JP2010076342A - Multilayer laminated film with easy peelability, transparency and gas barrier property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer laminated film combining practicability and fine appearance with excellent peelability, transparency and gas barrier property when used as a cover material of a container without stringiness or the like of a peel part, and a packaging container using the multilayer laminated film as the cover material. <P>SOLUTION: The multilayer laminated film has a seal resin layer (A)(1), and a base material resin layer (B)(2) and a base material resin layer (C)(3) sequentially laminated thereon, wherein (A) comprises (i) 90-30 pts.wt. of a low-density polyethylene or ethylene-α-olefine copolymer with a density of 0.915-0.930 g/cm<SP>3</SP>, and (ii) 10-70 pts.wt. of propylene elastomer with a density of 0.850-0.89 g/cm<SP>3</SP>, and the total of (i) and (ii) is 100 pts.wt., (B) comprises ethylene-maleic anhydride graft polymer or a propylene-maleic anhydride graft polymer, and (C) comprises an ethylene-vinyl alcohol copolymer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a multilayer laminated film mainly used as a lid for packaging containers such as foods and chemical products in the field of soft packaging, and is excellent in easy-opening and transparency, and is necessary for long-term storage of foods. The present invention relates to a multilayer laminated film having gas barrier properties and having little peeling at the peel portion and having both practicality and aesthetics, and a packaging container using the multilayer laminated film.

In recent years, packaging containers are required not only to sufficiently satisfy sealing properties for content protection and storage, but also to be easily opened (easy peel) that can be easily opened when consumed. Various proposals have been made as packaging films having both practical sealing properties and easy opening properties.
For example, as a film intended for easy opening, a heat-sealable laminated film composed of two layers of a blend layer of various acrylic acid copolymers and polyethylene (see Patent Document 1), a base material layer composed of polypropylene, A film in which a three-component blend layer of polybutene, polypropylene, and polyethylene is laminated (see Patent Document 2), a multilayer film having a layer made of a mixture of a methacrylic acid copolymer and polypropylene, and a polyethylene sealant layer (see Patent Document 3) There is known an easy peel film comprising a base material layer made of polypropylene and a blend layer of polybutene, polyethylene and polypropylene (see Patent Document 4).
JP-A-5-212835 JP-A-6-328639 JP 2002-283513 A JP-A-6-328639

  However, conventional films intended for easy opening have a high material cost, have a low degree of freedom in film forming conditions (blending conditions, etc.), and polybutene blended for the purpose of improving low-temperature sealing properties, etc. It was also not sufficient in terms of the beauty of the peeled surface. Furthermore, since these films do not have the gas barrier properties necessary for long-term storage of food, it is necessary to laminate a new gas barrier film. In addition, from the viewpoint of improving the product image during store display and the demand of consumers who want to confirm the appearance of the contents before purchasing the product, the development of lid materials with high transparency and excellent contents visibility is strong. It was desired.

  Therefore, as a result of various studies to solve the above problems, the present inventor, as a material constituting the sealing resin layer (A) in the multilayer laminated film for the lid of the packaging container, An ethylene-α-olefin copolymer and a propylene elastomer are used, and the sealing resin layer is composed of a two-component system comprising (i) a low density polyethylene or an ethylene-α-olefin copolymer and (ii) a propylene elastomer. An ethylene / maleic anhydride graft polymer or a propylene / maleic anhydride graft polymer as the base resin layer (B), and an ethylene / vinyl alcohol copolymer as the base resin layer (C). By using it, the desired peel strength can be obtained, and transparency and gas barrier properties can be imparted to the multilayer film. A multilayer laminated film for lids of packaging containers that has excellent easy-openability, content visibility, content storage stability, and has a beautiful peel surface. developed.

That is, this invention includes the invention shown to the following (1)-(8).
(1) A multilayer laminated film having a sealing resin layer (A), and a base resin layer (B) and a base resin layer (C) sequentially laminated thereon,
The sealing resin layer (A) comprises (i) 90 to 30 parts by weight of low density polyethylene or ethylene-α-olefin copolymer having a density of 0.915 to 0.930 g / cm ³ and (ii) a density of 0.850 to 0.89 g / cm 3. ³ consisting of 10 to 70 parts by weight of propylene elastomer, wherein the sum of (i) and (ii) is 100 parts by weight,
The base resin layer (B) is made of an ethylene / maleic anhydride graft polymer or a propylene / maleic anhydride graft polymer,
The base resin layer (C) is made of an ethylene / vinyl alcohol copolymer, and the layer thickness of the seal resin layer (A) is 1 to 20 μm, and the layer thickness of the base resin layer (B) is 1 to 20 μm, the thickness of the base resin layer (B) is 10 to 30 μm, and the total thickness of the base resin layer (B) and the base resin layer (C) is 30. A multilayer laminated film having a thickness of ˜50 μm.

(2) The propylene elastomer used for the seal resin layer (A) is an ethylene / propylene random copolymer, and the MFR (230 ° C.) is 1 to 12 g / 10 min. Multi-layer laminated film.
(3) A lid base material layer (D) selected from a stretched film obtained by depositing a stretched film and an inorganic oxide on the surface of the base resin layer (C) on the side opposite to the seal resin layer (A). The multilayer laminated film according to (1) or (2), wherein one or two layers are further laminated.

(4) The multilayer laminated film according to (3), wherein the inorganic oxide is alumina or silica.
(5) The multilayered film according to (3) or (4), wherein the oxygen permeability of the multilayer laminated film when measured by a method according to JIS K 7126 is 3.0 cc / m ² · day · atm or less Laminated film.
(6) The multilayer laminated film according to any one of (3) to (5), wherein the multilayer laminated film has a haze value of 40% or less.
(7) A packaging container using any one of the multilayer laminated films of (3) to (6) as a lid, wherein the sealing resin layer (A) of the lid is in contact with the opening of the container formed of polyethylene. A packaging container that is heat-sealed in such a stacked state and is opened by cohesive failure of the sealing resin layer (A) of the lid when opened.
(8) The method for producing a multilayer laminated film according to (1) or (2), wherein an inflation film-forming method is used.

  The multilayer laminated film of the present invention is excellent in easy opening, transparency and gas barrier properties, and has a beautiful peeled surface. Therefore, a container using this as a lid is excellent in both practicality and aesthetics. It is.

  That is, the multilayer laminated film of the present invention comprises a general-purpose resin two-component system in which the sealing resin layer (A) is incompatible, and the sea-island structure can be controlled by controlling the blend ratio and MFR (melt mass flow rate) of this layer. Can be controlled and can achieve an appropriate cohesive failure strength, reducing or inhibiting stringing after peeling, having excellent easy opening properties, and having a peelable surface after opening. A multilayer laminated film for a material can be provided. Moreover, in this invention, since a low density polyethylene is used for a sealing resin layer (A), the multilayer laminated film of this invention has the outstanding transparency. Furthermore, since an ethylene / vinyl alcohol copolymer having excellent gas barrier properties, particularly oxygen barrier properties, is used as the base resin layer (C), the multilayer laminated film of the present invention is suitable for long-term storage of contents. Is.

  In addition, the multilayer laminated film of the present invention can be produced by various methods known to those skilled in the art, but is preferably produced also by an inflation film-forming method that can be produced at low cost even in the case of a small lot. Can do. The inflation film-forming method is a film-forming method suitable for the production of various types of small quantities, but the application range is narrow and can be used only for limited materials. That is, the conventional easy-open (easy peel) film is relatively expensive, while the multilayer laminated film of the present invention can be applied with a general-purpose and inexpensive material and an inflation film-forming method. Therefore, there is a merit in terms of cost.

  Further, by providing a transparent stretched film or a stretched film on which an inorganic oxide is deposited as a lid base material layer (D) on the surface of the base resin layer (C), the haze value is 40%. Therefore, it is possible to provide a multilayer laminated film having a gas barrier property suitable for long-term storage of the contents.

The multilayer laminated film of the present invention will be described in detail.
As shown in FIG. 1, the multilayer laminated film of the present invention comprises a sealing resin layer (A), and a base resin layer (B) and a base resin layer (C) laminated in order on the sealing resin layer (A). Is the basic structure.

Next, materials constituting the multilayer laminated film of the present invention, manufacturing methods thereof, and the like will be described.
Hereinafter, the resin names used in the present invention are those commonly used in the industry. Moreover, the density said to this invention means what was measured based on "JISK7112".

<1> Seal resin layer (A)
(1) Low density polyethylene or ethylene-α-olefin copolymer constituting the sealing resin layer (A) In the present invention, the material constituting the sealing resin layer (A) is low density polyethylene or ethylene-α-olefin. A copolymer is used. Here, the ethylene-α-olefin copolymer includes a block or random copolymer of ethylene and another α-olefin (for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, etc.). Is included. In the present invention, as the sealing resin layer (A), it is particularly preferable to use low density polyethylene or a random copolymer of ethylene and 1-butene from the viewpoint of easy opening and transparency.
The density of the low-density polyethylene and ethylene-α-olefin copolymer constituting the sealing resin layer (A) is 0.915 to 0.930 g / cm ³ . Moreover, as said low density polyethylene and ethylene-alpha-olefin copolymer, MFR (190 degreeC) is 1-9 g / 10min, Preferably it is 1-7 g / 10min, and resin with comparatively high melt viscosity is used. It is preferable to use it.

In the above, if the density exceeds 0.930 g / cm ³ , for example, high density polyethylene or medium density polyethylene is used, the crystallinity is high and the transparency is lowered. In addition, if the density is less than 0.915 g / cm ³ , it is difficult to form a film by the inflation film forming method because of high fluidity, and the slipperiness of the film is deteriorated and the processability is inferior. It becomes. On the other hand, if the MFR (190 ° C.) is less than 1 g / 10 minutes, the flowability is lowered, and thus the production becomes difficult. On the other hand, when the above specified range is exceeded, the film-forming stability is inferior. Here, the MFR (190 ° C.) referred to in the present invention means a value measured according to “JIS K6922”.
Examples of the low-density polyethylene and ethylene-α-olefin copolymer suitable for use in the present invention include Evolu from Prime Polymer, Novatic LD from Nippon Polyethylene.

(2) Propylene Elastomer Constructing Seal Resin Layer (A) In the present invention, the propylene elastomer constituting the seal resin layer (A) includes propylene homopolymer, and block or random of propylene and other α-olefin. Copolymers are included. Here, the α-olefin includes, for example, ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, etc. In order to obtain an appropriate seal strength, a random mixture of propylene and ethylene is used. A propylene elastomer made of a copolymer is particularly preferred.

As the propylene elastomer, one having a density of 0.850 to 0.89 g / cm ³ , preferably 0.850 to 0.88 g / cm ³ is used. Moreover, it is preferable to use what has MFR (230 degreeC) of 1-12 g / 10min. An MFR (230 ° C.) of less than 1 g / 10 minutes is not preferable because unevenness occurs in the sealing resin layer (A). Moreover, when MFR (230 degreeC) exceeds 12 g / 10min, the slipperiness | lubricity of the seal | sticker resulting from a low molecular weight component and a low elastic modulus will fall, and it will be inferior to the workability at the time of dry lamination. Here, the MFR (230 ° C.) referred to in the present invention means a value measured according to “JIS K6921”.
In the seal resin layer (A), the low density polyethylene or ethylene-α-olefin copolymer and the propylene elastomer have a sea-island structure because they are incompatible, but the propylene elastomer is a propylene-ethylene copolymer. By using a polymer and increasing the ethylene content, compatibility with low-density polyethylene or ethylene-α-olefin copolymer can be improved, and the seal strength can be increased.
Suitable propylene elastomers for use in the present invention include, for example, Versify manufactured by Dow Chemical Co., Adflex manufactured by Basel.

(3) Blend ratio The blend ratio of the low-density polyethylene or ethylene-α-olefin copolymer and propylene elastomer in the seal resin layer (A) is 90-30 parts by weight, preferably 90-60 parts by weight of low-density polyethylene or It is desirable to comprise ethylene-α-olefin and 10 to 70 parts by weight, preferably 10 to 40 parts by weight of propylene elastomer.
If the content of the propylene elastomer is higher than the above range, the adhesive strength becomes too high and good easy-openability cannot be obtained, and if it is lower than the above range, sufficient adhesive strength cannot be obtained and the sealing performance as a packaging container is not obtained. I'm not satisfied.

  Further, the blend ratio is preferably changed in accordance with the adhesive strength required between the adherend and the adherend within the specified value range. For example, when the sealing layer of the packaging container is polyethylene, the sealing resin layer It is possible to improve the sealing strength by increasing the content of polyethylene or ethylene-α-olefin copolymer of (A), and when the sealing layer of the packaging container is polypropylene, the content of propylene elastomer is increased. Thus, the seal strength can be improved.

<2> Base resin layer (B)
As the resin constituting the base resin layer (B) of the multilayer laminated film of the present invention, an ethylene / maleic anhydride graft copolymer or a propylene / maleic anhydride graft copolymer is used.
In the present invention, since the resin used for the seal resin layer (A) and the resin used for the base resin layer (C) are incompatible, the adhesive force is weak. Therefore, by using the above resin as the base resin layer (B), the interlayer strength is improved and a multilayer laminated film having excellent practicality can be obtained. That is, the resin functions as an adhesive resin that can firmly bond the sealing resin layer (A) and the base resin layer (C). Examples of the ethylene / maleic anhydride graft copolymer or propylene / maleic anhydride graft copolymer suitable for use in the present invention include, for example, an ethylene / maleic anhydride graft copolymer (Admer) manufactured by Mitsui Chemicals, Inc. NF308), and a propylene / maleic anhydride graft copolymer (Admer QF551) manufactured by Prime Polymer Co., Ltd., and the like.

<3> Base resin layer (C)
As the resin constituting the base resin layer (C) of the multilayer laminated film of the present invention, an ethylene / vinyl alcohol copolymer is used. This resin has an oxygen barrier property that prevents permeation of oxygen. Examples of the ethylene-vinyl alcohol copolymer suitable for use in the present invention include Eval E105 and Eval H101 manufactured by Kuraray Co., Ltd.

<4> Layer Thickness Regarding the sealing resin layer (A), the layer thickness is 1 to 20 μm, preferably 1 to 10 μm. When the above range is exceeded, the release layer (cohesive failure layer) becomes dirty, the release surface is inferior in beauty, and the cost increases. Moreover, desired adhesiveness is not acquired as it is less than 1 micrometer.
The layer thickness of the base resin layer (B) is 1 to 20 μm, preferably 5 to 20 μm, and the layer thickness of the base resin layer (C) is preferably 10 to 30 μm. As for the base resin layer (B), when the layer thickness exceeds 20 μm, a film odor derived from maleic anhydride appears prominently, which may adversely affect the scent of the contents, and costs increase. On the other hand, if the layer thickness is 5 μm or even less than 1 μm, sufficient adhesion cannot be obtained. Moreover, about base-material resin layer (C), when it exceeds 30 micrometers, transparency will fall and cost will rise. On the other hand, if it is less than 10 μm, desired gas barrier properties cannot be obtained.
The total thickness of the base resin layers (B) and (C) is preferably designed to be 30 to 50 μm.

<5> Method for Producing Multilayer Laminated Film of the Present Invention Consisting of Sealing Resin Layer (A) and Substrate Resin Layer (B), (C) Next, the sealing resin layer (A) and the base resin layer (B), ( A method for producing the multilayer laminated film of the present invention comprising C) will be described. The laminating step in this production method is a method of laminating ordinary packaging materials, for example, wet lamination method, dry lamination method, solventless dry lamination method, extrusion lamination method, T-die extrusion molding method, coextrusion lamination method, inflation Although it can be performed by various methods known to those skilled in the art, such as a film forming method and a coextrusion inflation film forming method, among others, use an inflation film forming method that can be manufactured at low cost even in the case of a small lot. Is preferred.

<6> Lid base material layer (D)
On the surface of the base resin layer (C) of the multilayer laminated film of the present invention, as a lid base material layer (D), various transparent packaging materials, for example, stretched films, are laminated by one layer or two or more layers. be able to.
In the present invention, as the “stretched film”, polyesters such as polyethylene terephthalate, polybutylene terephthalate and 6-naphthalate, and polyamides such as nylon 6 and nylon 66 are used. Particularly preferable stretched films include stretched films made of polyester (polyethylene terephthalate), polyamide (nylon 6, nylon 66, nylon 6-66), etc., which are excellent in transparency, mechanical strength and packaging suitability. By laminating various stretched films on the multilayer laminated film of the present invention, the physical strength of the film is improved, and favorable properties for heat treatment such as heat shrinkability are imparted.
The packaging material as described above can be laminated by, for example, a dry lamination method, a solventless lamination method, an extrusion lamination method, a coextrusion lamination method, or the like.

  Moreover, in this invention, it is preferable to use what provided the gas-barrier layer on the said stretched film as a lid | cover material base for the purpose of improving a gas-barrier property further. As such a gas barrier layer, inorganic metal oxides such as silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), Examples include boron (B), titanium (Ti), lead (Pb), zirconium (Zr), oxides such as yttrium (Y), preferably vapor-deposited films of alumina and silica. The film thickness of the inorganic oxide vapor-deposited film varies depending on the metal to be used or the type of metal oxide, etc., but from the viewpoint of gas barrier properties, for example, it is optional within the range of 50 to 2000 mm, preferably 100 to 1000 mm. Can be selected. The inorganic oxide vapor-deposited film can be provided on the stretched film by physical vapor deposition or chemical vapor deposition.

Furthermore, in the present invention, for the purpose of further improving the gas barrier property, a gas barrier coating film developed by the present applicant, that is, the general formula: R ¹ _n M (OR ² ) _m (wherein M is a metal atom, R ¹ and R ² are organic groups having 1 to 8 carbon atoms, n is 0 or more, m is an integer of 1 or more, and n + m represents a valence of M), and at least one alkoxide, polyvinyl alcohol, and A gas barrier coating film made of a gas barrier composition obtained by polycondensation of a composition containing ethylene / vinyl alcohol by a sol-gel method may be provided on the inorganic oxide vapor-deposited film.
Various stretched films, or various stretched films provided with a gas barrier layer and a gas barrier coating film are transparent. By using these, the haze value can be suppressed to a low value of 40% or less. The lid material can be made beautiful and excellent in contents visibility. In addition, the haze value as used in the field of this invention means the value measured based on JIS K-7105.

<7> Physical Properties Next, factors in setting physical properties required for the multilayer laminated film of the present invention will be described.
(1) Cohesive failure (cohesive peeling) strength The easy-openability or cohesive failure strength of the multilayer laminated film of the present invention is controlled by low-density polyethylene or ethylene-α-olefin copolymer and propylene used for the seal resin layer (A). This is done by changing the blending ratio of the elastomer.

(2) Transparency The transparency of the multilayer laminated film of the present invention is controlled by controlling the density of the low density polyethylene or ethylene-α-olefin copolymer used for the sealing resin layer (A).
Specifically, for the sealing resin layer (A), a low-density polyethylene or ethylene-α-olefin copolymer having a density of 0.910 to 0.930 g / cm ^{3 and} a relatively small crystallinity is used. When the density exceeds 0.930 g / cm ³ , for example, high-density polyethylene or medium-density polyethylene is used, the desired transparency cannot be obtained due to high crystallinity.

(3) Gas barrier property The oxygen barrier property which blocks | prevents permeation | transmission of oxygen is obtained by laminating | stacking the layer which consists of an ethylene vinyl alcohol copolymer as a base resin layer (C). In order to obtain an oxygen barrier property sufficient for long-term storage of food, it is desirable that the base resin layer (C) has a layer thickness of at least 10 μm. In the multilayer laminated film of the present invention, the base resin layer (C) has a maximum thickness of 30 μm. When the layer thickness is made thicker than this, the transparency is lowered and the cost is increased.
Moreover, in order to suppress the quality deterioration of contents (food etc.), you may laminate | stack the packaging material which has oxygen and / or water vapor | steam barrier property further on the multilayer laminated film of this invention.
The multilayer laminated film of the present invention alone or in some cases, by further laminating an appropriate packaging material, the oxygen permeability is 3.0 cc / m ² · day · atm as a numerical value obtained by a method according to JIS K 7126. The following excellent oxygen barrier properties can be exhibited.

<8> Configuration of Lid Material Next, the configuration of an example of the lid material of the packaging container using the multilayer laminated film of the present invention will be described with reference to FIG. The lid of the packaging container in FIG. 2 is printed on a multilayer laminated film composed of the sealing resin layer (A), the base resin layer (B), and the base resin layer (C) according to the present invention as necessary. The lid material base layer (D) is further laminated on the laminate adhesive layer that has been subjected to the above.

<9> Packaging container The multilayer laminated film of the present invention is used for a sealant film for a lid of a packaging container. In particular, it is used for cup-shaped packaging containers in which the adhesive surface of the lid of the container opening is heat-sealed to the opening of the container formed of polyethylene, and the sealing resin layer (A) of the lid is coherently broken when opened. Opened. Such a packaging container may be formed with a plurality of containers via flanges, and in that case, means for separating the containers from the flanges, for example, a sewing machine that penetrates the flanges and lids of the containers. Eyes can also be provided.

The present invention will be described more specifically with reference to examples.
[Example 1]
(1) Seal resin layer (A)
As a resin composition for the sealing resin layer (A), low-density polyethylene (Prime Polymer Evolue SP1085: density = 0.919 g / cm ³ , MFR (190 ° C.) = 8.0 g / 10 min) 60 parts by weight, propylene elastomer 40 parts by weight (Dow Chemical Versify V2200: density = 0.888 g / cm ³ , MFR (230 ° C.) = 8.0 g / 10 min) was sufficiently kneaded and prepared.

(2) Base resin layer (B)
As a resin composition for the base resin layer (B), an ethylene / maleic anhydride graft copolymer (Admer NF308 manufactured by Mitsui Chemicals, Inc .: density = 0.932 g / cm ³ , MFR (230 ° C.) = 1.7 g / 10 100 parts by weight of the resin was prepared.

(3) Base resin layer (C)
As a resin composition for the base resin layer (C), an ethylene / vinyl alcohol copolymer (Eval E105 manufactured by Kuraray Co., Ltd .: density = 1.14 g / cm ³ , MFR (190 ° C.) = 5.5 g / 10 min) 100 parts by weight of a certain resin was prepared.
Using a top-blown air-cooled inflation coextrusion film forming machine, a multilayer laminated film with a total thickness of 35 μm (sealing resin layer (A) 5 μm / base resin layer (B) 5 μm / base resin layer (C) 25 μm ) Was manufactured.

Next, the surface of the base resin layer (C) is subjected to corona treatment, and a two-component curable urethane adhesive (main agent: polyester polyol, hardener: aliphatic isocyanate) is applied to the surface, and the cover base material layer As (D), a silica-deposited biaxially stretched PET film (Toyobo Co., Ltd. E5100 <single side treatment>: thickness 15 μm) and a biaxially stretched ONy film (Unitika Ltd. [Emblem NX] <Both side treatment>: Two layers having a thickness of 15 μm were sequentially laminated. The obtained laminate has a structure of silica-deposited PET15 / DL / ONy15 / DL / base resin layer (C) / base resin layer (B) / seal resin layer (A) (DL is an adhesive) Means part).
The haze value of the multilayer laminate produced above was measured using a haze computer (manufactured by Suga Test Instruments Co., Ltd .: HGM-2DP). Further, the oxygen permeability of the multilayer laminate was measured using OX-TRAN (manufactured by MOCON, USA).
Next, the multilayer laminate is made into a cup-shaped container (diameter 74φ, flange width) made of polyethylene resin.
5 mm, capacity 120 cc) was heat-sealed from a flat seal under the conditions of a seal temperature of 170 ° C., 3 kg / cm ² and 1 second. Thereafter, a 15 mm wide test piece was prepared from the cup, and the seal strength was measured by 180 ° peeling at a test speed of 300 mm / min. The obtained multilayer laminate was confirmed to have an appropriate sealing strength, a beautiful peel appearance, and a sufficient transparency and oxygen barrier property.

[Example 2]
(1) Seal resin layer (A)
As a resin composition for the sealing resin layer (A), low-density polyethylene (Prime Polymer Evolue SP1085: density = 0.919 g / cm ³ , MFR (190 ° C.) = 8.0 g / 10 min) 60 parts by weight, propylene elastomer 40 parts by weight (Dow Chemical Versify V2200: density = 0.888 g / cm ³ , MFR (230 ° C.) = 8.0 g / 10 min) was sufficiently kneaded and prepared.

(2) Base resin layer (B)
As the resin composition for the base resin layer (B), an ethylene / maleic anhydride graft copolymer (Admer NF308 manufactured by Mitsui Chemicals, Inc .: density = 0.932 g / cm ³ , MFR (230 ° C.) = 1.7 g / 10 Min) was prepared by 100 parts by weight.

(3) Base resin layer (C)
As a resin composition for the base resin layer (C), an ethylene / vinyl alcohol copolymer (Eval H101 manufactured by Kuraray Co., Ltd .: density = 1.17 g / cm ³ , MFR (190 ° C.) = 1.6 g / 10 min) 100 parts by weight of a certain resin was prepared.
Using a top-blown air-cooled inflation coextrusion film forming machine, a multilayer laminated film with a total thickness of 50 μm (sealing resin layer (A) 5 μm / base resin layer (B) 15 μm / base resin layer (C) 30 μm ) Was manufactured.
Thereafter, the same results as in Example 1 were obtained.

[Comparative Example 1]
(1) Seal resin layer (A)
As a resin composition for the sealing resin layer (A), low-density polyethylene (Prime Polymer Evolue SP2020: density = 0.923 g / cm ³ , MFR (190 ° C.) = 3.0 g / 10 min) 60 parts by weight, propylene elastomer 40 parts by weight (Dow Chemical Company Versify V2300: density = 0.867 g / cm ³ , MFR (230 ° C.) = 25 g / 10 min) was sufficiently kneaded and prepared.

(2) Base resin layer (B)
As the resin composition for the base resin layer (B), an ethylene / maleic anhydride graft copolymer (Admer NF308 manufactured by Mitsui Chemicals, Inc .: density = 0.932 g / cm ³ , MFR (230 ° C.) = 1.7 g / 10 Min) was prepared by 100 parts by weight.

(3) Base resin layer (C)
As a resin composition for the base resin layer (C), an ethylene / vinyl alcohol copolymer (Eval H101 manufactured by Kuraray Co., Ltd .: density = 1.17 g / cm ³ , MFR (190 ° C.) = 1.6 g / 10 min) 100 parts by weight of a certain resin was prepared.
Using a top-blown air-cooled inflation coextrusion film forming machine, a multilayer laminated film with a total thickness of 50 μm (sealing resin layer (A) 5 μm / base resin layer (B) 15 μm / base resin layer (C) 30 μm ) Was produced, but blocking occurred at the nip roll of the film forming machine, and the film could not be formed.

[Comparative Example 2]
(1) Seal resin layer (A)
As a resin composition for the sealing resin layer (A), low-density polyethylene (Novatec LD LC522 manufactured by Nippon Polyethylene Co., Ltd .: density = 0.922 g / cm ³ , MFR (190 ° C.) = 4.0 g / 10 min) 50 parts by weight, propylene 50 parts by weight of an elastomer (Versify V3200 manufactured by Dow Chemical Co., Ltd .: density = 0.866 g / cm ³ , MFR (230 ° C.) = 2.0 g / 10 min) was sufficiently kneaded and prepared.

(2) Base resin layer (B)
As a resin composition for the base resin layer (B), an ethylene / maleic anhydride graft copolymer (Admer NF308 manufactured by Mitsui Chemicals, Inc .: density = 0.932 g / cm ³ , MFR (230 ° C.) = 1.7 g / 10 Min) was prepared by 100 parts by weight.

(3) Base resin layer (C)
As a resin composition for the base resin layer (C), an ethylene / vinyl alcohol copolymer (Eval E105 manufactured by Kuraray Co., Ltd .: density = 1.14 g / cm ³ , MFR (190 ° C.) = 5.5 g / 10 min) 100 parts by weight of a certain resin was prepared.
Using a top-blown air-cooled inflation coextrusion film forming machine, a multilayer laminated film with a total thickness of 30 μm (sealing resin layer (A) 5 μm / base resin layer (B) 20 μm / base resin layer (C) 5 μm ) And various physical properties were evaluated, but the oxygen permeability was high and sufficient oxygen barrier properties could not be imparted.

[result]
Table 1 summarizes the seal strength, haze value, and oxygen permeability measured in the above Examples and Comparative Examples.
These physical properties were measured as follows.
(1) Layer thickness: Measured with a μ-meter manufactured by SONY Corporation.
(2) Seal strength: Sealed from a flat seal to a polypropylene cup under conditions of a seal temperature of 170 ° C., 3 kg / cm ² and 1 second. A strip-shaped test piece having a width of 15 mm was cut out from the tensile tester, and a tensile test was performed at 300 mm / min.
(3) Haze value: Measured using a haze computer (manufactured by Suga Test Instruments Co., Ltd .: HGM-2DP).
(4) Oxygen permeability: Measured by a method according to JIS K7126 using a measuring instrument (model name: OX-TRAN) manufactured by MOCON, USA under conditions of a temperature of 23 ° C. and a humidity of 90% RH.

As described above, it was confirmed that each of the multilayer laminated films of Examples 1 and 2 showed favorable seal strength and excellent easy-openability, and also had good transparency and gas barrier properties.
On the other hand, in the multilayer laminated film of Comparative Example 1, the MFR of the propylene elastomer used for the sealing resin layer (A) is as high as 25 g / 10 min, but cannot be produced by the inflation film forming method. It was confirmed to be a thing. In the multilayer laminated film of Comparative Example 2, the base resin layer (C) had a layer thickness as small as 5 μm, but the gas barrier property was remarkably inferior.

It is sectional drawing which shows the layer structure of the multilayer laminated film of this invention. It is sectional drawing which shows the layer structure of the multilayer laminated film of this invention.

Explanation of symbols

1 Sealing resin layer (A)
2 Base resin layer (B)
3 Base resin layer (C)
4 Laminating adhesive layer 5 Printing layer 6 Lid base material layer (D)

Claims (8)

A multi-layer laminated film having a sealing resin layer (A), and a base resin layer (B) and a base resin layer (C) sequentially laminated thereon,
The sealing resin layer (A) comprises (i) 90 to 30 parts by weight of low density polyethylene or ethylene-α-olefin copolymer having a density of 0.915 to 0.930 g / cm ³ and (ii) a density of 0.850 to 0.89 g / cm 3. ³ consisting of 10 to 70 parts by weight of propylene elastomer, wherein the sum of (i) and (ii) is 100 parts by weight,
The base resin layer (B) is made of an ethylene / maleic anhydride graft polymer or a propylene / maleic anhydride graft polymer,
The base resin layer (C) is made of an ethylene / vinyl alcohol copolymer, and the layer thickness of the seal resin layer (A) is 1 to 20 μm, and the layer thickness of the base resin layer (B) is 1 to 20 μm, the thickness of the base resin layer (C) is 10 to 30 μm, and the total thickness of the base resin layer (B) and the base resin layer (C) is 30. A multilayer laminated film having a thickness of ˜50 μm.   2. The multilayer according to claim 1, wherein the propylene elastomer used for the sealing resin layer (A) is an ethylene / propylene random copolymer, and the MFR (230 ° C.) is 1 to 12 g / 10 min. Laminated film.   One surface of the base material layer (D) selected from a stretched film and a stretched film on which an inorganic oxide is vapor-deposited on the surface of the base resin layer (C) opposite to the seal resin layer (A) Two or more layers are laminated | stacked, The multilayer laminated film of Claim 1 or 2 characterized by the above-mentioned.   The multilayer laminated film according to claim 3, wherein the inorganic oxide is alumina or silica. The multilayer laminated film according to claim 3 or 4, wherein the oxygen permeability of the multilayer laminated film when measured by a method according to JIS K 7126 is 3.0 cc / m ² · day · atm or less.   The multilayer laminated film according to any one of claims 3 to 5, wherein the multilayer laminated film has a haze value of 40% or less.   It is a packaging container which uses the multilayer laminated film of any one of Claims 3-6 as a cover material, Comprising: The sealing resin layer (A) of this cover material contacts the opening part of the container formed with polyethylene. A packaging container that is heat-sealed in such a stacked state and is opened by cohesive failure of the sealing resin layer (A) of the lid when opened.   The method for producing a multilayer laminated film according to claim 1 or 2, wherein an inflation film forming method is used.

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