JPS59166539A - Polyolefin foamed and drawn film and production thereof - Google Patents

Abstract

PURPOSE:The titled film that is formed by orienting the foam sheet made by melt-extruding a composition containing specific amounts of a specific crystalline propylene-alpha-olefin copolymer and a low-density polyethylene at a specific temperature, thus showing high thermal shrinkage and good cushion effect. CONSTITUTION:A composition composed of (A) 93-47wt% of a crystalline propylene-alpha-olefin copolymer having a crystal melting point of 115-145 deg.C, preferably an ethylene-propylene random copolymer containing 4-10wt% of ethylene, (B) 7-50wt% of a low density polyethylene and/or ethylene-vinyl acetate copolymer of less than 0.930 density, (C) 0.1-2.0wt% of a decomposition-type organic foaming agent, preferably azodicarbonamide and (D) 0.03-1.0wt% of a metal salt of higher fatty acid is melt-extruded at a temperature higher than the decomposition point of component C to form a foamed sheet. The sheet is oriented in at least one direction to give the objective film.

Description

【発明の詳細な説明】 本発明はポリオレフィン系発泡延伸フィルム及びその製
造方法１て関する。更に詳しくは、本発明はプロピレン
・α−オレフィン共重合体を特徴とする特定の組成物を
溶融押出し及び延伸して得られた該フィルム及び該製造
方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyolefin foam stretched film and a method for producing the same. More specifically, the present invention relates to a film obtained by melt extruding and stretching a specific composition characterized by a propylene/α-olefin copolymer, and a method for producing the same.

包装物品の外装、内容物の衝撃防止のためのタイト包装
、結束包装及びガラスびんもしくは容器の保護と商品の
表示を兼ねたラベル包装等用に一方向もしくは二方向に
延伸され異方性もしくは等方性の熱収縮性を有するプラ
スチックフィルム（収縮フィルム）を用いた収縮包装が
広く使用されている。しかし、近年の収縮包装技術の進
歩と共に、僅かの衝撃により破損し易して緩衝効果を有
する熱収縮性発泡フィルムが使用されるようになった。Stretched in one or two directions and anisotropic or etc. for the exterior of packaged goods, tight packaging to prevent the contents from impact, bundling packaging, and label packaging that also protects glass bottles or containers and displays products, etc. Shrink wrapping using a plastic film (shrink film) with directional heat shrinkability is widely used. However, with recent advances in shrink packaging technology, heat-shrinkable foamed films that are easily damaged by slight impacts and have a cushioning effect have come into use.

この熱収縮性発泡フィルムを用い物品を直接に収縮包装
する事によって、従来前記の物品の外周に、４０段ボー
ル、薄紙、発泡ポリスチレン等の緩衝機を巻き付け、紐
・バンド・テープ等で緊縛包装したり、口０段ボール・
ケースの間仕納等が不要となシ、包装工程の簡略化・輸
送空間の低減等の合理化およびコストダウンに大き５− なメリットが得られる。By directly shrink-wrapping an article using this heat-shrinkable foam film, conventionally, a buffer made of 40 pieces of cardboard, tissue paper, expanded polystyrene, etc. is wrapped around the outer periphery of the article, and the article is bound and wrapped with string, band, tape, etc. Or, 0 cardboard boxes.
There are major benefits such as no need to stock cases, rationalization such as simplification of packaging process and reduction of transportation space, and cost reduction.

従来、この種の熱収縮性発泡フィルムとしてポリスチレ
ン発泡延伸フィルムがよく知られて、おり、たとえば炭
酸飲料等のガラスびんのラベル兼保護膜として容器の周
側部に模様や商標を印刷したポリスチレン発泡延伸フィ
ルムを巻着し、ついで熱収縮させびんに密着させる事が
広く行われている。しかし、ポリスチレン発泡延伸フィ
ルムは耐衝撃性が劣るため薄肉化すると■緩衝効果が大
幅に低下するだけでなく、該フィルムで包装された炭酸
飲料入りびんの如く内圧のかかった状態で充填されたび
んを落下した場合、破損したびんがフィルムをつき破り
びんの破片が広く飛散し危険である等、又、■ガラスび
んの回収、再利用のための、ガラスの再溶融時フィルム
が黒煙や煤を発生ト謳焼し環境衛生上好呼しくないとい
う問題があるため、ガラスびんの溶融前置、ラベルすな
わち該フィルムを一枚・一枚剥ぐ必要があり、コスト高
の原因となる等の欠点がある。Conventionally, polystyrene foam stretched film is well known as this type of heat-shrinkable foam film. It is widely practiced to wrap a stretched film around the bottle and then heat-shrink it to make it adhere tightly to the bottle. However, since stretched polystyrene foam film has poor impact resistance, thinning the film will not only significantly reduce its cushioning effect, but also cause problems in bottles that are filled with internal pressure, such as carbonated beverage bottles wrapped with this film. If the glass is dropped, the broken bottle will break through the film and the bottle fragments will be scattered widely, which is dangerous. Also, when the glass is remelted for collection and reuse, the film may produce black smoke and soot. There is a problem that it is not good in terms of environmental hygiene due to the burning of the product, so it is necessary to melt the glass bottles beforehand and remove the labels one by one, which causes high costs. There is.

６− 一方、ポリプロピレン若しくけプロピレンを主とするエ
チレン・プロピレン共重合体等の延伸フィルムはポリス
チレンに比して耐衝撃性だ優れ、燃焼時の黒煙や煤の発
生も無いという利点があり、エチレン・プロピレン共重
合体を主とした延伸フィルムがポリプロピレン収縮フィ
ルムとして広く知られており、このラベル包装用尾もア
ンパランンヤル熱収縮性フィルム（特開昭５５−１０３
９５１号公報）、２〜３層のヒートンール性を付与した
複層熱収縮性フィルム（特開昭５７−４９５５４号公報
）等が提案されているが、緩衝効果を有する熱収縮性発
泡フィルムについては未だ知られていない。6- On the other hand, stretched films such as polypropylene or ethylene-propylene copolymers mainly composed of propylene have superior impact resistance compared to polystyrene, and have the advantage of not producing black smoke or soot when burned. , a stretched film mainly made of ethylene-propylene copolymer is widely known as polypropylene shrink film, and this label wrapping tail is also an unparalleled heat shrinkable film (Japanese Patent Application Laid-Open No. 103-1989).
951 (Japanese Patent Publication No. 951), a multilayer heat-shrinkable film with two to three layers of heat-curable properties (Japanese Patent Application Laid-open No. 57-49554), etc., but as for a heat-shrinkable foam film with a buffering effect, Not yet known.

ポリプロピレンは結晶性が高い事、押出時溶融粘度が調
整しに＜＜、かつ該粘度を高粘度に保ち難い事等から均
一微細発泡成形物が得難く、特に薄膜発泡シートを製造
すると発泡が不均一になったり粗大化する。しかも、ポ
リプロピレンはポリスチレン・ポリ塩化ビニルに比して
高倍率に延伸しないと厚みの均一な熱収縮性フィルムが
得られ難いが、このような不均一な発泡状態のシートを
一方向に少なくとも４倍以上高倍率延伸すると、発泡の
不均一性が更に増幅さ゛れるばかりか延伸破断を生じ品
質の安定した製品が得られない。又、該シートの発泡が
均一であっても発泡セルが粗大化すると延伸時該セルが
破壊し同様に延伸破断が生ずる。特にこの現象は高速延
伸品ではきわめて顕著であり実用化の大きな障害となっ
ている。Polypropylene has high crystallinity, its melt viscosity cannot be adjusted during extrusion, and it is difficult to maintain the viscosity at a high viscosity, so it is difficult to obtain uniform micro-foamed molded products.Especially when producing thin foam sheets, foaming is difficult. Become uniform or coarse. In addition, it is difficult to obtain a heat-shrinkable film with a uniform thickness with polypropylene unless it is stretched at a higher stretching ratio than polystyrene/polyvinyl chloride. If the stretching ratio is higher than that, the non-uniformity of foaming will not only be further amplified, but also stretch breakage will occur, making it impossible to obtain a product with stable quality. Further, even if the foaming of the sheet is uniform, if the foam cells become coarse, the cells will break during stretching, and stretching breakage will also occur. This phenomenon is particularly noticeable in high-speed drawn products and is a major obstacle to practical application.

本発明者等は、これらの現状に鑑み、熱収縮性に優れた
ポリプロピレン系発泡延伸フィルムおよびその製造方法
について種々検討した結果、特定のプロピレン・α−オ
レフィン共重合体に低密度ポリエチレンまたは／訃よび
エチレン・酢酸ビニル共重合体、有機分解型発泡剤、高
級脂肪酸の金属塩をそれぞれ特定量配合した混合組成物
から特定の条件下で原反発泡シートを作成した後・特定
の条件下で少なくとも一方向に３倍以上延伸する事によ
り、熱収縮性および緩衝効果に優れ、かつ、均質性に優
れた発泡延伸フィルムが高生産性下で得られる事を見出
し、本発明に到達した。以上の記述から明らかなように
本発明（二発明）の目的は新規なポリオレフィン系発泡
延伸フィルムおよびその製造方法を提供することを目的
とする。他の目゛的は、該フィルムを利用した包装資材
を提供することである。In view of these current circumstances, the present inventors have conducted various studies on polypropylene-based expanded stretched films with excellent heat shrinkability and methods for producing the same, and have found that low-density polyethylene or/and After creating a raw rebound foam sheet under specific conditions from a mixed composition containing specific amounts of ethylene/vinyl acetate copolymer, organic decomposable blowing agent, and metal salt of higher fatty acid, under specific conditions at least The present invention was achieved by discovering that by stretching the film in one direction three times or more, a foamed stretched film with excellent heat shrinkability and cushioning effect and excellent homogeneity can be obtained with high productivity. As is clear from the above description, the object of the present invention (second invention) is to provide a novel polyolefin foam stretched film and a method for producing the same. Another objective is to provide packaging materials using the film.

本発明は、下記（１）および（２）の主要構成を有する
。The present invention has the following main components (1) and (2).

（１）プロピレン含量７０重量％以上で、結晶融点が１
１５〜１４５℃の結晶性プロピノン−α−オレフィン共
重合体（Ｎに対し、 密度０．９３０以下の低密度ポリエチレンまたは／およ
びエチレン・酢酸ビニル共重合体（Ｂ）７〜５０重量％ 有機分解型発泡剤（Ｃ）　　　０１〜２．０重量％脂肪
酸の金属塩の）　　　０．０３〜ＬＯ重量％を配合した
混合組成物を該発泡剤（Ｃ）の分解温度以上で溶融押出
しし、かくして得た原反発泡シートヲ、該シートの少な
くとも一方向に９− ３倍以上延伸してなる事を特徴とするポリオレフィン系
発泡延伸フィルム。(1) The propylene content is 70% by weight or more and the crystal melting point is 1.
Crystalline propynone-α-olefin copolymer at 15-145°C (based on N, low-density polyethylene with a density of 0.930 or less or/and ethylene-vinyl acetate copolymer (B) 7-50% by weight, organic decomposition type) A mixed composition containing blowing agent (C) 0.01 to 2.0% by weight of metal salts of fatty acids) was melt-extruded at a temperature equal to or higher than the decomposition temperature of the blowing agent (C). 1. A polyolefin foam stretched film, which is obtained by stretching an original resilient foam sheet by a factor of 9-3 times or more in at least one direction.

（２）結晶融点が１１５〜１４，５℃の結晶性プロピ・
ノン−α−オレフィン共重合体（Ａ）　９３〜４７重量
％、密度０．９３０以下の低密度ポリエチレン、寸たは
／およびエチレン・酢酸ビニル共重合体（Ｆ３）　７〜
５０重量％、有機分解型発泡剤（Ｃ）０．１〜２．０重
量％および高級脂肪酸金属塩（ロ）０．０３〜１．０重
量％からなる組成物を該発泡剤（Ｃ）の分解温度具−ヒ
の温度で溶融押出し、後６０℃以下に急冷して、 （１）厚み０．１瓢以上、見掛は比重０．７以下の原反
発泡シートを作成し、ついで該発泡シートを前記共重合
体体）の融点より１０〜６０℃低い温度でタテ又はヨコ
方向に３〜１２倍延伸し、または、 （１）厚み０．２．以上、見掛は比重０．８以下の原反
発泡シートを作成し、ついで該発泡シートを前記共重合
体（ト）の融点より１０〜５０℃低い温度でタテ又はヨ
コ方向にそれぞれ１．１〜−１〇− １０倍延伸し、かつ、該延伸後の延伸フィルムのタテ×
ヨコの面積倍率を延伸前のシートの６〜３０倍とするこ
とを特徴とするポリオレフィン系発泡延伸フィルムの製
造方法。(2) Crystalline propylene with a crystal melting point of 115-14.5℃
Non-α-olefin copolymer (A) 93 to 47% by weight, low density polyethylene with a density of 0.930 or less, or/and ethylene/vinyl acetate copolymer (F3) 7 to
50% by weight of the blowing agent (C), 0.1 to 2.0% by weight of the organic decomposable blowing agent (C), and 0.03 to 1.0% by weight of the higher fatty acid metal salt (b). Melt and extrude at the temperature of decomposition temperature tool - A, then rapidly cool to 60°C or less to create (1) a raw rebound foam sheet with a thickness of 0.1 or more and an apparent specific gravity of 0.7 or less; The sheet is stretched 3 to 12 times in the vertical or horizontal direction at a temperature 10 to 60° C. lower than the melting point of the copolymer, or (1) has a thickness of 0.2. As described above, an original resilient foam sheet with an apparent specific gravity of 0.8 or less was prepared, and then the foam sheet was heated at a temperature 10 to 50 degrees Celsius lower than the melting point of the copolymer (T) in the vertical or horizontal direction by 1.1 ~-1〇- Stretched 10 times, and the length of the stretched film after stretching
A method for producing a polyolefin foam stretched film, characterized in that the horizontal area magnification is 6 to 30 times that of the sheet before stretching.

本発明においてプロピレン含ｉ７０重、ｐｔ　１以上で
結晶融点が１１５〜１４５℃の結晶性プロピレン・α−
オレフィン共重合体とは、プロピレンとエチレンまたば
／および炭素数４〜８のα−オレフィンとの共重合体で
ありプロピレン成分を７０重量−以上含み、かつ結晶融
点が１１５〜１４５℃のものである。このうち、沸ｌｉ
ｔ　ｎ−へブタン不溶部分”、（７０重ｉ％以上含み、
結晶融点が１１５〜１４０℃のエチレン・プロピレンラ
ンダム共重合体・エチレン・プロピレン・ブテン−１三
元共重合体が最も望寸しい。In the present invention, crystalline propylene α-
Olefin copolymer is a copolymer of propylene, ethylene and/or α-olefin having 4 to 8 carbon atoms, contains 70% by weight or more of propylene component, and has a crystal melting point of 115 to 145°C. be. Of these, boiling water
t n-hebutane insoluble portion” (contains 70% by weight or more,
Ethylene-propylene random copolymer and ethylene-propylene-butene-1 terpolymer having a crystal melting point of 115 to 140° C. are most desirable.

本発明において結晶融点（以下、Ｔｍと略称する）とは
、走査型差動熱量計を用いて窒素雰囲気中で試料を１０
℃／分の速度で昇温させて得られる結晶の融解に伴なう
吸熱カーブのピーク温度介さす。Ｔｍが１４５℃を超え
ると発泡が不均一になり、延伸破断を生じやすい。Ｔｍ
が１１５℃未満では得られた発泡成形品が＾わめて柔軟
化し作業性が大幅に低下するばかり休、フィルムが粘着
し易く好ましくない。In the present invention, the crystal melting point (hereinafter abbreviated as Tm) is defined as the crystal melting point (hereinafter abbreviated as Tm) when a sample is
The peak temperature of the endothermic curve accompanying the melting of the crystal obtained by increasing the temperature at a rate of °C/min. When Tm exceeds 145°C, foaming becomes non-uniform and stretching breaks easily. Tm
If the temperature is lower than 115°C, the obtained foamed molded product becomes extremely flexible, workability is significantly reduced, and the film tends to stick, which is undesirable.

本発明に使用される低密度ポリエチレンは、常温で固体
で、密ｉ　０．９３０以下のものであり、回しくエチレ
ン・酢酸ビニル共重合体は酢酸ビニル含量１〜４０重量
％のものである。この低密度ポリエチレンまたは／およ
びエチレン・酢酸ビニル共重合体を本発明に係る混合組
成物中に７〜５０重量％配合することによって、均一か
つ微細な発泡セルを有する発泡シートが得られ、延伸可
能温度幅が広くなり、かつ−高倍率高速延伸が可能とな
る。さらに得られた本発明のフィルムも適度々柔軟性を
有し、収縮応力を低減させ、かつ平滑性に優れた均一微
細発泡を有するフィルムとなる利点を有する。The low density polyethylene used in the present invention is solid at room temperature and has a density i of 0.930 or less, and the ethylene/vinyl acetate copolymer has a vinyl acetate content of 1 to 40% by weight. By blending 7 to 50% by weight of this low density polyethylene or/and ethylene/vinyl acetate copolymer into the mixed composition according to the present invention, a foamed sheet having uniform and fine foamed cells can be obtained and can be stretched. The temperature range becomes wider, and high-strength and high-speed stretching becomes possible. Furthermore, the obtained film of the present invention also has the advantage of being moderately flexible, reducing shrinkage stress, and having uniform fine foaming with excellent smoothness.

本発明に使用される有機分解型発泡剤（Ｃ）としては、
常温で固体であり該プロピレン・α−オレフィン共重合
体のＴｍより高い分解温度を有し、該分解温度以上忙加
熱されると窒素・炭酸ガス・アンモニアガス等のガスを
発生しながら分解する化合物であって、たとえば、アゾ
ジカルボンアミド、アゾジカルボンアミドの金属塩、ヒ
ドラゾジカルボンアミド、Ｎ、Ｎ’−ジニトロソペンタ
メチレンテトラミン、ｐ−）ルエンスルフオニルヒドラ
ジド等があげられる。該発泡剤の本発明に係る組成物へ
の配合量は、０．１〜２゜０重量％であり、０．１％に
達しないと発泡性が劣り、２．０重量％を超えると発泡
の調整がしとくくなり好ましくない。このうちアゾジカ
ルボンアミドをＯ０２〜０．８重量％配合するのが最も
望ましい。The organic decomposable blowing agent (C) used in the present invention includes:
A compound that is solid at room temperature, has a decomposition temperature higher than the Tm of the propylene/α-olefin copolymer, and decomposes while generating gases such as nitrogen, carbon dioxide, and ammonia gas when heated above the decomposition temperature. Examples thereof include azodicarbonamide, metal salts of azodicarbonamide, hydrazodicarbonamide, N,N'-dinitrosopentamethylenetetramine, p-)luenesulfonyl hydrazide, and the like. The amount of the foaming agent added to the composition according to the present invention is 0.1 to 2.0% by weight, and if it does not reach 0.1%, the foaming property will be poor, and if it exceeds 2.0% by weight, the foaming will be poor. It becomes difficult to adjust, which is not preferable. Among these, it is most desirable to blend azodicarbonamide in an amount of O02 to 0.8% by weight.

本発明で使用する高級脂肪酸（Ｄ）の金属塩とし１３− ては、ステアリン酸、１２−ヒドロキンステアリン酸等
の高級脂１１１ｊ酸とナトリウム・リチウム等のアルカ
リ金属、カルシウム・マグネシウム等のアルカル金匡等
との塩をあげることができ、それらは具体的１てはステ
アリン酸ナトリウム、１２−ヒドロキンステアリン酸リ
チウム、ステアリン酸カルシウム、１２−ヒドロキンス
テアリン酸カルシウム、ステアリン酸マグネシウム、ス
テアリン酸亜鉛等がある。該脂肪酸の金属塩の本発明に
係る組成物への配合量は０．０３〜１．０重量憾であり
、０．０３％に達しないと発泡が不均一であり、１．０
重量％を超えると押出機への喰い込みがきわめて悪化す
る。The metal salts of higher fatty acids (D) used in the present invention include higher fatty acids such as stearic acid and 12-hydroquine stearic acid, alkali metals such as sodium and lithium, and alkali metals such as calcium and magnesium. Specific examples include sodium stearate, lithium 12-hydroquine stearate, calcium stearate, calcium 12-hydroquine stearate, magnesium stearate, zinc stearate, etc. . The amount of the metal salt of the fatty acid added to the composition according to the present invention is 0.03 to 1.0% by weight, and if it does not reach 0.03%, foaming will be uneven;
If it exceeds % by weight, it becomes extremely difficult to feed into the extruder.

本発明で用いる上記のプロピレン・α−オレフィン共重
合体と低密度ポリエチレンまたは／およびエチレン・酢
酸ビニル共重合体、有機分解型発泡剤、脂肪酸の金属塩
との配合物中には酸化防止剤、紫外線吸収剤、帯電防止
剤、スリップ剤、顔料、脂肪酸・脂肪酸アミド等の滑剤
等を配合しても良い。これらを配合し混合組成１４− 物を得る方法は、該発泡剤の分解温度より低い温度で・
ヘンシエル・ミキサー（商品名）、リボン・ブレンダー
等で混合するだけでも良く、ロール混合、押出混練、ニ
ーダ−混練、バンバリーミキサ−混線等を併用しても良
い。An antioxidant, Ultraviolet absorbers, antistatic agents, slip agents, pigments, lubricants such as fatty acids and fatty acid amides, etc. may be added. The method of blending these to obtain mixed composition 14- is to
Mixing may be carried out using a Henschel mixer (trade name), a ribbon blender, or the like, or a combination of roll mixing, extrusion kneading, kneading, Banbury mixer, etc. may be used.

本発明の方法においては、特に発泡剤の分散を均一化す
る為に該共重合体のＴｍより高く、該発泡剤の分解温度
より低い温度で、押出混練、ニーダ−混線等を併用しチ
ップ状にした配合物す橙わち組成物を使用するのが最も
望寸しい。In the method of the present invention, in particular, in order to uniformize the dispersion of the blowing agent, extrusion kneading, kneader cross-wiring, etc. are used in combination at a temperature higher than the Tm of the copolymer and lower than the decomposition temperature of the blowing agent. It is most desirable to use an orange composition.

この場合、プロピレン−α−オレフィン共重合体のＴｍ
が１１５〜１４５℃であり、通常の結晶性ポリプロピレ
ン（Ｔ　ｍ　＝　１６５℃）に比して２０〜５０℃もＴ
ｍが低い為有利であり、該発泡剤の分解温度は、該共重
合体のＴｍよ９２０℃以上、望ましくは３０℃以上高い
ものを用いて行う方法が最も望ましい。In this case, the Tm of the propylene-α-olefin copolymer
is 115-145°C, and T m is 20-50°C lower than normal crystalline polypropylene (T m = 165°C).
This is advantageous because m is low, and the most desirable method is to use a blowing agent whose decomposition temperature is higher than Tm of the copolymer by 920° C. or more, preferably by 30° C. or more.

本発明のとの混合組成物を該発泡剤の分解温度以上で溶
融押出しして得た原反発泡シートを該シートの少なくと
も一方向に３倍以上延伸する事によって得られる本発明
のフィルムのうち、厚み０．０３〜０．４箭、見掛は比
重０．６以下、１２０℃における一方向の収縮率が２０
％以上であるフィルムが、熱収縮性と緩衝効果を兼備し
た発泡延伸フィルムとして、最も好ましい実施態様であ
る。厚みが０．０３＋ｏ＋未満では緩衝効果が不足し、
０．４　ｍｍを超えると収縮応力が大きく内容物が変形
し易くなり、又、収縮温度もきわめて高くなり好ましく
ない。又、見掛は比重が０．６を超えるものは緩衝効果
が不足し、１２０℃における一方向の収縮率が２０チに
達しないものは、ポリ塩化ビニル・ポリスチレンに比し
て熱収縮性がきわめて劣り、高温かつ長時間かけて熱収
縮させねばならず好ましくない。Among the films of the present invention obtained by melt-extruding a mixed composition of the present invention at a temperature higher than the decomposition temperature of the blowing agent and stretching the original rebound foam sheet three times or more in at least one direction of the sheet. , thickness 0.03 to 0.4 mm, apparent specific gravity 0.6 or less, shrinkage rate in one direction at 120°C 20
% or more is the most preferred embodiment as a foamed stretched film that has both heat shrinkability and a buffering effect. If the thickness is less than 0.03+o+, the cushioning effect will be insufficient,
If it exceeds 0.4 mm, the shrinkage stress will be large and the contents will be easily deformed, and the shrinkage temperature will also be extremely high, which is not preferable. Also, if the apparent specific gravity exceeds 0.6, the buffering effect will be insufficient, and if the shrinkage rate in one direction at 120°C does not reach 20 inches, the heat shrinkability will be lower than that of polyvinyl chloride or polystyrene. It is extremely inferior and requires heat shrinkage at high temperatures and over a long period of time, which is not preferable.

本発明のフィルムの好ましい製造方法としては、例えば
下記のような方法により得る事が出来る。As a preferred method for producing the film of the present invention, it can be obtained, for example, by the following method.

上記のプロピレン・α−オレフィン共重合体（Ａ）　１
００重量％に対し、密度０．９３０以下の低密度ポリエ
チレンまたは／およびエチレン・酢酸ビニル共重合体（
Ｂ）７〜５０重量％、好ましくは１０〜３５重量％、有
機分解型発泡剤を０．１〜２．０重量％、好ましくは０
．２〜０．８重量％、脂肪酸の金属塩０．０３〜１．０
重量％、好ましくは０．１〜０．５重量％を前記の方法
で配合し混合組成物を得る。The above propylene/α-olefin copolymer (A) 1
00% by weight, low-density polyethylene with a density of 0.930 or less or/and ethylene/vinyl acetate copolymer (
B) 7 to 50% by weight, preferably 10 to 35% by weight, and 0.1 to 2.0% by weight, preferably 0.
．． 2-0.8% by weight, metal salts of fatty acids 0.03-1.0
A mixed composition is obtained by blending % by weight, preferably 0.1 to 0.5% by weight, by the method described above.

次に該混合組成物を押出機に供給し、該発泡剤が実質的
に分解し、かつ得られる原反発泡シートの見掛は比重と
して所望のものが得られるように押出温度を調整して押
出機及びダイスから溶融押出し、６０℃以下に急冷する
。本発明でいう発泡剤の分解温度以上とは、該発泡剤の
公称分解温度以上を意味するものでは無く、見掛は比重
０．８以下の原反発泡シートが得られる押出温度を意味
する。次に、押出機及びダイスから出た溶融発泡シート
を６０℃以下に急冷する。該急冷の方法は、該シートを
６０℃以下に保った水中に浸漬してもよく、冷却ロール
に接触させても良い。又、本発明の場合はきわめて微細
な発泡セルを有する溶融状態の為、溶融未１７− 固化シートの冷却は厚み１−以上では片面のみでも良い
が、好ましくは該シートを一対の冷却ロールで挾みつけ
シートの両面を急冷する。かくして得られた原反発泡シ
ートの特性は次行程が一軸延伸か二軸延伸かによって若
干特性が累々り、又、延伸条件も異なる。すなわち、■
−軸延伸フイルムを得だい場合は予め厚み０．１鱈以上
望ましくは０．１５〜１．５ｗｎ、見掛は比重０．７以
下、望ましくは０．３〜０．７以下の原反発泡シートを
作成し、次いで該ソートを、該プロピレン・α−オレフ
ィン共重合体のＴｍより１０〜６０℃低い温度でタテ又
はヨコ方向に３〜１２倍−軸延伸する。Next, the mixed composition is fed to an extruder, and the extrusion temperature is adjusted so that the blowing agent is substantially decomposed and the resulting original rebound foam sheet has a desired apparent specific gravity. Melt extrusion is performed from an extruder and die, and the product is rapidly cooled to 60°C or less. The term "above the decomposition temperature of the blowing agent" as used in the present invention does not mean a temperature above the nominal decomposition temperature of the blowing agent, but rather an extrusion temperature at which a raw rebound foam sheet having an apparent specific gravity of 0.8 or less is obtained. Next, the molten foam sheet exiting the extruder and die is rapidly cooled to 60° C. or lower. The quenching method may be such that the sheet is immersed in water kept at 60° C. or lower, or may be brought into contact with a cooling roll. In addition, in the case of the present invention, since the sheet is in a molten state with extremely fine foam cells, cooling of the unmelted and solidified sheet may be performed on only one side if the thickness is 1 or more, but preferably the sheet is sandwiched between a pair of cooling rolls. Quickly cool both sides of the mitsuke sheet. The properties of the original resilient foam sheet thus obtained vary depending on whether the next step is uniaxial or biaxial stretching, and the stretching conditions also vary. In other words,■
- When the axially stretched film is obtained, it is prepared in advance as a raw rebound foam sheet with a thickness of 0.1 or more, preferably 0.15 to 1.5wn, and an apparent specific gravity of 0.7 or less, preferably 0.3 to 0.7 or less. is prepared, and then the sort is axially stretched 3 to 12 times in the vertical or horizontal direction at a temperature 10 to 60° C. lower than the Tm of the propylene/α-olefin copolymer.

この場合原反発泡シートの厚みが０．１鰭に達しないと
延伸破断したり、延伸時厚みムラを発生するので好まし
くない。又、見掛は比重は０．７より大きいと得られる
フィルムの緩衝効果が不足する。延伸温度は、該共重合
体のＴｍより１０〜６０℃低い温度に限定され、”　Ｔ
ｍ　１０℃″より高い温度ではシートが溶融して破断し
たり、得られるフィルムの収縮性が不足し″Ｔｍ−５Ｑ
℃″１８− よシ低い温度では延伸破断が多く、かつ、得られたフィ
ルムは常温で保存しても巻き締シが生じ好ましくない。In this case, if the thickness of the original resilient foam sheet does not reach 0.1 fin, it is not preferable because stretching may cause breakage or thickness unevenness may occur during stretching. Further, if the apparent specific gravity is greater than 0.7, the buffering effect of the obtained film will be insufficient. The stretching temperature is limited to a temperature that is 10 to 60°C lower than the Tm of the copolymer, and "T
At temperatures higher than 10°C, the sheet may melt and break, or the resulting film may lack shrinkage.
℃''18- It is undesirable that at a very low temperature, there will be many stretching breaks, and the obtained film will have curling wrinkles even if stored at room temperature.

■次に二軸延伸フィルムの場合は、厚み０゜２雪以上、
望１しくけ０．３〜２．０雪、見掛は比重０．８以下、
望ましくは０．２〜０．７調の原反発泡シートを作成し
、次いで、該シートを該プロピレン・α−オレフィン共
重合体のＴｍより１０〜５０℃低い温度で、イ、同時二
軸延伸の場合はタテ及びヨコ方向にタテ×ヨコの面積倍
率で６〜３０倍望ましくは、タテ方向に１．１〜６．０
倍、ヨコ方向に４〜６倍で、かつタテ×ヨコの面積倍率
が９〜３０倍になるように同時に延伸する。■Next, in the case of biaxially stretched film, the thickness is 0°2 or more,
Desired 0.3 to 2.0 snow, apparent specific gravity 0.8 or less,
A raw resilient foam sheet with a tone of preferably 0.2 to 0.7 is prepared, and then the sheet is simultaneously biaxially stretched at a temperature 10 to 50°C lower than the Tm of the propylene/α-olefin copolymer. In this case, the area magnification of vertical x horizontal in the vertical and horizontal directions is 6 to 30 times, preferably 1.1 to 6.0 in the vertical direction.
The film is simultaneously stretched so that the area magnification in the vertical and horizontal directions is 9 to 30 times.

又、ロ、逐次二軸延伸の場合はタテ方向に１．１〜３倍
望ましくは１．２〜２．５倍延伸した後ヨコ方向に５〜
１０倍望ましくは６〜９倍延伸する。In the case of sequential biaxial stretching, after stretching 1.1 to 3 times in the vertical direction, preferably 1.2 to 2.5 times,
It is stretched 10 times, preferably 6 to 9 times.

これらの二軸延伸の場合は、前述■の一軸延伸の場合に
比して、延伸破断がより発生し易いため、この範囲に限
定して行う事が望ましい。In the case of these biaxial stretching, stretch breakage is more likely to occur than in the case of the uniaxial stretching described in (2) above, so it is desirable to limit the stretching to this range.

本発明の方法においては、これらの−軸又は二軸延伸の
工程を多段階に分けて、行う事も可能であり、たとえば
、−軸延伸をタテ方向に２段階たとえば一段目に４倍延
伸した後更に二段目に１．５倍延伸する事も、二軸延伸
で“タテ×ヨコ×タテ“の如く三段階の延伸を行うも可
能である。このようにして延伸された本発明のフィルム
は必要に応じて緊張下又は若干緩和状−で熱固定し、空
冷・冷却ロール・冷却ベルト等で冷却される。又、該冷
却後コロナ放電処理等の表面処理を行っても良い。In the method of the present invention, it is also possible to carry out these -axis or biaxial stretching steps in multiple stages. For example, -axis stretching can be carried out in two stages in the vertical direction, for example, in the first stage, the process can be carried out by 4 times stretching. It is also possible to stretch the film by 1.5 times in the second stage, or to perform biaxial stretching in three stages such as "vertical x horizontal x vertical". The thus stretched film of the present invention is heat-set under tension or in a slightly relaxed state as required, and then cooled with air cooling, a cooling roll, a cooling belt, or the like. Further, after the cooling, surface treatment such as corona discharge treatment may be performed.

本発明で得られた発泡延伸フィルムはきわめて優れた熱
収縮性緩衝性を有し、かつ、耐衝撃性に優れており各種
のタイト包装、結束包装、ラベル包装等にきわめて有用
である。The expanded stretched film obtained in the present invention has extremely excellent heat-shrinkable cushioning properties and excellent impact resistance, and is extremely useful for various types of tight packaging, bundled packaging, label packaging, etc.

以下に、本発明を実施例、比較例で更に詳述するが、本
発明は以下の実施例に限定されるもので１はない。宵、
以下の実施例、比較例における特性値は下記の方法で測
定したものである。The present invention will be explained in more detail below using Examples and Comparative Examples, but the present invention is not limited to the following Examples. evening,
The characteristic values in the following Examples and Comparative Examples were measured by the following method.

・ＭＦＲ（メルトフローレート）： ＪＩＳ　　Ｋ７２１０−１９７６ ・ポリプロピレンおよびプロピレン・α−オレフィン共
重合体は条件１４（２３０℃、２．１６　Ｋｇｆ　　） ・ポリエチレンおよびエチレン・酢酸ビニル共重合体は
条件４（１９０℃、２．１６　Ｋｇｆ　）・見掛は比重
：ＪＩＳ　　Ｋ７１１２−１９７’７Ｂ法（ピラノメー
ター法）浸せき液＝水・１２０℃収縮率：１０ｃｒｎ平
方に切ったフィルムを１２０℃のグリセリン浴に１０秒
間浸せきしてとり出し、各辺の長さの縮み率（９１１を
もって表わした。数字の前に△をつけたものは逆に伸び
たことを表わす。・MFR (Melt Flow Rate): JIS K7210-1976 ・Polypropylene and propylene/α-olefin copolymer: Condition 14 (230°C, 2.16 Kgf) ・Polyethylene and ethylene/vinyl acetate copolymer: Condition 4 (190 °C, 2.16 Kgf)・Appearance is specific gravity: JIS K7112-197'7B method (pyranometer method) Immersion liquid = water・120℃ Shrinkage rate: 10crn Soak the film cut into squares in a glycerin bath at 120℃ for 10 seconds The shrinkage rate of the length of each side is expressed as 911. A △ in front of the number means that it has expanded.

・発泡状態：原反発泡シート及び発泡延伸フィルムの巾
及び長さ方向の発泡ムラの有無および発泡セルの大きさ
及び均一性を目視観察した。発泡ムラが無く、発泡セル
が微細均一なものを○、若干発泡にムラがあり発泡セル
が粗いものを△、発泡ムラが多く発泡セルが粗大でかつ
不均一なものをＸとして表わした。- Foaming condition: The presence or absence of uneven foaming in the width and length directions of the original resilient foam sheet and foamed stretched film, and the size and uniformity of the foamed cells were visually observed. A sample with no uneven foaming and fine and uniform foam cells was rated as ○, a sample with slight foaming unevenness and rough foam cells was rated as △, and a sample with a lot of uneven foaming and coarse and non-uniform foam cells was labeled as X.

２１− ・印刷性：市販のポリプロピレン用印刷インキ（東洋イ
ンキ■製、ポリプロカラー）を用いてグラビア印刷機で
、基盤目を印刷し、基盤目に濃淡が無く、インキのにじ
みも無く鮮明がものを０１（Ｃじみは無いが濃淡が若干
あったり、濃淡は無いが若干にじみがあったりしてやや
不鮮明なものを△、印刷に濃淡部が明確に区分出来たり
、インキかにじみ基盤目が不鮮明なものを×として表わ
した。21- ・Printability: Printing on a gravure printing machine using a commercially available printing ink for polypropylene (manufactured by Toyo Ink ■, Polypro Color) results in clear and clear printing with no shading or ink smearing on the base. 01 (C) There is no shading but there is some shading, or there is no shading but there is some smearing and it is a little unclear. Objects are represented as ×.

実施例１〜６、比較例１〜６ エチレン含量４．０重量子、ブテン−１含量５．２重量
子、Ｔｍ＝１３０℃、ＭＦＩＲ＝４．２のエチレン・プ
ロピレン・ブテン−１三元共重合体（酸化防止剤として
２，６−ジーｔ−ブチルー−ｐ−フェノール０．１５重
量％含む）に〔第１表〕に示す添加剤を配合し、ヘンシ
ェルミキサーで３分間配合し、１２種類の混合組成物を
得た。この混合組成物を口径６５恒のスクリュー及び幅
３５０咽のＴダイを有するシート押出装２２− 置を用いて樹脂温度２０５℃で溶融押出し、３０℃に保
った２本の冷却ロールで圧着しつつ急冷し、幅方向の両
端（耳部）を各２０籠カツトして、厚み０．５５調、幅
２５０ｆｉの原反発泡シートを得る。次に該シートを１
００℃に保つ／ζ加熱ロールで予熱したのち同温度に保
った加熱ａ−ル上でタテ方向に６．０倍延伸し、１０５
℃の加熱ロール上で熱処理し２２℃の冷却ロールで急冷
して厚み０６１０＋ｍｎの発泡−軸延伸フィルムを得た
。各混合組成物の原反発泡シートの見掛は比重、発泡状
態、得られた発泡−軸延伸フィルムの見掛は比重、発泡
状態、１２０℃収縮率及び印刷性を〔第１表〕に併記し
た。Examples 1 to 6, Comparative Examples 1 to 6 Ethylene/propylene/butene-1 ternary copolymer with ethylene content of 4.0 wt, butene-1 content of 5.2 wt, Tm = 130°C, MFIR = 4.2 Additives shown in [Table 1] were blended with a polymer (containing 0.15% by weight of 2,6-di-t-butyl-p-phenol as an antioxidant) and blended for 3 minutes in a Henschel mixer to obtain 12 types. A mixed composition was obtained. This mixed composition was melt-extruded at a resin temperature of 205°C using a sheet extruder 22 having a screw with a diameter of 65mm and a T-die with a width of 350°C, and the mixture was crimped with two cooling rolls kept at 30°C. After cooling rapidly, 20 baskets were cut at both ends (edges) in the width direction to obtain a raw rebound foam sheet with a thickness of 0.55 mm and a width of 250 fi. Next, the sheet is 1
00℃ / ζ After preheating with a heating roll, stretch 6.0 times in the vertical direction on a heating roll kept at the same temperature, 105
It was heat treated on a heating roll at 22°C and rapidly cooled on a cooling roll at 22°C to obtain a foamed, axially stretched film with a thickness of 0610+mm. The apparent specific gravity and foaming state of the original resilient foam sheet of each mixed composition, the apparent specific gravity, foaming state, 120°C shrinkage rate, and printability of the resulting foamed-axially stretched film are also listed in [Table 1]. did.

実施例７〜９、比較例７〜９ 〔第２表〕に示すポリプロピレン、プロピレン・α−オ
レフィン共重合体（酸化防止剤として２，６−ジーｔ−
ブチル−ｐ−フェノール０．１重量％含む）に、密度０
，９１９、ＭＦＲ＝１．０の低密度ポリエチレン１５重
量％、アゾジカルボンアミド０．５重量％、ステアリン
酸カルシウム０．３ｉ量チを配合し、ヘンンエルミキサ
ーで４０℃で３分間混合し６種類の混合組成物を得だ。Examples 7 to 9, Comparative Examples 7 to 9 Polypropylene, propylene/α-olefin copolymer shown in [Table 2] (2,6-di-t-
(contains 0.1% by weight of butyl-p-phenol), density 0
, 919, 15% by weight of low-density polyethylene with MFR = 1.0, 0.5% by weight of azodicarbonamide, and 0.3i of calcium stearate were mixed at 40°C for 3 minutes in a Hennel mixer to form 6 types. A mixed composition is obtained.

この混合組成物を実施例１で用いたシート押出装置を用
いて樹脂温ｌＶ′２００℃で溶融押出し、２０℃に急冷
して厚み１．８調の原反発泡シートを得た。このシート
を小型パンタグラフ型延伸装置（Ｔ、Ｍ、　Ｌｏｎｇ社
（ト）製）を用いて〔第２表〕に示す延伸温度でタテ・
ヨコ各々４．５（？１１時延伸し、厚み０゜０９ｗ１１
の発泡二軸延伸フィルムを得た。各混合組成物の原反発
泡シートの見掛は比重、延伸性、得られた発泡二軸延伸
フィルムの見掛は密度、発泡状態、１２０℃収縮率を〔
第２表〕に併記した。同、延伸性は同条件で繰返し１０
回延伸した場合の延伸破断回数（単位二回）をもって表
わしだ。数字が少ないほど延伸性は良好であり、０は全
く破断じなかった事を意味する。又１０は全く延伸出来
なかった事を意味する。This mixed composition was melt-extruded using the sheet extrusion apparatus used in Example 1 at a resin temperature of 1V' of 200°C and rapidly cooled to 20°C to obtain an original rebound foam sheet with a thickness of 1.8 mm. This sheet was vertically stretched using a small pantograph type stretching device (T, M, manufactured by Long Co., Ltd.) at the stretching temperature shown in [Table 2].
Each width is 4.5 (?11 o'clock stretched, thickness 0゜09w11
A foamed biaxially stretched film was obtained. [
Table 2]. Same, stretchability is repeated 10 times under the same conditions.
It is expressed by the number of times of stretching breakage (unit: 2 times) when double stretching is performed. The smaller the number, the better the stretchability, and 0 means that there was no breakage at all. Also, 10 means that it could not be stretched at all.

実施例１Ｏ 二手レゾ含−１ｉ５．０重量４、ブテン−１含量４．３
重量％、’ｒｍ＝１２６℃、ＭＩｉ’Ｒ：２，２１７）
エチレン・プロピレン・ブテン−１三元共重合体（酸化
防止剤として、２，６−ジーｔ−ブチル−ｐ−フェノー
ル０．１５重量％、テトラキス〔メチレン−３−（３’
、５’−ジ−ｔ−ブチル−４′−ヒドロキシフェニル）
プロピオネートコメタフ０．１０重量係含む）に密度０
．９２２、ＭＦＲ・＝１．５の低密度ポリエチレン２５
重量％、アゾジカルボンアミド０．４重量％、１２−ヒ
ドロキだ後、押出機を通して樹脂温度１６８℃でストラ
ンド状に溶融押出し、冷却カットしてペレット化した未
発泡の混合組成物を得た。この混合組成物を、押出機・
原反シート製造装置、加熱ロール式タテ延伸装置および
テンター法横延伸装置を具備した逐次二軸延伸装置を用
いて・２０７℃で溶融押出し、４０℃に保った２本の冷
却ロールで挾みつけながら急冷して引取シ、厚み１．２
恒、見掛は比重０．５５の原反発泡シートを得だ。この
シートを１００℃でタテ方向に１゜５倍延伸し、引続き
ヨコ方向建１１０℃で８．２倍延伸し同温度で５秒間熱
固定を行った後、２５℃に冷却し、厚み０．１謔の発泡
二軸延伸フィルムを得た。このフィルムは、見掛は比重
０．３Ｂ　、発泡状態○、１２０℃収縮率タテ１１チ、
ヨコ４８チ、印刷性○であった。Example 1O Two-handed reso-1i 5.0 weight 4, butene-1 content 4.3
Weight %, 'rm=126°C, MIi'R: 2,217)
Ethylene-propylene-butene-1 terpolymer (0.15% by weight of 2,6-di-t-butyl-p-phenol as an antioxidant, tetrakis[methylene-3-(3')
, 5'-di-t-butyl-4'-hydroxyphenyl)
Propionate Cometaf 0.10 (weight ratio included) has a density of 0.
．． 922, low density polyethylene 25 with MFR・=1.5
% by weight, 0.4% by weight of azodicarbonamide, and 12-hydroxide, and then melt-extruded through an extruder at a resin temperature of 168° C. into a strand shape, cooled and cut to obtain an unfoamed mixed composition that was pelletized. This mixed composition is passed through an extruder
Using a sequential biaxial stretching device equipped with a raw sheet manufacturing device, a heated roll type vertical stretching device, and a tenter method horizontal stretching device, the sheet was melt extruded at 207°C and sandwiched between two cooling rolls kept at 40°C. Rapidly cooled and collected, thickness 1.2
He obtained a repulsion foam sheet with an apparent specific gravity of 0.55. This sheet was stretched 1.5 times in the vertical direction at 100°C, then stretched 8.2 times in the horizontal direction at 110°C, heat-set at the same temperature for 5 seconds, and then cooled to 25°C to a thickness of 0. One piece of foamed biaxially stretched film was obtained. This film has an apparent specific gravity of 0.3B, a foaming state of ○, a shrinkage rate of 120℃ vertically, and a vertical shrinkage of 11cm.
The print quality was 48 cm across and the printability was ○.

このフィルムに基盤目を印刷し、超音波シーラーで、高
さ１００簡、直径７５ｍｍの円筒状にヨコ方向が直径方
向になるように成形した。このフィルム円筒を、高さ１
００　ｍｍ　ｓ直径７０露の紙製管状体にかぶせ２２０
℃で５秒間加熱した。この結果、フィルムの直径方向は
管状体に完全に密着し、高さ方向は全く収縮せず、印刷
の基盤目も全く歪みがない密着包装体が得られた。A base pattern was printed on this film, and it was molded using an ultrasonic sealer into a cylindrical shape with a height of 100 mm and a diameter of 75 mm so that the horizontal direction was the diametrical direction. This film cylinder has a height of 1
00 mm s Cover a paper tubular body with a diameter of 70 mm 220 mm
Heated at ℃ for 5 seconds. As a result, a close-fitting package was obtained in which the film adhered completely to the tubular body in the diametrical direction, did not shrink at all in the height direction, and had no distortion at all in the printed base pattern.

以上that's all

Claims (1)

【特許請求の範囲】 （１）結晶融点が１１５〜１４５℃の結晶性プロピレン
−α−オレフィン共重合体（Ａ）　９３〜４７重婿係、
密度０．９３０以下の低密度ポリエチレン、オたは／お
よびエチレン・酢酸ビニル共重合体中）７〜５０重量％
、有機分解型発泡剤（Ｃ）０．１〜２．０重量％および
高級脂肪酸金属塩（Ｄ）０．０３〜１．０重量％からな
る組成物を該発泡剤（Ｃ）の分解温度以上の温間で溶融
押出しし、かぐして得られた原反発泡シートを該シート
の少なくとも一方向に３倍以上延伸してなるポリオレフ
ィン系発泡延伸フィルム。 （２）結晶性プロピレン−α−オレフィン共重合体（８
）がエチレン含量４〜１０重量％のエチレン・プロピレ
ンランダム共重合体寸たけエチレン含奇０．５〜６重−
潅チ、ブテン−１含贋１〜１５重騎チのエチレン・プロ
ピレン・ブテン−１共重合体であり、有機分解型発泡剤
（Ｃ）がアゾジカルボンアミドである特許請求の範囲第
（１）項に記載のポリオレフィン系発泡延伸フィルム。 （３）結晶融点が１１５〜１４５℃の結晶性プロピレン
−α−オレフィン共重合体（Ａ）９３〜４７３〜４７重
量％°、９３０以下の低密度ポリエチレン、または／お
よびエチレン・酢酸ビニル共重合体の）７〜５０重量％
、有機分解型発泡剤（Ｃ）　　０．１〜２．０重量％お
よび高級脂肪酸金属塩（至）０．０３〜１．０重量（％
）からなる組成物を該発泡剤（Ｃ’）の分解温度以上の
温度で溶融押出し後６０℃以下に急冷して１ （１）厚み０，１　ｔａｇ以上、見掛は比重０．７以下
の原反発泡シートを作成し・ついで該発泡シートを前記
共重合体（５）の融点より１０〜６０℃低い温度でタテ
又はヨコ方向に３〜１’２倍延伸し、または （ｌＩ）厚み０．２ｗｎ以上、見掛は比重０．８以下の
原反発泡シートを作成し、ついで該発泡シートを前記共
重合体（イ）の融点より１０〜５０℃低い温度でタテ又
はヨコ方向にそれぞれ１．１〜１０倍延伸し、かつ、該
延伸後の延伸フィルムのタテ×ヨコの面積倍率を延伸前
のシートの６〜３０倍とすることを特徴とするポリオレ
フィン系発泡延伸フィルムの製造方法。 （４）結晶融点が１１５〜１４５℃の結晶性プロピレン
−α−オレフィン共重合体（８）９３〜４７重量係、重
量００９３０以下の低密度ポリエチレンまたは／シよび
エチレン・酢酸ビニル共重合体中）７〜５０重量係重量
機分解型発泡剤（Ｃ）０．１〜２．０重量部および高級
脂肪酸金属塩の）０．０３〜１．０重量部からなる組成
物を前記共重合体（５）の融点より高く、前記発泡剤（
Ｃ）の分解温字より低い温度で溶融混練してチップ状に
成形して使用する特許請求の範囲第（３）項に記載の製
造方法。 （５）溶融押出し後の押出し物を６０℃以下に保った少
なくとも一対の冷却ロールで挾みつけ圧着することによ
りシート状に成形し、ひきつづき該シートの両面を急冷
［−て後該シートを一軸若しくけ二＠延伸する特許請求
の範囲第・（３）項に記載の製造方法。 （６）結晶性プロピレン−α−オレフィン共重合体（Ａ
）がエチレン含量４〜１０重”４　％のエチレン・フｒ
ｙピレンランダム共重合体オたはエチレン含骨０．５〜
６重箒係、ブテン−１含燐ｌ〜１５重量％のエチレン・
プロピレン・ブテン−１共重合体であり、有機分解型発
泡剤（Ｃ）がアゾジカルボンアミドである特許請求の範
囲第（３）項に記載の製造方法。[Scope of Claims] (1) Crystalline propylene-α-olefin copolymer (A) having a crystal melting point of 115 to 145°C,
Low density polyethylene with a density of 0.930 or less, or/and ethylene/vinyl acetate copolymer) 7 to 50% by weight
, a composition consisting of 0.1 to 2.0% by weight of an organic decomposable blowing agent (C) and 0.03 to 1.0% by weight of a higher fatty acid metal salt (D) is heated to a temperature higher than the decomposition temperature of the blowing agent (C). 1. A polyolefin foam stretched film obtained by stretching a raw rebound foam sheet obtained by melt extrusion and smelting at a warm temperature of 3 times or more in at least one direction of the sheet. (2) Crystalline propylene-α-olefin copolymer (8
) is an ethylene/propylene random copolymer with an ethylene content of 4 to 10% by weight and an ethylene content of 0.5 to 6%.
Claim No. 1, which is an ethylene-propylene-butene-1 copolymer containing 1 to 15% butene-1, and the organic decomposable blowing agent (C) is azodicarbonamide. The polyolefin foam stretched film described in 2. (3) Crystalline propylene-α-olefin copolymer with a crystalline melting point of 115 to 145°C (A) 93 to 473 to 47% by weight, low density polyethylene of 930 or less, or/and ethylene/vinyl acetate copolymer ) 7-50% by weight
, organic decomposable blowing agent (C) 0.1 to 2.0% by weight and higher fatty acid metal salt (to) 0.03 to 1.0% by weight
) is melt-extruded at a temperature higher than the decomposition temperature of the blowing agent (C') and then rapidly cooled to 60°C or lower to obtain 1 (1) with a thickness of 0.1 tag or more and an apparent specific gravity of 0.7 or less. A raw resilient foam sheet is prepared, and then the foam sheet is stretched 3 to 1'2 times in the vertical or horizontal direction at a temperature 10 to 60°C lower than the melting point of the copolymer (5), or (lI) the thickness is 0. .2wn or more and an apparent specific gravity of 0.8 or less is prepared, and then the foamed sheet is heated at a temperature 10 to 50°C lower than the melting point of the copolymer (a) in the vertical or horizontal direction for 1 hour each. . A method for producing a polyolefin foam stretched film, which comprises stretching the stretched film by 1 to 10 times, and making the vertical x horizontal area magnification of the stretched film 6 to 30 times that of the sheet before stretching. (4) Crystalline propylene-α-olefin copolymer with a crystalline melting point of 115-145°C (8) Low-density polyethylene or/and ethylene/vinyl acetate copolymer with a weight ratio of 93-47 and a weight of 00930 or less) A composition consisting of 0.1 to 2.0 parts by weight of a mechanically decomposable blowing agent (C) and 0.03 to 1.0 parts by weight of a higher fatty acid metal salt is added to the copolymer (5 to 50 parts by weight). ) is higher than the melting point of the blowing agent (
The manufacturing method according to claim (3), wherein the method is melt-kneaded at a temperature lower than the decomposition temperature of C) and molded into chips. (5) The extrudate after melt extrusion is formed into a sheet by sandwiching and pressing it between at least a pair of cooling rolls maintained at 60°C or below, and then the both sides of the sheet are rapidly cooled. The manufacturing method according to claim 3, which involves stretching. (6) Crystalline propylene-α-olefin copolymer (A
) has an ethylene content of 4% to 10% by weight.
y Pyrene random copolymer or ethylene bone content 0.5~
6-layer broomstick, butene-1 phosphorus-containing 1 to 15% by weight ethylene.
The manufacturing method according to claim (3), wherein the propylene-butene-1 copolymer is used, and the organic decomposable blowing agent (C) is azodicarbonamide.