JPH0334465B2 - - Google Patents
Info
- Publication number
- JPH0334465B2 JPH0334465B2 JP59200593A JP20059384A JPH0334465B2 JP H0334465 B2 JPH0334465 B2 JP H0334465B2 JP 59200593 A JP59200593 A JP 59200593A JP 20059384 A JP20059384 A JP 20059384A JP H0334465 B2 JPH0334465 B2 JP H0334465B2
- Authority
- JP
- Japan
- Prior art keywords
- density polyethylene
- layer
- multilayer film
- ethylene
- low
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229920001684 low density polyethylene Polymers 0.000 claims description 18
- 239000004702 low-density polyethylene Substances 0.000 claims description 18
- 239000005977 Ethylene Substances 0.000 claims description 17
- 239000004711 α-olefin Substances 0.000 claims description 17
- 229920000089 Cyclic olefin copolymer Polymers 0.000 claims description 16
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 16
- 229920001903 high density polyethylene Polymers 0.000 claims description 12
- 239000004700 high-density polyethylene Substances 0.000 claims description 12
- 229920000573 polyethylene Polymers 0.000 claims description 7
- 239000011342 resin composition Substances 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 4
- 229920000642 polymer Polymers 0.000 claims 1
- 238000000034 method Methods 0.000 description 9
- 238000007789 sealing Methods 0.000 description 9
- 238000004806 packaging method and process Methods 0.000 description 7
- 229920005989 resin Polymers 0.000 description 5
- 239000011347 resin Substances 0.000 description 5
- 229920001577 copolymer Polymers 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 239000003337 fertilizer Substances 0.000 description 2
- 229920006262 high density polyethylene film Polymers 0.000 description 2
- 239000005022 packaging material Substances 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- AFFLGGQVNFXPEV-UHFFFAOYSA-N 1-decene Chemical compound CCCCCCCCC=C AFFLGGQVNFXPEV-UHFFFAOYSA-N 0.000 description 1
- LIKMAJRDDDTEIG-UHFFFAOYSA-N 1-hexene Chemical compound CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 description 1
- UPZFLZYXYGBAPL-UHFFFAOYSA-N 2-ethyl-2-methyl-1,3-dioxolane Chemical compound CCC1(C)OCCO1 UPZFLZYXYGBAPL-UHFFFAOYSA-N 0.000 description 1
- WSSSPWUEQFSQQG-UHFFFAOYSA-N 4-methyl-1-pentene Chemical compound CC(C)CC=C WSSSPWUEQFSQQG-UHFFFAOYSA-N 0.000 description 1
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 241000209140 Triticum Species 0.000 description 1
- 235000021307 Triticum Nutrition 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 1
- 229920006244 ethylene-ethyl acrylate Polymers 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 229920000092 linear low density polyethylene Polymers 0.000 description 1
- 239000004707 linear low-density polyethylene Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- YWAKXRMUMFPDSH-UHFFFAOYSA-N pentene Chemical compound CCCC=C YWAKXRMUMFPDSH-UHFFFAOYSA-N 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 229920006163 vinyl copolymer Polymers 0.000 description 1
Landscapes
- Laminated Bodies (AREA)
Description
本発明は多層フイルムに関し、詳しくは、機械
的強度、特に低温耐衝撃性にすぐれ、薄肉化が可
能であり、しかもヒートシール性、耐ブロツキン
グ性などの性質にすぐれた多層フイルムに関す
る。
従来、肥料、米、麦などの重量物包装材として
は、低密度ポリエチレンフイルムや高密度ポリエ
チレンフイルムが用いられている。しかし、高圧
法低密度ポリエチレンフイルムは機械的強度が小
さいため厚肉としなければならず、また高密度ポ
リエチレンフイルムは引裂強度が十分でなく、し
かもシール性や突起物に対する強さに問題がある
と共に、外観上も好ましいものではない。このた
め、これらポリエチレンフイルムの欠点を解消す
るためゴム類などを添加する方法などが提案され
ている。しかしながら、このフイルムはシール性
は向上するものの機械的強度や外観の点で問題が
あるなど、包装材料として総合的にみた場合十分
なものではなかつた。
そこで、上述のポリエチレンフイルムの問題点
を解消する目的で、また特に省資源の立場からの
薄肉化の要請に対して近時二層ないし三層からな
る種々の多層フイルムが提案されている。例え
ば、(1)低密度ポリエチレンよりなる層と高密度ポ
リエチレンよりなる層を積層したフイルム、(2)高
密度ポリエチレンとエチレン・α−オレフイン共
重合体とを混合した樹脂よりなる層と低密度ポリ
エチレンよりなる層を積層したフイルムあるいは
(3)高密度ポリエチレンを中間層として、この両面
に外層としての低密度ポリエチレン層を積層して
なる三層積層フイルムなどがある。
しかしながら、(1)のフイルムでは機械的強度や
外観上は特に支障はないが、シール性、パンクチ
ヤー強度、実用落下強度など必ずしも満足できる
ものではない。さらに、(2)のフイルムでは剛性が
十分でなく、また自動包装に適さず、しかも内層
を低密度ポリエチレン層とする袋を製造した場
合、シール性が不足すると共に外観が劣るという
欠点がある。(3)のフイルムは光学的性質にすぐれ
ているものの、パンクチヤー強度や重量物包装に
おけるシール性が不足するという欠点がある。
そこで、本願出願人はこのような従来の問題点
を解消するものとして、既に高密度ポリエチレン
100重量部とエチレン・α−オレフイン共重合体
10〜100重量部を配合してなる樹脂組成物よりな
る中間層に、エチレン・α−オレフイン共重合体
よりなる外層を両面に積層してなる積層フイルム
を提案している（特開昭59−11252号）。
この積層フイルムは数々のすぐれた特徴を有す
るものであるが、厳しい寒冷地での使用や冷蔵物
品の包装などにおいて低温落下強度に限界があ
り、その使用が制限される虞れがあつた。
本発明は上記問題点の改良された多層フイルム
の提供を目的とするものである。
すなわち本発明は、少なくとも三層からなる多
層フイルムにおいて、密度0.900〜0.940ｇ／cm3の
直鎖状エチレン・α−オレフイン共重合体55〜90
重量％と高密度ポリエチレン45〜10重量％とから
なる樹脂組成物よりなる層を中間層とし、両外層
の少なくとも一層を、直鎖状エチレン・α−オレ
フイン共重合体と高圧法低密度ポリエチレンとの
混合物からなる密度0.900〜0.940ｇ／cm3のエチレ
ン系重合体よりなる層としたことを特徴とする多
層フイルムを提供するものである。
本発明の多層フイルムにおいて中間層として
は、上記の如く直鎖状エチレン・α−オレフイン
共重合体と高密度ポリエチレンとの樹脂組成物が
用いられる。
ここで直鎖状エチレン・α−オレフイン共重合
体は中・低圧法で得られる直鎖状低密度ポリエチ
レンであり、密度0.900〜0.940ｇ／cm3、好ましく
は0.905〜0.930ｇ／cm3、メルトインデツクス
（MI）が0.1〜20ｇ／10分、好ましくは0.2〜10
ｇ／10分のものが用いられる。なお、この共重合
体中のα−オレフイン含量は通常１〜20重量％で
あり、α−オレフインとしては炭素数３〜20個の
ものが用いられ、具体的にはプロピレン、ブテン
−１、ペンテン−１、ヘキセン−１、４−メチル
ペンテン−１、オクテン−１、ノネン−１、デセ
ン−１などを挙げることができる。
また、高密度ポリエチレンは密度0.945〜0.970
ｇ／cm3、好ましくは0.948〜0.965ｇ／cm3、MI0.01
〜20ｇ／10分、好ましくは0.02〜10ｇ／10分のも
のが用いられる。
中間層たる樹脂組成物の配合割合は、直鎖状エ
チレン・α−オレフイン共重合体55〜90重量％に
対し、高密度ポリエチレン45〜10重量％、好まし
くは前者60〜85重量％に対し、後者40〜15重量％
であり、多層フイルムの使用目的などを考慮して
適宜決定すればよい。ここで直鎖状エチレン・α
−オレフイン共重合体の配合量が55重量％未満で
あると、耐低温衝撃性が劣り、また90重量％を超
えると、剛性が低下し、自動充填特性が悪化する
ので好ましくない。
本発明の多層フイルムにおける中間層は、基本
的には上記の直鎖状エチレン・α−オレフイン共
重合体および高密度ポリエチレンよりなるもので
あるが、さらに必要により高圧法低密度ポリエチ
レン、エチレン−酢酸ビニル共重合体などの他の
樹脂を加えてもよい。ここで高圧法低密度ポリエ
チレンとしては密度0.910〜0.940ｇ／cm3、好まし
くは0.915〜0.930ｇ／cm3、MI0.05〜20.0ｇ／10分、
好ましくは0.1〜10ｇ／10分のものが適当である。
次に、本発明の多層フイルムにおける両外層、
すなわち前記中間層の内層および外層はエチレン
系重合体よりなるものである。ここでエチレン系
重合体は、直鎖状エチレン・α−オレフイン共重
合体と高圧法低密度ポリエチレンからなる密度
0.900〜0.940ｇ／cm3のものである。ここで直鎖状
エチレン・α−オレフイン共重合体は前記中間層
を構成する直鎖状エチレン・α−オレフイン共重
合体と同様の密度、MIを有し、炭素数３〜20個
のα−オレフインのものが用いられ、中間層で用
いたものと同一のものを使用してもよく、或いは
異なつたものを使用してもよい。
また、高圧法低密度ポリエチレンとしても前記
したものが用いられる。すなわち、密度0.910〜
0.940ｇ／cm3、好ましくは0.915〜0.930ｇ／cm3、
MI0.05〜20.0ｇ／10分、好ましくは0.1〜10ｇ／
10分のものが適当である。この両外層に用いられ
る高圧法低密度ポリエチレンとしては、前記の中
間層に必要により配合されたものと同一のものを
使用してもよく、或いは異なつたものを使用して
もよい。
上記のように、この両外層には直鎖状エチレ
ン・α−オレフイン共重合体と高圧法低密度ポリ
エチレンの混合物が好ましく用いられるが、両者
は通常、前者：後者＝30〜99：70〜１、好ましく
は50〜98：50〜２の割合で混合される。
また、両外層に用いられるエチレン系重合体は
全く同一のもの、すなわち全く同一の密度やMI
を有するものを同じ組合せで用いてもよいし、或
いはこれらのうち６いずれかまたは全部を変えた
全く異なつたものを用いてもよい。
なお、両外層、すなわち前記中間層の内層およ
び外層のいずれか一層にのみ高圧法低密度ポリエ
チレンを使用する場合、換言すれば高圧法低密度
ポリエチレンを配合した樹脂組成物よりなる層
を、内層および外層のいずれか一層にのみ使用す
る場合、この層を内層とすることがインフレーシ
ヨン法により成形する際には好ましい。また、高
圧法低密度ポリエチレンを内層および外層のいず
れにも使用する場合、外層より内層により多く配
合することが好ましい。
本発明の多層フイルムは少なくとも三層からな
り、上記中間層および両外層のほかに他の層を積
層させることもできる。例えば低密度ポリエチレ
ン、高密度ポリエチレン、エチレン系共重合体
（例えば、エチレン・酢酸ビニル共重合体、エチ
レン・アクリル酸エチル共重合体などのエチレ
ン・不飽和エステル共重合体等）などよりなる樹
脂層を必要により適当な位置（中間層と外層の
間、外層の外側）に重ねて積層することもでき
る。
本発明の多層フイルムが上記した内層および外
層ならびに中間層の三層からなるものである場
合、各層の層厚比は通常、内層：中間層：外層＝
２〜60：96：〜10：２〜60、好ましくは５〜50：
90〜15：５〜50、より好ましくは10〜50：80〜
20：10〜50である。ここで内層および外層の厚さ
が増すと相対的に中間層が薄くなり、多層フイル
ムの機械的強度が低下する。一方、内層および外
層の厚さが極端に薄いとシール強度が低下して好
ましくない。多層フイルムの厚みは特に制限はな
く、全体の厚みが10〜300μ、好ましくは20〜
200μ程度とする。
本発明の多層フイルムはインフレーシヨン法、
Ｔ−ダイ法など種々の方法で製造することができ
るが、特に包装用袋としての用途を考慮して以下
の方法により製造することが望ましい。
まず、上記した各層を構成する成分を溶融混練
等により混練し、これらを共押出ダイ内接着イン
フレーシヨン法により成形して目的とする多層フ
イルムを製造する。この場合、ブロー比は通常１
〜７、好ましくは1.2〜５でインフレーシヨン成
形を行なう。
本発明の多層フイルムは、引張強度、引裂強
度、衝撃強度などの機械的強度が大きく、特に低
温耐衝撃性にすぐれたものである。さらに、従来
のものよりも薄肉化が可能であるため安価に製造
することができ、しかも省資源にも寄与するもの
である。また、表面特性も良好であつて、ヒート
シール性が良好で、シール強度が高く、しかもシ
ール収縮も小さいため、シール外観に縮みなどは
みられない。また、夾雑物シール性も良好である
ため、粉体含有物などの包装袋として有用であ
る。さらに、耐ブロツキング性が良好であり、開
口性にすぐれている。しかも、剛性にもすぐれて
いるので、自動充填特性も良好である。また、内
外層に用いる樹脂を適宜選択することにより、使
用目的に最適な表面特性を有するフイルムを得る
ことができる。
したがつて、本発明の多層フイルムは包装用、
特に重量物包装用資材として極めて有用である。
次に、本発明の実施例を示す。
実施例１〜５および比較例１〜２
中間層および両外層（内層、外層）を構成する
第１表に示した所定の原料樹脂（重量部）を径40
mmφの３台の押出機によりそれぞれ溶融混練し、
ダイ内接着型のサーキユラー・ダイ（ダイ径200
mmφ、リツプ間隙２mm、ダイ温度180℃）に導入
して押出し、ブロー比1.7にてインフレーシヨン
成形して厚み140μの多層フイルムを得た。
このようにして得られた多層フイルムの各種物
性試験などの評価結果を第１表に示す。なお、試
験法は次の方法に準拠して行なつた。
引張特性 JIS Ｚ 1702
引裂強度 JIS Ｚ 1702
パンクチヤー強度 JIS Ｐ 8134
低温落下試験 440mm×660mmの袋に化成肥料20
Kgを充填し、200℃でヒートシールした後、−10
℃にて10時間養生後、所定の高さよりコンクリ
ート床に落下させ破袋を観察した。
○……破袋なし
△……破袋50％以下
×……破袋50％以上
The present invention relates to a multilayer film, and more particularly to a multilayer film that has excellent mechanical strength, particularly low-temperature impact resistance, can be made thin, and has excellent properties such as heat sealability and blocking resistance. Conventionally, low-density polyethylene films and high-density polyethylene films have been used as packaging materials for heavy items such as fertilizer, rice, and wheat. However, high-pressure low-density polyethylene film has low mechanical strength, so it must be made thick, and high-density polyethylene film does not have sufficient tear strength, and has problems with sealing performance and strength against protrusions. , which is not desirable in terms of appearance. Therefore, in order to eliminate these drawbacks of polyethylene films, methods of adding rubbers and the like have been proposed. However, although this film improves sealing performance, it has problems in mechanical strength and appearance, and is not sufficient as a packaging material overall. Therefore, in order to solve the above-mentioned problems with polyethylene films, and especially in response to the demand for thinner films from the standpoint of resource conservation, various multilayer films having two or three layers have recently been proposed. For example, (1) a film made of a layer made of low-density polyethylene and a layer made of high-density polyethylene, (2) a layer made of a resin made of a mixture of high-density polyethylene and an ethylene/α-olefin copolymer, and a layer made of low-density polyethylene. A film made of laminated layers or
(3) There are three-layer laminated films made of high-density polyethylene as an intermediate layer and low-density polyethylene layers as outer layers on both sides. However, although the film (1) has no particular problems in terms of mechanical strength or appearance, it is not necessarily satisfactory in terms of sealability, puncture strength, and practical drop strength. Furthermore, the film (2) does not have sufficient rigidity and is not suitable for automatic packaging, and furthermore, when a bag is manufactured with a low-density polyethylene layer as the inner layer, there are drawbacks such as insufficient sealing performance and poor appearance. Although the film (3) has excellent optical properties, it has drawbacks such as insufficient puncture strength and sealing performance for packaging heavy items. Therefore, the applicant has already developed high-density polyethylene as a solution to these conventional problems.
100 parts by weight and ethylene/α-olefin copolymer
proposed a laminated film in which an outer layer made of an ethylene/α-olefin copolymer was laminated on both sides of an intermediate layer made of a resin composition containing 10 to 100 parts by weight (Japanese Patent Application Laid-Open No. 1983-1983). No. 11252). Although this laminated film has many excellent features, there is a limit to its low-temperature drop strength when used in severely cold regions or when packaging refrigerated items, which may limit its use. The object of the present invention is to provide a multilayer film that has improved the above-mentioned problems. That is, the present invention provides a multilayer film consisting of at least three layers, in which a linear ethylene/α-olefin copolymer having a density of 0.900 to 0.940 g/cm 3 is used.
The intermediate layer is a layer made of a resin composition consisting of 45 to 10% by weight of high-density polyethylene and 45 to 10% by weight of high-density polyethylene, and at least one of both outer layers is made of a linear ethylene/α-olefin copolymer and high-pressure low-density polyethylene. The present invention provides a multilayer film characterized in that the layer is made of an ethylene polymer having a density of 0.900 to 0.940 g/cm 3 and made of a mixture of the following. In the multilayer film of the present invention, as the intermediate layer, a resin composition of a linear ethylene/α-olefin copolymer and high-density polyethylene is used as described above. Here, the linear ethylene/α-olefin copolymer is a linear low density polyethylene obtained by a medium/low pressure method, and has a density of 0.900 to 0.940 g/cm 3 , preferably 0.905 to 0.930 g/cm 3 , and a melt Index (MI) is 0.1~20g/10min, preferably 0.2~10
g/10 minutes is used. The α-olefin content in this copolymer is usually 1 to 20% by weight, and α-olefins having 3 to 20 carbon atoms are used, specifically propylene, butene-1, pentene, etc. -1, hexene-1, 4-methylpentene-1, octene-1, nonene-1, decene-1, and the like. Also, high density polyethylene has a density of 0.945 to 0.970.
g/ cm3 , preferably 0.948-0.965g/ cm3 , MI0.01
~20g/10min, preferably 0.02~10g/10min is used. The blending ratio of the resin composition for the intermediate layer is 55-90% by weight of the linear ethylene/α-olefin copolymer and 45-10% by weight of high-density polyethylene, preferably 60-85% by weight of the former. The latter 40-15% by weight
It may be determined as appropriate, taking into consideration the purpose of use of the multilayer film. Here, linear ethylene α
- If the amount of the olefin copolymer is less than 55% by weight, the low-temperature impact resistance will be poor, and if it exceeds 90% by weight, the rigidity will decrease and the automatic filling characteristics will deteriorate, which is not preferred. The intermediate layer in the multilayer film of the present invention basically consists of the above-mentioned linear ethylene/α-olefin copolymer and high-density polyethylene, but if necessary, high-pressure low-density polyethylene, ethylene-acetic acid Other resins such as vinyl copolymers may also be added. Here, the high pressure low density polyethylene has a density of 0.910 to 0.940 g/cm 3 , preferably 0.915 to 0.930 g/cm 3 , an MI of 0.05 to 20.0 g/10 min,
Preferably, 0.1 to 10 g/10 minutes is appropriate. Next, both outer layers in the multilayer film of the present invention,
That is, the inner layer and outer layer of the intermediate layer are made of an ethylene polymer. Here, the ethylene polymer is composed of linear ethylene/α-olefin copolymer and high-pressure low-density polyethylene.
It is 0.900 to 0.940 g/cm 3 . Here, the linear ethylene/α-olefin copolymer has the same density and MI as the linear ethylene/α-olefin copolymer constituting the intermediate layer, and has 3 to 20 carbon atoms. An olefin is used, and it may be the same as that used in the intermediate layer, or a different one may be used. Furthermore, the above-described materials can be used as the high-pressure low-density polyethylene. That is, density 0.910~
0.940g/ cm3 , preferably 0.915-0.930g/ cm3 ,
MI0.05~20.0g/10min, preferably 0.1~10g/
10 minutes is appropriate. The high-pressure low-density polyethylene used in both outer layers may be the same as that blended into the intermediate layer, or a different one may be used. As mentioned above, a mixture of a linear ethylene/α-olefin copolymer and a high-pressure low-density polyethylene is preferably used for both outer layers, but the ratio of the former to the latter is usually 30 to 99:70 to 1. , preferably in a ratio of 50-98:50-2. In addition, the ethylene polymers used for both outer layers are exactly the same, that is, they have exactly the same density and MI.
The same combination of six may be used, or completely different ones may be used in which any or all of six of them are changed. In addition, when high-pressure low-density polyethylene is used only in both outer layers, that is, either the inner layer or the outer layer of the intermediate layer, in other words, a layer made of a resin composition containing high-pressure low-density polyethylene is used as the inner layer and When used in only one of the outer layers, it is preferable to use this layer as the inner layer when molding by the inflation method. Furthermore, when high-pressure low-density polyethylene is used for both the inner layer and the outer layer, it is preferable to blend it in a larger amount in the inner layer than in the outer layer. The multilayer film of the present invention is composed of at least three layers, and other layers may be laminated in addition to the above-mentioned intermediate layer and both outer layers. For example, a resin layer made of low-density polyethylene, high-density polyethylene, ethylene-based copolymers (e.g., ethylene-unsaturated ester copolymers such as ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, etc.) If necessary, they can be laminated at appropriate positions (between the intermediate layer and the outer layer, outside the outer layer). When the multilayer film of the present invention is composed of the above-described three layers, ie, the inner layer, the outer layer, and the intermediate layer, the thickness ratio of each layer is usually inner layer:intermediate layer:outer layer=
2-60:96:-10:2-60, preferably 5-50:
90-15:5-50, more preferably 10-50:80-
20:10-50. Here, when the thicknesses of the inner layer and the outer layer increase, the intermediate layer becomes relatively thinner, and the mechanical strength of the multilayer film decreases. On the other hand, if the inner layer and outer layer are extremely thin, the sealing strength will decrease, which is undesirable. The thickness of the multilayer film is not particularly limited, and the total thickness is 10 to 300μ, preferably 20 to 300μ.
It should be about 200μ. The multilayer film of the present invention is produced by the inflation method,
Although it can be manufactured by various methods such as the T-die method, it is preferable to manufacture it by the following method, especially considering the use as a packaging bag. First, the components constituting each layer described above are kneaded by melt kneading or the like, and then molded by a coextrusion die adhesion inflation method to produce the desired multilayer film. In this case, the blow ratio is usually 1
Inflation molding is carried out at a temperature of 7 to 7, preferably 1.2 to 5. The multilayer film of the present invention has high mechanical strengths such as tensile strength, tear strength, and impact strength, and has particularly excellent low-temperature impact resistance. Furthermore, since it can be made thinner than conventional products, it can be manufactured at low cost and also contributes to resource saving. In addition, the surface properties are good, the heat sealability is good, the sealing strength is high, and the sealing shrinkage is small, so that no shrinkage is observed in the seal appearance. Furthermore, since it has good contaminant sealing properties, it is useful as a packaging bag for powder-containing materials. Furthermore, it has good blocking resistance and excellent opening properties. Moreover, since it has excellent rigidity, it also has good automatic filling characteristics. In addition, by appropriately selecting the resins used for the inner and outer layers, a film having surface characteristics optimal for the intended use can be obtained. Therefore, the multilayer film of the present invention can be used for packaging,
It is particularly useful as a material for packaging heavy goods. Next, examples of the present invention will be shown. Examples 1 to 5 and Comparative Examples 1 to 2 Predetermined raw material resins (parts by weight) shown in Table 1 constituting the intermediate layer and both outer layers (inner layer, outer layer) were
Melt and knead using three mmφ extruders,
In-die adhesive circular die (Die diameter 200
mmφ, lip gap of 2 mm, die temperature of 180° C.) and extruded, and inflation molding was performed at a blow ratio of 1.7 to obtain a multilayer film with a thickness of 140 μm. Table 1 shows the evaluation results of various physical property tests of the multilayer film thus obtained. The test method was conducted in accordance with the following method. Tensile properties JIS Z 1702 Tear strength JIS Z 1702 Puncture strength JIS P 8134 Low temperature drop test Compound fertilizer 20 in a 440mm x 660mm bag
After filling Kg and heat sealing at 200℃, −10
After curing at ℃ for 10 hours, the bags were dropped from a predetermined height onto a concrete floor and the bags were observed for breakage. ○...No bag breakage△...Bag breakage of 50% or less ×...Bag breakage of 50% or more
【表】【table】
【表】【table】
Claims (1)
て、密度0.900〜0.940ｇ／cm3の直鎖状エチレン・
α−オレフイン共重合体55〜90重量％と高密度ポ
リエチレン45〜10重量％とからなる樹脂組成物よ
りなる層を中間層とし、両外層の少なくとも一層
を、直鎖状エチレン・α−オレフイン共重合体と
高圧法低密度ポリエチレンとの混合物からなる密
度0.900〜0.940ｇ／cm3のエチレン系重合体よりな
る層としたことを特徴とする多層フイルム。1 In a multilayer film consisting of at least three layers, linear ethylene with a density of 0.900 to 0.940 g/cm 3
The intermediate layer is a layer made of a resin composition consisting of 55 to 90% by weight of α-olefin copolymer and 45 to 10% by weight of high-density polyethylene, and at least one of the outer layers is composed of linear ethylene/α-olefin copolymer. A multilayer film comprising a layer made of an ethylene polymer having a density of 0.900 to 0.940 g/cm 3 and made of a mixture of a polymer and high-pressure low density polyethylene.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20059384A JPS6178644A (en) | 1984-09-27 | 1984-09-27 | Multilayer film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20059384A JPS6178644A (en) | 1984-09-27 | 1984-09-27 | Multilayer film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6178644A JPS6178644A (en) | 1986-04-22 |
| JPH0334465B2 true JPH0334465B2 (en) | 1991-05-22 |
Family
ID=16426927
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20059384A Granted JPS6178644A (en) | 1984-09-27 | 1984-09-27 | Multilayer film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6178644A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3091069B2 (en) * | 1992-12-28 | 2000-09-25 | 三井化学株式会社 | Resin laminate and its use |
| JP4140989B2 (en) * | 1997-04-09 | 2008-08-27 | ダイセル化学工業株式会社 | Composite film and manufacturing method thereof |
| JPH11147294A (en) * | 1997-11-19 | 1999-06-02 | Dainippon Printing Co Ltd | Chemical-resistant laminated film and paper container composed of laminated body thereof |
| JP4700230B2 (en) * | 2001-07-17 | 2011-06-15 | 花王株式会社 | bag |
| JP6035765B2 (en) * | 2012-02-15 | 2016-11-30 | 凸版印刷株式会社 | Self-supporting packaging bag |
| JP6496981B2 (en) * | 2014-03-28 | 2019-04-10 | 凸版印刷株式会社 | Sealant film, and film laminate and standing pouch using the same |
| JP6690467B2 (en) * | 2016-08-25 | 2020-04-28 | 日本ポリエチレン株式会社 | Coextruded film and multilayer coextruded laminate |
| AR112245A1 (en) * | 2017-06-30 | 2019-10-09 | Dow Global Technologies Llc | LAMINATES AND MULTILAYER POLYETHYLENE FILMS FOR USE IN FLEXIBLE PACKAGING MATERIALS |
| JP7310445B2 (en) * | 2018-09-12 | 2023-07-19 | 東ソー株式会社 | Polyethylene resin composition, laminate and medical container |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5911252A (en) * | 1982-07-12 | 1984-01-20 | 出光石油化学株式会社 | Laminated film |
-
1984
- 1984-09-27 JP JP20059384A patent/JPS6178644A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5911252A (en) * | 1982-07-12 | 1984-01-20 | 出光石油化学株式会社 | Laminated film |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6178644A (en) | 1986-04-22 |
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