JP2003001768A - Heat fusion bonding film and package comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat fusion bonding film excellent in the heat fuse bonding property with an ethylene polymer or propylene polymer layer, having easily opening properties at the time of opening and a soft feeling at the time of closing and excellent in blocking resistance, sanitariness, film forming processability and lamination processability, a lid material comprising the heat fusion bonding film and a package using the heat fusion bonding film. SOLUTION: The heat fusion bonding film has a heat fusion bonding layer comprising a resin composition (C) consisting of 99-20 wt.% of an ethylene/vinyl ester copolymer (A) and 1-80 wt.% of a propylene polymer (B). The package having an easily openable packaging material and a container lid material, both of which use the heat fusion bonding film, and a heat sealing layer comprising the ethylene polymer or propylene polymer layer and excellent in easily opening properties at the time of opening and a soft feeling at the time of closing is also disclosed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an easy-opening property provided with a heat-sealing layer made of a resin composition of an ethylene / vinyl ester copolymer and a propylene polymer, a soft feeling upon opening,
The present invention relates to a heat-sealing film having excellent blocking resistance, hygiene properties, film-forming processability, and laminating processability, a container lid material made of such a heat-sealing film, and a package using the same.

[0002]

2. Description of the Related Art Snack confectionery such as rice crackers and potato chips, packaging of snacks such as jelly, milk, yogurt, pudding, tofu, lactic acid beverages, blister packaging, and packaging for other daily necessities and miscellaneous goods such as bottles, cups, or A package in which a tray-shaped plastic container is sealed with a lid material made of a plastic laminated film or an aluminum foil laminated film is widely adopted.
What is required of such a package is mechanical strength to endure a distribution channel, seal strength capable of maintaining hygiene, and good unsealing property during use.

[0003] As one of the materials used for such packaging, one of the categories is a film having a category called an easy-opening (easy peel) film as a heat-sealing layer which is the innermost layer, or a lid material. The package used for is widely used. However, the various heat-sealing layers proposed so far have high heat-sealing strength for sealing, but the easy peeling property at the time of opening is not always sufficient, and a proper balance between the two can be obtained. It has been demanded. The characteristics required for easy peeling here are not only the ease of opening, but also that there is no residue of resin fragments adhering to the opening after the opening due to a stringing phenomenon and the appearance of the opening is also good. It is a comprehensive evaluation including the quality of the product.

As a means for solving the above drawbacks, for example, a heat-sealable resin composition comprising an ethylene-vinyl ester copolymer, a low crystalline or amorphous ethylene copolymer and a tackifier (Japanese Patent Publication No. 63- 29894), ethylene-α-olefin copolymer, propylene-
An easily-openable resin composition for heat-sealing, which comprises an ethylene copolymer and low-density polyethylene (JP-A-2-18554).
No. 7) is proposed.

However, when a sealing material having such a constitution is used in a paper container laminated with low-density polyethylene, it becomes a complete seal with the low-density polyethylene layer, and when opened, the low-density polyethylene peels off and peels off the paper. There is a risk that paper waste or the like will fall onto the contents, or the container will be deformed and the contents will spill. In addition, a film having such a composition layer may be easily blocked, and it may be difficult to unwind the film wound into a roll, and the appearance may be deteriorated due to blocking marks.

[0006]

DISCLOSURE OF THE INVENTION The present invention is excellent in blocking resistance, soft unsealing property, hygiene property and processability, and when heat-sealed with a heat-sealing layer comprising an ethylene polymer layer or a propylene polymer layer. The temperature dependence of the heat-sealing strength of the product is small, and there is no risk of the package being leaked during transportation, etc. In order to obtain a film and packaging that can be opened by a clean interface peeling or cohesive peeling without stringing with the ethylene polymer that is soft and coated / extruded on the surface of the paper container. In such a case the temperature is 30
50 to 60 at ℃ or above, or during distribution / storage
Even when stored at a high temperature of about ℃, there is heat resistance against air leaks and punctures at the seal part, especially the step of the container and the lid material seal part, that is, the sealing property as a container is excellent. Various studies were conducted in order to obtain a heat-sealing film and a package which can be easily opened.

[0007]

According to the present invention, 99 to 20% by weight of an ethylene / vinyl ester copolymer (A) having a vinyl ester content of 3 to 30% by weight and 1 to 80% by weight of a propylene polymer (B) are used. And a heat-sealing film having a heat-sealing layer made of the resin composition (C), an easily-openable packaging material and a container lid material using the heat-sealing film, the opposite surfaces having a vinyl ester content of 3 ~ 30 wt% ethylene
A heat-sealing layer made of a resin composition (D) of 99-40% by weight of a vinyl ester copolymer (A) and 1-60% by weight of a propylene polymer (B), and a heat-sealing layer made of an ethylene polymer layer. 95 to 20% by weight of an ethylene / vinyl ester copolymer (A) having a vinyl ester content of 3 to 30% by weight.
And a heat-sealing layer made of a resin composition (E) containing 5 to 80% by weight of a propylene polymer (B) and a heat-sealing layer made of a propylene polymer layer.

[0008]

[Detailed Description of the Invention] Ethylene / vinyl ester copolymerization
Body (A) The ethylene / vinyl ester copolymer (A) according to the present invention is a copolymer of ethylene and a vinyl ester such as vinyl acetate or vinyl propionate, and is a vinyl present in the copolymer. The ester content is in the range of 3 to 30% by weight, preferably 5 to 15% by weight. When the vinyl ester content is within this range, a good balance between the heat seal strength and the easy peeling property is maintained, and the heat resistance required for filling foods is obtained, which is preferable. The melt flow rate (MFR) of this copolymer is JIS
A copolymer having a value measured according to 6730 in the range of usually 1 to 40, preferably 1.5 to 30 (g / 10 minutes) has good extrudability and is sufficient as a packaging film. It has mechanical strength. The ethylene / vinyl ester copolymer (A) has an effect of imparting low temperature heat sealability when used as a heat fusion layer.

Propylene Polymer (B) The propylene polymer (B) according to the present invention is a resin generally manufactured and sold under the name of polypropylene, which is suitable for film use, and usually has a density of 0.890 to.
0.930 g / cm ³ , MFR (ASTM D1238
Load 2160g, temperature 230 ° C) is 0.5-60g /
It is a homopolymer of propylene for 10 minutes, preferably 0.5 to 10 g / 10 minutes, or a random or block copolymer of propylene and a small amount of other α-olefins such as ethylene, butene and hexene-1.

Resin composition (C) The resin composition (C) according to the present invention is
The vinyl ester copolymer (A) comprises 99 to 20% by weight, preferably 98 to 40% by weight, and the propylene polymer (B) comprises 1 to 80% by weight, preferably 2 to 60% by weight. (ASTM D1238 load 216
0 g, temperature 190 ° C.) is in the range of 0.1 to 40 g / 10 minutes, preferably 1 to 30 g / 10 minutes. When the amount of the propylene polymer (B) is less than 1% by weight, when the resin composition (C) faces are heat-sealed, the heat-sealing strength tends to be too strong and the easy-open property tends to be poor, while the weight is 80% by weight. %, The low-temperature heat-sealing property, the unsealing strength, the practical sealing property, and the sealing property (heat resistance) tend to be poor.

Resin composition (D) The resin composition (D) according to the present invention is
The vinyl ester copolymer (A) is 99 to 40% by weight, preferably 98 to 60% by weight, and the propylene polymer (B) is 1 to 60% by weight, preferably 2 to 40% by weight. (ASTM D1238 load 216
0 g, temperature 190 ° C.) is in the range of 0.1 to 40 g / 10 minutes, preferably 1 to 30 g / 10 minutes. If the amount of the propylene polymer (B) is less than 1% by weight, the heat seal strength tends to be too strong when heat-sealed with the ethylene polymer layer and the easy-open property tends to be poor, while if it exceeds 60% by weight. It tends to be inferior in low-temperature heat sealability, unsealing strength, practical sealing performance, and sealing performance (heat resistance).

Resin composition (E) The resin composition (E) according to the present invention is
The vinyl ester copolymer (A) is 95 to 20% by weight, preferably 80 to 40% by weight, and the propylene polymer (B) is 5 to 80% by weight, preferably 20 to 60% by weight. (ASTM D1238 load 216
0 g, temperature 190 ° C.) is in the range of 0.1 to 40 g / 10 minutes, preferably 1 to 30 g / 10 minutes. When the amount of the propylene polymer (B) is less than 5% by weight, the heat seal strength is low when heat-sealed with the propylene polymer layer, and the unsealing strength, the practical sealing performance and the sealing performance tend to be poor. While 8
If it exceeds 0% by weight, the heat seal strength tends to be too strong and the easy-open property tends to be poor.

The ethylene / vinyl ester copolymer (A), propylene polymer (B) or resin compositions (C), (D) and (E) thereof according to the present invention do not impair the object of the present invention. Additives such as an antioxidant, a weather resistance stabilizer, an antistatic agent, and an antifogging agent which are commonly used can be blended in the range as required. In particular, by adding an anti-blocking agent and a slip agent, it is possible to improve the workability and workability during film forming, laminating, packaging, and the like.

Thermal Fusion Film The thermal fusion film according to the present invention is a film having a resin composition (C) with the ethylene / vinyl ester copolymer (A) and the propylene polymer (B) as a thermal fusion layer. Is. Such a heat-sealing film can be manufactured by various known methods. For example, the ethylene / vinyl ester copolymer (A) and the propylene polymer (B) are mixed in a predetermined amount, and then directly charged into a film molding machine to form a film using a T-die, a ring die or the like. In the method, ethylene-vinyl ester copolymer (A) and propylene polymer (B) are mixed in a predetermined amount and melt-kneaded with an extruder or the like to obtain a resin composition (C). A method of forming a film using a die, an annular die or the like can be exemplified.

The heat-fusion film can be used as a single layer,
It is a laminated film with an ethylene polymer such as high pressure low density polyethylene, linear low density polyethylene, medium density polyethylene and high density polyethylene as a reinforcing layer, and an olefin polymer layer such as polybutene and ethylene / vinyl acetate copolymer. May be. Among these, the density is 0.905
-0.935 g / cm < ³ >, preferably 0.910-0.
935 g / cm ³ , MFR (ASTM D1238 load 2160 g, temperature 190 ° C.) is 0.5 to 30 g / 10.
A homopolymer of ethylene which is polymerized under high pressure for 1 minute, preferably 1 to 10 g / 10 minutes, or a copolymer with 5% by weight or less of other α-olefin or a vinyl compound such as vinyl acetate, Low-density polyethylene called high-pressure low-density polyethylene, and ethylene and α-olefins having 3 to 10 carbon atoms, such as propylene, butene-1, heptene-1, hexene-1, octene-1, 4,
-Random copolymer of methyl-pentene-1, molecular weight distribution (weight average molecular weight: Mw, and number average molecular weight: M
n, ratio: Mw / Mn) is usually 1.5 to 4.
A laminated film with a film obtained from an ethylene / α-olefin random copolymer or the like, which is generally called linear low density polyethylene (LLDPE), in the range of 0, preferably 1.8 to 3.5 is obtained. Particularly, when a linear low density polyethylene is used for the reinforcing layer, it is excellent in low-temperature sealability, and when the heat-sealed surface is opened, cohesive peeling occurs, and the peeled surface (opening surface) A clean open surface can be obtained without causing stringing.

In the case of obtaining such a laminated film, the resin composition to be the heat-sealing layer and the olefin polymer used for the reinforcing layer can be coextruded using a multilayer die to obtain the heat-sealing film. Alternatively, a resin composition may be extrusion-laminated or extrusion-coated on the reinforcing layer obtained in advance to form a laminate having a heat-sealing layer, or the separately obtained films may be laminated to each other to have a heat-sealing layer. It may be a laminated body. When used as a lid material, the single layer or laminated film or sheet-like laminated body having the heat-sealing layer obtained by the above-mentioned manufacturing method may be used as it is as a lid material, or may be printed and used. . Further, it may be laminated with printed or unprinted paper, aluminum foil or the like to form a lid material.
In addition, depending on the application, the lid material may be cut beforehand according to the shape of the container.

The thickness of the heat-sealing film can be appropriately determined depending on the application, but is usually in the range of 1 to 1000 μm, preferably 2 to 100 μm. When the heat-fusion film is used as a single-layer film, a thickness of 5 μm or more is required due to the molding process. However, when the heat-fusion film can be used as a laminate with the reinforcing layer, the heat-fusion layer is used. Excellent sealing characteristics can be exhibited even if the thickness is as thin as 1 μm.

Substrate Layer The substrate layer to be laminated on the heat- sealing layer according to the present invention is not particularly limited. For example, a thermoplastic resin such as a polyester film represented by polyethylene terephthalate, a polyamide film, a polypropylene film or the like. Examples include film-making, aluminum foil, paper and the like. The reinforcing material composed of such a thermoplastic resin film may be unstretched or may be a uniaxially or biaxially stretched film or a base material such as a sheet. Of course, the base material layer may be one layer or two or more layers.

Heat-sealing layer The heat-sealing layer according to the present invention has various shapes such as films, sheets, trays, cups, bottles, etc. made of ethylene polymer or propylene polymer according to the material to be packaged by various known methods. It is a thing. In the case of a film or a sheet, it can be manufactured by the same method as that for the heat-sealing film. In the case of a tray or a cup, it can be manufactured by once producing a sheet by the above-mentioned method and then forming it into a container such as a tray or a cup by thermoforming such as vacuum forming or pressure forming. In the case of a cup or a bottle, it can be molded as a container by injection molding, injection blow molding (injection blow), blow molding or the like. Further, depending on the intended use, a laminate obtained by extruding an ethylene polymer or a propylene polymer on the above base material layer such as paper by extrusion laminating or extrusion coating may be processed into the above various shapes. Such ethylene polymers are high-pressure low-density polyethylene, linear low-density polyethylene, medium-density polyethylene and high-density polyethylene, and the propylene polymer is in the same category as the propylene polymer (B) used for the heat-sealing film. However, the individual physical properties may be the same or different.

Container lid material The container lid material relating to the easy-open packaging material of the present invention comprises the heat-sealing film as the innermost layer. In the case of a container lid material, various materials exemplified as a base material layer are usually laminated on the heat fusion film.

Packaging Body One of the packaging bodies of the present invention has, on the opposite side, 99 to 40% by weight, preferably 98 to 40% by weight of an ethylene / vinyl ester copolymer (A) having a vinyl ester content of 3 to 30% by weight. 60
From a heat-sealing layer composed of the resin composition (D) containing 1 to 60% by weight, preferably 2 to 40% by weight of the propylene polymer (B), and a heat-sealing layer composed of an ethylene polymer layer. It is a package characterized by being. By forming the heat-sealing layer made of the resin composition (D) and the heat-sealing layer made of the ethylene polymer layer on the opposite surfaces, excellent low-temperature heat-sealing property is achieved and the heat-sealing (heat-sealing) surface is completely sealed Since it has a proper heat seal strength (peeling strength) of 1 to 20 N / 15 mm, there is no risk of the packaged item leaking during transportation or handling, and it is easy to remove the packaged item. Can be opened, and when opening, cohesive peeling does not occur and the heat-sealing surface does not cause stringing during opening.

Another aspect of the package of the present invention is that, on the opposite side, the ethylene / vinyl ester copolymer (A) having a vinyl ester content of 3 to 30% by weight is 95 to 20% by weight, preferably 80%. To 40% by weight and 5 to 80% by weight, preferably 20 to 60% by weight of the propylene polymer (B), the heat-sealing layer made of the resin composition (E), and the heat-sealing layer made of the propylene polymer layer. It is a package characterized by comprising and. By forming the heat-sealing layer made of the resin composition (E) and the heat-sealing layer made of the propylene polymer layer on the opposite surfaces, excellent low-temperature heat-sealing property and complete heat-sealing (heat-sealing) surface can be obtained. Not a seal, 1-20N / 1
Since it has an appropriate heat seal strength (peel strength) of 5 mm, there is no risk of the packaged item leaking during transportation or handling, and it can be easily opened when the packaged item is taken out, and when it is opened. Since the interfacial peeling or the cohesive peeling occurs, stringing does not occur on the heat-sealing surface during opening.

The shape of the member having the heat-sealing layer that constitutes the package of the present invention is not limited to a film-like or sheet-like object, and trays, cups, bottles and the like can be exemplified, but not limited thereto. On the back surface of the heat-sealing layer, a layer which is the same as or different from the base material layer laminated on the heat-sealing layer may be laminated according to various uses.

[0024]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

The raw materials used in Examples and Comparative Examples are as follows. (1) Ethylene / vinyl acetate copolymer (EVA) manufactured by Mitsui DuPont Polychemical (trade name: Evaflex, brand name: P-1405C): vinyl acetate-containing 14% by weight, density 0.93 g / cm ³ , MFR3. 5 g / 10
Min, melting point 90 ° C. (2) Propylene polymer-1 (PP-1) Propylene random copolymer having 3 mol% ethylene content and 1.6 mol% butene content: Density 0.90 g / cm ³ , M
FR 7.0 g / 10 min, melting point 138 ° C. (3) Propylene polymer-2 (PP-2) Propylene homopolymer: Density 0.90 g / cm ³ , MF
R2.0 g / 10 minutes, melting point 160 ° C. (4) Ethylene polymer-1 (single-site catalytic polymerization linear low-density polyethylene) manufactured by Mitsui Chemicals, Inc. (trade name: Evolution, brand name: SP25
40) Density 0.925 g / cm ³ , MFR 4 g / 10 minutes, melting point 120 ° C. (5) Ethylene polymer-2 (linear low density polyethylene) manufactured by Mitsui Chemicals, Inc. (trade name: ULTOZEX, brand name: UZ
3523 L) Density 0.935 g / cm ³ , MFR 2.1 g / 10 minutes,
Melting point 123 ° C

Example 1 A resin composition obtained by dry-blending EVA: 97% by weight and PP-1: 3% by weight as a heat fusion layer, and an ethylene polymer composition (ethylene polymer-1: Ethylene polymer-2 = 30% by weight: 70% by weight) are fed to separate extruders, and heat fusion is performed by a two-layer coextrusion film having a constitution of heat fusion layer / reinforcement layer by T-die method. A wearing film was obtained. The total thickness of the film was 30 μm, and the thickness of each layer was thermal fusion layer: reinforcement layer = 4: 26 μm.

Example 2 In place of the resin composition obtained by dry blending 97% by weight of EVA and 1: 3% by weight of PP used in Example 1, EV was used.
A: The same procedure as in Example 1 was carried out except that a resin composition obtained by dry blending 95% by weight and PP-1: 5% by weight was used.
A heat-sealing layer: Reinforcing layer = 4: 26 μm was obtained as a heat-sealing film.

Example 3 The same procedure as in Example 1 was carried out except that a resin composition obtained by dry blending EVA: 90% by weight and PP-1: 10% by weight was used instead of the resin composition used in Example 1. A heat-sealing film having a heat-sealing layer: reinforcing layer = 4: 26 μm was obtained.

Example 4 The same procedure as in Example 1 was carried out except that a resin composition obtained by dry blending EVA: 70% by weight and PP-1: 30% by weight was used instead of the resin composition used in Example 1. A heat-sealing film having a heat-sealing layer: reinforcing layer = 4: 26 μm was obtained.

Example 5 The same procedure as in Example 1 was repeated except that the resin composition used in Example 1 was replaced by a dry blended resin composition of EVA: 50% by weight and PP: 1: 50% by weight. A heat-sealing film having a heat-sealing layer: reinforcing layer = 4: 26 μm was obtained.

Comparative Example 1 The same procedure as in Example 1 was repeated except that EVA was used in place of the resin composition used in Example 1, and the heat-sealing layer: the reinforcing layer = 4:
A heat fusion film having a thickness of 26 μm was obtained.

Comparative Example 2 The procedure of Example 1 was repeated except that PP-1 was used in place of the resin composition used in Example 1, and the heat-sealing layer: the reinforcing layer =
A heat fusion film having a thickness of 4:26 μm was obtained.

Example 6 The same procedure as in Example 1 was carried out except that a resin composition obtained by dry blending EVA: 97% by weight and PP-2: 3% by weight was used instead of the resin composition used in Example 1. , Thermal fusion layer:
A heat fusion film having a reinforcing layer of 4:26 μm was obtained.

Example 7 The same procedure as in Example 1 was carried out except that a resin composition obtained by dry-blending EVA: 95% by weight and PP-2: 5% by weight was used instead of the resin composition used in Example 1. , Thermal fusion layer:
A heat fusion film having a reinforcing layer of 4:26 μm was obtained.

Example 8 The same procedure as in Example 1 was carried out except that a resin composition obtained by dry blending EVA: 90% by weight and PP-2: 10% by weight was used instead of the resin composition used in Example 1. A heat-sealing film having a heat-sealing layer: reinforcing layer = 4: 26 μm was obtained.

Example 9 The same procedure as in Example 1 was carried out except that a resin composition obtained by dry blending EVA: 70% by weight and PP-2: 30% by weight was used instead of the resin composition used in Example 1. A heat-sealing film having a heat-sealing layer: reinforcing layer = 4: 26 μm was obtained.

Example 10 The same procedure as in Example 1 was carried out except that a resin composition obtained by dry blending EVA: 50% by weight and PP-2: 50% by weight was used instead of the resin composition used in Example 1. A heat-sealing film having a heat-sealing layer: reinforcing layer = 4: 26 μm was obtained.

Comparative Example 3 The same procedure as in Example 1 was carried out except that PP-2 was used in place of the resin composition used in Example 1, and the heat-sealing layer: the reinforcing layer =
A heat fusion film having a thickness of 4:26 μm was obtained.

(1) Evaluation of heat-sealing property: Laminated film: A heat-bonding film obtained in each of the above Examples and Comparative Examples on a biaxially stretched polyethylene terephthalate film (PET) having a thickness of 12 μm. The reinforcing layer was laminated by dry lamination using a urethane adhesive to obtain a laminated film. Substrate: Heat fusion with the above laminated film
As the adherend to be used, the following types of adherends were used. a. Biaxially stretched polyethylene terephthalate with a thickness of 12 μm
As a coating layer (heat sealing layer) on a transparent film (PET),
20μm thick high pressure low density polyethylene (HP-LD
A laminated film obtained by extrusion laminating PE and density: 0.923 g / cm ³ . b. Biaxially stretched polyamide film (O-
As a coating layer (heat-sealing layer) on NY, a linear low-density polyethylene (L-LDPE, thickness: 50 μm, density: 0.
915 g / cm ³ ) Extrusion-laminated laminated film. c. Polypropylene sheet with a thickness of 300 μm (PPS,
Heat seal layer). d. The heat fusion film. Heat-sealing test: 1) The heat-sealing layer surface of the laminated film and the surface of the adherend layer of each of the adherends are superposed and sealed at a predetermined temperature with a seal bar having a width of 5 mm and a pressure of 0.2 MPa for 1 second. After that, it was left to cool. A test piece with a width of 15 mm was cut from this, the heat-sealed portion was peeled off at a crosshead speed of 500 mm / min, and the strength was taken as the heat-sealed strength (N / 15 mm). 2) Adherend a. In the evaluation, no cohesive peeling stringing was evaluated as ◯, interfacial peeling was evaluated as Δ, completely heat-sealed one was evaluated as x, and one having threading and having a tendency to be delaminated was marked as □. . 3) adherend b. In the evaluation, the cohesive peeling was ◯, the interfacial peeling was Δ, and the completely heat-sealed one was X. 4) adherend c. In the evaluation, the cohesive peeling was ⊚, the interfacial peeling was ∘, and the completely heat-sealed one was x. 5) Adherend d. The evaluation is that there is no cohesive peeling stringing.
And

(2) Evaluation of sealing property and unsealing property with container Adjustment of package: A container made of a paper base material having a high pressure method low density polyethylene laminated on the inner surface [manufactured by Tokan Kogyo Co., Ltd .: type AC-430EP ( Plain)) and the heat-sealing film obtained in each of the above-mentioned examples and comparative examples, using an A-shinpak sealer semi-automatic O type manufactured by A-shinpak Kogyo Co., Ltd. The mouth portion was heat-sealed (cup seal) at a heat seal actual pressure of 900 N and a seal time of 1 second. Evaluation of sealing property: Seal Tester manufactured by Sun Kagaku Co., Ltd.
Using the FKT type, the burst strength of the package obtained by the above adjustment method was measured. In the burst strength test, after heat-treating for 24 hours in a container not heat-treated and in an oven at 60 ° C, 23 ° C.
It was performed in a heat-treated container after being left for 24 hours in an atmosphere of relative humidity of 65%. The evaluation of the sealing property is that the change in the burst strength between the unheat-treated container and the heat-treated container is small, and the burst strength after the heat treatment exceeds 10 MPa is ○, and the burst strength around 10 MPa is ○ to △, less than 10 The thing was marked with x. Evaluation of openability: Using the sample whose burst strength was measured, the heat-sealing film was peeled off by hand, and the openability was evaluated according to the following criteria. a. Opening strength: comparable to the opening strength of a snack container (commercial item) sealed with a hot melt material:
◎, slightly weaker: ○, weaker: △, weaker:
X, strong: xx. b. Stringing when opened: No stringing: ⊙, Trace: ○, Slightly: △, Many: × c. Paper peeling: When a heat-sealing film is peeled from a paper-based container, the phenomenon in which the high-pressure low-density polyethylene laminated on the inner surface of the paper peels off from the paper is called paper peeling. ◎, there is a small amount: ○, 1 / the opening of the container
Paper peeling was observed in less than 4: Δ, paper peeling of ¼ or more of the container opening portion was evaluated: x.

The characteristic values of the films obtained in the respective examples, comparative examples and reference examples are shown in Tables 1 and 2.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

The heat-sealing film of the present invention is made of ethylene.
It is a heat-sealing film having a heat-sealing layer in which a composition of a vinyl acetate copolymer and a propylene polymer are mixed in a specific ratio. A packaging material such as a packaging bag in which the film is used as a heat-sealing layer using the heat-sealing film, or a packaging material made of an adherend having an ethylene polymer or a propylene polymer as the heat-sealing layer is a packaged object. Has a low-temperature heat-sealing property (low-temperature heat-sealing property) and has a wide heat-sealing temperature range, and the obtained package has an appropriate heat-sealing strength. Therefore, it has a characteristic that it can be opened easily and softly. Further, the heat fusion film of the present invention is also excellent in blockability.

The paper container using the container lid material of the present invention has a small temperature dependence of the heat-sealing strength, and has a heat-sealing strength such that the packaged article does not leak during transportation, It can be opened easily when the items to be packaged are taken out, and when opened, it is soft and does not cause stringing with the ethylene polymer layer on the surface of the paper container, and paper peeling does not occur, and it can be opened with a clean cohesive peeling. .
In addition, when the temperature is 30 ° C or more in the case of summer climate, or when stored at a high temperature of 50 to 60 ° C during distribution or storage, the seal part, especially the step of the container and the cover material -It has a feature that it is excellent in heat resistance that does not cause air leakage or puncture in the part of the ring, that is, the sealing property as a container.

Taking advantage of such characteristics, the heat-fusible film, the easy-open packaging material, the container lid material of the present invention, or the container made of these materials is widely used in various yogurt,
Pudding, jelly, snacks, snacks, noodles and other paper plastic containers for food packaging and blister packaging, other daily goods and miscellaneous goods such as bag packaging, bottles, cups, and plastic packaging for trays, etc. It can be suitably used as a body.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 23/08 C08L 23/08 23/10 23/10 F term (reference) 3E067 AB01 BA11A BA17A BB14A BB25A CA17 CA24 EA06 EB01 FC01 GD07 3E086 AB01 AC07 AD01 AD23 BA04 BA15 BB41 BB51 BB90 CA01 4F100 AK03B AK04B AK07A AK68A AL05A AL05B AT00C BA03 BA07 BA10A BA10C EH20 GB15 GB18 JL12A JL14 4J12X15BB06W

Claims (6)

[Claims] 1. A resin composition (C) comprising 99 to 20% by weight of an ethylene / vinyl ester copolymer (A) having a vinyl ester content of 3 to 30% by weight and 1 to 80% by weight of a propylene polymer (B). A heat-sealing film comprising a heat-sealing layer made of 2. The heat-sealing film according to claim 1, wherein a reinforcing layer made of an olefin polymer layer is laminated on one surface of the heat-sealing layer. 3. An easy-open packaging material comprising a base material layer and the heat-sealing film according to claim 1 laminated on at least one surface of the base material layer. 4. A container lid material made of the easy-open packaging material according to claim 3. 5. The vinyl ester content of the opposite surfaces is 3 to.
30% by weight of ethylene / vinyl ester copolymer (A)
A package comprising a heat-sealing layer made of a resin composition (D) containing 99 to 40% by weight and a propylene polymer (B) of 1 to 60% by weight, and a heat-sealing layer made of an ethylene polymer layer. body. 6. The vinyl ester content of the opposite surfaces is 3 to.
30% by weight of ethylene / vinyl ester copolymer (A)
A package comprising a heat-sealing layer made of a resin composition (E) of 95 to 20% by weight and a propylene polymer (B) of 5 to 80% by weight, and a heat-sealing layer made of a propylene polymer layer. body.