JP4043598B2 - Gas barrier multilayer heat seal film and bag body using the same - Google Patents

Description

【００２５】
表１に示したＡ〜Ｆの各層の樹脂組成物は次のとおりである。
・Ａ 密度０．９１５ｇ／ｃｍ³ ＭＦＲ４．０ｇのＬＬＤＰＥ：密度０．９１５ｇ／ｃｍ³ 、ＭＦＲ１０．０ｇのＬＬＤＰＥ＝１：１の組成物
・Ｂ 密度０．８９５ｇ／ｃｍ³ 、ＭＦＲ１．６ｇのＬＬＤＰＥ
・Ｃ 密度０．９１５ｇ／ｃｍ³ ＭＦＲ４．０ｇのＬＬＤＰＥ
・Ｄ ＭＦＲ１．６ｇの酸無水物グラフト重合ポリエチレン
・Ｅ エチレン含有率 ３８モル％、ＭＦＲ１．６ｇのＥＶＯＨ
・Ｆ 密度０．９２０ｇ／ｃｍ³ 、ＭＦＲ１．６ｇのＬＤＰＥ
・Ｎ 密度１．１４０ｇ／ｃｍ³ 、ナイロン６とナイロン６６の共重合体
また、ドライは、ドライラミネーションを、そしてサンドは、ＬＤＰＥを接着性樹脂層としたサンドイッチラミネーションによる貼合である。
【００２６】
実施例１〜３及び比較例１〜４で作成したバリア性多層ＨＳフィルム１０の成膜キャリア層６と、厚みが２０μｍの二軸延伸延伸ポリプロピレン（基材フィルム８）にウレタン系２液反応接着剤６を塗工した面（接着剤層６）とを貼合して、図２に示す積層フィルム１５、又は図３に示すようにプライマー層６１を介して低密度ポリエチレンを接着樹脂６２としたサンドイッチラミネーションによる積層フィルム１６を作成した。
【００２７】
実施例及び比較例の成膜適性、成膜の安定性や、酸素透過度、ヒートシール開始温度、はく離強度、製袋適性の評価となるＨＳ層の滑りを評価した。
次いで、積層フィルム１５を用いて、図４に示すように内部折込み部９１、外部折曲げ部９２及びヒートシール部９５、折込み巾９３が１５ｍｍの縦×横＝３００×１５０ｍｍ² 、ヒートシール巾１０ｍｍのガセット袋（袋体９０）を作成し、製袋適性（及び折込み部のピンホール発生の有無）を評価した。その評価結果を表２に示す。
【００２８】
【表２】
評価結果

【００２９】
表２に示す各測定項目の評価法は、以下に示すとおりである。
（評価方法）
・成膜適性
成膜時における流れムラの発生頻度及びバルーンの安定性を目視により総合的に評価した。
・酸素透過度
ＪＩＳ Ｋ７１２６ Ｂ法（等圧法）に準拠してＭＯＤＥＲＮ ＣＯＮＴＲＯＬ ＩＮＣ．社製 ＯＸ−ＴＲＡＮ２／２０を用いて、２３℃、相対湿度６５％の条件で酸素透過量（ｃｃ／ａｔｍ・ｍ² ２４ｈ）を測定した。
・ヒートシール（ＨＳ）開始温度
積層フィルムのＨＳ層を相対して、圧力１ｋｇ／ｃｍ² ×１ｓｅｃの条件で１０ｍｍ巾にヒートシールした後、１５ｍｍ巾でヒートシール方向に垂直に断裁し、そのはく離強度を、はく離速度３００ｍｍ／ｍｉｎで測定し、その強度が２Ｋｇ／１５ｍｍとなるときの温度をヒートシール（ＨＳ）開始温度とした。
・はく離強度
上記の条件で１５０℃で測定したときの１５ｍｍ巾においてはく離強度を測定した。
・フィルムの外観
上記の樹脂組成物で１０時間の成膜を続け、ゲルの発生頻度、及びフィルムの透明性（ＪＩＳ Ｋ７１０５ー１９８１）から総合的に評価した。
・動摩擦係数
積層フィルムのＨＳ層のステンレス面に対する滑りをＪＩＳ Ｋ７２１４ー１９８７に準じて測定した。
・製袋適性（密封性）
積層フィルムを縦型のピロータイプの製袋機で製袋を行った後、袋体中にピンホールチェック液（アルコール可溶性染料をオクチルアルコールに溶解し、着色した試験液）を注入し、シール部への滲透の有無を確認した。
評価基準
◎ 非常に良好である。
○ 良好であり、実用性に全く問題なし。
△ 若干の問題はあるが、用途を選択して実用できる。
× 欠点が多く実用性はない。
【００３０】
【発明の効果】
以上詳細に説明したように、本発明のバリア性多層ＨＳフィルムは、ヒートシールに安定した性能をもつＬＬＤＰＥとプラストマ層とからなるＨＳ層を１５μｍ以上に構成している。そして、安定した成膜性をもつ成膜キャリア層とエチレン含有率が少ないＥＶＯＨとからなる多層共押出しフィルムの成膜を安定して行えるようにしたものである。そして、ヒートシールに安定した性能をもつＬＬＤＰＥをＨＳ面として、更にプラストマ層を含んで１５μｍ以上の厚みに構成した、バリア性多層ＨＳフィルムは、比較例のものと比較して成膜適性、バリア性、密封性及び製袋適性のバランスがとれた共押出しフィルムを提供できる効果を奏する。
【図面の簡単な説明】
【図１】バリア性多層ＨＳフィルムの断面の概念を示す図である。
【図２】バリア性多層ＨＳフィルムを用いて貼合した積層フィルムの断面の概念を示す図である。
【図３】バリア性多層ＨＳフィルムを用いて貼合した他の形態の積層フィルムの断面の概念を示す図である。
【図４】バリア性多層ＨＳフィルムの積層フィルムから形成したピロー袋体の概念を示す斜視図である。
【符号の説明】
１ ＨＳ層
２ ＬＬＤＰＥ
３ プラストマ層
４ バリア層
５ 成膜キャリア層
６ 接着剤層
７ 絵柄層
８ 基材フィルム
１０ バリア性多層ＨＳフィルム
１５、１６ 積層フィルム
２１、２２ 接着性樹脂層
６１ プライマー層
６２ 接着樹脂
９０ 袋体
９１ 内部折込み部
９２ 外部折曲げ部
９３ 折込み巾
９５ ヒートシール部[0001]
BACKGROUND OF THE INVENTION
An ethylene-vinyl alcohol copolymer that forms a gas barrier layer of water vapor, especially oxygen, etc. in a laminated film for bags that can be heat-sealed. , EVOH)), a multilayer coextruded film excellent in bending resistance using a gas barrier heat-seal multilayer film (hereinafter referred to as a barrier multilayer HS film) and a bag body using the same .
[0002]
[Prior art]
A flexible packaging film based on a plastic film has been widely used for a bag body excellent in heat-sealability and required to be sealed. And a bag body excellent in water vapor barrier properties (hereinafter referred to as moisture proof) and gas barrier properties such as oxygen (hereinafter simply referred to as barrier properties) allows moisture to permeate through the bag and absorb and desorb moisture. In addition, it has been difficult to avoid alteration of the contents due to oxidation by an active gas such as oxygen. In order to prevent deterioration due to moisture, a multilayer film comprising a stretched plastic film and a polyolefin such as polyethylene and polypropylene as a heat sealant layer (hereinafter referred to as HS layer) has been used. And when better moisture resistance is required, from films with excellent moisture resistance, such as aluminum foil, plastic films deposited with metal aluminum and silicon oxide, and laminated films with films coated with vinylidene chloride A bag was used. Further, in the case of contents that want to avoid moisture, a hygroscopic agent such as silica or calcium oxide is also enclosed in the bag, which is once satisfied as a bag having moisture resistance.
[0003]
When the contents are altered by gas, especially oxygen gas, the above polyolefin is used as an HS layer, and a film having excellent barrier properties as a barrier layer, for example, EVOH, modified polyamide, aluminum foil, metal aluminum or silicon oxide vapor deposited plastic The bag body which consists of a laminated film which bonded the film and the film which coated polyvinyl alcohol and vinylidene chloride was used. And, for the purpose of preventing deterioration due to oxygen gas remaining in the bag body, “vacuum packaging” from which gas has been removed, “gas replacement packaging” in which oxygen is replaced with an inert gas such as carbon dioxide gas, or oxygen gas is absorbed. The so-called “oxygen scavenger” was enclosed in a bag.
[0004]
However, vinylidene chloride constituting the barrier layer is not necessarily a preferable packaging material because there is a concern of air pollution by chlorine compounds when packaging materials are incinerated and discarded, and there is a problem of cost of removing pollutants. is there.
In addition, since laminates bonded with plastic films deposited with aluminum foil, metal aluminum or silicon oxide are inferior in malleability compared to plastic films, the above materials have pinholes at the bent and bent portions. In addition to being unable to maintain the initial barrier properties, the contents are not visible. In addition, although vapor deposition films are relatively difficult to generate pinholes, they are inferior to plastic films, and thin films that require vapor deposition suitability are heat stable, thick and thin. There were restrictions such as accuracy and dimensional stability. In particular, a pillow type gusset bag or a purse-like packaging bag having a twisted portion has a problem that pinholes are likely to occur in the deposited film.
[0005]
Laminated films including polyvinyl alcohol films exhibit excellent barrier properties when dried, but are poor in bending resistance and easily generate pinholes, and the barrier properties are significantly reduced due to moisture under high humidity. was there. EVOH is a material that is less susceptible to moisture than a polyvinyl alcohol film. However, oxygen permeability is significantly affected by the copolymerization ratio of ethylene. For example, the oxygen permeability at 20 ° C. of EVOH having a copolymerization ratio of ethylene of 32 mol% is 0.3 to 0.5 cc · 20 μm / m ² · 24 h · atm, and the copolymerization ratio of ethylene is 47 mol%. The EVOH is 4.5 to 5.3 cc · 20 μm / m ² · 24 h · atm. Therefore, when EVOH with a low ethylene content is used, which is a grade with excellent gas barrier properties, pinholes are generated due to bending and heating / pressure of the heat-sealed parts, as with polyvinyl alcohol, and the barrier properties decrease accordingly. It was difficult to avoid the problem of being easy.
[0006]
The above EVOH is a resin that easily undergoes thermal decomposition. For example, when a film is coextruded with another resin by the T-die method, it decomposes at high temperatures to form a carbide or for a gel-like material. It tends to cause poor appearance. Further, at the EVOH film formation temperature, the viscosity of the linear polyethylene (hereinafter referred to as LLDPE) serving as the HS layer was remarkably reduced, and the film formation was not stable. On the other hand, there is a problem that unevenness occurs in the flow of the resin at a low temperature in accordance with the processing suitability of the resin of the HS layer, and unevenness in the stripe shape occurs in the flow direction of the film formation.
In addition, when a film is formed by a circular die method (inflation method), when a multi-layer film is formed using LLDPE having excellent heat sealability as an HS layer at a processing temperature of 200 to 235 ° C. suitable for EVOH processing, LLDPE When the processing is performed at the film forming temperature of LLDPE, the melt viscosity of EVOH is insufficient, and the shape of the balloon necessary for film formation (the tube formed by the molten resin when forming a film by inflation) fluctuates. There has been a problem that the film thickness and width fluctuate to cause film formation defects.
[0007]
[Problems to be solved by the invention]
The present invention is excellent in barrier properties but has poor flex resistance as a film. When EVOH with a low ethylene content ratio is used, bending and generation of pinholes found in fold seal portions in heat seal portions, particularly gusset bags, etc. It is an object of the present invention to provide a film which has produced a barrier multi-layer HS film which prevents a decrease in the barrier property associated therewith without thermal decomposition during film formation and thickness fluctuation.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, the barrier multilayer HS film of the present invention has a density of 0.915 g / cm ^3. A linear low density polyethylene resin having a melt flow rate of 4 g and a density of 0.915 g / cm ³ At least two of LLDPE consisting of a 1: 1 composition with a linear low density polyethylene resin with a melt flow rate of 10 g and a plastomer layer consisting of a polyethylene resin with a density of 0.880 to 0.895 g / cm ^3. Gas barrier layer composed of EVOH having a total thickness of 15 to 30 μm, an adhesive resin layer, an ethylene content of 3 to 5 μm and an ethylene content of 25 to 50 mol%, and a saponification rate of 90% or more It is a barrier multilayer HS film comprising a resin layer and a film forming carrier layer made of low density polyethylene having a melt flow rate of 2.5 g or less . And the said film-forming carrier layer is a barrier property multilayer HS film comprised from a polyethylene-type resin or polyamide.
[0009]
It is the bag formed from the laminated | multilayer film which bonded the film-forming carrier layer of the said multilayer multilayer HS film, and a base film.
Moreover, the said base film is a bag formed with the laminated | multilayer film which consists of a uniaxial or biaxially stretched polypropylene film.
And the said bag body is a bag body which has a bending part (gusset part) in one side and the other.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, the barrier multilayer film of the present invention has a density measured according to JIS K7122 B method (Pycnometer method) of 0.900 as shown in FIG. 0.920g / cm LLDPE2 and density of ³ total thickness of at least two layers of a plastomer layer 3 of 0.880~0.895g / cm ³ is 15 to 30 [mu] m HS layer 1, the adhesive resin layer 22, the thickness Is a barrier multi-layer HS film comprising an EVOH barrier layer 4, an adhesive resin layer 21, and a film forming carrier layer 5 having an ethylene content of 25 to 50 mol% and a saponification rate of 90% or more. 10.
And the said film-forming carrier layer 5 is the barrier property multilayer HS film 10 comprised from a polyethylene-type resin or polyamide.
[0011]
As shown in FIG. 2, an adhesive layer 6 is formed by forming a film forming carrier layer 5 of the barrier multi-layer HS film 10 and a base film 8 provided with a printed picture layer 7 or an unprinted base film. 3 and a laminated film 16 that is sandwich-laminated by providing a layer corresponding to the adhesive layer 6 composed of a primer layer 61 and an adhesive resin 62 provided as necessary as shown in FIG.
Further, as shown in FIG. 4, a bag body 90 in which a heat seal portion 95 is formed by providing an inner folding portion 91 and an outer folding portion 92 on the laminated film 15 or the laminated film 16.
[0012]
The film-forming carrier layer of the present invention can be selected from thermoplastic resins that are preferably carrier layers that can stabilize the film-forming process of the entire multilayer film. For example, low density polyethylene, medium density polyethylene, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer, ionomer, nylon 6, copolymer nylon (nylon 6 / nylon 66, nylon 6 / nylon 12), A copolymer polyester is selected from those capable of forming a film at 235 ° C. or lower. Preferably, it is a low density polyethylene whose melt flow rate (MFR) measured based on the test condition 4 prescribed | regulated to Table 1 of JIS K7210 A method is 2.5 g or less. When the MFR is 3 g or more, the balloon during film formation tends to fluctuate.
When an HS layer made of LLDPE having stable heat sealability is formed as the innermost layer, the HS layer may be oxidized by air to cause a bad odor or generate an oxide that inhibits heat seal. In order to suppress this, an inert gas (carbon dioxide gas and / or nitrogen gas) is sealed to form a balloon for film formation. Further, the treatment effect can be stabilized by performing the corona discharge treatment immediately after the film formation for the film formation carrier layer after the film formation is completed to give suitability with the adhesive layer.
[0013]
A lubricant is added to LLDPE for the purpose of stabilizing the running performance of the bag making machine. The lubricant is an alcohol-based cetyl alcohol or stearyl alcohol having 16 or more carbon atoms, or a fatty acid metal having 12 or more carbon atoms. It can be selected from soaps, fatty acid amides such as oleic acid amide, liquid paraffin, petrolatum and the like.
In addition, there are inorganic fine particles such as silica, calcium carbonate, magnesium carbonate, and aluminum hydroxide. In addition, a surfactant as an antistatic agent can be added as desired, such as when the content is powder.
[0014]
The adhesive resin layer is a layer provided in order to adhere both resins when the film-forming carrier layer and the barrier layer are coextruded to form a film. When the barrier layer is EVOH as in the present invention, it can be appropriately selected from graft polymerization containing acid anhydride, or copolymerized polyethylene, modified ethylene / vinyl acetate copolymer, modified nylon, etc., preferably EVOH and It is a graft-polymerized polyethylene containing an acid anhydride having the same flow characteristics as low-density polyethylene.
[0015]
EVOH having a high vinyl alcohol ratio has excellent barrier properties, but tends to have poor bending strength and yield point elongation. Therefore, there exists a problem that what is excellent in barrier property is inferior to pinhole resistance. Accordingly, those having a relatively large vinyl alcohol component having an ethylene content of 25 to 50 mol% (EVOH of 75 to 50 mol%) are preferred from the viewpoint of maintaining barrier properties. Those having an ethylene content of less than 25 mol% are inferior in flexibility of the barrier layer, and it is difficult to avoid a decrease in barrier properties due to the generation of pinholes.
[0016]
The plastomer layer of the present invention has a function of preventing the occurrence of pinholes in the barrier layer, and at the same time, when a bag body composed of a barrier multi-layer HS film is hermetically sealed and constructed by heat sealing, The effect which prevents also the pinhole generation | occurrence | production of the laminated | multilayer film which generate | occur | produces in the edge part of a part is show | played.
Therefore, it is preferable that the constituting polymer is excellent in flexibility and that the glass transition point is higher than the use temperature and the softening temperature is lower than the temperature of the HS layer in order to realize the flexibility. Therefore, polyethylene having a density of 0.895 g / cm ³ or less can be preferably used, but other than ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer, ionomer, etc. Those having a low softening temperature such as polybutadiene, polyisobutylene, ethylene / propylene copolymer rubber and butyl rubber can be selected regardless of the density and blended with polyolefin or used alone as a plastomer layer.
[0017]
The total thickness of the barrier multi-layer HS film is not particularly limited, although the target thickness is 15 to 100 μm, which enables normal melt extrusion film formation.
The film forming carrier layer is preferably 10% or more of the total thickness of the multilayer film for the purpose of stabilizing the film formation. The adhesive resin layer has a minimum thickness of 2 μm or more that can be formed, the gas barrier layer is defined by the desired barrier property, and is 3 to 8 μm. If the thickness is 3 μm or less, the barrier property is insufficient, and if it exceeds 8 μm, heat sealing Sometimes it impairs the sealing performance and is also disadvantageous in terms of cost. The HS layer is preferably 15 μm or more, and the synergistic effect of the LLDPE and the plastomer layer stabilizes the sealing performance and heat sealing performance. If it is 15 μm or less, it becomes difficult to exhibit the heat seal strength of LLDPE and the sealing property of the plastomer layer, and the function as the HS layer cannot be satisfied.
The plastomer layer is preferably set to 10 to 40 μm as thick as possible in order to achieve the effect.
[0018]
As long as the film is formed by a co-extrusion multilayer film forming machine, either a circular die type or a T die type may be used, but a circular die type capable of absorbing the fluctuation of the total thickness by rotating the winding shaft is preferable. Moreover, the cooling of the produced multilayer film can use either air cooling or water cooling. In the case of air cooling, the processing temperature can be set low, the formation of gelled products is small, and the contact residence time of the resin in the film state in the die is long, so that the adhesive strength between the layers can be increased. Further, the water-cooling method capable of suppressing the degree of crystallinity of the film is an effective method depending on the resin used, such as using polyamide for the film forming carrier layer.
The formation and adhesion of each layer may be either a feed block method or a multi-manifold method, and may be either in-die adhesion or out-die adhesion, but is effective for thin film formation. An in-die bonding method is preferred.
[0019]
The base film which forms the laminated film by laminating with the above-mentioned barrier multilayer HS film uses 1 to 3 kinds of films from what becomes a base material of a normal film-like bag body. For example, it can be appropriately selected from stretched or non-stretched films such as polyethylene, polypropylene, polyester, polyamide, and cellulose acetate, paper, and cellophane. Preferably, it is a biaxially stretched polypropylene film that is excellent in bending resistance and advantageous in terms of cost.
[0020]
The lamination of the barrier multi-layer HS film and the above film to form a laminated film includes wet lamination using an emulsion adhesive, dry lamination using a reaction curable adhesive (an adhesive containing a solvent). Used lacquer lamination, including solvent-free non-solation), petroleum wax, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer, ionomer, synthetic rubber, tackifying Via hot-melt lamination with hot-melt adhesives (including hot lacquers that are used in the heated state by adding a solvent) and adhesive resin that is melt-extruded with a primer layer if necessary Standard methods such as sandwich lamination to laminate Selected and used appropriately depending on the application.
[0021]
In order to form a bag body from a laminated film, the above-mentioned base film is set on the outside, and the HS layer is set on the inside, and bag making or automatic filling packaging is performed in an appropriate shape. The form of the bag body is not particularly questioned, such as a pillow bag or a gusset bag having a folded gusset portion, and the traveling of the laminated film bag making machine can be supplied to the bag making regardless of the vertical type or the horizontal type.
[0022]
Hereinafter, the present invention will be described in more detail based on experimental examples.
[0023]
(Examples 1-3 and Comparative Examples 1-4)
The resin compositions (A to F and N) having the following compositions were formed into thicknesses shown in Table 1 using a 6-layer, 6-layer circular die-type film forming machine of a feed block type from a melt extruder having a layer of 50 mm. Thus, a barrier multilayer multilayer film having a processing temperature of 230 ° C. and a total thickness of 50 μm was prepared and subjected to corona discharge treatment on the side of the film forming carrier layer as shown in Table 1 and Comparative Examples 1 and 2 Four samples were made.
[0024]
[Table 1]
Resin composition of each layer and its thickness unit μm

[0025]
The resin compositions of the respective layers A to F shown in Table 1 are as follows.
A density: 0.915 g / cm ³ MFR: 4.0 g LLDPE: density: 0.915 g / cm ³ ; MFR: 10.0 g LLDPE = 1: 1 composition • B density: 0.895 g / cm ³ , MFR: 1.6 g LLDPE
-LLDPE having a C density of 0.915 g / cm ³ MFR of 4.0 g
D MFR 1.6 g of acid anhydride graft polymerized polyethylene E Ethylene content 38 mol%, MFR 1.6 g EVOH
・ LDPE with F density of 0.920 g / cm ³ and MFR of 1.6 g
N density 1.140 g / cm ³ , copolymer of nylon 6 and nylon 66 Dry is dry lamination, and sand is sandwich lamination using LDPE as an adhesive resin layer.
[0026]
Urethane-based two-component reaction bonding to the film-forming carrier layer 6 of the barrier multi-layer HS film 10 prepared in Examples 1 to 3 and Comparative Examples 1 to 4 and a biaxially stretched polypropylene (base film 8) having a thickness of 20 μm. The surface coated with the agent 6 (adhesive layer 6) is bonded to the laminated film 15 shown in FIG. 2, or low density polyethylene as the adhesive resin 62 via the primer layer 61 as shown in FIG. A laminated film 16 was produced by sandwich lamination.
[0027]
The slipping of the HS layer, which is an evaluation of film forming suitability, film forming stability, oxygen permeability, heat seal start temperature, peel strength, and bag-making suitability of Examples and Comparative Examples, was evaluated.
Next, using the laminated film 15, as shown in FIG. 4, the inner folding part 91, the outer folding part 92 and the heat sealing part 95, the folding width 93 is 15 mm in length × width = 300 × 150 mm ² , and the heat sealing width is 10 mm. A gusset bag (bag body 90) was prepared and evaluated for bag-making suitability (and the presence or absence of pinholes in the folded portion). The evaluation results are shown in Table 2.
[0028]
[Table 2]
Evaluation results

[0029]
The evaluation method of each measurement item shown in Table 2 is as follows.
(Evaluation methods)
-Film formation suitability Visually evaluated the occurrence frequency of flow unevenness and the stability of the balloon during film formation.
-Oxygen permeability MODERN CONTROL INC. In accordance with JIS K7126 B method (isobaric method). The oxygen permeation amount (cc / atm · m ² 24 h) was measured under the conditions of 23 ° C. and relative humidity 65% using OX-TRAN 2/20 manufactured by KK
-Heat sealing (HS) start temperature The HS layer of the laminated film is relatively heat-sealed to a width of 10 mm under the condition of a pressure of 1 kg / cm ² × 1 sec, then cut vertically to the heat-sealing direction at a width of 15 mm, and then peeled off. The strength was measured at a peeling speed of 300 mm / min, and the temperature at which the strength reached 2 kg / 15 mm was defined as the heat seal (HS) start temperature.
Peeling strength The peeling strength was measured at a width of 15 mm when measured at 150 ° C. under the above conditions.
-Appearance of film Film formation was continued for 10 hours with the above resin composition, and the film was evaluated comprehensively from the occurrence frequency of gel and transparency of the film (JIS K7105-1981).
-Dynamic friction coefficient The sliding of the HS layer of the laminated film with respect to the stainless steel surface was measured according to JIS K7214-1987.
-Bag making suitability (sealability)
After the laminated film is made with a vertical pillow type bag making machine, a pinhole check solution (a test solution colored by dissolving an alcohol-soluble dye in octyl alcohol) is injected into the bag body, and a seal portion The presence or absence of penetration into the skin was confirmed.
Evaluation criteria ◎ Very good.
○ Good and practically no problem.
Δ: Although there are some problems, it can be used by selecting the application.
× There are many disadvantages and not practical.
[0030]
【The invention's effect】
As described above in detail, the barrier multi-layer HS film of the present invention has an HS layer composed of LLDPE and a plastomer layer having a stable performance for heat sealing to be 15 μm or more. Then, a multilayer coextruded film composed of a film forming carrier layer having a stable film forming property and EVOH having a low ethylene content can be stably formed. The barrier multi-layer HS film is composed of LLDPE having stable performance for heat sealing as the HS surface and further including a plastomer layer to a thickness of 15 μm or more. Effect of providing a co-extruded film having a good balance of properties, sealing properties and bag-making suitability.
[Brief description of the drawings]
FIG. 1 is a view showing the concept of a cross section of a barrier multilayer HS film.
FIG. 2 is a view showing a concept of a cross section of a laminated film bonded using a barrier multilayer HS film.
FIG. 3 is a diagram showing the concept of a cross section of another form of laminated film bonded using a barrier multilayer HS film.
FIG. 4 is a perspective view showing a concept of a pillow bag formed from a laminated film of a barrier multilayer HS film.
[Explanation of symbols]
1 HS layer 2 LLDPE
3 Plastomer layer 4 Barrier layer 5 Film-forming carrier layer 6 Adhesive layer 7 Picture layer 8 Base film 10 Barrier multilayer HS films 15 and 16 Laminated films 21 and 22 Adhesive resin layer 61 Primer layer 62 Adhesive resin 90 Bag 91 Internal folding part 92 External folding part 93 Folding width 95 Heat seal part

Claims (5)

Density is 0.915 g / cm ³ A linear low density polyethylene resin having a melt flow rate of 4 g and a density of 0.915 g / cm ³ A linear polyethylene comprising a 1: 1 composition with a linear low density polyethylene resin having a melt flow rate of 10 g and a plastomer layer comprising a polyethylene resin having a density of 0.880 to 0.895 g / cm ^3. Coexistence of two layers of heat sealant layer with a total thickness of 15 to 30 μm, adhesive resin layer, ethylene content of 25 to 50 mol% with a thickness of 3 to 5 μm, and saponification rate of vinyl acetate of 90% or more A gas barrier multilayer heat seal film comprising a gas barrier layer made of coalescence, an adhesive resin layer, and a film forming carrier layer made of low density polyethylene having a melt flow rate of 2.5 g or less .   The gas barrier multilayer heat seal film according to claim 1, wherein the film forming carrier layer is made of polyethylene resin or polyamide.   A bag body comprising a laminated film obtained by bonding the film forming carrier layer of the gas barrier multilayer heat seal film according to claim 1 or 2 and a base film.   The bag according to any one of claims 1 to 3, wherein the base film according to claim 3 is a uniaxial or biaxially stretched polypropylene film.   The bag according to any one of claims 1 to 4, wherein the bag has a bent portion on one side and the other side.

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