成形機の条件設定を行
い、ダイスからフラツトシート状に押出させる。
そしてこの際押出しと同時に発泡するようにすれ
ば好適である。
しかる後縦延伸を行うが、延伸手段については
前述の通りである。
本発明に係る発泡材料の用途としては、ビン等
に用いる印刷された外装用熱収縮性発泡ラベルと
しても最も多用され、延伸方向がビン等の円周方
向と一致するように筒状化して用いればよいが、
その他各種容器、各種物品の包装用材料として多
用されその応用範囲は広く特に制限はない。こう
した用途からみても発泡材料はシートもしくはフ
イルム状態で用いることが最も好ましいわけであ
る。
本発明は以上の通りであり、本発明に係る発泡
材料は例えばビン等の外装用ラベルとして用いる
と、特に破ビン防止効果や緩衝効果に優れる。
また、強度等の諸物性にも優れ、従来のものゝ
如く脆くないので、例えば筒状体としても折りた
たむことが可能で、折りたゝみの際に生じた折目
は熱収縮の際に消滅するという特性もある上に、
材料の端縁から層状となつて剥離し易いという欠
点もなく強靭である等の如く顕著な効果を奏す
る。
以下本発明の実施例を比較例と共に挙げる。
実施例 １
エチレン含有量4.5モル％のエチレン−プロピ
レンランダム共重合体70重量％と、酢酸ビニル含
有量15重量％のエチレン−酢酸ビニル共重合体30
重量％の配合物100重量部に対し、重炭酸ナトリ
ウムとクエン酸の混合物からなる発泡剤１重量部
を配合し、押出成型機のダイスを通してフラツト
シート状押出製膜を行つた。この際、ダイスより
押出した時に発泡するように条件設定を行つたと
ころ、厚さ1000μの発泡シートを得た。しかる後
表面温度100〜110℃を有する等速の予熱ロール３
連により充分予熱し、次いで速度比１：５、表面
温度45℃の延伸ロールを通して縦方向に５倍に延
伸し、更に延伸ロールと同速で表面温度30℃の冷
却ロールを通すことにより、厚さ200μの縦方向
に熱収縮する発泡フイルムを得た。この際、発泡
剤の重炭酸ナトリウムが分解して気泡を生じさせ
た。
実施例 ２
エチレン含有量92モル％、密度0.90ｇ／cm3、結
晶化度約10％のエチレン−１−ブテンランダム共
重合体を用いる以外は実施例１と同様にして、同
様の発泡フイルムを得た。
実施例 ３
発泡剤として重炭酸ナトリウムとクエン酸を使
用（使用量20重量％）してなる主成分が、ポリエ
チレンであるマスターペレツト５重量部（発泡剤
成分は１重量部）を用いる以外は実施例１と同様
の配合物を用い、押出製膜して厚さ1000μのフラ
ツト状発泡シートを得た。しかる後、実施例１と
同様にロール延伸を行い、厚さ200μの縦方向に
熱収縮する発泡フイルムを得た。
比較例 １
エチレン含有量4.5モル％のエチレン−プロピ
レンランダム共重合体100重量部に重炭酸ナトリ
ウムとクエン酸とからなる発泡剤１重量部を配合
した組成物を、実施例１と同様に処理し発泡フイ
ルムを得た。このフイルムは発泡状態が悪く、セ
ルがところどころ破裂して表面が毛羽立つて見え
る上に、使用の際の縦割れによる解繊化が起こり
易いものであつた。
比較例 ２
ポリスチレンに比較例１と同様の発泡剤を同量
加え、同様に製膜し、110℃の温度で３倍にロー
ル延伸を行つたところ、縦方向に熱収縮する厚さ
200μの発泡フイルムを得た。
以上の実施例１、２、３と比較例１、２で得ら
れた発泡フイルムの各物性を下記第１表に掲げ
る。
The present invention relates to a foamed material having excellent cushioning effects and heat shrinkability in the longitudinal direction. Conventionally, heat-shrinkable foam materials such as foam sheets and films have mainly been made from polystyrene, which has been particularly effective in preventing bottles from breaking when used for the exterior of containers such as bottles. It is well known as a useful packaging material because it exhibits a cushioning effect. However, the heat-shrinkable foamed material made of polystyrene is weak and brittle against impact due to the characteristics of its raw material, and even if it is attached to a label that has the effect of preventing bottles from breaking or having a cushioning effect, etc. The disadvantage is that the foamed material is damaged during the cleaning process, filling process, and even during transportation.Also, even if the surface of the material is printed, it cannot be clearly printed, and furthermore, the foamed material is layered from the edges. Phenomena such as curling and partial peeling have been seen, which has become a problem. This invention was made in order to solve the above-mentioned problems, and is a foamed material having heat shrinkability in the longitudinal direction with an ethylene content of 1 to 10 mol%.
and ethylene-vinyl acetate copolymer with a vinyl acetate content of 3 to 40% by weight and/or ethylene-vinyl acetate copolymer with a crystallinity of 3 to 20%.
The gist of the present invention is to form a film from a composition blended with a 1-butene copolymer and a blowing agent, and then uniaxially stretch the film in the longitudinal direction in a range of 3 to 8 times. The present invention will be explained in detail below. The ethylene-propylene copolymer used in the present invention usually has an ethylene content of 1 to 10 mol%, preferably 2 to 6 mol%; if the ethylene content exceeds 10 mol%, the produced foam material becomes sticky. If it is less than 1 mol %, its properties approach those of polypropylene, and therefore the shrinkage rate is small even when stretched, making it unsatisfactory as a heat-shrinkable member, and the foam cells may be torn. The phenomenon of fluffing becomes more likely. Preferably, the copolymer contains ethylene randomly. At this time, the amount of the copolymer to be used may be an appropriate amount that exhibits the effect, but it is preferably about 50 to 90% by weight based on the total amount of the polymer. Next, the vinyl acetate content used in the present invention is 3 to 40
Ethylene-vinyl acetate copolymer and/or ethylene-1-butene copolymer with a crystallinity of 3 to 20% by weight are added to impart elasticity to the foam cells of the foam material. - If vinyl acetate copolymer and/or ethylene-1-butene copolymer is not added, the internal pressure during foaming will not be able to withstand, and the foam cells will easily expand, making it difficult to obtain a fine foam structure. do not have. This ethylene-vinyl acetate copolymer and/or ethylene-vinyl acetate copolymer has the property of imparting elasticity to cells during foaming, and has a vinyl acetate content of 3 to 40% by weight. Combined and/or ethylene content 85-95 mol%
Examples include ethylene-1-butene random copolymers having a density of 0.86 to 0.91 g/cm 3 and a crystallinity of 3 to 20%. This vinyl acetate content is 3 to 40% by weight.
The amount of the ethylene-vinyl acetate copolymer and/or the ethylene-1-butene copolymer with a crystallinity of 3 to 20% may be at least as long as the amount that exhibits its effect, and is preferably added to the total amount of the polymer. vs. 10-50
It may be about % by weight. Further, the blowing agent used in the present invention may be any known blowing agent. Examples of suitable blowing agents include pentane, butane, etc. as volatile ones, and hydrazine type as organic ones. , nitrone type, azo type, etc., and inorganic types such as sodium bicarbonate, ammonia carbonate, etc. In this case, more preferable examples include azo dicarbonamide, azobisisobutyronitrile, etc. for the azo blowing agent, carbonates such as sodium bicarbonate and ammonium carbonate, and organic acids such as citric acid and tartaric acid for the inorganic blowing agents. I can give you something consisting of. The amount of blowing agent to be used should be at least enough to exhibit its effect, but ethylene-propylene copolymer with an ethylene content of 1 to 10 mol% and ethylene with a vinyl acetate content of 3 to 40% by weight should be used. -Vinyl acetate copolymer and/or crystallinity 3~
The total amount including 20% ethylene-1-butene copolymer can be 0.2 to 5 parts by weight, more preferably about 0.5 to 2 parts by weight, based on 100 parts by weight of the total polymer.
The above blowing agent may be directly blended with the ethylene-propylene copolymer according to the present invention, blended with the addition of master pellets containing a high concentration of blowing agent, or appropriately added to the copolymer in advance. It may be used by kneading a certain amount, and there is no particular restriction on its usage. In addition, in the present invention, appropriate additives, fillers, etc. may be added in addition to the above three components, and for example, lubricants, antistatic agents, etc. may be added as necessary to improve physical properties. If necessary, desired coloring can be achieved by adding a pigment. Examples of the foamed material according to the present invention include those in the form of a film or sheet, and the shape is not particularly limited, but a film or sheet-shaped material is a suitable example because it can be easily stretched. In the present invention, a composition containing the above components is formed into a film, and then stretched in the longitudinal direction. Here,
The purpose of stretching in the longitudinal direction is to impart heat shrinkability in the longitudinal direction, and this is achieved by stretching in the direction in which the foamed material is manufactured, that is, in the longitudinal direction.
This longitudinal stretching can be carried out after the composition is formed into a film and foamed, or after foaming and film formation (in some cases, foaming may be performed during stretching). The most favorable results can be obtained by so-called roll stretching, which is carried out between rolls having different speeds. At this time, a specific example of roll stretching is a method in which the film is preheated to a temperature that allows stretching by passing through several preheating rolls at a constant speed, and then stretched to a desired magnification by stretching rolls set at a predetermined stretching ratio. I can give an example. The preheating roll temperature may be set as appropriate, but preferably
It is recommended to set the temperature between 90 and 130℃. If the temperature is too high, the low-temperature shrinkability will be impaired, requiring high temperatures during shrinkage, resulting in energy loss and the problem of partial melting of the sheet; if it is too low, large stresses will occur during stretching. However, it is possible to implement this method, although it is not preferable since the mechanical load may increase and tearing may occur. The above-mentioned stretching roll temperature may be set as appropriate, but it is generally set lower than the preheating roll, for example, 60°C or less, and then the stretched sheet is gradually lowered by several cooling rolls, and natural shrinkage occurs at room temperature. One way is to make it more difficult. Although the above description has been made using a flat foam material as an example, tubular foam materials such as films and sheets may also be produced from time to time. In this case, a tubular foam sheet or film may be formed by extruding the material using an annular die and applying pressurized air to the inside at an appropriate balloon ratio. Next, the film may be stretched in the longitudinal direction through nip rolls having different speeds, and if necessary, pressurized air may be introduced inside the film in a conventional manner. At this time, some orientation may occur in the lateral direction due to the pressurized air during extrusion or stretching, but these are all within the scope of the present invention, and the same applies to flat shapes. Note that the stretching means in the longitudinal direction is not limited to those described above. Next is the stretching temperature (including preheating temperature), which can be selected as appropriate, but for example 90
~130°C is preferred. Further, the stretching ratio may be selected from 3 to 8 times depending on the necessity, and if the stretching is carried out under the above-mentioned numerical conditions, a foamed material having preferable heat shrinkability in the longitudinal direction can be obtained. As an example of creating a foam material according to the present invention,
A method of forming a film or sheet using an extruder and then stretching it will be described below. First, an ethylene-propylene copolymer with an ethylene content of 1 to 10 mol% and a vinyl acetate content of 3 to 10 mol%
40% by weight of ethylene-vinyl acetate copolymer and/or
Alternatively, a composition containing an ethylene-1-butene copolymer having a crystallinity of 3 to 20% and a foaming agent is extruded from the die into a flat sheet by setting the conditions of the extrusion molding machine to such an extent that foaming does not occur within the die.
At this time, it is preferable to perform foaming simultaneously with extrusion. Thereafter, longitudinal stretching is performed, and the stretching means is as described above. The foamed material according to the present invention is most often used as a printed exterior heat-shrinkable foamed label for bottles, etc., and is used in a cylindrical shape so that the stretching direction coincides with the circumferential direction of the bottle, etc. Good luck, but
It is also widely used as a packaging material for various containers and articles, and its range of applications is wide and there are no particular limitations. Considering these uses, it is most preferable to use the foamed material in the form of a sheet or film. The present invention is as described above, and when the foamed material according to the present invention is used, for example, as an exterior label for a bottle or the like, it is particularly excellent in bottle breakage prevention effect and cushioning effect. It also has excellent physical properties such as strength, and is not as brittle as conventional products, so it can be folded into a cylindrical body, for example, and the creases that occur when folding disappear when heat shrinks. In addition to having the characteristic of
It does not have the disadvantage that it forms a layer from the edge of the material and is easily peeled off, and it has remarkable effects such as being strong and strong. Examples of the present invention will be listed below along with comparative examples. Example 1 70% by weight of an ethylene-propylene random copolymer with an ethylene content of 4.5 mol% and an ethylene-vinyl acetate copolymer 30 with a vinyl acetate content of 15% by weight
1 part by weight of a blowing agent consisting of a mixture of sodium bicarbonate and citric acid was added to 100 parts by weight of the composition, and the mixture was extruded into a flat sheet through a die of an extrusion molding machine. At this time, conditions were set so that it would foam when extruded from the die, and a foamed sheet with a thickness of 1000 μm was obtained. After that, a constant speed preheating roll 3 with a surface temperature of 100 to 110°C
The film is thoroughly preheated by a continuous process, then stretched five times in the longitudinal direction through stretching rolls with a surface temperature of 45°C at a speed ratio of 1:5, and further passed through cooling rolls with a surface temperature of 30°C at the same speed as the stretching rolls to obtain a thickness. A foamed film with a length of 200 μm that is heat-shrinkable in the longitudinal direction was obtained. At this time, the foaming agent, sodium bicarbonate, decomposed and produced bubbles. Example 2 A similar foamed film was produced in the same manner as in Example 1, except that an ethylene-1-butene random copolymer having an ethylene content of 92 mol%, a density of 0.90 g/cm 3 and a crystallinity of about 10% was used. Obtained. Example 3 Sodium bicarbonate and citric acid were used as blowing agents (amount used: 20% by weight), except that 5 parts by weight of master pellets whose main component was polyethylene (the blowing agent component was 1 part by weight) was used. Using the same formulation as in Example 1, a flat foam sheet with a thickness of 1000 μm was obtained by extrusion film formation. Thereafter, roll stretching was performed in the same manner as in Example 1 to obtain a foamed film having a thickness of 200 μm and shrinkable by heat in the longitudinal direction. Comparative Example 1 A composition containing 100 parts by weight of an ethylene-propylene random copolymer with an ethylene content of 4.5 mol% and 1 part by weight of a blowing agent consisting of sodium bicarbonate and citric acid was treated in the same manner as in Example 1. A foamed film was obtained. This film had a poor foaming condition, with cells bursting in places and the surface looking fluffy, and was prone to fibrillation due to vertical cracking during use. Comparative Example 2 The same amount of foaming agent as in Comparative Example 1 was added to polystyrene, a film was formed in the same manner, and roll stretching was performed at a temperature of 110°C to three times the thickness.
A foamed film of 200μ was obtained. The physical properties of the foamed films obtained in Examples 1, 2, and 3 and Comparative Examples 1 and 2 are listed in Table 1 below.
【表】
上記の第１表から本発明の実施例１、２、３の
各発泡材料は強靭で、引裂強度に優れ、衝撃強度
が抜群で、伸度も適度に備わつた極めて実用的な
熱収縮性材料であることが立証された。これに対
し比較例１のものは満足な材料とならなかつたし
比較例２の従来品は衝撃強度その他諸物性が極め
て悪く、緩衝効果がもう一つ不充分であつた。
このことからも本発明の顕著な効果がうかがえ
る。[Table] From Table 1 above, the foamed materials of Examples 1, 2, and 3 of the present invention are tough, have excellent tear strength, excellent impact strength, and have moderate elongation, making them extremely practical. It was proven to be a heat-shrinkable material. On the other hand, the material of Comparative Example 1 was not a satisfactory material, and the conventional product of Comparative Example 2 had extremely poor impact strength and other physical properties, and was also insufficient in its cushioning effect. This also shows the remarkable effects of the present invention.
Claims (1)
ロピレン共重合体50〜90重量％と、酢酸ビニル含
有量３〜40重量％のエチレン−酢酸ビニル共重合
体および／または結晶化度３〜20％のエチレン−
１−ブテン共重合体10〜50重量％及び全重合体
100重量部に対し発泡剤0.2〜５重量部とを配合し
た組成物を製膜し、しかる後縦方向に３〜８倍の
範囲で一軸延伸してなることを特徴とする縦方向
に熱収縮性を有する発泡材料。1. Ethylene-propylene copolymer with ethylene content of 1-10 mol% from 50-90% by weight and ethylene-vinyl acetate copolymer with vinyl acetate content of 3-40% by weight and/or crystallinity of 3-20% of ethylene-
10-50% by weight of 1-butene copolymer and total polymer
Heat-shrinkable in the longitudinal direction, characterized by forming a film from a composition containing 0.2 to 5 parts by weight of a blowing agent to 100 parts by weight, and then uniaxially stretching the film in a range of 3 to 8 times in the longitudinal direction. Foam material with properties.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57161283A JPS5951048A (en) | 1982-09-16 | 1982-09-16 | Foamed material having heat shrinkage in londitudinal direction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57161283A JPS5951048A (en) | 1982-09-16 | 1982-09-16 | Foamed material having heat shrinkage in londitudinal direction |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5951048A JPS5951048A (en) | 1984-03-24 |
| JPH0428737B2 true JPH0428737B2 (en) | 1992-05-15 |
Family
ID=15732156
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57161283A Granted JPS5951048A (en) | 1982-09-16 | 1982-09-16 | Foamed material having heat shrinkage in londitudinal direction |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5951048A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1990005758A1 (en) * | 1986-01-07 | 1990-05-31 | Toshio Taka | Heat-resistant foam-shrinkable film |
| JPS63265933A (en) * | 1987-04-23 | 1988-11-02 | Sekisui Plastics Co Ltd | Heat-shrinkable sheet |
| JPH074190Y2 (en) * | 1988-04-06 | 1995-02-01 | 東洋製罐株式会社 | Hollow container with label |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3734273A (en) * | 1969-09-24 | 1973-05-22 | Asahi Dow Ltd | Heat-shrinking package using foamed plastic sheet |
| JPS5336A (en) * | 1976-06-24 | 1978-01-05 | Mitsubishi Electric Corp | Data input unit |
| JPS5653491A (en) * | 1979-10-08 | 1981-05-13 | Tokyo Shibaura Electric Co | Seal structure of shielding plug in nuclear reactor |
-
1982
- 1982-09-16 JP JP57161283A patent/JPS5951048A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3734273A (en) * | 1969-09-24 | 1973-05-22 | Asahi Dow Ltd | Heat-shrinking package using foamed plastic sheet |
| JPS5336A (en) * | 1976-06-24 | 1978-01-05 | Mitsubishi Electric Corp | Data input unit |
| JPS5653491A (en) * | 1979-10-08 | 1981-05-13 | Tokyo Shibaura Electric Co | Seal structure of shielding plug in nuclear reactor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5951048A (en) | 1984-03-24 |
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