JP2905098B2 - Heat shrinkable multilayer film - Google Patents
Heat shrinkable multilayer filmInfo
- Publication number
- JP2905098B2 JP2905098B2 JP21167894A JP21167894A JP2905098B2 JP 2905098 B2 JP2905098 B2 JP 2905098B2 JP 21167894 A JP21167894 A JP 21167894A JP 21167894 A JP21167894 A JP 21167894A JP 2905098 B2 JP2905098 B2 JP 2905098B2
- Authority
- JP
- Japan
- Prior art keywords
- propylene
- weight
- heat
- component
- ethylene
- 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 - Fee Related
Links
Landscapes
- Laminated Bodies (AREA)
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、特に、柔軟性、透明
性、ヒートシール性及び熱収縮性が優れた、オーバーラ
ップ包装に好適な熱収縮性多層フィルムの提供に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-shrinkable multilayer film excellent in flexibility, transparency, heat-sealing property and heat-shrinkability and suitable for overlap packaging.
【０００２】[0002]
【従来の技術】従来より、一般の商品等では、緩やかな
包装が施された後に、加熱収縮され密着密封包装され
る、所謂オーバラップ包装法によって包装されているも
のがある。このようなオーバラップ包装に用いられる熱
収縮性フィルムとしては、例えば、ポリプロピレン系樹
脂、ポリエチレン系樹脂等からなるフィルムが２軸延伸
（例えば、チューブラー延伸法）等により延伸されて使
用される。しかしながら、前記のフィルムは柔軟性が乏
しく、また、収縮包装されたフィルムは感触が硬く、特
に、角部が固くなりシワ等が発生し易く包装仕上りが悪
くなる傾向があり、好ましくないものであった。また、
例えば、ポリプロピレン系樹脂から成るフラット状フィ
ルム（単独または複合フィルム等）が逐次２軸延伸法で
延伸された熱収縮性ポリプロピレン系フィルムは、縦方
向と横方向の収縮性に極端な差が発生し易く、収縮仕上
りに問題がある。2. Description of the Related Art Conventionally, general products and the like have been packaged by a so-called overlap packaging method, in which loose packaging is performed, followed by heat shrinkage and tightly sealed packaging. As the heat-shrinkable film used for such overlap packaging, for example, a film made of a polypropylene-based resin, a polyethylene-based resin, or the like is used after being stretched by biaxial stretching (for example, a tubular stretching method) or the like. However, the above-mentioned film has poor flexibility, and the shrink-wrapped film has a hard feel, and in particular, the corners are hard and wrinkles are liable to occur, and the packaging finish tends to be poor, which is not preferable. Was. Also,
For example, in the case of a heat-shrinkable polypropylene film in which a flat film made of a polypropylene-based resin (single or composite film or the like) is successively stretched by a biaxial stretching method, an extreme difference occurs in shrinkage between the longitudinal direction and the transverse direction. Easy and has a problem with shrink finish.
【０００３】更に、柔軟性に優れたポリプロピレン系熱
収縮性フィルムを成膜するために、ポリプロピレン系樹
脂にエチレン−酢酸ビニル共重合体（ＥＶＡ）を配合し
た組成物からオーバラップ包装用熱収縮性フィルムが成
膜されている。斯かる柔軟性フィルムは延伸後、透明性
が低下する等の傾向があり、特に、透明性が要求される
包装分野には使用できないという問題が指摘されてい
る。また、逐次２軸延伸する場合に、例えば、縦方向に
延伸後、引続いて横方向に延伸すると、厚みムラ、破断
等が発生し易く、優れた熱収縮性フィルムが得られない
傾向があった。Further, in order to form a heat-shrinkable polypropylene-based film having excellent flexibility, a heat-shrinkable film for an overlap packaging is prepared from a composition obtained by blending an ethylene-vinyl acetate copolymer (EVA) with a polypropylene-based resin. A film has been deposited. Such a flexible film tends to have reduced transparency after stretching, and it has been pointed out that it cannot be used particularly in the packaging field where transparency is required. Further, in the case of successive biaxial stretching, for example, if stretching is performed in the longitudinal direction and subsequently in the transverse direction, thickness unevenness, breakage, and the like are likely to occur, and an excellent heat-shrinkable film tends not to be obtained. Was.
【０００４】[0004]
【発明が解決使用とする課題】本発明は、上記したよう
な状況に鑑み、柔軟性、透明性、ヒートシール性及び熱
収縮性に優れ、オーバーラップ包装に好適な熱収縮性多
層フィルムの提供を目的とする。SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention provides a heat-shrinkable multilayer film which is excellent in flexibility, transparency, heat-sealing property and heat-shrinkability and is suitable for overlap packaging. With the goal.
【０００５】[0005]
【課題を解決するための手段】本発明者らは、上記目的
のために鋭意検討を重ねた結果、特定組成を有するプロ
ピレン−エチレンランダム共重合体からなる両表面層
が、ポリブテン成分とプロピレン−エチレンランダム共
重合体成分又はプロピレン成分及びプロピレン−エチレ
ンランダム共重合体成分とからなるブロック共重合体を
含有するプロピレン−エチレンランダム共重合体からな
る中間層を介して積層され、２軸延伸され、表面層の合
計厚みと中間層の厚みの比率を特定される熱収縮性多層
フイルムが上記目的を達成することを見出し、本発明に
到達した。Means for Solving the Problems As a result of intensive studies for the above-mentioned object, the present inventors have found that both surface layers composed of a propylene-ethylene random copolymer having a specific composition have a polybutene component and a propylene-ethylene copolymer. Laminated via an intermediate layer made of a propylene-ethylene random copolymer containing a block copolymer consisting of an ethylene random copolymer component or a propylene component and a propylene-ethylene random copolymer component, and biaxially stretched, The inventors have found that a heat-shrinkable multilayer film in which the ratio of the total thickness of the surface layer to the thickness of the intermediate layer is specified achieves the above object, and has reached the present invention.
【０００６】本発明の特徴とするところは、（Ａ）エチ
レン成分含有量が２〜５重量％のプロピレン−エチレン
ランダム共重合体９８〜７０重量％と石油樹脂２〜３０
重量％の組成物からなる両外面層、及び（Ｂ）ポリブテ
ン成分とプロピレン−エチレンランダム共重合体成分又
はプロピレン成分及びプロピレン−エチレンランダム共
重合体成分とからなるブロック共重合体１０〜９０重量
％と、エチレン成分含有量が２〜５重量のプロピレン−
エチレンランダム共重合体９０〜１０重量％との組成物
からなる中間層とが、少なくとも３層に積層されると共
に、フラット状に成膜され、且つ、縦方向及び横方向に
２軸延伸され熱収縮性が付与され、前記（Ａ）層の合計
厚みと（Ｂ）層の合計厚みとの比が１：１０〜５：１で
ある熱収縮性多層フイルムを提供するところにある。The present invention is characterized in that (A) 98 to 70% by weight of a propylene-ethylene random copolymer having an ethylene content of 2 to 5% by weight and 2 to 30% of a petroleum resin.
(B) 10 to 90% by weight of a block copolymer comprising a polybutene component and a propylene-ethylene random copolymer component or a propylene component and a propylene-ethylene random copolymer component. Propylene having an ethylene content of 2 to 5 wt.
An intermediate layer comprising a composition of 90 to 10% by weight of an ethylene random copolymer is laminated in at least three layers, formed into a flat film, and biaxially stretched in the vertical and horizontal directions. An object of the present invention is to provide a heat-shrinkable multilayer film which is provided with shrinkability and has a ratio of the total thickness of the layer (A) to the total thickness of the layer (B) of 1:10 to 5: 1.
【０００７】本発明の両表面層（Ａ）に係るプロピレン
−エチレンランダム共重合体は、エチレン含有量が２〜
５重量％であるプロピレン−エチレンランダム共重合体
であればよい。エチレン含有量が５重量％を超える場合
は、柔軟になり過ぎ、引張弾性率が大幅に低下する傾向
があり、自動包装機で包装する際に、包装用フィルムと
自動包装機の金属案内部との滑り性、包装用フィルムの
自動包装機への自動供給性が悪くなり、包装体に皺、ス
クラッチ、擦り傷等が発生する傾向があり，又２重量％
未満の場合は、柔軟性が乏しく、延伸性が低下し、厚み
ムラが発生し易く、透明性が悪くなる傾向があり好まし
くない。The propylene-ethylene random copolymer according to the both surface layers (A) of the present invention has an ethylene content of 2 to 2.
Any propylene-ethylene random copolymer of 5% by weight may be used. If the ethylene content exceeds 5% by weight, it tends to be too flexible and the tensile modulus tends to be significantly reduced. The slipperiness of the film and the automatic feeding of the packaging film to the automatic packaging machine are deteriorated, and the package tends to have wrinkles, scratches, scratches, etc., and 2% by weight.
If it is less than 10, the flexibility is poor, the stretchability is reduced, the thickness unevenness is likely to occur, and the transparency tends to deteriorate, which is not preferable.
【０００８】また 両表面層（Ａ）のプロピレン−エチ
レンランダム共重合体は、沸騰ｎ−ヘプタン抽出不溶分
が９０重量％以上のものであればよく、メルトフローレ
イト（ＭＦＲ）は０．５〜２０ｇ／１０分、好ましくは
１〜１０ｇ／１０分、より好ましくは１〜５ｇ／１０分
のものを例示できる。両表面層（Ａ）層におけるプロピ
レン−エチレンランダム共重合体の含有量は９８〜７０
重量％であり、９８重量％を超えるとヒートシール性が
低下し、自動包装機での低温高速ヒートシールが困難に
なる傾向があり、７０重量％未満になると引張弾性率が
低下し柔らかくなり過ぎ好ましくない。The propylene-ethylene random copolymer of both surface layers (A) may have a boiling n-heptane extraction insoluble content of 90% by weight or more, and a melt flow rate (MFR) of 0.5 to 0.5%. 20 g / 10 min, preferably 1 to 10 g / 10 min, more preferably 1 to 5 g / 10 min. The content of the propylene-ethylene random copolymer in both surface layers (A) is 98 to 70.
If it exceeds 98% by weight, the heat sealability tends to decrease, and low-temperature and high-speed heat sealing with an automatic packaging machine tends to be difficult. If it is less than 70% by weight, the tensile elasticity decreases and the material becomes too soft. Not preferred.
【０００９】本発明の（Ａ）層を構成する石油樹脂とし
ては、石油ナフサ等の熱分解により精製される不飽和炭
化水素を含む留分を重合することにより得られる脂肪族
系石油樹脂（Ｃ５留分系）、芳香族系石油樹脂（Ｃ９留
分系）、シクロペンタジエン系石油樹脂及びこれらの水
素化された水素添加石油樹脂を例示できる。具体的に
は、イソプレン、１−ペンテン、１・３ペンタジエン、
ビニルトルエン、インデン、メチルスチレン、スチレ
ン、メチルインデン、ブタジエン、ピペリレン、ペンチ
レン、ジシクロペンタジエン等の不飽和炭化水素を重
合、共重合した石油樹脂及びこれ等の水素添加石油樹脂
を挙げることができる。As the petroleum resin constituting the layer (A) of the present invention, an aliphatic petroleum resin (C) obtained by polymerizing a fraction containing an unsaturated hydrocarbon purified by pyrolysis of petroleum naphtha or the like can be used. 5 fraction system), aromatic petroleum resin (C 9 fraction system), cyclopentadiene petroleum resin, and hydrogenated hydrogenated petroleum resin thereof. Specifically, isoprene, 1-pentene, 1.3 pentadiene,
Examples thereof include petroleum resins obtained by polymerizing and copolymerizing unsaturated hydrocarbons such as vinyltoluene, indene, methylstyrene, styrene, methylindene, butadiene, piperylene, pentylene, and dicyclopentadiene, and hydrogenated petroleum resins thereof.
【００１０】上記のような石油樹脂の含有量は、２〜３
０重量％が好ましい。石油樹脂の含有量が２重量％未満
になると、延伸性が低下し、厚みムラ、未延伸部が発生
し易く好ましくない。石油樹脂の含有量が３０重量％を
超えると、摩擦抵抗が高くなる傾向があり、自動包装機
で包装する際に、包装材料の自動包装機への自動供給性
が悪く、包装体に傷、皺、スクラッチが発生し易く、ま
た収縮後タイトな包装物が得難く好ましくない。更に、
逐次２軸延伸する場合に、延伸用加熱ロールに融着、粘
着する傾向があり好ましくない。The content of the above petroleum resin is 2-3
0% by weight is preferred. When the content of the petroleum resin is less than 2% by weight, the stretchability is reduced, and the thickness unevenness and the unstretched portion are easily generated, which is not preferable. If the content of the petroleum resin exceeds 30% by weight, the frictional resistance tends to be high, and when packaging with an automatic packaging machine, the automatic supply of the packaging material to the automatic packaging machine is poor, and the packaging body is damaged. It is not preferable because wrinkles and scratches are easily generated and a tight package after shrinkage is difficult to obtain. Furthermore,
In the case of successive biaxial stretching, there is a tendency of fusing and sticking to a heating roll for stretching, which is not preferable.
【００１１】次に、本発明に係る、中間層（Ｂ）を形成
するプロピレン−エチレンランダム共重合体としては、
前記表面層（Ａ）に用いられるプロピレン−エチレンラ
ンダム共重合体と同種のものでよいが、プロピレン−エ
チレンランダム共重合体のメルトフローレート（２３０
℃、２．１６ｋｇ）が、０．１〜３０ｇ／１０ｍｉｎ、
より好ましくは０．５〜１０ｇ／１０ｍｉｎ．のものが
例示できる。メルトフローレートが０．１ｇ／１０ｍｉ
ｎ．未満では、例えば、共押出成形（特にＴダイス共押
出成形）の際に、表面層（Ａ）との相互溶融流動性が悪
く、流れムラが発生し易く、表面層（Ａ）との接着性が
低下する傾向があり、３０ｇ／１０ｍｉｎ．を超える
と、厚み安定性が低下する傾向があり好ましくない。Next, the propylene-ethylene random copolymer forming the intermediate layer (B) according to the present invention includes:
The same type as the propylene-ethylene random copolymer used for the surface layer (A) may be used, but the melt flow rate of the propylene-ethylene random copolymer (230
° C, 2.16 kg) is 0.1 to 30 g / 10 min,
More preferably, 0.5 to 10 g / 10 min. Can be exemplified. Melt flow rate is 0.1g / 10mi
n. If it is less than, for example, during co-extrusion molding (especially T-die co-extrusion molding), the mutual melt fluidity with the surface layer (A) is poor, flow unevenness easily occurs, and the adhesion with the surface layer (A) , And tends to decrease, and 30 g / 10 min. If it exceeds, the thickness stability tends to decrease, which is not preferred.
【００１２】本発明の中間層（Ｂ）に係るブロック共重
合体とは、ポリブテン成分とプロピレン−エチレンラン
ダム共重合体成分又はポリプロピレン成分及びプロピレ
ン−エチレンランダム共重合体成分とがそれぞれブロッ
ク共重合してなるものが好ましい。斯かるブロック共重
合体は、ポリブテン成分が０．１〜１０重量％、プロピ
レン−エチレンランダム共重合体成分とポリプロピレン
成分との合計量が９９．９〜９０重量％とからなるブロ
ック共重合体及びポリプロピレン成分を０〜３０重量％
含むブロック共重合体が好ましい。ここで、該プロピレ
ン−エチレンランダム共重合体成分は、エチレンに基づ
く単量体単位を１５〜８０モル％、プロピレンに基づく
単量単位を８５〜２０モル％含むランダム共重合体から
構成されたものを例示することができる。更に、柔軟
性、延伸性、熱収縮特性（低温熱収縮性、収縮仕上り）
等を考慮すると、該ブロック共重合体はビカット軟化点
が４０〜１００℃及びメルトフローレートが０．５〜１
０ｇ／１０ｍｉｎ．のものが好ましい。The block copolymer according to the intermediate layer (B) of the present invention is a block copolymer of a polybutene component and a propylene-ethylene random copolymer component or a polypropylene component and a propylene-ethylene random copolymer component. Are preferred. Such a block copolymer is a block copolymer comprising a polybutene component of 0.1 to 10% by weight, a total amount of a propylene-ethylene random copolymer component and a polypropylene component of 99.9 to 90% by weight, and 0 to 30% by weight of polypropylene component
Block copolymers containing are preferred. Here, the propylene-ethylene random copolymer component is composed of a random copolymer containing 15 to 80 mol% of a monomer unit based on ethylene and 85 to 20 mol% of a monomer unit based on propylene. Can be exemplified. Furthermore, flexibility, stretchability, heat shrinkage properties (low temperature heat shrinkage, shrink finish)
In consideration of the above, the block copolymer has a Vicat softening point of 40 to 100 ° C. and a melt flow rate of 0.5 to 1
0 g / 10 min. Are preferred.
【００１３】この際、ポリブテン成分が１０重量％を超
えると、ブロック共重合体の均一溶融が困難になる傾向
があり、成膜が難しく好ましくない。ポリブテン成分が
０．１重量未満であると、ブロック共重合体からなるフ
ィルムの透明性が低下する傾向があり好ましくない。一
方、ポリブテン成分とポリプロピレン成分０〜３０重量
％及びプロピレン−エチレンランダム共重合体成分から
なるブロック共重合体は、ポリプロピレン成分が３０重
量％以下の場合には、ブロックム共重合体の流動性が良
くなり、フィルムの機械的強度（例えば、引張弾性
率）、耐熱性等が向上する傾向がある。ポリプロピレン
成分が３０重量％を超えるとフィルムの柔軟性、透明性
等が低下し本発明の目的を達成できない。At this time, if the polybutene component exceeds 10% by weight, it tends to be difficult to uniformly melt the block copolymer, and it is difficult to form a film, which is not preferable. If the polybutene component is less than 0.1% by weight, the transparency of the film composed of the block copolymer tends to decrease, which is not preferred. On the other hand, a block copolymer comprising a polybutene component, 0 to 30% by weight of a polypropylene component and a propylene-ethylene random copolymer component has a flowability of the block copolymer when the content of the polypropylene component is 30% by weight or less. This tends to improve the mechanical strength (eg, tensile modulus), heat resistance, and the like of the film. When the content of the polypropylene component exceeds 30% by weight, the flexibility, transparency and the like of the film decrease, and the object of the present invention cannot be achieved.
【００１４】ここで、（Ｂ）層に用いられるプロピレン
−エチレンランダム共重合体成分はエチレンに基づく単
量体単位が１５モル％未満、プロピレンに基づく単量体
単位が８５モル％を超える場合は、本発明多層フィルム
の中間層（Ｂ）の柔軟性が十分でなくなり好ましくな
い。また、エチレンに基づく単量体単位が８０モル％を
超え、プロピレンに基づく単量体単位が２０モル％未満
である場合には、本発明多層フィルムの中間層（Ｂ）の
引張強度及び耐熱性が低下する傾向があり好ましくな
い。Here, the propylene-ethylene random copolymer component used in the layer (B) has a monomer unit based on ethylene of less than 15 mol% and a monomer unit based on propylene exceeding 85 mol%. However, the flexibility of the intermediate layer (B) of the multilayer film of the present invention is not sufficient, which is not preferable. When the monomer unit based on ethylene exceeds 80 mol% and the monomer unit based on propylene is less than 20 mol%, the tensile strength and heat resistance of the intermediate layer (B) of the multilayer film of the present invention Tends to decrease, which is not preferred.
【００１５】更に、本発明に係る（Ｂ）層は、エチレン
成分含有量が２〜５重量のプロピレン−エチレンランダ
ム共重合体９０〜１０重量％に前記記載のブロック共重
合体を１０〜９０重量％を含有してなる組成物からなる
ことが好ましい。この際、ブロック共重合体が１０重量
％未満であると柔軟性が低下する傾向になり、９０重量
％を超えると透明性が悪くなり好ましくない。Further, the layer (B) according to the present invention comprises 90 to 10% by weight of a propylene-ethylene random copolymer having an ethylene component content of 2 to 5% by weight and 10 to 90% by weight of the block copolymer described above. % Of the composition. In this case, if the amount of the block copolymer is less than 10% by weight, the flexibility tends to decrease, and if the amount exceeds 90% by weight, the transparency deteriorates, which is not preferable.
【００１６】本発明に係る、（Ａ）層のプロピレン−エ
チレンランダム共重合体に石油樹脂を含有してなる樹脂
組成物及び（Ｂ）層のプロピレン−エチレンランダム共
重合体にブロック共重合体を含有してなる組成物の調製
方法としては、特に制限はないが、従来の各種樹脂組成
物の製法で慣用されている方法、例えば、ニーダー、バ
ンバリーミキサー、ロール等の混練機、リボンブレンダ
ー、ヘンシェルミキサー等の混合機、一軸又は二軸押出
機を用いて加熱溶融混練して行なう方法等が例示でき
る。According to the present invention, a resin composition containing a petroleum resin in the propylene-ethylene random copolymer of the layer (A) and a block copolymer in the propylene-ethylene random copolymer of the layer (B) are used. The method for preparing the composition to be contained is not particularly limited, but may be any of the methods commonly used in the conventional methods for producing various resin compositions, for example, kneaders, Banbury mixers, kneaders such as rolls, ribbon blenders, Henschel. Examples thereof include a method in which the mixture is heated and melt-kneaded using a mixer such as a mixer or a single-screw or twin-screw extruder.
【００１７】本発明に係る熱収縮性多層フィルムは、上
記した両外面層（Ａ）及び中間層（Ｂ）とからなる少な
くとも３層から構成され、例えば、（Ａ）／（Ｂ）／
（Ａ）、（Ａ）／（Ｂ）／（Ａ）／（Ｂ）／（Ａ）等の
ような多層構成にすることが好ましい。The heat-shrinkable multilayer film according to the present invention comprises at least three layers consisting of the above-mentioned outer layer (A) and intermediate layer (B). For example, (A) / (B) /
It is preferable to form a multilayer structure such as (A), (A) / (B) / (A) / (B) / (A).
【００１８】本発明に係る熱収縮性多層フィルムを構成
する各層の厚さは、両外面層（Ａ）層の合計厚さと中間
層（Ｂ）の合計厚さとの比率が１：１０〜５：１にする
ことが好ましい。この際、両外面層（Ａ）の合計厚さが
（Ｂ）層の厚さを合計した厚さの５倍を越える場合、本
発明の熱収縮性多層フィルムに柔軟性を付与することが
難しく、（Ａ）層の厚さを合計した厚さが、中間層
（Ｂ）層の合計厚さの０．１倍未満である場合、本発明
の熱収縮性多層フィルムは、機械的強度、例えば、引張
弾性率が低下し、また透明性が悪くなり好ましくない。The thickness of each layer constituting the heat-shrinkable multilayer film according to the present invention is such that the ratio of the total thickness of both outer layers (A) to the total thickness of the intermediate layer (B) is from 1:10 to 5: It is preferably set to 1. At this time, if the total thickness of both outer layers (A) exceeds 5 times the total thickness of the layers (B), it is difficult to impart flexibility to the heat-shrinkable multilayer film of the present invention. When the total thickness of the layers (A) and (A) is less than 0.1 times the total thickness of the intermediate layer (B), the heat-shrinkable multilayer film of the present invention has mechanical strength, for example, However, the tensile modulus is lowered, and the transparency is deteriorated.
【００１９】本発明の熱収縮性多層フィルムの製法は、
特に制限はないが、例えば、共押出法、ラミネーション
法、ドライラミネーション法等を例示できる。これ等の
内、ダイスの内又は外で溶融接着する共押出法で多層化
するが好ましい。具体的には、多層化する数に見合う数
台の押出機に、例えば、Ｔダイスを連結し、溶融押出
し、溶融状態で多層化した後、冷却ロール、水冷又は空
冷で冷却する方法を用いて多層フィルムとする方法が例
示できる。又、環状ダイスを用いてチューブ状フィルム
を成膜した後、切り開いてフラット状にしたものでもよ
い。The method for producing the heat-shrinkable multilayer film of the present invention is as follows:
Although there is no particular limitation, examples thereof include a coextrusion method, a lamination method, and a dry lamination method. Of these, it is preferable to form a multilayer by a co-extrusion method in which melt bonding is performed inside or outside a die. Specifically, to a number of extruders corresponding to the number of layers to be multilayered, for example, a T-die is connected, melt-extruded, and after being multilayered in a molten state, using a cooling roll, a method of cooling with water or air cooling. A method of forming a multilayer film can be exemplified. Alternatively, a tubular film may be formed by using an annular die, and then cut into a flat shape.
【００２０】本発明に係る多層フィルムに熱収縮性を付
与するためには、延伸することが好ましい。延伸方法と
しては、逐次２軸延伸法、同時２軸延伸法チューブ延伸
法等等で延伸すればよいが、就中、逐次２軸延伸法が便
利である。In order to impart heat shrinkage to the multilayer film according to the present invention, it is preferable to stretch. As the stretching method, the stretching may be performed by a sequential biaxial stretching method, a simultaneous biaxial stretching method, a tube stretching method, or the like. Among them, the sequential biaxial stretching method is convenient.
【００２１】逐次２軸延伸法で製造する場合、延伸条件
としては、延伸倍率が縦方向に２〜５倍、好ましくは３
〜４倍、横方向に２〜７倍、好ましくは３〜５倍を例示
できる。延伸温度としては、逐次２軸延伸法の場合、第
１段目は６０〜１１０℃、好ましくは７０〜１００℃の
熱ロールで縦方向に延伸し、第２段目は７０〜１１０
℃、好ましくは８０〜１００℃でテンターによって横方
向に延伸する方法が例示できる。この際、縦方向の延伸
温度が６０℃未満では延伸負荷が大きく、透明性が低下
する傾向になり、１１０℃を越えるとフィルムがロール
に密着しロールに巻き付いたり、延伸段模様等が発生す
る傾向があり好ましくない。また、延伸倍率が２倍未満
では延伸ムラ等が発生し易く、延伸倍率が６倍を越える
と２段目の延伸時に破断等が発生する傾向があり好まし
くない。テンターで横延伸を行なう場合、テンター内の
雰囲気温度が７０℃未満では透明性の低下、延伸ムラ、
フィルムの破断等が発生する傾向があり、１１０℃を越
えると、収縮特性（例えば、低温熱収縮性）が不良にな
る傾向があり好ましくない。テンターでの延伸倍率が２
倍未満では、未延伸が発生し、延伸倍率が７倍を越える
と破断等が発生し易い傾向になり好ましくない。In the case of manufacturing by the successive biaxial stretching method, the stretching conditions are such that the stretching ratio is 2 to 5 times, preferably 3 times in the machine direction.
４4 times, 2-7 times, preferably 3-5 times in the horizontal direction. As the stretching temperature, in the case of the successive biaxial stretching method, the first stage is stretched in the longitudinal direction by a hot roll at 60 to 110 ° C, preferably 70 to 100 ° C, and the second stage is 70 to 110 ° C.
The method of extending | stretching in a horizontal direction with a tenter at 80 degreeC, Preferably 80-100 degreeC can be illustrated. At this time, if the stretching temperature in the longitudinal direction is less than 60 ° C., the stretching load is large, and the transparency tends to decrease. If the temperature exceeds 110 ° C., the film adheres to the roll and winds around the roll, or a stretching step pattern occurs. There is a tendency and it is not preferable. If the stretching ratio is less than 2 times, stretching unevenness or the like is likely to occur, and if the stretching ratio exceeds 6 times, breakage or the like tends to occur during the second stage stretching, which is not preferable. When performing transverse stretching with a tenter, if the ambient temperature in the tenter is lower than 70 ° C., the transparency decreases, stretching unevenness occurs,
If the temperature exceeds 110 ° C., shrinkage characteristics (for example, low-temperature heat shrinkability) tend to be poor, which is not preferable. Stretch ratio of 2 in tenter
If the ratio is less than 2 times, unstretching occurs, and if the stretching ratio exceeds 7 times, breakage or the like tends to occur, which is not preferable.
【００２２】本発明に係る、両表面層（Ａ）及び中間層
（Ｂ）には、必要に応じて、各層の特性を阻害しない範
囲で、各種添加材、充填材、例えば、耐熱安定剤、酸化
防止剤、光安定剤、帯電防止剤、滑剤、核剤、難燃剤、
顔料又は染料、炭酸カルシウム、硫酸カルシウム、硫酸
バリウム、水酸化マグネシウム、マイカ、タルク、クレ
ー等を添加できる。更に、本発明の特性を阻害しない限
り、他のα−オレフィン系樹脂、熱可塑性エラストマ
ー、ゴム類、炭化水素樹脂等を配合してもよい。The surface layer (A) and the intermediate layer (B) according to the present invention may include various additives and fillers such as a heat stabilizer, if necessary, as long as the properties of each layer are not impaired. Antioxidants, light stabilizers, antistatic agents, lubricants, nucleating agents, flame retardants,
Pigments or dyes, calcium carbonate, calcium sulfate, barium sulfate, magnesium hydroxide, mica, talc, clay and the like can be added. Further, other α-olefin resins, thermoplastic elastomers, rubbers, hydrocarbon resins, and the like may be blended as long as the characteristics of the present invention are not impaired.
【００２３】本発明に係る表面層（Ａ）は、印刷性、ラ
ミネート性等を向上させるために、表面処理を行なうこ
とができる。表面処理の方法としては、コロナ放電処
理、プラズマ処理、火炎処理、酸処理等が例示でき、特
に制限はない。連続処理が可能であり、該フィルムの製
造過程の巻き取り工程前に容易に実施できるコロナ放電
処理、プラズマ処理、火炎処理が好ましく、特に操作
性、設置容易性等の点からコロナ放電処理が好ましい。The surface layer (A) according to the present invention can be subjected to a surface treatment in order to improve printability, laminability and the like. Examples of the surface treatment method include, but are not particularly limited to, corona discharge treatment, plasma treatment, flame treatment, and acid treatment. A corona discharge treatment, a plasma treatment, and a flame treatment, which can be continuously processed and can be easily performed before the winding step in the production process of the film, are preferable, and the corona discharge treatment is particularly preferable in terms of operability, ease of installation, and the like. .
【００２４】[0024]
【作用】本発明は、（Ａ）エチレン成分含有量が２〜５
重量％のプロピレン−エチレンランダム共重合体９８〜
７０重量％と石油樹脂２〜３０重量％との組成物からな
る両表面層、（Ｂ）ポリブテン成分が０．１〜１０重量
％とエチレン成分含有量が２〜５重量％プロピレン−エ
チレンランダム共重合体成分９９．９〜９０重量％とか
らなるブロック共重合体、及びポリブテン成分が０．１
〜１０重量％とポリプロピレン成分０〜３０重量％を含
むポリプロピレン成分及びエチレン−プロピレンランダ
ム共重合体成分の合計が９９．９〜９０重量％とからな
るブロック共重合体等のブロック共重合体１０〜９０重
量％と、エチレン成分含有量が２〜５重量％のプロピレ
ン−エチレンランダム共重合体９０〜１０重量％を含有
してなる中間層とからなり、少なくとも３層に積層さ
れ、２軸延伸されてなるフラット状多層フィルムであ
り、該フイルムの表面層（Ａ）の合計厚みと中間層
（Ｂ）の合計厚みとの比率を特定することにより、優れ
た柔軟性、透明性、ヒートシール性及び熱収縮性を有す
るオーバーラップ包装に好適な熱収縮性多層フィルムが
提供できる。According to the present invention, (A) the ethylene component content is from 2 to 5
98% by weight of a propylene-ethylene random copolymer
Both surface layers comprising a composition of 70% by weight and 2 to 30% by weight of petroleum resin, (B) 0.1 to 10% by weight of polybutene component and 2 to 5% by weight of ethylene component A block copolymer comprising 99.9 to 90% by weight of a polymer component and 0.1% of a polybutene component;
Block copolymers such as block copolymers comprising a total of 99.9 to 90% by weight of a polypropylene component containing 10 to 10% by weight and a polypropylene component of 0 to 30% by weight and an ethylene-propylene random copolymer component. 90% by weight, and an intermediate layer containing 90 to 10% by weight of a propylene-ethylene random copolymer having an ethylene component content of 2 to 5% by weight, laminated at least three layers, and biaxially stretched. A flat multilayer film comprising: a film having excellent flexibility, transparency, heat-sealing properties and a ratio of the total thickness of the surface layer (A) to the total thickness of the intermediate layer (B). A heat-shrinkable multilayer film suitable for heat-shrinkable overlap packaging can be provided.
【００２５】[0025]
【実施例】以下、実施例に基づいて詳細に説明する。本
発明の下記実施例において、柔軟性（引張弾性率で評
価）、透明性（ヘイズで評価）、ヒートシール性（溶断
シール強度で評価）、熱収縮率は下記の方法により評価
を行なった。 ［引張弾性率（ｋｇ／ｃｍ２）］ ＡＳＴＭ Ｄ８８２
に準じて測定した。 ［ヘイズ：Ｈａｚｅ（％）］ ＡＳＴＭ Ｄ１００３に
準じて測定した。 ［ヒートシール強度（ｋｇ／ｃｍ）］ 溶断シールの１
８０度剥離強度を測定した。 ［熱収縮率（％）］ ８０〜１２０℃のグリセリン浴中
に３０秒浸漬したときの収縮率を測定した。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. In the following Examples of the present invention, flexibility (evaluated by tensile modulus), transparency (evaluated by haze), heat sealability (evaluated by fusing seal strength), and heat shrinkage were evaluated by the following methods. [Tensile modulus (kg / cm 2 )] ASTM D882
It measured according to. [Haze (%)] Measured according to ASTM D1003. [Heat seal strength (kg / cm)] Fusing seal 1
The 80 degree peel strength was measured. [Thermal Shrinkage (%)] The shrinkage when immersed in a glycerin bath at 80 to 120 ° C. for 30 seconds was measured.
【００２６】実施例１ 両表面層（Ａ）を構成する組成物として、エチレン−プ
ロピレンランダム共重合体（エチレン成分含有量３．２
重量％、メルトフローレート２ｇ／１０分）９５重量％
と石油樹脂（脂肪族炭化水素系樹脂、ビカット軟化点１
１５℃）５重量％及び適宜な量の滑剤、アンチブロッキ
ング剤とを配合した組成物を用いた。また、中間層
（Ｂ）を構成する組成物として、エチレン−プロピレン
ランダム共重合体（エチレン成分含有量３．２重量％、
メルトフローレート２ｇ／１０分）５０重量％と、ポリ
ブテン成分及びプロピレン−エチレンランダム共重合体
成分とからなるブロック共重合体（ビカット軟化点６０
℃、メルトフローレート１．５ｇ／１０分）５０重量％
及び適宜な量の滑剤、アンチブロッキング剤とを配合し
てなる組成物を用いた。Example 1 As a composition constituting both surface layers (A), an ethylene-propylene random copolymer (ethylene content: 3.2
Weight%, melt flow rate 2g / 10min) 95% by weight
And petroleum resin (aliphatic hydrocarbon resin, Vicat softening point 1
(15 ° C.) A composition containing 5% by weight and appropriate amounts of a lubricant and an antiblocking agent was used. Further, as a composition constituting the intermediate layer (B), an ethylene-propylene random copolymer (an ethylene component content of 3.2% by weight,
A block copolymer (Vicat softening point of 60) comprising 50% by weight of a melt flow rate (2 g / 10 minutes) and a polybutene component and a propylene-ethylene random copolymer component.
° C, melt flow rate 1.5g / 10min) 50% by weight
A composition prepared by blending an appropriate amount of a lubricant and an antiblocking agent was used.
【００２７】上記で得られた組成物を用いた、（Ａ）／
（Ｂ）／（Ａ）の厚み構成比が２：１０：２になるよう
にし、３層各々独立した３台の押出機及びこれに連結し
た３層Ｔダイを用いて、押出機のバレル及びダイ温度２
３０℃で溶融共押出した後、キャストロールで急冷し３
層積層シートを得た。次いで、得られた３層積層シート
を９０℃の加熱ロールを用いて縦方向に３．５倍延伸
し、引続いて、雰囲気温度１００℃のテンターで横方向
に４．０倍延伸することによって、柔軟性、透明性、ヒ
ートシール性、熱収縮性が優れた厚さ１５μのオーバー
ラップ包装用３層積層フィルムが安定して成膜できた。
該３層積層フィルムの引張弾性率、ヘイズ、溶断シール
強度、熱収縮率を表１に示す。Using the composition obtained above, (A) /
The thickness ratio of (B) / (A) is set to 2: 10: 2, and three extruders each having three independent layers and a three-layer T-die connected thereto are used to form a barrel of the extruder and Die temperature 2
After co-extrusion at 30 ° C, quenched with cast roll
A layer laminated sheet was obtained. Next, the obtained three-layer laminated sheet is stretched 3.5 times in the longitudinal direction using a heating roll at 90 ° C., and subsequently stretched 4.0 times in the transverse direction using a tenter at an ambient temperature of 100 ° C. Thus, a 15-μm-thick three-layer laminated film for overlap packaging having excellent flexibility, transparency, heat sealability, and heat shrinkage was formed stably.
Table 1 shows the tensile modulus, haze, fusing seal strength, and heat shrinkage of the three-layer laminated film.
【００２８】実施例２ 中間層（Ｂ）を構成するブロック共重合体が、ポリブテ
ン成分とプロピレン−エチレン共重合体成分及びプロピ
レンからなるブロック共重合体（ビカット軟化点 ８
０．０℃、メルトフローレート１．５ｇ／１０分）以外
は実指例１と同様にして柔軟性、透明性、ヒートシール
性、熱収縮性が優れた熱収縮性多層フィルムを得た。該
３層積層フィルムの引張弾性率、ヘイズ、溶断シール強
度、熱収縮率を表１に示す。Example 2 The block copolymer constituting the intermediate layer (B) is a block copolymer comprising a polybutene component, a propylene-ethylene copolymer component and propylene (Vicat softening point 8
A heat-shrinkable multilayer film having excellent flexibility, transparency, heat-sealing properties, and heat-shrinkability was obtained in the same manner as in Example 1 except for the temperature and the melt flow rate, which were 0.0 ° C. and a melt flow rate of 1.5 g / 10 minutes. Table 1 shows the tensile modulus, haze, fusing seal strength, and heat shrinkage of the three-layer laminated film.
【００２９】比較例１ エチレン−プロピレンランダム共重合体（エチレン成分
含有量３．２重量％、メルトフローレート２ｇ／１０
分）をＴダイを付した押出機のバレル及びダイ温度２３
０℃で溶融押出した後、キャストロールで急冷し単層シ
ートを得た。次いで９０℃の加熱ロールを用いて縦方向
に３．５倍延伸し、引続いて、雰囲気温度１００℃のテ
ンターで横方向に４，０倍延伸することによって熱収縮
性単層フィルムを得た。該フィルムの引張弾性率、ヘイ
ズ、溶断シール強度、熱収縮率を表１に示す。Comparative Example 1 Ethylene-propylene random copolymer (content of ethylene component: 3.2% by weight, melt flow rate: 2 g / 10
Min) the barrel of an extruder equipped with a T die and the die temperature 23.
After melt-extrusion at 0 ° C., the mixture was quenched with a cast roll to obtain a single-layer sheet. Then, the film was stretched 3.5 times in the machine direction using a heating roll at 90 ° C., and subsequently, stretched 4.0 times in the transverse direction using a tenter at an ambient temperature of 100 ° C. to obtain a heat-shrinkable single-layer film. . Table 1 shows the tensile modulus, haze, fusing seal strength, and heat shrinkage of the film.
【００３０】[0030]
【表１】 [Table 1]
【００３１】表１から明らかなように、本発明に係る熱
収縮性多層フイルムは、従来のエチレン−プロピレンラ
ンダム共重合体からなる単層の熱収縮性フィルムよりも
柔軟性（引張弾性率が小さい）、透明性、ヒートシール
強度、熱収縮性が優れたものである。As is clear from Table 1, the heat-shrinkable multilayer film according to the present invention is more flexible (has a lower tensile modulus) than a single-layer heat-shrinkable film made of a conventional ethylene-propylene random copolymer. ), Transparency, heat seal strength, and heat shrinkability.
【００３２】[0032]
【発明の効果】本発明の熱収縮性多層フィルムは、柔軟
性、透明性、ヒートシール性、熱収縮性が良好であり、
オーバーラップ包装に好適な軟質フイルムである。本発
明により、従来のポリオレフィン系フィルムの柔軟性、
透明性、ヒートシール性、熱収縮性が改善され、また軟
質塩化ビニルフイルムのような衛生性及び環境汚染等の
問題がなく自動包装機適性、収縮包装仕上り良好な、包
装用熱収縮性多層フィルムを得ることができる。更に、
本発明は包装分野以外の各種用途に使用できるものであ
る。The heat shrinkable multilayer film of the present invention has good flexibility, transparency, heat sealability and heat shrinkability,
It is a soft film suitable for overlap packaging. According to the present invention, the flexibility of the conventional polyolefin film,
Heat-shrinkable multilayer film for packaging with improved transparency, heat-sealing properties, heat-shrinkability, no problems with hygiene and environmental pollution such as soft vinyl chloride film, suitable for automatic wrapping machines, good shrink wrapping finish Can be obtained. Furthermore,
The present invention can be used for various uses other than the packaging field.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｂ２９Ｋ 23:00 105:02 Ｂ２９Ｌ 9:00 (58)調査した分野(Int.Cl.6，ＤＢ名) B32B 1/00 - 35/00 ──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. 6 identification symbol FI B29K 23:00 105: 02 B29L 9:00 (58) Investigated field (Int.Cl. 6 , DB name) B32B 1/00- 35/00
Claims (1)
％のプロピレン−エチレンランダム共重合体９８〜７０
重量％と石油樹脂２〜３０重量％を含有してなる組成物
からなる両外面層、及び（Ｂ）ポリブテン成分とプロピ
レン−エチレンランダム共重合体成分又はプロピレン成
分及びプロピレン−エチレンランダム共重合体成分とか
らなるブロック共重合体１０〜９０重量％と、エチレン
成分含有量が２〜５重量のプロピレン−エチレンランダ
ム共重合体９０〜１０重量％との組成物からなる中間層
が少なくとも３層に積層されると共に、フラット状に成
膜され、且つ、縦方向及び横方向に２軸延伸され熱収縮
性が付与されてなる多層フィルムであり、前記Ａ層の合
計厚みとＢ層の合計厚みとの比が１：１０〜５：１であ
ることを特徴とする熱収縮性多層フィルム。1. A propylene-ethylene random copolymer having an ethylene component content of 2 to 5% by weight.
(B) a polybutene component and a propylene-ethylene random copolymer component or a propylene component and a propylene-ethylene random copolymer component. And a propylene-ethylene random copolymer having an ethylene component content of 2 to 5% by weight, and an intermediate layer of a composition of 10 to 90% by weight and an ethylene layer content of 2 to 5% by weight. And a multilayer film that is formed into a flat shape, and is biaxially stretched in the longitudinal and lateral directions and imparted with heat shrinkage. The total thickness of the A layer and the B layer A heat-shrinkable multilayer film having a ratio of 1:10 to 5: 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21167894A JP2905098B2 (en) | 1994-08-01 | 1994-08-01 | Heat shrinkable multilayer film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21167894A JP2905098B2 (en) | 1994-08-01 | 1994-08-01 | Heat shrinkable multilayer film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0839744A JPH0839744A (en) | 1996-02-13 |
| JP2905098B2 true JP2905098B2 (en) | 1999-06-14 |
Family
ID=16609784
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21167894A Expired - Fee Related JP2905098B2 (en) | 1994-08-01 | 1994-08-01 | Heat shrinkable multilayer film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2905098B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3879513B2 (en) * | 2002-01-11 | 2007-02-14 | 住友化学株式会社 | Shrink wrapping film and label |
-
1994
- 1994-08-01 JP JP21167894A patent/JP2905098B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0839744A (en) | 1996-02-13 |
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