JP2888855B2 - Heat shrinkable film - Google Patents
Heat shrinkable filmInfo
- Publication number
- JP2888855B2 JP2888855B2 JP1091579A JP9157989A JP2888855B2 JP 2888855 B2 JP2888855 B2 JP 2888855B2 JP 1091579 A JP1091579 A JP 1091579A JP 9157989 A JP9157989 A JP 9157989A JP 2888855 B2 JP2888855 B2 JP 2888855B2
- Authority
- JP
- Japan
- Prior art keywords
- heat
- film
- shrinkable
- temperature
- heat shrinkage
- 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
- 229920006257 Heat-shrinkable film Polymers 0.000 title claims description 50
- 229920000092 linear low density polyethylene Polymers 0.000 claims description 23
- 239000004707 linear low-density polyethylene Substances 0.000 claims description 22
- 229920005989 resin Polymers 0.000 claims description 22
- 239000011347 resin Substances 0.000 claims description 22
- 230000000903 blocking effect Effects 0.000 claims description 20
- 238000002844 melting Methods 0.000 claims description 17
- 230000008018 melting Effects 0.000 claims description 17
- 239000004743 Polypropylene Substances 0.000 claims description 13
- -1 polypropylene Polymers 0.000 claims description 13
- 229920001155 polypropylene Polymers 0.000 claims description 13
- 239000011342 resin composition Substances 0.000 claims description 9
- 239000010410 layer Substances 0.000 description 48
- 238000000034 method Methods 0.000 description 37
- 238000004806 packaging method and process Methods 0.000 description 20
- 229920001577 copolymer Polymers 0.000 description 7
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 6
- 239000005977 Ethylene Substances 0.000 description 6
- 238000007789 sealing Methods 0.000 description 6
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 5
- 239000004711 α-olefin Substances 0.000 description 5
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 4
- 229920005673 polypropylene based resin Polymers 0.000 description 4
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 4
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 4
- WSSSPWUEQFSQQG-UHFFFAOYSA-N 4-methyl-1-pentene Chemical compound CC(C)CC=C WSSSPWUEQFSQQG-UHFFFAOYSA-N 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 125000004432 carbon atom Chemical group C* 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 235000009508 confectionery Nutrition 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 229920000915 polyvinyl chloride Polymers 0.000 description 3
- 239000004800 polyvinyl chloride Substances 0.000 description 3
- 230000037303 wrinkles Effects 0.000 description 3
- 235000013361 beverage Nutrition 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000002537 cosmetic Substances 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 235000011187 glycerol Nutrition 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- 229920001684 low density polyethylene Polymers 0.000 description 2
- 239000004702 low-density polyethylene Substances 0.000 description 2
- 239000000314 lubricant Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- LIKMAJRDDDTEIG-UHFFFAOYSA-N 1-hexene Chemical compound CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- 235000008766 Murraya exotica Nutrition 0.000 description 1
- 240000001899 Murraya exotica Species 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000002216 antistatic agent Substances 0.000 description 1
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000012792 core layer Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 210000005069 ears Anatomy 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 239000012793 heat-sealing layer Substances 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 229920005684 linear copolymer Polymers 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000123 paper Substances 0.000 description 1
- YWAKXRMUMFPDSH-UHFFFAOYSA-N pentene Chemical compound CCCC=C YWAKXRMUMFPDSH-UHFFFAOYSA-N 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 229920005606 polypropylene copolymer Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- 238000009517 secondary packaging Methods 0.000 description 1
- 229920002050 silicone resin Polymers 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、包装されるべき物品を、熱収縮性フイルム
で一次的にラフに包装したあと、その一次包装体を加熱
して熱収縮性フイルムを収縮させて二次的にタイトな包
装体を得る、といういわゆる熱収縮包装方法において使
用される熱収縮性フイルムに関するものであり、さらに
詳しくは、フイルムを熱収縮させる前の一次包装体を得
るに際し、全てのフイルム端部の密封をヒートシールや
静電シール等で行なわず、一部、又は、全てをフイルム
端部が重ね合わされただけの状態とし、そのまま該一次
包装体のフイルムを熱収縮させる方法（以下、オーバラ
ップ方式による熱収縮包装方法と称する）に使用される
熱収縮性フイルムに関するものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a method for producing a heat-shrinkable article by temporarily wrapping an article to be packed with a heat-shrinkable film and then heating the primary package. The present invention relates to a heat-shrinkable film used in a so-called heat-shrinkable packaging method of shrinking a film to obtain a tightly-sealed package, and more specifically, a primary package before thermally shrinking the film. At the time of obtaining, all the film ends are not sealed by heat sealing or electrostatic sealing, etc., and a part or all of the film is made to be in a state where the film ends are overlapped, and the film of the primary package is heated as it is. The present invention relates to a heat-shrinkable film used for a shrinking method (hereinafter, referred to as a heat shrink wrapping method by an overlap method).
（従来の技術） 熱収縮包装方法は、品物の形状にぴったり沿ったタイ
トにしあがり、見栄えが良くなる等の特徴を有してい
る。又、複数個の品物を一度に包装する集積包装に好都
合であるとか、或いは、包装コストの低減が図られる等
の数多くの特徴を有している。そのため、容器入りの食
料品や飲料品、或いは、化粧箱入りの化粧品や医薬品、
更には、書籍等の個々の包装や集積包装に広く利用され
ている。特に、ポリプロピレン系樹脂からなる熱収縮性
フイルムは、その本来有している透明性、光沢、防湿
性、或いは、無公害性、更には、生産性等の面に優れて
いるので好んで用いられている。(Prior Art) The heat shrink wrapping method is characterized in that the heat shrink wrapping method is tightly fitted to the shape of the product and improves the appearance. In addition, it has a number of features such as being convenient for integrated packaging for packaging a plurality of items at once, or reducing packaging costs. Therefore, food and beverages in containers, cosmetics and pharmaceuticals in cosmetic boxes,
Further, it is widely used for individual packaging and accumulation packaging of books and the like. In particular, a heat-shrinkable film made of a polypropylene-based resin is preferably used because it is excellent in transparency, glossiness, moisture-proofness, or pollution-free properties, and furthermore, in terms of productivity and the like. ing.
ところが、従来一般によく行なわれている溶断ヒート
シール方式により一次包装体のフイルム密封がなされた
熱収縮包装体は、密封部にフイルム端部が無いために見
栄えは良くなるが、逆に、開封がしにくいと言う欠点を
有している。However, the heat-shrinkable package, in which the film of the primary package is sealed by the conventional heat-sealing method, is generally good in appearance because there is no film end in the sealing portion. It has the disadvantage of being difficult to do.
そこで、この欠点を改良するためにいわゆるオーバラ
ップ方式による熱収縮包装方法が行なわれている。この
方法によると、フイルム端部の重ね合わせ部分が完全に
接着されておらず、しかもフイルム端部が存在している
ために、この部分より容易に開封する事が出来る。そし
て、この方法にはポリ塩化ビニルからなる熱収縮性フイ
ルムが一般に使用されている。Therefore, in order to improve this drawback, a so-called overlap type heat shrink wrapping method has been used. According to this method, the overlapping portion of the film end is not completely adhered, and since the film end is present, the film can be more easily opened than this portion. In this method, a heat-shrinkable film made of polyvinyl chloride is generally used.
しかしながら、ポリ塩化ビニルの熱収縮性フイルム
は、添加されている可塑剤により被包装体が汚染される
問題や、フイルム廃棄物を焼却した際に発生する塩素ガ
スによる腐食や環境汚染等の問題がある。However, heat-shrinkable polyvinyl chloride film suffers from problems such as contamination of the package by the added plasticizer, corrosion by chlorine gas generated when the film waste is incinerated, and environmental pollution. is there.
又、ポリプロピレン系樹脂からなる単層の熱収縮性フ
イルムや両外層に従来のヒートシール層等を設けた積層
熱収縮性フイルムを用いて、オーバラップ方式により熱
収縮包装方法を行なおうとすると、熱収縮時にフイルム
端部の重ね合わせ部分が開いてしまい良好なる熱収縮包
装仕上がりが得られなかった。即ち、熱収縮時に該重ね
合わせ部分が開いてしまうと、一次包装体内部の空気が
一度に排出され、該一次包装体のフイルムが一度も膨れ
た状態になることなく、当該熱収縮性フイルムがすぐに
被包装物品に接触してしまい、該フイルムが充分加熱さ
れず熱収縮量が少なくなるために、得られる二次包装体
にフイルムの皺が発生してしまう。又、該重ね合わせ部
分が開いていると、該フイルム端部には何等負荷が掛か
っていない状態になるので、該フイルムが過度に熱収縮
して、ますます大きな穴となってしまう。Also, when using a single-layer heat-shrinkable film made of a polypropylene-based resin or a laminated heat-shrinkable film provided with a conventional heat-sealing layer on both outer layers, a heat-shrinkable packaging method is to be performed by an overlap method. At the time of heat shrinkage, the overlapping portion of the film ends was opened, and a good heat shrink wrapping finish could not be obtained. That is, if the overlapped portion is opened during heat shrinkage, the air inside the primary package is exhausted at one time, and the film of the primary package does not expand once, and the heat shrinkable film is The film immediately contacts the article to be packaged, and the film is not sufficiently heated and the amount of heat shrinkage is reduced, so that the obtained secondary package has wrinkles on the film. Also, if the overlapping portion is open, no load is applied to the end of the film, so that the film is excessively heat-shrinked and becomes a larger hole.
（本発明が解決しようとする課題） 本発明は、ポリプロピレン系樹脂の熱収縮性フイルム
が有している数多くの優れた特性を備えた、しかもオー
バラップ方式による熱収縮包装方法が可能な熱収縮性フ
イルムを提供しようとするものである。そして、熱収縮
包装体を開封しようとする時にはフイルム端部の重ね合
わせ部分から容易に開封する事が出来、しかも、該熱収
縮包装体が通常の一般的な取り扱いをされても、容易に
は該フイルム端部の重ね合わせ部分から破袋しない様な
ポリプロピレン系樹脂の多層熱収縮性フイルムを提供し
ようとするものである。(Problems to be Solved by the Invention) The present invention provides a heat-shrinkable packaging method having a number of excellent characteristics of a heat-shrinkable film of a polypropylene resin and capable of performing a heat-shrinkable packaging method by an overlap method. It is intended to provide a sex film. When the heat-shrinkable package is to be opened, the heat-shrinkable package can be easily opened from the overlapped portion of the film ends, and even if the heat-shrinkable package is subjected to ordinary general handling. It is an object of the present invention to provide a multi-layer heat-shrinkable film made of a polypropylene resin so as not to break the bag from the overlapping portion of the film ends.
（問題点を解決するための手段） 本願発明者は上記目的を達成するために、ポリプロピ
レン系熱収縮性フイルムの両最外層に特定の樹脂層を積
層させ、特定な性能を付与させた熱収縮性フイルムを見
いだし、本発明を成し遂げた。(Means for Solving the Problems) In order to achieve the above object, the present inventor laminated a specific resin layer on both outermost layers of a polypropylene-based heat-shrinkable film, and provided a specific heat-shrinkable film. The present invention has been accomplished by finding a sex film.
即ち、本発明は、オーバラップ方式による熱収縮包装
方法に用いる熱収縮性フイルムとして、両最外層がビカ
ット軟化温度105℃以下の直鎖状低密度ポリエチレンを
主体とする樹脂組成からなり、中間層が少なくとも一層
のポリプロピレン系樹脂からなり、しかも、フイルムの
少なくとも一方向の最大熱収縮力がフィルム幅10mmにつ
き60g以下で、その上、少なくとも一方向の熱収縮率が
５％に達する温度でのブロッキング値と、最外層の直鎖
状低密度ポリエチレンの融点より10℃低い温度でのブロ
ッキング値が、それぞれ40g/cm2以上と100g/cm2以上の
フイルムである。That is, the present invention provides a heat-shrinkable film used in a heat-shrinkable packaging method by an overlap method, wherein both outermost layers are made of a resin composition mainly composed of a linear low-density polyethylene having a Vicat softening temperature of 105 ° C or lower, and an intermediate layer. Consists of at least one layer of polypropylene resin, and the film has a maximum heat shrinkage force in at least one direction of not more than 60 g per 10 mm of film width, and further, has a heat shrinkage in at least one direction of 5%. And a blocking value at a temperature 10 ° C. lower than the melting point of the linear low-density polyethylene in the outermost layer are 40 g / cm 2 or more and 100 g / cm 2 or more, respectively.
以下本発明の内容を詳細に説明する。 Hereinafter, the contents of the present invention will be described in detail.
先ず、本発明に到達する前提として、ポリプロピレン
系樹脂を用いた熱収縮性フイルムでオーバラップ方式に
よる熱収縮包装を行なう際には、熱収縮時に一次包装体
のフイルム端部の重ね合せ部分が開かず、良好なる熱収
縮二次包装体が得られる様にするためには、該熱収縮性
フイルムが熱収縮するときの熱収縮力と、ある特定温度
でのフイルム同士が密着する程度を検討する必要があ
る。即ち、良好なる熱収縮二次包装体を得るには、熱収
縮時に一次包装体のフイルム端部の重ね合わせ部分を加
熱密着させて、熱収縮力と内部空気の膨張により生ずる
フイルムの張力により重ね合わせ部分が開くのを抑える
様にする事が必要である。又、得られた熱収縮二次包装
体の重ね合わせ部分は、一般に取扱程度では開かない様
に加熱密着させておく事が必要である。First, as a prerequisite to reaching the present invention, when performing heat shrink wrapping by an overlap method with a heat shrinkable film using a polypropylene resin, the overlapping portion of the film end of the primary package is opened during heat shrinkage. In order to obtain a good heat-shrinkable secondary package, heat shrinkage force when the heat-shrinkable film thermally shrinks and the degree of close contact between the films at a specific temperature are examined. There is a need. That is, in order to obtain a good heat-shrinkable secondary package, the overlapping portion of the film end portion of the primary package is heated and adhered during the heat shrinkage, and the heat-shrinkage force and the film tension generated by the expansion of the internal air are used to stack the film. It is necessary to keep the joints from opening. In addition, it is generally necessary that the overlapped portion of the obtained heat-shrinkable secondary package is heated and adhered so that it does not open when handled.
そして、この様な熱収縮包装方法に用いる熱収縮性フ
イルムの熱収縮力としては、該熱収縮性フイルムが全温
度域に於いて生じる最大熱収縮力によって評価し、フイ
ルム同士の密着の程度としては、少なくとも一方向の熱
収縮率が５％に達する温度でのブロッキング値と、最外
層の直鎖状低密度ポリエチレンの融点より10℃低い温度
でのブロッキング値で評価する事が望ましい事が判っ
た。The heat shrinkage of the heat shrinkable film used in such a heat shrink wrapping method is evaluated by the maximum heat shrinkage generated in the entire temperature range of the heat shrinkable film. It can be seen that it is desirable to evaluate the blocking value at a temperature at which the heat shrinkage in at least one direction reaches 5% and the blocking value at a temperature 10 ° C. lower than the melting point of the linear low density polyethylene in the outermost layer. Was.
そこで、これらの特性について色々調べた結果、本発
明の熱収縮性フイルムを提供する事が出来る様になった
ものである。Therefore, as a result of investigating these characteristics in various ways, the heat-shrinkable film of the present invention can be provided.
まず、フイルムの両最外層に用いる直鎖状低密度ポリ
エチレンとしては、エチレンとα−オレフィンとを共重
合させ、直鎖状の主鎖に短鎖分岐を導入させた樹脂で、
しかも、そのビカット軟化温度が105℃以下の樹脂であ
る。そして、α−オレフィンとしては、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などが一般に用いられる。First, as the linear low-density polyethylene used for both outermost layers of the film, a resin obtained by copolymerizing ethylene and an α-olefin and introducing a short-chain branch into a linear main chain,
In addition, the resin has a Vicat softening temperature of 105 ° C. or less. And, as the α-olefin, butene-1, pentene-1, hexene-1, octene-1, 4-methyl-pentene-1 and the like are generally used.
ビカット軟化温度が105℃以下の直鎖状低密度ポリエ
チレン樹脂を両最外層に用いると、積層延伸する際に、
ポリプロピレン系樹脂の延伸加工性を損なう事なく、良
好なる延伸加工性を示し、しかも、熱収縮性フイルムと
して重要な特性である低温熱収縮性を向上させる事が出
来る。更に、本発明の特定条件である熱収縮時の熱収縮
力を弱める事が出来、しかも、ブロッキング値も高くす
る事が出来る。When the Vicat softening temperature uses a linear low-density polyethylene resin having a temperature of 105 ° C. or less for both outermost layers, when laminating and stretching,
A good stretchability can be exhibited without impairing the stretchability of the polypropylene resin, and the low-temperature heat shrinkability, which is an important property as a heat-shrinkable film, can be improved. Furthermore, the heat shrinkage force during heat shrinkage, which is a specific condition of the present invention, can be reduced, and the blocking value can be increased.
尚、該直鎖状低密度ポリエチレン樹脂のビカット軟化
温度が60℃未満であると、本発明の目的とは異なる別の
問題、例えば、共押出し方法による未延伸原反の製膜性
が劣ったり、或いは、自動包装機械適正が悪くなる等の
問題を生じ、本発明の熱収縮性フイルムには余り好まし
くない。When the linear low-density polyethylene resin has a Vicat softening temperature of less than 60 ° C., there is another problem different from the object of the present invention, for example, the film forming property of an unstretched raw material by a co-extrusion method is poor. Alternatively, problems such as deterioration of the suitability of the automatic packaging machine occur, which is not preferable for the heat shrinkable film of the present invention.
直鎖状低密度ポリエチレンを主体とする樹脂組成物と
は、該直鎖状低密度ポリエチレン単体は勿論、該直鎖状
低密度ポリエチレンに少量の一般的な低密度ポリエチレ
ン樹脂やポリプロピレン樹脂、或いは、エチレン−酢酸
ビニル共重合体等のポリオレフィン系樹脂を一種類、或
いは、二種類以上を混合させた樹脂組成物等を示す。更
に、該直鎖状低密度ポリエチレンを主体とする樹脂組成
物には、滑剤、アンチブロッキング剤、粘着付与剤、静
電防止剤、防曇剤等の添加剤を加えても何等支障はな
い。The resin composition mainly composed of linear low-density polyethylene means, in addition to the linear low-density polyethylene alone, a small amount of general low-density polyethylene resin or polypropylene resin in the linear low-density polyethylene, or It shows a resin composition or the like obtained by mixing one or more polyolefin-based resins such as an ethylene-vinyl acetate copolymer. Further, addition of additives such as a lubricant, an antiblocking agent, a tackifier, an antistatic agent and an antifogging agent to the resin composition mainly composed of the linear low-density polyethylene does not cause any problem.
尚、フイルム両最外層の樹脂組成は、必ずしも同じ樹
脂組成である必要はないが、生産性等の面からは同一の
樹脂組成であることが好ましい。The resin compositions of the outermost layers of the films need not necessarily be the same, but are preferably the same from the viewpoint of productivity and the like.
又、中間層に用いるポリプロピレン系樹脂としては、
一般に熱収縮性フイルムに用いられている樹脂を使用す
ることが出来る。例えば、融点が135〜150℃の範囲で、
プロピレンにエチレンを共重合させたものや、プロピレ
ンにエチレンとブテンとを共重合させたもの、或いは、
プロピレンに炭素数が２〜８個のα−オレフィンを共重
合させ、ビカット軟化温度を70〜110℃にしたもの等が
使用される。そして、これらのポリプレピレン系樹脂に
は、前記直鎖状低密度ポリエチレンを主体とする樹脂組
成物と同様、上記の様な種々の添加剤を加える事もでき
る。Also, as the polypropylene resin used for the intermediate layer,
Resins generally used for heat-shrinkable films can be used. For example, if the melting point is in the range of 135 to 150 ° C,
Propylene copolymerized with ethylene, or propylene copolymerized with ethylene and butene, or
A copolymer obtained by copolymerizing propylene with an α-olefin having 2 to 8 carbon atoms and having a Vicat softening temperature of 70 to 110 ° C. is used. As in the case of the resin composition mainly composed of the linear low-density polyethylene, various additives as described above can be added to these polypropylene resins.
これらのポリプロピレン系樹脂は、延伸加工性に優れ
ているばかりか、熱収縮包装に必要な熱収縮包装性にも
優れている。特に、ビカット軟化温度が70〜110℃のプ
ロピレンと炭素数が２〜８個のα−オレフィンとの共重
合体を用いた場合には、低温熱収縮性に優れ、しかも、
熱収縮力を弱くすることが出来る。These polypropylene resins are excellent not only in stretch processability but also in heat shrink wrapping property required for heat shrink wrapping. In particular, when a copolymer of propylene having a Vicat softening temperature of 70 to 110 ° C. and an α-olefin having 2 to 8 carbon atoms is used, the heat shrinkability at low temperature is excellent, and
Heat shrink force can be reduced.
尚、中間層としては、上記ポリプロピレン系樹脂から
なる単層のものは勿論、上記ポリプロピレン系樹脂層に
他の樹脂からなる層を積層させた多層のものをも含む。The intermediate layer includes not only a single layer made of the above-mentioned polypropylene-based resin but also a multi-layer formed by laminating a layer made of another resin on the above-mentioned polypropylene-based resin layer.
そして、本発明の熱収縮性フイルムは少なくとも一方
向の最大熱収縮力をフイルム幅10mmにつき60g以下にな
る様にする。そして、この最大熱収縮力は次の様な方法
によって測定されたものである。The heat-shrinkable film of the present invention has a maximum heat-shrinkage force in at least one direction of 60 g or less per 10 mm of the film width. The maximum heat shrink force is measured by the following method.
即ち、測定しようとする熱収縮性フイルムの各温度で
の熱収縮力を縦方向、横方向それぞれ求める事により、
縦方向、横方向それぞれの最大熱収縮力を求める。尚、
縦方向、横方向それぞれ10mm幅のタンザク状に切断して
得られた試料を40mm間隔のチャック間に弛みが無く、し
かも、無負荷の状態に挟持し、該試料が熱収縮を起こさ
ない様にチャック間に固定し、その後、チャック間に挟
持されたままの試料を各温度に設定されたグリセリン槽
中に約30秒間浸漬させ、チャック間に生じる平均熱収縮
力をｇの単位で求めた。In other words, by determining the heat shrinkage force at each temperature of the heat shrinkable film to be measured in the vertical and horizontal directions,
Determine the maximum heat shrinkage force in each of the vertical and horizontal directions. still,
Samples obtained by cutting into 10 mm wide tanks in the vertical and horizontal directions are not loosened between chucks at 40 mm intervals, and are clamped under no load so that the samples do not undergo thermal shrinkage. After being fixed between the chucks, the sample held between the chucks was immersed in a glycerin bath set at each temperature for about 30 seconds, and the average heat shrinkage generated between the chucks was determined in units of g.
その結果は、熱収縮性フイルムの一方向の最大熱収縮
力が60g以下でないと、熱収縮力と内部空間の膨張によ
り生ずるフイルムの張力によってフイルム端部の重ね合
わせ部分が開いてしまい、良好なる熱収縮包装体が得ら
れないことが知見された。As a result, if the maximum heat shrinkage force in one direction of the heat shrinkable film is not less than 60 g, the overlapped portion of the film end is opened due to the heat shrinkage force and the tension of the film caused by the expansion of the internal space, so that it is good. It was found that a heat-shrinkable package could not be obtained.
尚、オーバラップ方式による熱収縮包装方法に於いて
は、この最大熱収縮力が60g以下であるフイルムの方向
を、フイルム端部を重ね合わせた際に、該フイルム端と
直角に交わる様な方向にする。例えば、前記したピロー
方式により自動包装する際には、フイルムの横方向を最
大熱収縮力が60g以下になる様にする。In the heat shrink wrapping method by the overlap method, the direction of the film having the maximum heat shrinkage force of 60 g or less is a direction which intersects the film end perpendicularly when the film ends are overlapped. To For example, when automatic packaging is performed by the pillow method described above, the maximum heat shrinkage force in the lateral direction of the film is set to 60 g or less.
又、本発明の熱収縮性フイルムは、少なくとも一方向
の熱収縮率が５％に達する温度でのブロッキング値と、
最外層の直鎖状低密度ポリエチレンの融点より10℃低い
温度でのブロッキング値が、それぞれ40g/cm2以上と100
g/cm2以上なる様にする。そして、これらのブロッキン
グ値は次の様な方法によって測定されたものである。
尚、フイルム両最外層の直鎖状低密度ポリエチレンの融
点が相違する場合には低い法の融点を用いる。まず、測
定しようとする熱収縮性フイルムを50mm×100mmのタン
ザク状に切断して試料とする。そして、長手方向のフイ
ルム端部が互いに50mm重ね合わされる様に２枚の試料を
重ね合わせ、その上に5Kgの荷重を掛け、所定の温度に
設定された熱風乾燥機で１時間加熱する。その後、30分
間冷却した後、重ね合わせていない他方のフイルム端を
100mm/minの速度で引っ張り、その際生じる最大剪断荷
重を接触面積で割り、g/cm2の単位で求めた。Further, the heat shrinkable film of the present invention has a blocking value at a temperature at which the heat shrinkage in at least one direction reaches 5%,
The blocking value at a temperature 10 ° C. lower than the melting point of the linear low-density polyethylene of the outermost layer is 40 g / cm 2 or more and 100, respectively.
g / cm 2 or more. These blocking values are measured by the following method.
If the melting points of the linear low-density polyethylene in the outermost layers of the films are different, the melting point of the lower method is used. First, a heat-shrinkable film to be measured is cut into a 50 mm x 100 mm tank shape to obtain a sample. Then, the two samples are overlapped so that the film ends in the longitudinal direction are overlapped with each other by 50 mm, a load of 5 kg is applied thereon, and the sample is heated for 1 hour by a hot air dryer set to a predetermined temperature. Then, after cooling for 30 minutes, remove the other non-overlapping film edge.
Pulling was performed at a speed of 100 mm / min, and the maximum shear load generated at that time was divided by the contact area to obtain a unit in g / cm 2 .
フイルム両最外層の直鎖状低密度ポリエチレンが相違
する場合には、相違する樹脂面同士が互いに接する様に
重ね合わせる。又、少なくともフイルムの一方向の熱収
縮率が５％に達する温度は、次の様な方法によって求め
る。まず、測定しようとする熱収縮性フイルムの各温度
での熱収縮率を縦方向、横方向それぞれ求める事によ
り、５％の熱収縮率を示す熱収縮温度を縦方向、横方向
をそれぞれ求める。そして、その内の高い方の温度を本
発明中の５％の熱収縮率に達する熱収縮温度とする。
尚、各温度での熱収縮率は、縦方向、横方向が共に100m
mの正方形に切断して得られた試料を、各所定温度に設
定されたグリセリン槽中に約30秒間浸漬させて熱収縮さ
せ、各温度ごとに縦方向、横方向各々の熱収縮量を熱収
縮前の長さの100分率で求めた。When the linear low-density polyethylenes of the outermost layers of the films are different, they are overlapped so that the different resin surfaces are in contact with each other. The temperature at which the heat shrinkage in at least one direction of the film reaches 5% is determined by the following method. First, the heat shrinkage at each temperature of the heat shrinkable film to be measured is obtained in each of the vertical and horizontal directions, so that the heat shrinkage temperature showing a heat shrinkage of 5% is obtained in the vertical and horizontal directions. Then, the higher one of them is defined as the heat shrinkage temperature that reaches the heat shrinkage of 5% in the present invention.
The heat shrinkage rate at each temperature was 100 m in both the vertical and horizontal directions.
A sample obtained by cutting into a square of m is immersed in a glycerin bath set at each predetermined temperature for about 30 seconds to be thermally shrunk, and the amount of heat shrinkage in each of the vertical and horizontal directions at each temperature is measured. It was determined as a percentage of the length before shrinkage.
熱収縮性フイルムの少なくとも一方向において、その
熱収縮率が５％に達する温度でのブロッキング値が40g/
cm2以上でないと、熱収縮時にフイルム端部の重ね合わ
せ部分の密着性が劣る様になるため、熱収縮力と内部空
気の膨張により生ずるフイルムの張力によってフイルム
端部の重ね合わせ部分が開いてしまう。In at least one direction of the heat shrinkable film, the blocking value at a temperature at which the heat shrinkage reaches 5% is 40 g /
If not more than 2 cm, the adhesiveness of the overlapped portion of the film ends during heat shrinkage will be poor, so the overlapped portion of the film end will open due to the heat shrinkage force and the tension of the film caused by the expansion of the internal air. I will.
又、最外層の直鎖状低密度ポリエチレンの融点より10
℃低い温度でのブロッキング値が100g/cm2以上でない
と、得られた熱収縮二次包装体の該重ね合わせ部分の密
着性が劣り、一般的な取扱時に於いて破袋を生じてしま
う。例えば、得られた二次包装体をダンボール箱に詰め
込む際等に、該重ね合わせ部分から破袋を生じてしま
う。In addition, the melting point of the linear low density polyethylene of the outermost layer is 10
If the blocking value at a temperature lower by ° C. is not more than 100 g / cm 2 , the adhesiveness of the overlapped portion of the obtained heat-shrinkable secondary package is inferior, and the bag is broken during general handling. For example, when the obtained secondary package is packed in a cardboard box, the bag is broken from the overlapping portion.
本発明の熱収縮性フイルムの熱収縮率については特に
限定されるものではないが、一般の熱収縮性フイルムが
必要とされている熱収縮率は必要である。例えば良好な
る包装仕上がりを得るためには、最大熱収縮力が40％以
上である事が好ましい。又、低温での熱収縮率が高い方
が良好なる熱収縮包装体を得るのに適している。The heat shrinkage of the heat shrinkable film of the present invention is not particularly limited, but a heat shrinkage required for a general heat shrinkable film is required. For example, in order to obtain a good packaging finish, the maximum heat shrink force is preferably 40% or more. Further, it is suitable for obtaining a heat-shrinkable package having a better heat-shrinkage rate at a low temperature.
又、本発明の熱収縮性フイルムの厚みについても特に
限定されるものではなく、被包装物の種類、形態等によ
り適宜選択されればよいが、一般的には10〜100μ程度
が好ましい。又、各層の厚み構成についても特に限定さ
れるものではなく、熱収縮特性や機械的強度、更には、
ブロッキング値等から適宜決定されればよいが、好まし
くは、両最外層の厚みがそれぞれ1.0μ以上で、しか
も、それぞれ全体厚みに対して10〜30％程度である事が
望ましい。The thickness of the heat-shrinkable film of the present invention is not particularly limited, and may be appropriately selected depending on the type, form, and the like of the article to be packaged. Generally, the thickness is preferably about 10 to 100 μm. Also, there is no particular limitation on the thickness configuration of each layer, heat shrinkage properties and mechanical strength, furthermore,
The thickness may be appropriately determined from a blocking value or the like, but preferably, the thickness of each of the outermost layers is preferably 1.0 μm or more, and each is preferably about 10 to 30% of the total thickness.
本発明の熱収縮性フイルムを用いるオーバラップ方式
による熱収縮包装方法は、特に限定された方法により行
なわれるものではなく、従来、ポリ塩化ビニルからなる
熱収縮性フイルムに用いられている装置をそのまま使用
する事が出来る。例えば、熱収縮前の一次包装体を、従
来のピロー方式の自動包装機を用い、前後は従来の溶断
ヒートシール方式により密封し、包装体の流れ方向はフ
イルム端部を重ね合わせることにより得る。そして、得
られた該一次包装体を従来の熱収縮トンネル内を通すこ
とにより熱収縮二次包装体を得る。The heat shrink wrapping method by the overlap method using the heat shrinkable film of the present invention is not particularly performed by a limited method, and the apparatus conventionally used for the heat shrinkable film made of polyvinyl chloride is used as it is. Can be used. For example, the primary package before heat shrinking is obtained by using a conventional pillow type automatic packaging machine, sealing the front and rear parts by a conventional fusing heat sealing method, and stacking the film ends in the flow direction of the package. Then, the obtained primary package is passed through a conventional heat-shrink tunnel to obtain a heat-shrinkable secondary package.
尚、熱収縮トンネル等の加熱装置により熱収縮させる
際には、フイルム端部の重ね合わせ部分が下側になる様
に一次包装体を置き、該部分に被包装体の荷重が掛かる
様にする。又、フイルム端部を重ね合わせる幅として
は、10〜50mm程度が好ましい。When heat shrinking by a heating device such as a heat shrink tunnel, the primary package is placed so that the overlapping portion of the film ends is on the lower side, and the load of the package is applied to this portion. . Further, the width for overlapping the film ends is preferably about 10 to 50 mm.
又、本発明の熱収縮性フイルムを製造する方法として
は、特に限定されるものではないが、次の様な方法によ
り製造されるのが好ましい。即ち、複数の押出機を用い
て積層ダイスより積層未延伸原反シートを共押出し、冷
却固化させた後、延伸可能な温度まで再加熱して、イン
フレーション方式や、テンター方式によって延伸した
り、或いは、速度差を有する二組のピンチロール間で縦
方向に延伸した後、テンター延伸機により横方向に延伸
する事により得られる。尚、延伸倍率は特に限定される
ものではないが、面積倍率で６〜30倍程度が適当であ
る。The method for producing the heat-shrinkable film of the present invention is not particularly limited, but is preferably produced by the following method. That is, a co-extruded laminated unstretched raw sheet from a lamination die using a plurality of extruders, after cooling and solidifying, reheating to a stretchable temperature, stretching by an inflation method, a tenter method, or After stretching in the longitudinal direction between two sets of pinch rolls having a speed difference, the film is stretched in the transverse direction by a tenter stretching machine. The stretching magnification is not particularly limited, but is suitably about 6 to 30 times in area magnification.
尚、本発明の特定条件の一つであるフイルムの少なく
とも一方向の最大熱収縮力については、各層の樹脂組成
や厚み構成などを適宜選択したり、或いは、延伸条件や
熱処理条件等を適宜選べばよい。例えば、芯層のポリプ
ロピレン樹脂層を薄くしたり、各層にビカット軟化温度
の低い樹脂を使用したりする事により、該最大熱収縮力
を弱くする事が出来る。Regarding the maximum heat shrinkage force in at least one direction of the film, which is one of the specific conditions of the present invention, the resin composition and thickness configuration of each layer can be appropriately selected, or the stretching conditions and heat treatment conditions can be appropriately selected. I just need. For example, by reducing the thickness of the polypropylene resin layer of the core layer or using a resin having a low Vicat softening temperature for each layer, the maximum heat shrinkage force can be reduced.
又、少なくともフイルム一方向の熱収縮率が５％に達
する温度でのブロッキング値や、最外層の直鎖状低密度
ポリエチレンの融点より10℃低い温度でのブロッキング
値等の特定条件については、両最外層の樹脂組成や厚
み、或いは、滑剤やアンチブロッキング剤等の添加剤を
適宜選択すればよい。更には、適当な表面処理を施すこ
とによっても適宜変えることもできる。例えば、両最外
層にビカット軟化温度の低い樹脂を用いたり、エラスト
マーを添加したりする事により、これらのブロッキング
値を高める事が出来る。The specific conditions such as the blocking value at a temperature at which the heat shrinkage in at least one direction of the film reaches 5% and the blocking value at a temperature lower by 10 ° C. than the melting point of the linear low density polyethylene of the outermost layer, The resin composition and thickness of the outermost layer, or additives such as a lubricant and an antiblocking agent may be appropriately selected. Furthermore, it can be changed as appropriate by performing an appropriate surface treatment. For example, by using a resin having a low Vicat softening temperature for both outermost layers or adding an elastomer, these blocking values can be increased.
（発明の効果） 本発明の熱収縮性フイルムは、オーバラップ方式によ
る熱収縮包装方法に用いた際に、一次包装体のフイルム
端部の重ね合わせ部分が熱収縮時に開く様な事もなく、
良好な熱収縮二次包装体を容易に得る事が出来る。しか
も、得られた熱収縮二次包装体は、該フイルム端部の重
ね合わせ部分から容易に開封する事ができ、その上、通
常の取扱時には該部分から破袋する様な事もない。又、
ポリプロピレン系熱収縮性フイルムが有している透明
性、防湿性、無公害性、或いは、生産性等の優れた特性
をも備えている。(Effect of the Invention) When the heat shrinkable film of the present invention is used in the heat shrink wrapping method by the overlap method, the overlapping portion of the film end of the primary package does not open at the time of heat shrinkage,
A good heat-shrinkable secondary package can be easily obtained. In addition, the obtained heat-shrinkable secondary package can be easily opened from the overlapping portion of the film ends, and furthermore, there is no possibility that the bag is broken from the portion during normal handling. or,
It also has excellent properties such as transparency, moisture proofness, non-pollutability, and productivity that a polypropylene-based heat-shrinkable film has.
そのため、本発明の熱収縮性フイルムは、飲料品等の
紙パック容器、菓子類や化粧品等の箱、更には、書籍等
の包装に優れた特徴を発揮する。For this reason, the heat-shrinkable film of the present invention exhibits excellent characteristics for paper pack containers such as beverages, boxes for confectionery and cosmetics, and further for packaging books and the like.
（実施例） 以下、実施例を示し、本発明をより具体的に説明する
が、本発明はこれに限定されるものではない事は勿論で
ある。EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it is needless to say that the present invention is not limited thereto.
（実施例１） 融点が137℃のエチレン−プロピレン共重合体を中間
層とし、ビカット軟化温度が100℃で、融点が120℃のエ
チレンと４−メチル−ペンテン−１との共重合体である
線状低密度ポリエチレンを両最外層とするチューブ状共
押出し積層未延伸原反シートを、スクリュー口径が65φ
の押出機（中間用）とスクリュー口径が40φの押出機２
台（最外層用）、及び、口径が110φの三層共押出し用
環状ダイスによって得た。次に、該チューブ状積層未延
伸原反シートの片端を切断して開き、シート幅が370mm
の未延伸原反シートを得た。尚、中間層の厚みは360μ
で、両最外層の厚みは各々45μであった。(Example 1) An ethylene-propylene copolymer having a melting point of 137 ° C as an intermediate layer, a copolymer of ethylene and 4-methyl-pentene-1 having a Vicat softening temperature of 100 ° C and a melting point of 120 ° C. A tube-shaped co-extruded laminated unstretched raw sheet having linear low-density polyethylene as both outermost layers, with a screw diameter of 65φ
Extruder (for intermediate) and extruder 2 with screw diameter of 40φ
It was obtained by a stand (for the outermost layer) and an annular die for three-layer coextrusion with a diameter of 110φ. Next, one end of the tubular laminated unstretched raw sheet is cut and opened, and the sheet width is 370 mm.
Was obtained. The thickness of the intermediate layer is 360μ
The thickness of each of the outermost layers was 45 μm.
このシートを速度差を有する二組のピンチロール間に
通して縦方向に３倍延伸し、引き続き、テンター延伸機
で横方向に６倍延伸し、フイルム厚みが25μ、フイルム
幅が1300mmの熱収縮性フイルムを得た。This sheet is passed between two sets of pinch rolls having a speed difference, stretched three times in the machine direction, and then stretched six times in the transverse direction by a tenter stretching machine. The film has a heat shrinkage of 25 μm and a film width of 1300 mm. Sex film was obtained.
得られた熱収縮性フイルムは、少なくとも一方向の最
大熱収縮力がフイルム幅100mmにつき42gであり、少なく
とも一方向の熱収縮率が５％に達する温度でのブロッキ
ング値は94g/cm2であり、共に本発明の特定条件を満た
すものであった。尚、これらの方向は共にフイルムの横
方向であった。又、最外層の直鎖状低密度ポリエチレン
の融点より10℃低い温度でのブロッキング値は300g/cm2
以上で、フイルム破断を生じてしまい測定不能であった
が、本発明の特定条件は満足するものであった。The obtained heat-shrinkable film has a maximum heat shrink force in at least one direction of 42 g per 100 mm of the film width, and a blocking value at a temperature at which the heat shrinkage in at least one direction reaches 5% is 94 g / cm 2 . And both satisfied the specific conditions of the present invention. Note that these directions were all transverse to the film. The blocking value at a temperature 10 ° C. lower than the melting point of the linear low-density polyethylene of the outermost layer is 300 g / cm 2
As described above, the film was broken and measurement was impossible, but the specific conditions of the present invention were satisfied.
この熱収縮性フイルムを更に両端を切断して、フイル
ム幅が620mmのロール巻とし、横ピロー方式の自動包装
機により、幅250mm×長さ300mm×高さ30mmの菓子入り化
粧箱を一次包装した。尚、フイルム端部の重ね合わせ部
分は、化粧箱の裏面中央部に長さ方向と平行に幅が20mm
となる様にした。又、長さ方向の両端部は共に箱の端よ
り25mmの余裕をもたせて溶断シールした。The heat-shrinkable film was further cut at both ends to form a roll with a film width of 620 mm, and a horizontal pillow type automatic packaging machine was used to primarily package a confectionery box with a width of 250 mm x length of 300 mm x height of 30 mm. . The overlapping part of the film edge is 20mm wide at the center of the back of the dressing box, parallel to the length direction.
It was made to become. Further, both ends in the length direction were sealed by fusing with a margin of 25 mm from the end of the box.
この熱収縮前の一次包装体を、170℃に設定された収
縮トンネル内を８秒間で通過させて熱収縮二次包装を行
った。尚、熱収縮させる際には、フイルム端部の重ね合
わせ部分は下側になる様に置いた。The primary package before the heat shrinkage was passed through a shrink tunnel set at 170 ° C. for 8 seconds to perform a secondary heat shrink package. When heat shrinking, the film was placed such that the overlapping portion of the film end was on the lower side.
得られた熱収縮二次包装体は、フイルム端部の重ね合
わせ部分が密着しており、良好なる熱収縮包装仕上がり
を有していた。又、該重ね合わせ部分は、ダンボール箱
への詰め込み等の通常の取扱時には破袋しないが、開封
しようとする時には該重ね合わせ部分から容易に開封す
る事が出来た。The obtained heat-shrinkable secondary package had a good heat-shrinkable packaging finish because the overlapping portion of the film end was in close contact. The overlapped portion did not break during normal handling such as packing in a cardboard box, but could be easily opened from the overlapped portion when attempting to open.
（実施例２） プロピレンに炭素数２と４のα−オレフィンを合計で
15wt％程度共重合させた、ビカット軟化温度が78℃の共
重合体を中間層とし、ビカット軟化温度が67℃で、融点
が115℃のエチレンとブテン−１との共重合体である線
状低密度ポリエチレンを両最外層とするチューブ状共押
出し積層未延伸原反シートを、スクリュー口径が65φの
押出機（中間層用）とスクリュー口径が40φの押出機２
台（最外層用）、及び、口径が110φの三層の共押出し
用環状ダイスによって得た。尚、得られた積層未延伸原
反シートの各層の厚みは、中間層が160μ、両最外層が8
0μで、チューブ幅は180mmであった。(Example 2) Total of propylene and α-olefins having 2 and 4 carbon atoms
A linear copolymer that is a copolymer of ethylene and butene-1 having a Vicat softening temperature of 67 ° C and a melting point of 115 ° C is used as an intermediate layer with a copolymer having a Vicat softening temperature of 78 ° C copolymerized at about 15 wt%. An extruder with a screw diameter of 65φ (for the intermediate layer) and an extruder with a screw diameter of 40φ are used to form a tubular co-extruded laminated unstretched raw sheet having both outermost layers of low-density polyethylene.
It was obtained by a platform (for the outermost layer) and a three-layer co-extrusion ring die having a diameter of 110φ. The thickness of each layer of the obtained laminated unstretched raw sheet was 160 μm for the intermediate layer and 8 μm for both outermost layers.
At 0μ, the tube width was 180mm.
この積層未延伸原反シートを、従来のインフレーショ
ン方式によって、縦方向、横方向共に４倍に延伸し、そ
の後、多少の弛緩を与えながら熱固定を行い、全体厚み
が23μの熱収縮性フイルムを得た。This laminated unstretched raw sheet is stretched 4 times in both the longitudinal and transverse directions by a conventional inflation method, and then heat-set while giving some relaxation, to give a heat-shrinkable film having a total thickness of 23μ. Obtained.
得られた熱収縮性フイルムは、少なくとも一方向の最
大熱収縮力がフイルム幅10mmにつき25gであり、少なく
とも一方向の熱収縮率が５％に達する温度でのブロッキ
ング値は168g/cm2であり、共に本発明の特定条件を満た
すものであった。尚、これらの方向は共にフイルムの横
方向であった。又、最外層の直鎖状低密度ポリエチレン
の融点より10℃低い温度でのブロッキング値は280g/cm2
以上で、フイルム破断を生じてしまい測定不能であった
が、本発明の特定条件は満足するものであった。The obtained heat-shrinkable film has a maximum heat shrinkage force in at least one direction of 25 g per 10 mm of the film width, and a blocking value at a temperature at which the heat shrinkage ratio in at least one direction reaches 5% is 168 g / cm 2 . And both satisfied the specific conditions of the present invention. Note that these directions were all transverse to the film. The blocking value at a temperature 10 ° C. lower than the melting point of the linear low-density polyethylene of the outermost layer is 280 g / cm 2
As described above, the film was broken and measurement was impossible, but the specific conditions of the present invention were satisfied.
このチューブ状熱収縮性フイルムの両耳を切断して、
フイルム幅が480mmのロール巻とし、横ピロー方式の自
動包装機により、横180mm×縦260mm×厚み30mmの書籍を
一次包装した。尚、フイルム端部の重ね合わせ部分は、
書籍の裏側中央部に縦方向と平行に幅が30mmとなる様に
した。又、縦方向の両端部は共に書籍の端より25mmの余
裕をもたせて溶断シールした。Cut both ears of this tubular heat-shrinkable film,
A book with a width of 480 mm and a width of 480 mm, a length of 260 mm, and a thickness of 30 mm was primarily packaged by a horizontal pillow type automatic packaging machine. The overlapping part of the film end is
The width of the book was 30 mm parallel to the vertical direction at the center of the back side of the book. Both ends in the vertical direction were sealed by fusing with a margin of 25 mm from the end of the book.
この熱収縮前の一次包装体を、10℃に設定された収縮
トンネル内を８秒間で通過させる以外は、実施例１と同
様な方法によって熱収縮二次包装を行った。The heat-shrinkable secondary packaging was performed in the same manner as in Example 1 except that the primary package before the heat shrinkage was passed through a shrink tunnel set at 10 ° C. for 8 seconds.
得られた熱収縮二次包装体は、実施例１と同様、フイ
ルム端部の重ね合わせ部分は密着しており、良好なる熱
収縮包装仕上がりを有していた。又、該重ね合わせ部分
は、ダンボール箱への詰め込み等の通常の取扱時には破
袋しないが、開封しようとする時には該重ね合わせ部分
から容易に開封する事が出来た。The obtained heat-shrinkable secondary package had a good heat-shrinkable packaging finish, as in Example 1, with the overlapped portions of the film ends being in close contact. The overlapped portion did not break during normal handling such as packing in a cardboard box, but could be easily opened from the overlapped portion when attempting to open.
（比較例１） 中間層を融点が142℃でエチレン−プロピレン共重合
体とし、両最外層をビカット軟化温度が113℃で、融点
が123℃のエチレンと４−メチル−ペンテン−１との共
重合体である直鎖状低密度ポリエチレンとする以外は、
実施例１と同様な方法によって熱収縮性フイルムを得
た。(Comparative Example 1) The intermediate layer was an ethylene-propylene copolymer having a melting point of 142 ° C, and the outermost layers were copolymers of ethylene and 4-methyl-pentene-1 having a Vicat softening temperature of 113 ° C and a melting point of 123 ° C. Except for the polymer, a linear low-density polyethylene,
A heat-shrinkable film was obtained in the same manner as in Example 1.
得られた熱収縮性フイルムを用いて、実施例１と同
様、菓子入り化粧箱の熱収縮包装を行った。しかし、こ
の場合は、熱収縮時に一次包装体のフイルム端部の重ね
合わせ部分が開き、得られた二次包装体には皺が多く、
しかも、緊迫性に劣るものであった。又、該重ね合わせ
部分には大きな穴が開いていた。Using the obtained heat-shrinkable film, a heat-shrinkable packaging of a confectionery box was performed in the same manner as in Example 1. However, in this case, the overlapping portion of the film end of the primary package opens during heat shrinkage, and the obtained secondary package has many wrinkles,
Moreover, it was intense. Also, a large hole was opened in the overlapped portion.
尚、該熱収縮性フイルムの最大熱収縮力は、両方向と
もフイルム幅10mmにつき60gを超えるものであり、本発
明の少なくとも一方向が60g以下であると言う特定条件
を満足させるものではなかった。The maximum heat shrink force of the heat-shrinkable film exceeded 60 g per 10 mm in film width in both directions, and did not satisfy the specific condition that at least one direction of the present invention was 60 g or less.
（比較例２） 実施例２で得たと同じチューブ状共押出し積層未延伸
原反シートに、シリコーン樹脂粉末を塗布し、実施例２
と同様、インフレーション方式により熱収縮性フイルム
を得た。Comparative Example 2 A silicone resin powder was applied to the same tubular co-extruded laminated unstretched raw sheet obtained in Example 2, and
Similarly to the above, a heat-shrinkable film was obtained by an inflation method.
得られた熱収縮性フイルムを用いて、実施例２と同
様、書籍の熱収縮包装を行った。しかし、この場合は、
熱収縮時に一次包装体のフイルム端部の重ね合わせ部分
が開き、得られた二次包装体には皺が多く、しかも、緊
迫性に劣るものであった。又、該重ね合わせ部分には大
きな穴が開いていた。Using the obtained heat-shrinkable film, the book was heat-shrink-wrapped in the same manner as in Example 2. But in this case,
At the time of heat shrinkage, the overlapping portion of the film end of the primary package opened, and the obtained secondary package had many wrinkles and was inferior in tightness. Also, a large hole was opened in the overlapped portion.
尚、該熱収縮性フイルムの少なくとも一方向の熱収縮
率が５％に達する温度と、最外層の直鎖状低密度ポリエ
チレンの融点より10℃低い温度でブロッキング値は、そ
れぞれ18g/cm2と68g/cm2で、共に本発明中のこれらの特
定条件を満足させるものではなかった。In addition, the blocking value at a temperature at which the heat shrinkage of at least one direction of the heat shrinkable film reaches 5% and at a temperature 10 ° C. lower than the melting point of the linear low density polyethylene of the outermost layer is 18 g / cm 2 , respectively. At 68 g / cm 2 , neither of these conditions satisfied the specific conditions in the present invention.
Claims (1)
直鎖状低密度ポリエチレンを主体とする樹脂組成からな
り、中間層が少なくとも一層のポリプロピレン系樹脂か
らなり、しかも、フイルムの少なくとも一方向の最大熱
収縮力がフィルム幅10mmにつき60g以下で、その上、少
なくとも一方向の熱収縮率が５％に達する温度でのブロ
ッキング値と、最外層の直鎖状低密度ポリエチレンの融
点より10℃低い温度でのブロッキング値がそれぞれ40g/
cm2以上と100g/cm2以上である熱収縮性フイルム。1. Both outermost layers are made of a resin composition mainly composed of linear low-density polyethylene having a Vicat softening temperature of 105 ° C. or lower, the intermediate layer is made of at least one layer of a polypropylene resin, and in at least one direction of the film. The maximum heat shrinkage is 60 g or less per 10 mm of film width, and the blocking value at a temperature at which the heat shrinkage in at least one direction reaches 5% and the melting point of the linear low density polyethylene of the outermost layer is 10 ° C. Low temperature blocking value of 40 g / each
A heat-shrinkable film of not less than cm 2 and not less than 100 g / cm 2 .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1091579A JP2888855B2 (en) | 1989-04-10 | 1989-04-10 | Heat shrinkable film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1091579A JP2888855B2 (en) | 1989-04-10 | 1989-04-10 | Heat shrinkable film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02269046A JPH02269046A (en) | 1990-11-02 |
| JP2888855B2 true JP2888855B2 (en) | 1999-05-10 |
Family
ID=14030452
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1091579A Expired - Fee Related JP2888855B2 (en) | 1989-04-10 | 1989-04-10 | Heat shrinkable film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2888855B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5897941A (en) * | 1996-04-12 | 1999-04-27 | Cryovac, Inc. | High modulus film |
-
1989
- 1989-04-10 JP JP1091579A patent/JP2888855B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02269046A (en) | 1990-11-02 |
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