JPH01304938A - Heat-shrinkable multilayer film - Google Patents
Heat-shrinkable multilayer filmInfo
- Publication number
- JPH01304938A JPH01304938A JP63135422A JP13542288A JPH01304938A JP H01304938 A JPH01304938 A JP H01304938A JP 63135422 A JP63135422 A JP 63135422A JP 13542288 A JP13542288 A JP 13542288A JP H01304938 A JPH01304938 A JP H01304938A
- Authority
- JP
- Japan
- Prior art keywords
- ethylene
- film
- olefin
- density
- melt index
- 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.)
- Granted
Links
- 239000004711 α-olefin Substances 0.000 claims abstract description 24
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims abstract description 20
- 239000005977 Ethylene Substances 0.000 claims abstract description 20
- 229920005684 linear copolymer Polymers 0.000 claims abstract description 17
- -1 polyethylene Polymers 0.000 claims abstract description 13
- 239000004698 Polyethylene Substances 0.000 claims abstract description 11
- 229920000573 polyethylene Polymers 0.000 claims abstract description 11
- 239000000155 melt Substances 0.000 claims abstract description 9
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 claims description 6
- LIKMAJRDDDTEIG-UHFFFAOYSA-N 1-hexene Chemical compound CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 claims description 4
- YWAKXRMUMFPDSH-UHFFFAOYSA-N pentene Chemical compound CCCC=C YWAKXRMUMFPDSH-UHFFFAOYSA-N 0.000 claims description 4
- KWKAKUADMBZCLK-UHFFFAOYSA-N 1-octene Chemical compound CCCCCCC=C KWKAKUADMBZCLK-UHFFFAOYSA-N 0.000 claims 2
- 150000001336 alkenes Chemical class 0.000 claims 1
- TVMXDCGIABBOFY-UHFFFAOYSA-N n-Octanol Natural products CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 claims 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 claims 1
- 230000000903 blocking effect Effects 0.000 abstract description 10
- 238000001816 cooling Methods 0.000 abstract description 2
- 229920000092 linear low density polyethylene Polymers 0.000 description 10
- 239000004707 linear low-density polyethylene Substances 0.000 description 10
- 238000000034 method Methods 0.000 description 7
- 229920006257 Heat-shrinkable film Polymers 0.000 description 6
- 238000000137 annealing Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 230000000704 physical effect Effects 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- DCTOHCCUXLBQMS-UHFFFAOYSA-N 1-undecene Chemical compound CCCCCCCCCC=C DCTOHCCUXLBQMS-UHFFFAOYSA-N 0.000 description 4
- 125000004432 carbon atom Chemical group C* 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 238000002834 transmittance Methods 0.000 description 3
- AFFLGGQVNFXPEV-UHFFFAOYSA-N 1-decene Chemical compound CCCCCCCCC=C AFFLGGQVNFXPEV-UHFFFAOYSA-N 0.000 description 2
- CRSBERNSMYQZNG-UHFFFAOYSA-N 1-dodecene Chemical compound CCCCCCCCCCC=C CRSBERNSMYQZNG-UHFFFAOYSA-N 0.000 description 2
- WSSSPWUEQFSQQG-UHFFFAOYSA-N 4-methyl-1-pentene Chemical compound CC(C)CC=C WSSSPWUEQFSQQG-UHFFFAOYSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229920001684 low density polyethylene Polymers 0.000 description 2
- 239000004702 low-density polyethylene Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000003348 petrochemical agent Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229920000089 Cyclic olefin copolymer Polymers 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000002216 antistatic agent Substances 0.000 description 1
- 239000002981 blocking agent Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 210000004905 finger nail Anatomy 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- 239000002654 heat shrinkable material Substances 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000005022 packaging material Substances 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 238000007788 roughening Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 229920006300 shrink film Polymers 0.000 description 1
Landscapes
- Laminated Bodies (AREA)
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は収縮包装材料に関し、より詳細には厚みムラが
小さく且つ低温収縮性、透明性、耐ブロッキング性が共
に優れたポリエチレン系熱収縮性多層フィルムに関する
ものである。Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a shrink packaging material, and more specifically to a polyethylene heat shrinkable material with small thickness unevenness and excellent low-temperature shrinkability, transparency, and blocking resistance. It relates to multilayer films.
（従来の技術）
従来、熱収縮性フィルムとしては、ポリ塩化ビニル、ポ
リプロピレン、ポリエチレン系等の延伸フィルムなどが
知られている。(Prior Art) Stretched films of polyvinyl chloride, polypropylene, polyethylene, and the like are conventionally known as heat-shrinkable films.
この内ポリエチレン系熱収縮性フィルムは、ヒートシー
ル性を有し低価格である等の点から実用されており、特
に近年エチレンとα−オレフィンとの線状低密度共重合
体（以下単に線状低密度ポリエチレンと略す。）を用い
たポリエチレン系熱収縮性フィルムは、その耐衝撃性、
ヒートシール強度などにおいて優れている点で注目され
、多くの分野での利用が期待されている。Among these, polyethylene-based heat-shrinkable films have been put into practical use because of their heat-sealability and low cost, and in recent years, linear low-density copolymers of ethylene and α-olefin (hereinafter simply referred to as linear Polyethylene heat-shrinkable film made using low-density polyethylene (abbreviated as low-density polyethylene) has excellent impact resistance,
It has attracted attention for its excellent heat sealing strength and is expected to be used in many fields.
（発明が解決しようとする課題）
しかしながら、従来知られているチューブラ−二軸延伸
法（特公昭５７−３６１４２号公報）により線状低密度
ポリエチレンの熱収縮性フィルムを製造すると、延伸チ
ューブの安定性、延伸の均一性が必ずしも満足ゆくもの
でなく、厚みムラが大きい欠点を持つと共に、延伸配向
効果が十分に成り難くこの為低温での収縮特性にも難を
残していた。(Problems to be Solved by the Invention) However, when a heat-shrinkable film of linear low-density polyethylene is produced by the conventionally known tubular biaxial stretching method (Japanese Patent Publication No. 57-36142), the stretched tube becomes stable. The properties and uniformity of stretching were not necessarily satisfactory, and the film had the disadvantage of large thickness unevenness, and it was difficult to achieve a sufficient stretching orienting effect, resulting in problems in shrinkage characteristics at low temperatures.
このような問題点を解消するものとして、本発明者らは
特定のエチレン−α−オレフィン共重合体を主とする熱
収縮性フィルムを先に提案している（特開昭６２−２０
１２２９号公報）。この提案の方法を実施することによ
り厚みムラは小さくなり低温における熱収縮性は改善さ
れるが耐ブロッキング性は必ずしも十分満足しろるもの
ではなく、耐ブロッキング性を満足させようとすると透
明性が低下するという問題点があった。従って厚みムラ
が小さく且つ低温収縮性、透明性、耐ブロッキング性が
共に優れたものが望まれていた。In order to solve these problems, the present inventors have previously proposed a heat-shrinkable film mainly composed of a specific ethylene-α-olefin copolymer (Japanese Unexamined Patent Publication No. 62-2011).
1229). By implementing this proposed method, thickness unevenness is reduced and heat shrinkability at low temperatures is improved, but blocking resistance is not necessarily fully satisfied, and transparency decreases when trying to satisfy blocking resistance. There was a problem with that. Therefore, there has been a desire for a material with small thickness unevenness and excellent low-temperature shrinkability, transparency, and anti-blocking properties.
（課題を解決するための手段）
本発明者らは上記従来の問題点を解消し、厚みムラが小
さく且つ低温収縮性、透明性、耐ブロッキング性が共に
優れたポリエチレン系熱収縮性フィルムを提供するため
に鋭意検討した結果、特定のエチレンとα−オレフィン
線状共重合体を使用し、特定の層構成比に設定して共押
出しすることにより初めて、本発明の目的を達成しうろ
ことを見い出し本発明に到達したものである。(Means for Solving the Problems) The present inventors have solved the above-mentioned conventional problems and provided a polyethylene heat-shrinkable film with small thickness unevenness and excellent low-temperature shrinkability, transparency, and blocking resistance. As a result of intensive studies, we have found that the purpose of the present invention can be achieved only by using a specific ethylene and α-olefin linear copolymer and coextruding it at a specific layer composition ratio. Heading This invention is arrived at.
即ち、本発明は中間層が密度０．８７０〜０．９１５ｇ
／ｃｍ３、メルトインデックス０．１〜３．０ ｇ／１
０分のエチレンとα−オレフィンとの線状共重合体（Ａ
）、内外層が密度０．９１５〜０．９３０ ｇ／ｃｎ＋
３、メルトインデックス０．２〜３．０ ｇ／１０分の
エチレンとα−オレフィンとの線状共重合体（Ｂ）より
なり、全層に対する中間層の比が３０％以上、内外層の
厚みが少くとも各々０．５μ以上、厚みムラが２０％以
下であり、９０’Ｃにおける面積収縮率が２０％以上で
あることを特徴とする二軸延伸したポリエチレン系熱収
縮性多層フィルムに関する。That is, in the present invention, the intermediate layer has a density of 0.870 to 0.915 g.
/cm3, melt index 0.1-3.0 g/1
Linear copolymer of ethylene and α-olefin (A
), inner and outer layers have a density of 0.915 to 0.930 g/cn+
3. Made of a linear copolymer (B) of ethylene and α-olefin with a melt index of 0.2 to 3.0 g/10 min, the ratio of the intermediate layer to the total layer is 30% or more, and the thickness of the inner and outer layers The present invention relates to a biaxially stretched polyethylene heat-shrinkable multilayer film, characterized in that each film is at least 0.5 μm or more, the thickness unevenness is 20% or less, and the area shrinkage rate at 90'C is 20% or more.
本発明の中間層に使用されるエチレンとα−オレフィン
との線状共重合体（Ａ）は密度０．８７０〜０．９１５
ｇ／ｃＩ１３、メルトインデックス０．１〜３．０ ｇ
／１０分の特性値を有するものが用いられ、より好まし
くは密度０．８９０〜０．９１５ｇ／ｃｍ＋３、メルト
インデックス０．２〜２．０ ｇ／１０分の特性値を有
するものが用いられる。The linear copolymer (A) of ethylene and α-olefin used in the intermediate layer of the present invention has a density of 0.870 to 0.915.
g/cI13, melt index 0.1-3.0 g
A material having a characteristic value of /10 minutes is used, and more preferably a material having a density of 0.890 to 0.915 g/cm+3 and a melt index of 0.2 to 2.0 g/10 minutes is used.
密度が０．８７０ｇ／ｃｍ＋３未満では引張強度が低く
なるため好ましくなく、密度が０．９１５３／ｃｍ３を
超えると低温収縮性が小さくなるため好ましくない。If the density is less than 0.870 g/cm+3, the tensile strength will be low, which is undesirable, and if the density exceeds 0.9153/cm3, the low-temperature shrinkability will be undesirable.
メルトインデックス０．１３１１０分未満では溶融押出
時のモーター負荷の増大が著しく、加工性が悪くなるの
で実用性が乏しく、３．０ ｇ／１０分を超えると延伸
安定性の点で好ましくない。If the melt index is less than 0.13110 minutes, the motor load during melt extrusion will increase significantly and processability will deteriorate, resulting in poor practicality, and if it exceeds 3.0 g/10 minutes, it is unfavorable in terms of stretching stability.
また、上記のエチレンとα−オレフィンとの共重合体（
Ａ）は、１種単独であるか２種以上の混合物であること
ができる。上記（Ａ）においてエチレンと共重合される
α−オレフィンとしては特に限定されるものではなく、
炭素数が４〜１２のもの、例えばブテン−１、ペンテン
−１、ヘキセン−１、オクテン−１，４−メチルペンテ
ン−１、デセン−１、ウンデセン−１、ドデセン−１等
があげられるが、炭素数４〜８のα−オレフィンがより
好ましい。In addition, the above copolymer of ethylene and α-olefin (
A) can be used alone or in a mixture of two or more. The α-olefin copolymerized with ethylene in (A) above is not particularly limited,
Examples include those having 4 to 12 carbon atoms, such as butene-1, pentene-1, hexene-1, octene-1,4-methylpentene-1, decene-1, undecene-1, dodecene-1, etc. α-olefins having 4 to 8 carbon atoms are more preferred.
内外層に使用されるエチレンとα−オレフィンとの線状
共重合体（Ｂ）は密度０．９１５〜０．９３０３／ｃｍ
３、メルトインデックス０．２〜３．０ ｇ／１０分の
特性値を有するものが用いられ、より好ましくは密度が
０．９１５〜０．９２５３／ａｍ３、メルトインデック
スが０．２〜２．０ ｇ／１０分の特性値を有するもの
が用いられる。The linear copolymer (B) of ethylene and α-olefin used for the inner and outer layers has a density of 0.915 to 0.9303/cm
3. A material having a characteristic value of melt index 0.2 to 3.0 g/10 min is used, more preferably a density of 0.915 to 0.9253/am3 and a melt index of 0.2 to 2.0. A material having a characteristic value of g/10 minutes is used.
密度が０．９１５３／ｃｍ３未満では耐ブロッキング性
の点で好ましくなく、密度が０．９３０３／ｃｍ３を超
えると低温収縮性の点で好ましくない。If the density is less than 0.9153/cm3, it is unfavorable in terms of blocking resistance, and if the density exceeds 0.9303/cm3, it is unfavorable in terms of low-temperature shrinkability.
メルトインデックスが０．２３１１０分未満では加工性
の低下及びフィルム表面の粗面化による透明性の低下の
点で好ましくなく、３．０ ｇ／１０分を超えると延伸
安定性の点で好ましくない。If the melt index is less than 0.23110 minutes, it is unfavorable in terms of deterioration in processability and in transparency due to roughening of the film surface, and if it exceeds 3.0 g/10 minutes, it is unfavorable in terms of stretching stability.
エチレンとα−オレフィンとの線状共重合体（Ｂ）は１
種単独であるか、２種以上の混合物であることができる
。エチレンと共重合されるα−オレフィンとしては特に
限定されるものではなく、炭素数が４〜１２のもの、例
えばブテン−１、ペンテン−１、ヘキセン−１、ヘプテ
ン−１、オクテン−１，４−メチルペンテン−１、デセ
ン−１、ウンデセン−１、ドデセン−１等が挙げられる
が、炭素数４〜８のα−オレフィンがより好ましい。The linear copolymer (B) of ethylene and α-olefin is 1
It can be a single species or a mixture of two or more species. The α-olefin copolymerized with ethylene is not particularly limited, and includes those having 4 to 12 carbon atoms, such as butene-1, pentene-1, hexene-1, heptene-1, octene-1,4 -Methylpentene-1, decene-1, undecene-1, dodecene-1, etc., but α-olefins having 4 to 8 carbon atoms are more preferred.
これらのエチレンとα−オレフィンとの線状共重合体（
Ａ）及び（Ｂ）は、いわゆるチーグラーナツタ型触媒を
使った低中圧法によって容易に得ることが出来、これら
の製造法については特公昭５０−３２２７０号公報、特
開昭４９−３５３４５号公報、特開昭５５−７８００４
号公報、特開昭５５−８６８０４号公報、特開昭５４−
１５４４８８号公報などに開示される技術によることが
出来る。These linear copolymers of ethylene and α-olefin (
A) and (B) can be easily obtained by a low-medium pressure method using a so-called Ziegler-Natsuta type catalyst, and their production methods are described in Japanese Patent Publication No. 50-32270, Japanese Patent Application Laid-open No. 49-35345, Japanese Patent Publication No. 55-78004
No. 1, JP-A-55-86804, JP-A-54-
The technology disclosed in Japanese Patent No. 154488 can be used.
延伸後のフィルムの全層に対する中間層の比は３０％以
上であり、内外層の厚みは少なくとも各々０．５μ以上
であることが必要である。It is necessary that the ratio of the intermediate layer to all the layers of the stretched film is 30% or more, and the thickness of the inner and outer layers is at least 0.5 μm or more each.
中間層の比が３０％未満では延伸フィルムの低温収縮性
が不十分なものとなり、又、内外層の厚みが各々０．５
μ未満では厚みのコントロールが困難となる。If the ratio of the intermediate layer is less than 30%, the low temperature shrinkability of the stretched film will be insufficient, and the thickness of the inner and outer layers will be 0.5% each.
If it is less than μ, it will be difficult to control the thickness.
更に本発明の目的に支障をきたさない範囲であれば、滑
剤、アンチブロッキング剤、帯電防止剤、防曇剤等の添
加剤がそれぞれの有効な作用を具備される目的で適宜使
用されるのは当然である。Furthermore, additives such as lubricants, anti-blocking agents, antistatic agents, and antifogging agents may be used as appropriate to provide their respective effective effects, as long as they do not impede the purpose of the present invention. Of course.
本発明の熱収縮性多層フィルムは二軸延伸法によって製
造されるが、以下にその一例としてチューブラ一方式の
製造方法の場合について詳しく説明する。The heat-shrinkable multilayer film of the present invention is produced by a biaxial stretching method, and a tubular one-type production method will be described in detail below as an example.
まず前記のエチレンとα−オレフィンとの線状共重合体
（Ａ）を中間層、エチレンとα−オレフィンとの線状共
重合体（Ｂ）を内外層となるように２台の押出機により
溶融混練し三層環状ダイより共押出し、冷却固化して原
反とする。First, the above-mentioned linear copolymer of ethylene and α-olefin (A) was used as an intermediate layer, and the linear copolymer of ethylene and α-olefin (B) was used as an inner and outer layer using two extruders. The mixture is melt-kneaded, co-extruded through a three-layer annular die, cooled and solidified to form a raw fabric.
得られたチューブ状未延伸原反を例えば第１図で示すよ
うなチューブラ−延伸装置に供給し、有効な高度の配向
が起きる温度域でチューブ内部にガス圧を適用して縦横
各々２倍以上、好ましくは２゜５倍以上膨張延伸して同
時二軸配向を行なわしめる。延伸装置から取り出したフ
ィルムは必要に応じてアニーリングすることが出来る。The obtained tubular unstretched original fabric is fed to a tubular stretching apparatus such as shown in Fig. 1, and gas pressure is applied inside the tube in a temperature range where effective high degree of orientation occurs, and the length and width are doubled or more. , preferably by expanding and stretching by a factor of 2.5 times or more to achieve simultaneous biaxial orientation. The film taken out from the stretching device can be annealed if necessary.
（実施例）
以下に本発明を実施例により具体的に説明するが本発明
はこれらの実施例に限定されるものではない。(Examples) The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples.
尚、本実施例中に示した諸測定は以下の方法によった。The various measurements shown in this example were carried out by the following methods.
ｌ）厚みムラ
接触型電子マイクロメーター（安立電気（株）製に３０
６Ｃ型）を使用し、フルスケール８μｍで測定したチュ
ーブ円周方向のチャートについて最大値（Ｔｍａｘ）、
最小値（Ｔｍｉｎ）及び平均値（Ｔ）を求め、次式より
算出した。l) Thickness unevenness contact type electronic micrometer (manufactured by Anritsu Electric Co., Ltd. 30
Maximum value (Tmax) for the chart in the tube circumferential direction measured at a full scale of 8 μm using
The minimum value (Tmin) and average value (T) were determined and calculated using the following formula.
但し、Ｔは測定フィルムの１０ｍｍ間隔に相当するチャ
ート位置から読み取った値の算術平均値である。However, T is the arithmetic mean value of the values read from chart positions corresponding to 10 mm intervals on the measurement film.
２）透明性（ヘイズ）
ＪＩＳ−に６７１４に準拠した積分球式光線透過率測定
装置を用い、散乱光線透過率の平行光線透過率に対する
割合を％で示した。2) Transparency (Haze) Using an integrating sphere type light transmittance measuring device based on JIS-6714, the ratio of scattered light transmittance to parallel light transmittance was expressed in %.
３）面積収縮率
縦横共１０ｃｍの正方形に切り取ったフィルムを所定温
度のグリセリン浴中に１０秒間浸漬し、次式により算出
した。3) Area shrinkage rate A film cut into a square of 10 cm in length and width was immersed in a glycerin bath at a predetermined temperature for 10 seconds, and the shrinkage rate was calculated using the following formula.
面積収縮率＝１００−ＡＸＢ
但し、Ａ、Ｂは浸漬後の縦横それぞれの長さ（単位はｃ
ｍ）を示す。Area shrinkage rate = 100-AXB However, A and B are the vertical and horizontal lengths after immersion (unit: c
m).
４）耐ブロッキング性
縦６０ｎｕ＋＋、横５０ｍｍｊこ切り取ったフィルム試
片８枚をガラス板の上に表面が上面になる様に順次重ね
合わせて載せる。この上にガラス板と鉛製のおもりを載
せて９０ ｇ／ｃｎ２の荷重となるようにし、そのまま
デシケータ−へ入れる。デシケータ−は４０℃に保たれ
るように恒温器中で保温し、２４時部間、フィルム試片
を重ねたまま取り出す。4) Blocking Resistance Eight film specimens cut out with a length of 60 nu++ and a width of 50 mm were stacked one on top of the other in order on a glass plate with the surface facing upward. A glass plate and a lead weight were placed on top of this to give a load of 90 g/cn2, and the sample was placed directly into a desiccator. The desiccator was kept at 40° C. in a thermostatic oven, and the film specimens were stacked on top of each other for 24 hours and then taken out.
フィルム試片の１角を指でつまみ、その対角を指のツメ
の表面で軽くたたく。この操作をフィルム試片の４角そ
れぞれについて行い、耐ブロッキング性の判定を次のよ
うに行った。Pinch one corner of the film specimen with your fingers and tap the opposite corner lightly with the surface of your fingernail. This operation was performed on each of the four corners of the film specimen, and the blocking resistance was evaluated as follows.
Ｏ・・・８枚のフィルム試片が容易にはがれる。O: 8 film specimens were easily peeled off.
△・・・つまんだ指でずりを与えると、はがれる。△: If you squeeze it with your fingers, it will peel off.
×・・・両手で引き離さないとはがれない。×: It cannot be removed unless it is pulled apart with both hands.
実施例１
密度０．９１２３／ｃｍ３、メルトインデックス１．０
ｇ／ｌＯ分の線状低密度ポリエチレン（商品名： Ｄｏ
ｗｌｅｘ４００１ダウケミカル製）を中間層、密度０．
９２０３／Ｃｌ１１３、メルトインデックス２−ｏｇｌ
ｔｏ分の線状低密度ポリエチレン（商品名： Ｕｌｔ
ｚｅｘ ２０２ＯＬ三井石油化学製）を内外層となるよ
うに２台の押出機を用いて、２００〜２５０℃で溶融混
練し、２５０℃に保った３Ｎ環状ダイスより下向きに共
押出した。Example 1 Density 0.9123/cm3, melt index 1.0
linear low-density polyethylene (product name: Do
wlex4001 (manufactured by Dow Chemical) as an intermediate layer, with a density of 0.
9203/Cl113, melt index 2-ogl
linear low-density polyethylene (product name: Ult
ZEX 202OL (manufactured by Mitsui Petrochemicals) was melt-kneaded using two extruders to form the inner and outer layers at 200 to 250°C, and coextruded downward from a 3N annular die maintained at 250°C.
この時、内外層と中間層の層比は表１に示す様に設定し
た。３層環状ダイスのスリットの直径は７５ｍａｉｔで
、スリットのギャップは、０．８ｎ＋＊であった。At this time, the layer ratio between the inner and outer layers and the middle layer was set as shown in Table 1. The slit diameter of the three-layer annular die was 75 mait, and the slit gap was 0.8 n+*.
共押出しされた溶融チューブ状フィルムをダイス直下に
取付けた外径６６ｎ＋ｍで内部に２０℃の冷却水を循環
している円筒状マンドレルの外表面を摺動させながら、
外側は水槽を通すことにより水冷して室温に冷却して引
取り、直径約６５ｎ＋ｎ＋、厚み３２０μのチューブ状
未延伸フィルムを得た。While sliding the coextruded molten tubular film on the outer surface of a cylindrical mandrel with an outer diameter of 66n+m and inside which circulating cooling water at 20°C was attached directly below the die,
The outside was cooled with water by passing through a water tank, cooled to room temperature, and taken out to obtain a tubular unstretched film having a diameter of about 65n+n+ and a thickness of 320μ.
この未延伸フィルムを原反とし、これを第１図に示した
２軸延伸装置に導き９５〜１０５℃で縦・横それぞれ４
倍に延伸した。延伸されたフィルムは、チューブ状アニ
ーリング装置にて７５℃の熱風で１０秒間アニーリング
した後、室温に冷却し、折り畳んで巻き取った。延伸チ
ューブの安定性は良好で延伸点の上下動やチューブの揺
動もなく、又、ネッキングなどの不均一延伸状態も観察
されなかった。This unstretched film was used as a raw material, and it was introduced into a biaxial stretching device shown in Fig. 1 at 95 to 105°C for 4
Stretched twice. The stretched film was annealed with hot air at 75° C. for 10 seconds in a tubular annealing device, cooled to room temperature, folded and rolled up. The stability of the stretched tube was good, with no vertical movement of the stretching point or swinging of the tube, and no uneven stretching conditions such as necking were observed.
得られた延伸フィルムは、厚み２１．５μであり、厚み
ムラは８．７％、９０℃における面積収縮率は３１．５
％であった。他の物性データと共に表１に示す。The obtained stretched film had a thickness of 21.5μ, thickness unevenness of 8.7%, and area shrinkage rate at 90°C of 31.5.
%Met. It is shown in Table 1 along with other physical property data.
実施例２
密度０．９０６ ｇ／ｃｍ３、メルトインデックス０．
８ｇ／１０分の線状低密度ポリエチレン（商品名： Ｎ
ｕＣＦＬＸＤＦＤＡ−１１３７、日本ユニカー製）を中
間層、密度０゜９２０ｇ／ｃｍ３、メルトインデックス
１．０ｇ／１０分の線状低密度ポリエチレン（商品名：
Ｄｏｗｌｅｘ ２０４５、ダウケミカル製）を内外層
となるようにし、未延伸フィルムの厚みを１９０μ、延
伸温度９０〜１００℃、縦・横それぞれ３倍に延伸を行
った他は実施例１と同様な方法、条件で製膜・延伸・ア
ニーリングを行った。延伸点の上下動やチューブの揺動
もなく、延伸チューブの安定性は良好で、又、不均一な
延伸状態も観察されなかった。Example 2 Density 0.906 g/cm3, melt index 0.
8g/10min linear low density polyethylene (product name: N
uCFLXDFDA-1137, manufactured by Nippon Unicar) as the intermediate layer, linear low-density polyethylene (product name:
Dowlex 2045 (manufactured by Dow Chemical) were used as the inner and outer layers, the thickness of the unstretched film was 190μ, the stretching temperature was 90 to 100°C, and the method was the same as in Example 1, except that the length and width were stretched 3 times each. Film formation, stretching, and annealing were performed under the following conditions. There was no vertical movement of the stretching point or swinging of the tube, and the stability of the stretched tube was good, and no uneven stretching was observed.
得られた延伸フィルムは厚み２０．２１１であり、厚み
ムラは１６．３％、９０℃における面積収縮率は２２．
６％であった。他の物性データと共に表１に示す。The obtained stretched film had a thickness of 20.211 mm, thickness unevenness of 16.3%, and area shrinkage rate at 90° C. of 22.21 mm.
It was 6%. It is shown in Table 1 along with other physical property data.
実施例３
密度０．８９０ ｇ／ｃｎ＋３、メルトインデックス１
．０ ｇ／１０分の線状低密度ポリエチレン（商品名：
ＮＵＣ−ＦＬＸ ＤＦＤＡ−１２１０、日本ユニカー
製）を中間層密度０゜９２３３／ｃｍ３、メルトインデ
ックス０．８ ｇ／１０分の線状低密度ポリエチレン（
商品名： Ｎｅｏｚｅｘ ２００６Ｈ１三井石油化学
製）を内外層となるようにし、実施例１と同様な方法、
条件で製膜・延伸・アニーリングを行った。延伸チュー
ブの安定性は良好で、延伸点の上下動やチューブの揺動
もなく、又、不均一な延伸状態も観察されなかった。Example 3 Density 0.890 g/cn+3, melt index 1
．． 0 g/10 min linear low density polyethylene (product name:
NUC-FLX DFDA-1210, manufactured by Nippon Unicar) was made of linear low-density polyethylene (
Product name: Neozex 2006H1 manufactured by Mitsui Petrochemicals) were used as the inner and outer layers, and the same method as in Example 1 was carried out.
Film formation, stretching, and annealing were performed under the following conditions. The stability of the stretched tube was good, with no vertical movement of the stretching point or rocking of the tube, and no uneven stretching conditions were observed.
得られた延伸フィルムは厚み２０．４μであり、厚みム
ラは１２．６％、９０℃における面積収縮率は３０．５
％であった。他の物性データと共に表１に示す。The obtained stretched film has a thickness of 20.4μ, a thickness unevenness of 12.6%, and an area shrinkage rate of 30.5 at 90°C.
%Met. It is shown in Table 1 along with other physical property data.
比較例１
実施例３の中間層を実施例１の内外層で用いた線状低密
度ポリエチレンとした他は実施例３と同様な方法、条件
で製膜・延伸・アニーリングを行った。延伸チュー、ブ
の安定性は良好で延伸点の上下動やチューブの揺動はな
かったが、延伸の均一性にやや難があるように観察され
た。Comparative Example 1 Film formation, stretching, and annealing were performed in the same manner and under the same conditions as in Example 3, except that the intermediate layer in Example 3 was made of the linear low-density polyethylene used in the inner and outer layers of Example 1. The stability of the stretched tube and tube was good, and there was no vertical movement of the stretching point or shaking of the tube, but it was observed that there was some difficulty in the uniformity of stretching.
得られた延伸フィルムは厚み２１．２μであり、厚みム
ラは２６．０％と大きく、９０℃における面積収縮率は
１８．３％と低かった。また、ヘイズも４．３％と実施
例１〜３よりも大きな値となった。他の物性データと共
に表１に示す。The obtained stretched film had a thickness of 21.2μ, a large thickness unevenness of 26.0%, and a low area shrinkage rate of 18.3% at 90°C. Further, the haze was also 4.3%, which was a larger value than Examples 1 to 3. It is shown in Table 1 along with other physical property data.
比較例２
実施例１の内外層を実施例２の中間層で用いた線状低密
度ポリエチレンとした他は実施例１と同様な方法、条件
て製膜・延伸・アニーリングを行った。延伸チューブの
安定性は、延伸点の上下動やチューブの揺動はほとんど
観察されず、はぼ良好であった。Comparative Example 2 Film formation, stretching, and annealing were performed in the same manner and under the same conditions as in Example 1, except that the inner and outer layers of Example 1 were made of the linear low-density polyethylene used in the intermediate layer of Example 2. The stability of the stretched tube was very good, with almost no vertical movement of the stretching point or rocking of the tube observed.
得られた延伸フィルムは厚み２０．８μであり、厚みム
ラは１８．５％、９０℃における面積収縮率は２８．９
％であった。また、耐ブロッキング性は悪く、判定は×
てあった。他の物性データと共に表１に示す。The obtained stretched film has a thickness of 20.8μ, a thickness unevenness of 18.5%, and an area shrinkage rate of 28.9 at 90°C.
%Met. In addition, the blocking resistance is poor, and the judgment is ×
There was. It is shown in Table 1 along with other physical property data.
［以下、余白コ
比較例３
密度０．９１２３／ｃｒｎ３、メルトインデックス３．
３３／ｌＯ分の線状低密度ポリエチレン（商品名： Ｄ
ｏｗｌｅｘ４０００、ダウケミカル製）を中間層として
用いた他は実施例１と同様な方法、条件で製膜・延伸・
アニーリングを行った。延伸チューブの安定性は、延伸
点の上下動やチューブの揺動が観察され、良好とはいえ
なかった。[Below, blank space Comparative Example 3 Density 0.9123/crn3, Melt index 3.
Linear low density polyethylene (product name: D
owlex 4000, manufactured by Dow Chemical Co., Ltd.) was used as the intermediate layer, film formation, stretching, and
Annealing was performed. The stability of the stretched tube was not good, as vertical movement of the stretching point and rocking of the tube were observed.
得られた延伸フィルムは厚み２１．２μであり、厚みム
ラは２７．３％と大きく、９０℃における面積収縮率は
２４．６％であった。他の物性データと共に表１に示す
。The obtained stretched film had a thickness of 21.2 μm, a large thickness unevenness of 27.3%, and an area shrinkage rate at 90° C. of 24.6%. It is shown in Table 1 along with other physical property data.
（作用及び効果）
本発明のポリエチレン系熱収縮性多層フィルムは、各層
の原料として特定の条件を満足するものを用いて構成し
ているため安定な延伸が可能であり、その結果フィルム
の厚みムラを小さくすることができる。しかも特定な原
料を用いた層構成のため、低温収縮性、透明性、耐ブロ
ッキング性も共ここ優れた収縮フィルムを得ることがで
きる。(Functions and Effects) The polyethylene heat-shrinkable multilayer film of the present invention is constructed using materials that satisfy specific conditions as raw materials for each layer, so stable stretching is possible, and as a result, the thickness of the film is uniform. can be made smaller. Moreover, because of the layer structure using specific raw materials, it is possible to obtain a shrink film with excellent low-temperature shrinkability, transparency, and blocking resistance.
第１図は本発明の実施例に用いた二軸延伸装置の説明用
断面図である。
図中
１・・・未延伸フィルム
２・・・低速ニップロール
３・・・高速ニップロール
４・・・予熱器
５・・・主熱器
６・・・冷却エヤーリング
７・・・折りたたみロール群FIG. 1 is an explanatory cross-sectional view of a biaxial stretching apparatus used in an example of the present invention. In the figure 1...Unstretched film 2...Low speed nip roll 3...High speed nip roll 4...Preheater 5...Main heater 6...Cooling air ring 7...Folding roll group
Claims (1)
、メルトインデックス０．１〜３．０ｇ／１０分のエチ
レンとα−オレフィンとの線状共重合体（Ａ）、内外層
が密度０．９１５〜０．９３０ｇ／ｃｍ＾３、メルトイ
ンデックス０．２〜３．０ｇ／１０分のエチレンとα−
オレフィンとの線状共重合体（Ｂ）からなり、全層に対
する中間層の比が３０％以上、内外層の厚みが少くとも
各々０．５μ以上、厚みムラが２０％以下であり、９０
℃における面積収縮率が２０％以上であることを特徴と
する二軸延伸したポリエチレン系熱収縮性多層フィルム
。 ２）エチレンとα−オレフィンとの線状共重合体（Ａ）
が、エチレン−ブテン−１線状共重合体であることを特
徴とする特許請求の範囲第１項記載のポリエチレン系熱
収縮性多層フィルム。 ３）エチレンとα−オレフィンとの線状共重合体（Ｂ）
のα−オレフィンがブテン−１、ペンテン−１、ヘキセ
ン−１、オクテン−１、４−メチルペンテン−１の群か
ら選ばれたα−オレフィンであることを特徴とする特許
請求の範囲第１項記載のポリエチレン系熱収縮性多層フ
ィルム。[Claims] 1) The intermediate layer has a density of 0.870 to 0.915 g/cm^3
, a linear copolymer of ethylene and α-olefin (A) with a melt index of 0.1 to 3.0 g/10 min, an inner and outer layer having a density of 0.915 to 0.930 g/cm^3, and a melt index of 0. 2-3.0g/10min of ethylene and α-
Consisting of a linear copolymer (B) with olefin, the ratio of the intermediate layer to the total layer is 30% or more, the thickness of the inner and outer layers is at least 0.5μ or more each, and the thickness unevenness is 20% or less,
A biaxially stretched polyethylene heat-shrinkable multilayer film characterized by an area shrinkage rate of 20% or more at °C. 2) Linear copolymer of ethylene and α-olefin (A)
The polyethylene heat-shrinkable multilayer film according to claim 1, wherein is an ethylene-butene-1 linear copolymer. 3) Linear copolymer of ethylene and α-olefin (B)
Claim 1, wherein the α-olefin is an α-olefin selected from the group of 1-butene, 1-pentene, 1-hexene, 1-octene, and 1-4-methylpentene. The polyethylene heat-shrinkable multilayer film described above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63135422A JP2688827B2 (en) | 1988-06-03 | 1988-06-03 | Heat shrinkable multilayer film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63135422A JP2688827B2 (en) | 1988-06-03 | 1988-06-03 | Heat shrinkable multilayer film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01304938A true JPH01304938A (en) | 1989-12-08 |
| JP2688827B2 JP2688827B2 (en) | 1997-12-10 |
Family
ID=15151363
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63135422A Expired - Lifetime JP2688827B2 (en) | 1988-06-03 | 1988-06-03 | Heat shrinkable multilayer film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2688827B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009096119A (en) * | 2007-10-18 | 2009-05-07 | Prime Polymer:Kk | Freshness keeping film and food packaging container |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6422548A (en) * | 1987-07-17 | 1989-01-25 | Okura Industrial Co Ltd | Heat-shrinkable film |
-
1988
- 1988-06-03 JP JP63135422A patent/JP2688827B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6422548A (en) * | 1987-07-17 | 1989-01-25 | Okura Industrial Co Ltd | Heat-shrinkable film |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009096119A (en) * | 2007-10-18 | 2009-05-07 | Prime Polymer:Kk | Freshness keeping film and food packaging container |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2688827B2 (en) | 1997-12-10 |
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