JP2002205763A - Packaging bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging bag improved in moisture barrier properties, excellent in a combination of unsealing properties by tearing and rigidity, and further excellent in a combination of the unsealing properties and environmental stress cracking resistance. SOLUTION: The packaging bag is formed of a laminate composed of an outer layer film made of an oriented plastic film and an inner layer film consisting of a single layer, or of a multi-layer, made of an olefinic resin. In this packaging bag, at least one layer of the inner layer film is made of an ethylenic polymer whose density is 0.930 g/cm3 or more, and steam permeability (40 deg.C, 90%RH) of the laminate is at most 1.50 g/m2.day. Thus, the packaging bag is excellent in moisture barrier properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging bag used for solid or liquid packaging of detergents, bleaching agents, softening agents, various daily necessities, confectionery, beverages, various foods, and the like. The present invention relates to a packaging bag which is excellent in moisture barrier properties and further excellent in a combination of tear-openability and rigidity.

[0002]

2. Description of the Related Art Heretofore, packaging bags such as standing pouches have been known in which an inner film of an olefin resin is laminated on a base material such as a biaxially stretched plastic film or aluminum foil.

Japanese Patent Application Laid-Open No. 7-241967 is characterized in that at least the outer film is a biaxially stretched plastic film, and the inner film is a laminated film which is a coextruded film of linear low-density polyethylene having different densities. A standing pouch is described.

Japanese Patent Application Laid-Open No. 7-232418 discloses a packaging material comprising at least a base film layer and a heat-sealing resin layer, wherein the innermost layer of the heat-sealing resin layer is ethylene polymerized by using a single-site catalyst. -A packaging material characterized by being an α-olefin copolymer film is described.

In JP-A-10-24539, a low-density polyethylene layer formed by a single-site catalyst is formed on at least one surface of a base film via a low-density polyethylene or linear low-density polyethylene layer. A tear-resistant packaging material characterized by this is described.

[0006] JP-A-10-86300 discloses that the density
Is 0.860 to 0.925 g / cm ³, Weight average molecular weight
/ Linear low-density polyethylene having a number average molecular weight of 1 to 3
A sealing layer having a density of 0.900 to 0.935 g /
cm³Base made of linear low-density polyethylene
Layer, density 0.910 to 0.950 g / cm³The line that is
Laminated layer made of fibrous low-density polyethylene and biaxially rolled
Make sure that the stretched plastic film layers are
The characteristic linear low-density polyethylene composite film
It is listed.

JP-A-9-31263 discloses that (A) the density is 0.86 to 0.96 g / cm ³ , the melt flow rate is 0.1 to 200 g / 10 min, and the molecular weight distribution is 1.
4 to 4.5, 98 to 20% by weight of an ethylene / α-olefin copolymer having a specific range of orthodichlorobenzene soluble matter, density and MFR, and (B) other ethylene polymer 2 A polyethylene composition comprising 80% by weight and a container made of the same are described.

[0008]

The conventional packaging bag has a satisfactory level of heat sealability and the like, but has a problem of a moisture barrier property and a shortage of weight over time.

[0009] Further, the conventional packaging bag still has a problem to be improved with respect to the combination of the opening property and the rigidity due to tearing of the bag. That is, the standing pouch is required to be upright with the contents filled therein, and for that purpose, the laminated film or sheet constituting the pouch is required to have stiffness (rigidity). .
On the other hand, the polyethylene resin used as the inner film material for heat sealing accounts for the majority of the thickness of the laminated film for pouches, but the elastic modulus of the polyethylene resin is at a smaller level than other resins. Therefore, in order to increase the rigidity, the thickness must be increased.

However, the tearability and rigidity of the bag are incompatible with each other. In the above example, when the thickness of the inner film material of the polyethylene resin is increased, the rigidity is increased, but the tearability is opposite. There is a problem that it decreases.

Another problem with the conventional polyethylene resin inner film material is that it is inferior in resistance to environmental stress cracking as compared with other resins such as polypropylene. In this case, there is a problem that a stress crack is easily generated.

Accordingly, it is an object of the present invention to provide a packaging bag having improved moisture barrier properties, an excellent combination of tear-openability and rigidity, and an excellent combination of environmental stress crack resistance. is there. Another object of the present invention is to provide a packaging bag useful as a standing pouch for filling a liquid detergent or the like.

[0013]

According to the present invention, there is provided a stretching press.
An outer layer film consisting of a plastic film and one or more layers
Is the product with the inner layer film composed of multilayer olefin resin.
In packaging bags consisting of layers, at least
Also one layer has a density of 0.930 g / cm³More Echile
Water vapor transmission rate of the laminated body (40
° C, 90% RH) 1.50 g / m²・ Below day
Packaging bags with excellent moisture barrier properties
Provided. The ethylene polymer has ethylene and carbon number
It is preferably a copolymer with four or more α-olefins.
New Further, in the packaging bag of the present invention, the inner layer film
Is preferably a laminated film of at least three layers.
The intermediate layer of the inner layer film has a density of 0.930 g / cm.
³Consisting of the above ethylene polymer,
The inner layer has a density of 0.930 g / cm³Less than ethylene
It preferably comprises a polymer. Further, the density is 0.93
0 g / cm³When the layer composed of the ethylene polymer is 20
It preferably exists in a thickness of from 200 to 200 μm.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The packaging bag of the present invention comprises a laminate of an outer layer film made of a stretched plastic film and an inner layer film made of one or more layers of an olefin-based resin. Is composed of an ethylene polymer having a density of 0.930 g / cm ³ or more, and a water vapor transmission rate (40 ° C.,
(90% RH) is 1.50 g / m ² · day or less.

Generally, it is generally known that the density of an olefin resin and the water vapor transmission rate are closely related, and that the higher the density, the lower the water vapor transmission rate. However,
Ethylene polymers, especially linear low density polyethylene,
When the density is around 0.930 g / cm ³ , the change in water vapor permeability is sharp, and the density of the ethylene polymer used is 0.930 g / cm ³ or more, preferably 0.932 g / cm ³ or more.
It was found that the water vapor transmission rate of the laminate can be suppressed to a low value by selecting a material having a size of cm ³ or more.

As already pointed out, when the packaging bag is filled with water-containing contents, the moisture in the contents is lost due to the permeation of water vapor through the wall of the bag, resulting in a shortage of weight.
According to the present invention, the above problem can be reduced by using the inner layer film containing the ethylene polymer having the specific density.

In the present invention, when an inner layer film containing an ethylene polymer having the above density, particularly an ethylene-α-olefin copolymer, is laminated with a stretched plastic film, the tear strength of a packaging bag made of the laminated film is reduced to a small value. It has been found that the rigidity of the laminated film can be increased while maintaining the stiffness, and the rigidity (lumbar) required for the packaging bag can be increased while improving the openability by tearing the packaging bag. . In addition, since the thickness of the film required to obtain a certain rigidity can be reduced, the cost required for manufacturing the packaging bag can be reduced, and it is suitable for the purpose of resource saving and waste reduction.

In the packaging bag of the present invention, the inner layer film is a laminated film of at least three layers, and the intermediate layer of the inner layer film is made of an ethylene polymer having a density of 0.930 g / cm ³ or more. When the inner layer is made of an ethylene polymer having a density of less than 0.930 g / cm ³ , the heat sealing property of the packaging bag can be improved without impairing the above-mentioned advantages. That is, the ethylene polymer having a density of 0.930 g / cm ³ or more has a problem that the heat sealing temperature is high and the heat sealing property is inferior. However, the ethylene polymer having the high density is used as the intermediate layer and the density is low. This problem can be solved by disposing the ethylene-based polymer in the innermost layer and the outermost layer.

In the present invention, the density is 0.930 g / cm ³
The layer comprising the above-mentioned ethylene polymer has a thickness of 20 to 200 μm.
It is preferable that the compound has a thickness of m from the viewpoint of water vapor barrier properties, heat sealing properties, rigidity and tearability.

In FIG. 1, which shows a preferred example of the cross-sectional structure of the laminated film in the packaging bag of the present invention, the laminated film 1 is composed of an outer film 2 made of a stretched plastic film and an inner film 3 made of a multilayer olefin resin. The inner layer film 2 includes an innermost layer (heat sealing layer) 4 for performing heat sealing,
A middle layer (water vapor barrier layer) 5 composed of an ethylene polymer having a density of 0.930 g / cm ³ or more and an outermost surface layer (bonding layer) for bonding with a stretched plastic film.
Consists of six. The innermost layer (heat seal layer) 6
As already pointed out, it is preferred that the material be made of an ethylene polymer having a density of less than 0.930 g / cm ³ .

The inner layer film 3 is preferably made of a laminated film of linear low-density polyethylene. In particular, the innermost layer 4 of the ethylene / butene-1 copolymer produced using a metallocene catalyst,・ Butene-1
It is preferable to use a laminate of the copolymer intermediate layer 5 and the ethylene / hexene-1 copolymer bonding layer 6 in view of the above-mentioned combination characteristics.

As the inner film 3 laminated on the stretched plastic film 2, three types of linear low-density polyethylenes having different comonomer constitutions and different polymerization catalysts are laminated to provide excellent sealing properties. A combination of easy opening by tearing, resistance to environmental stress cracking, and appropriate waist (rigidity) suitable for a standing pouch or the like can be achieved.

In the inner layer film 2 of the packaging bag 1 of the present invention, when the ethylene / butene-1 copolymer produced by using a metallocene catalyst is used as the innermost layer (heat seal layer) 5, this specific The linear low-density polyethylene is particularly preferable because it has a characteristic of not only good heat sealability but also good tearability, and is particularly suitable for the innermost surface layer 4. Further, as a characteristic of the linear low-density polyethylene produced by using the metallocene-based catalyst, the linear low-density polyethylene has excellent resistance to environmental stress cracking and has an advantage in terms of resistance to contents.

Further, the ethylene-hexene-1 copolymer is used as the bonding layer 6 to be bonded to the stretched plastic film 2 because this copolymer has excellent lamination strength with the stretched plastic film substrate. Along with
Due to its excellent flexibility. That is, when sufficient lamination strength is not obtained between the stretched plastic film 2 and the linear low-density polyethylene-based inner layer film 3, at the time of opening by tearing, between the tearing direction of the base material and the tearing direction of the inner surface material. There is a tendency for misalignment to occur, which often results in a loss of tear relief. On the other hand, when the lamination strength of both films is high, the tear start points coincide and are fixed at one point, and in this case, the tearing of the film becomes much easier. In the bonding layer 6 used in the present invention, it is considered that the branched chains in the copolymer derived from the hexene-1 comonomer contribute to increasing the laminate strength and imparting flexibility.

The reason why the ethylene / butene-1 copolymer is interposed between the innermost layer 4 and the bonding layer 6 as the intermediate layer 5 is that the intermediate layer 5 is suitable for a standing pouch or the like. It has excellent waist (rigidity) and excellent tearability.

In the inner film 3 of the packaging bag 1 of the present invention,
As the innermost surface layer 4, the intermediate layer 5, and the bonding layer 6, linear low-density polyethylene having good tearability is selected and combined, but the innermost surface layer 4 has a heat sealing property, and the intermediate layer 5 has a rigid and bonding layer. In No. 6, the combination characteristics described above are achieved by selecting the copolymer composition of the ethylene / α-olefin copolymer in consideration of the laminate strength and flexibility.

The density of the resin in each layer of the inner film 3 also
There is an optimum density range in terms of the above combination characteristics. When the density of the resin of the innermost layer 4 is d _I , the density of the resin of the intermediate layer 5 is d _M, and the density of the bonding layer 6 is d _L , it is preferred that the density is in the relation satisfying the formula d _{M> d L} and _{d L>} d _I.

The overall thickness of the inner film 3 is generally 2
The thickness is preferably in the range of 0 to 200 μm, particularly 50 to 150 μm. When the thickness is less than the above range, the heat sealing workability tends to decrease, or the final packaging bag tends to have a low stiffness. If it exceeds the range, the tearability tends to decrease, which is not preferable. It is preferable in terms of combination characteristics that the innermost layer 4 has a thickness ratio of 10 to 45% and the bonding layer 6 has a thickness ratio of 10 to 45%.

[Inner Film] (1) Innermost Layer Resin The resin used for the innermost layer 4 in the present invention is an ethylene polymer having the above-mentioned density.
It is obtained by polymerizing a mixture with butene-1 among olefins in the presence of a metallocene catalyst.

The metallocene catalyst is a metallocene, that is, a transition metal component composed of a complex composed of two substituted or unsubstituted cyclopentadienyl rings and various transition metals, an organoaluminum component, particularly, aluminoxane. The transition metal component is a metal of Group IVb, Vb or VIb of the periodic table, particularly titanium or zirconium. As a transition metal component in the catalyst, generally, in the following formula (Cp) ₂ MR ₂ , Cp is a substituted or unsubstituted cyclopentadienyl ring, M is a transition metal, and R is a halogen atom or an alkyl group. Is generally used.

The aluminoxane is obtained by reacting an organic aluminum compound with water, and includes a linear aluminoxane and a cyclic aluminoxane. These aluminoxanes can be used alone or in combination with other organic aluminum.

A polymerization method of ethylene or ethylene and an α-olefin using a metallocene catalyst is disclosed in
-19309 and other publications, which are synthesized by polymerization in an organic solvent, in a liquid monomer or in a gas phase method in the presence of the metallocene catalyst.
Any of these known methods that satisfy the above conditions can be used for the purpose of the present invention.

The resin of the innermost layer 4 which contains butene-1 as an α-olefin comonomer and is polymerized with a metallocene catalyst is used in combination with the heat sealing property and the tear property. And also has resistance to contents such as detergents, which are liable to cause environmental stress cracking.

The resin of the innermost layer 4 has a density of 0.930 g.
/ Cm ^{3 or} less and 0.860 g / cm ³ or more in terms of heat sealability, tearability, and moldability. If the density is out of the above range, heat sealability or tearing is preferred. It tends to worsen.

(2) Resin for Intermediate Layer The resin used for the intermediate layer 5 has a density of 0.930 g / cm.
It is an ethylene / butene-1 copolymer produced at a ratio of ³ or more, particularly 0.932 g / cm ³ or more, preferably using a usual Ziegler catalyst.

It is preferable that the resin of the intermediate layer 5 has a density in the above range from the viewpoint of water vapor barrier properties, stiffness (rigidity) and tearability required for a standing pouch, and furthermore, moldability. When the ratio is below the range, the water vapor barrier property decreases, and the rigidity decreases. When the ratio exceeds the above range, the tearability tends to decrease.

In order to further improve the tearability,
In the mid layer 5, the ethylene / butene-1 copolymer was added in an amount of 0.1%.
High-density polyethylene or low-density polyethylene may be blended at a ratio of 1 to 80% by weight, preferably 5 to 50% by weight. When the proportion of the high-density polyethylene or the low-density polyethylene is less than 0.1% by weight, substantially no further improvement in the tearing property is observed, and when it exceeds 80% by weight, the drop strength decreases.

The reason why the ethylene / butene-1 copolymer is blended with a high-density polyethylene or a low-density polyethylene to improve the tearing property is that the compatibility between the ethylene / butene-1 copolymer and these polyethylene resins is poor. This results in a non-uniform structure.

In the present invention, the use of the above resin as the intermediate layer 5 is also important from the viewpoint of the coextrusion moldability of the laminate. The ethylene / butene-1 copolymer produced using a metallocene catalyst used for the innermost layer 4 has a narrow molecular weight distribution and is difficult to mold. By performing co-extrusion on the resin, the moldability can be improved. This applies to the bonding layer 6 as well.

(3) Resin for the bonding layer The resin used for the bonding layer 6 is an ethylene polymer having the above-mentioned density, and is preferably a copolymer obtained by copolymerizing hexene-1 with ethylene among α-olefins. It is a united material, has a large lamination strength with a stretched plastic film, and is flexible, and has a function of absorbing the impact of the composite film and improving the delamination resistance upon impact.

The resin of the bonding layer 6 is less dense than the density _{d M} of the resin of the intermediate layer 5, in particular having a density less 0.01 g / cm ³ or more than the density of the resin of the intermediate layer 5, and most it is preferred to have a density greater than the density d _I of the resin of the inner surface layer 4.

Generally, the resin of the bonding layer 6 has a density of 0.9.
The density is preferably in the range of 0 to 0.930 g / cm ³ in terms of lamination strength and flexibility, and furthermore, moldability. When the density is lower than the above range, the lamination strength is reduced, and when the density is higher than the above range, the flexibility is higher. Tends to decrease.

(4) Inner Film Material The inner film 3 used in the present invention is produced by co-extruding the innermost layer 4, the intermediate layer 5, and the bonding layer 6 described above. The overall thickness of the inner film 3 composed of the laminate varies depending on the application, but generally ranges from 20 to 20.
It is preferably in the range of 0 μm, especially 50 to 150 μm. That is, when the thickness exceeds the above range, the flexibility of the laminate of the inner film 3 tends to be lost, while when the thickness is below the above range, the rigidity of the film is lost or the heat sealing property is impaired. Tend.

It is preferable that the thickness ratio of each layer in the inner film 3 composed of a laminate is in the above-mentioned range. If the thickness ratio of the innermost layer 4 falls below the above range, the heat sealing property tends to decrease, and if the thickness of the intermediate layer 5 falls below the above range, the stiffness (rigidity) of the inner film 3 tends to decrease. When the bonding layer 6 falls below the above range, the lamination strength of the inner film tends to decrease. Inner film 3
When the thickness ratio of each layer is within the above range, the most excellent tear openability and the balance of each property can be obtained.

The inner film 3 made of a laminate by coextrusion is manufactured by using an extruder corresponding to the type of each resin layer.
This is performed by superimposing the melts of the respective resins in a multilayer multiplex die and extruding the melt from a die orifice. This inner surface film material can be formed into a film in advance by a T-die method, an inflation film forming method, or the like, and used for lamination with a stretched plastic film, or can be extrusion-coated on a stretched plastic film in the form of a molten web. You can also.

Another substrate 2 on which the inner film 3 is laminated
Examples include various stretched plastic films other than polyethylene. As a stretched plastic film, polyethylene terephthalate (PET),
Polyester films such as polybutylene terephthalate, polyethylene naphthalate, ethylene terephthalate / isophthalate copolymer: nylon 6, nylon 6,
6, Nylon 11, Nylon 12, Polyamide (Ny) film such as Nylon 6 / Nylon 6,6 copolymer: Propylene polymer film (PP): Polyvinyl chloride film: Polyvinylidene chloride film: Ethylene vinyl alcohol copolymer A coalesced film (EVOH) can be used. These films may be uniaxially stretched or biaxially stretched.

Among the above-mentioned stretched films, the biaxially stretched polyethylene terephthalate film is a material excellent in mechanical strength, pinhole resistance, crack resistance and heat resistance.
Particularly suitable as the outermost layer of a packaging container. Further, the uniaxially stretched polypropylene film has an effect of imparting tearing properties in the stretching direction. This uniaxially stretched polypropylene film is preferably provided on the side joined to the inner surface material. It is desirable that the thickness is generally in the range of 3 to 50 μm, particularly 5 to 40 μm.

The above-mentioned stretched plastic films can be used alone or in combination of two or more. For example, by combining two or more kinds of stretched plastic films having different properties, it is possible to obtain a desired combination property in the composite film.

To bond a plurality of stretched plastic films, an adhesive known per se, for example, an isocyanate adhesive, an epoxy adhesive, an acid-modified olefin resin, a polyester adhesive, a polyether adhesive,
A polyamide adhesive or the like can be used.

Further, these stretched plastic films may be subjected to printing, metal deposition, formation of a silicon oxide (SiOx) deposition layer, etc. before or after lamination with the inner film. it can. For example, when a laminate of a stretched PET film and a stretched polyamide film is used, the above-described printing, metal deposition, formation of a silicon oxide (SiOx) deposition layer, and the like are performed on the inner surface side of the stretched PET film that is the outermost surface layer. It is convenient because you can do it.

On the other hand, an aluminum foil can be used as the metal foil, and its thickness is preferably in the range of 5 to 30 μm. The lamination of the inner surface film composed of the laminate and the stretched plastic film or metal foil can be performed by means known per se, such as extrusion coating, sandwich lamination, dry lamination, and the like. In the extrusion coating method, a urethane-based or titanate-based anchoring agent or a corona discharge treatment can be applied to the surface on the side where the laminated inner surface material is applied, in order to increase the adhesive strength. In sandwich lamination, an inner film material composed of a laminate is divided into two layers, and one of the divided layers is formed into a film in advance. Between the film, melt extruded the other split resin layer,
The film of one of the divided layers and the stretched plastic film are joined via the other divided resin layer,
It is a composite film. Also in this case, it is needless to say that the inner surface material of the formed composite film must have the above-mentioned laminated structure. Furthermore, in dry lamination, a urethane-based inner film and a stretched plastic film made of a laminate formed in advance are used.
Adhesion is performed using an adhesive such as titanate.

Suitable examples of the laminated film of the packaging bag include a polyethylene resin inner film as PE, a two-layer structure: PE / Ny, PE / PET, PE / OPP, and a three-layer structure: PE / Ny / PET. , PE / Al / PET,
PE / EVOH / Ny, PE / EVOH / PET, PE
/ EVOH / OPP, four-layer structure: PE / PET / Al / PET.

The packaging bag of the present invention can be used as various types of packaging bags by utilizing the above-mentioned excellent properties, and the bag can be produced by a bag production method known per se. Examples include ordinary pouches with three-sided or four-sided seals, pouches with gussets, standing pouches, pillow packaging bags, and the like, but are not limited to these examples.

[0054]

EXAMPLES The present invention will be further described with reference to the following examples, but the present invention is not limited to the following examples.

Method for measuring water vapor transmission rate: The measurement of water vapor transmission rate was determined according to Dr. LYSYY water vapor permeability meter L80-40
The measurement was carried out according to JIS K 7129 using 00. The measurement conditions were as follows: temperature 40 ° C./relative humidity 90%. The test method was a humidity sensor method, and the water vapor supply surface was on the inner film side.

(Example 1) An outer layer film having a thickness of 15
μm biaxially stretched nylon film, and as the inner film, the innermost surface layer has a density of 0.910 g / cm ^{3 and} a thickness of 30 μm.
m ethylene / butene-1 copolymer, and the intermediate layer has a density of 0.
935 g / cm ³ of 60 μm thick ethylene butene
1 copolymer and a three-layer coextruded polyethylene resin film having a total thickness of 120 μm, which is a 30 μm-thick ethylene / hexene-1 copolymer having a density of 0.920 g / cm ³ and a bonding layer, And laminated by a dry lamination method to produce a laminated film. The water vapor permeability of this laminated film is 1.01 g / m ² · d
It was ay.

Example 2 An outer layer film having a thickness of 15
μm biaxially stretched nylon film, and as the inner film, the innermost surface layer has a density of 0.910 g / cm ^{3 and} a thickness of 30 μm.
m ethylene / butene-1 copolymer, and the intermediate layer has a density of 0.
934 g / cm ³ of ethylene butene having a thickness of 60 μm.
1 copolymer, the bonding layer is an ethylene-hexene-1 copolymer having a thickness of 30μm of density 0.920 g / cm ^3, and a three-layer co-extruded polyethylene resin film having a total thickness of 120 [mu] m, the bonding layer And laminated by a dry lamination method to produce a laminated film. The water vapor permeability of this laminated film is 1.03 g / m ² · d
It was ay.

(Example 3) A film having a thickness of 15
μm biaxially stretched nylon film, and as the inner film, the innermost surface layer has a density of 0.910 g / cm ^{3 and} a thickness of 30 μm.
m ethylene / butene-1 copolymer, and the intermediate layer has a density of 0.
933 g / cm ³ of 60 μm thick ethylene butene
1 copolymer and a three-layer coextruded polyethylene resin film having a total thickness of 120 μm, which is a 30 μm-thick ethylene / hexene-1 copolymer having a density of 0.920 g / cm ³ and a bonding layer, And laminated by a dry lamination method to produce a laminated film. The water vapor permeability of this laminated film is 1.11 g / m ² · d
It was ay.

(Example 4) A film having a thickness of 15
μm biaxially stretched nylon film, and as the inner film, the innermost surface layer has a density of 0.910 g / cm ^{3 and} a thickness of 30 μm.
m ethylene / butene-1 copolymer, and the intermediate layer has a density of 0.
923g / cm ³ of low density polyethylene 30 wt% and density 0.935 g / cm ³ of ethylene butene-1 copolymer 70 wt% with a blend layer of a thickness of 60μm, the junction layer density 0.920 g / cm ³ Ethylene with a thickness of 30 μm
A hexene-1 copolymer, a three-layer co-extruded polyethylene resin film having a total thickness of 120 μm, was laminated by a dry lamination method via the joining layer to produce a laminated film. The density of the intermediate layer of the inner film was 0.931 g / cm ³ , and the water vapor permeability of the laminated film was 1.46 g / m ² · day.

(Comparative Example 1) An outer layer film having a thickness of 15
A biaxially stretched nylon film having a thickness of μm and an ethylene / butene-1 copolymer having a density of 0.917 g / cm ^{3 and} a thickness of 150 μm as an inner film were laminated by a dry lamination method to produce a laminated film. The water vapor permeability of this laminated film is 2.19 g / m ² · da
y.

Comparative Example 2 An outer layer film having a thickness of 15
A biaxially stretched nylon film having a thickness of μm and an ethylene / butene-1 copolymer having a density of 0.907 g / cm ^{3 and} a thickness of 150 μm as an inner surface film were laminated by a dry lamination method to prepare a laminated film. The water vapor permeability of this laminated film is 2.39 g / m ² · da
y.

[0062]

According to the present invention, a stretched plastic film is provided.
Outer layer film made of LUM and one-layer or multi-layer OLEF
Package consisting of a laminate with an inner-layer film made of resin
In the packaging, at least one layer of the inner film
And the density is 0.930 g / cm ³Above ethylene polymerization
The use of a body made of
The excess rate (40 ° C., 90% RH) is 1.50 g / m²・ Da
y or less and has excellent moisture barrier properties
A packaging bag can be provided. This packaging bag is
Not only the rear is improved, but also due to tearing
Excellent combination of openability and rigidity, and environmental stress cracking
Excellent combination with sex. For this reason, the packaging of the present invention
The bag is made up of a standing pouch filled with liquid detergent, etc.
It is useful.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a sectional structure of a laminated film in a packaging bag of the present invention.

Continued on the front page F term (reference) 3E064 AA09 AB11 AB23 BA17 BA25 BA29 BA30 BA35 BA36 BA38 BA55 BB03 BC07 EA07 EA12 EA18 EA30 FA01 FA04 3E067 AA03 AA11 AB16 AB26 AB99 BA12A BB15A CA05 FC01 GA30 3E086 AD01 BA08 AD30 CA01 CA11 CA35 4F100 AK01A AK03B AK03C AK03D AK04B AK04C AK04J AK08 AK08J AK48 AK62B AK65 AL01 BA03 BA04 BA07 DA02 EH23 EJ37A EJ38 GB17 JA13B JA13C JA20 JD05 JK01 JK03 JK14

Claims (4)

[Claims] 1. A packaging bag comprising a laminate of an outer layer film made of a stretched plastic film and an inner layer film made of one or more layers of an olefin resin, wherein at least one layer of the inner layer film has a density of 0.930 g.
/ Cm ³ or more and a water vapor transmission rate (40 ° C., 90% RH) of the laminate is 1.50 g / m 3.
Moisture barrier property superior packaging bag, characterized in that it is ² · day or less. 2. The packaging bag according to claim 1, wherein the ethylene-based polymer is a copolymer of ethylene and an α-olefin having 4 or more carbon atoms. 3. The inner layer film is a laminated film of at least three layers, and the intermediate layer of the inner layer film has a density of 0.93.
Consists 0 g / cm ³ or more ethylene polymer, according to claim 1 or 2 innermost surface layer of the inner layer film is characterized by comprising the ethylene polymer of less than 0.930 g / cm ³
Packaging bag. 4. The packaging bag according to claim 1, wherein a layer made of an ethylene polymer having a density of 0.930 g / cm ³ or more exists in a thickness of 20 to 200 μm.