JP2022175586A - Resin composition and use thereof - Google Patents

Abstract

To provide: a sealant film and a laminated film having heat seal strength that is, while being able to protect a content, low to a degree where an easy-peel-property required in a market can be exhibited and having good appearance of a peeling surface; and a material thereof.SOLUTION: A resin composition comprises: 5 to 30 mass% of a butene-based polymer (A) that satisfies following (a-1) to (a-3); 42 to 90 mass% of high-pressure process low-density polyethylene (B); and 3 to 38 mass% of an ethylene/α-olefin copolymer (C) that satisfies the following (c-1) (where a total of (A), (B), and (C) is taken as 100 mass%), where a mass ratio of the high-pressure process low-density polyethylene (B) to the ethylene/α-olefin copolymer (C) is 60/40 to 93/7: (a-1) a ratio of a weight average molecular weight Mw to a number average molecular weight Mn (Mw/Mn) is 5-20; (a-2) a melting point as measured by DSC is 100 to 130°C; (a-3) an MFR (190°C, 2.16 kg load) is 0.3 to 10 g/10 min.; and (c-1) an MFR (190°C, 2.16 kg load) is 0.1 to 16 g/10 min.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a resin composition and its use, and more particularly to a resin composition suitable as a raw material for a sealant film, a sealant film, a laminate film using the sealant film, and the like.

Sealant films having easy peelability (easy peelability) used for container packaging materials are required to simultaneously satisfy the contradictory performances of sealing performance and easy peelability. Among them, regarding the sealability, it is required that the heat-sealing strength be at least sufficient to protect the contents at all times, and that the temperature dependence of the heat-sealing strength is small so that it can be used with a wide variety of substrates. ing. On the other hand, with respect to easy peelability, it is required to be heat-sealed to the extent that peeling by hand is easy.

Patent Document 1 describes a butene-based polymer in which the proportion of components having a molecular weight of 10,000 or less is 2% or more, the melting point is 100 to 130° C., and the MFR is 0.3 to 10 g/10 min; 90 to 40% by mass of high-pressure low-density polyethylene and 10 to 60% by mass of ethylene/α-olefin copolymer as the ethylene polymer (the ethylene polymer 100 mass %) composition is disclosed.

JP 2019-123842 A

There is a demand in the market for a sealant film that is easier to peel than the sealant film produced from the composition. However, in the composition described in Patent Document 1, for example, if the blending ratio of the butene polymer is increased in order to lower the heat seal strength, the thread-like resin will remain on the peeling surface of the sealant film, resulting in a peeled appearance. There is a problem that the

The present invention provides a sealant film and a laminated film that can protect the contents, yet has a low heat seal strength to the extent that the easy peel property required in the market can be exhibited, and a good appearance of the peel surface, and a material thereof. intended to

As a result of the research conducted by the present inventors, it was found that the above problems can be solved by the following configuration example. A configuration example of the present invention is as follows.
In this specification, "A to B" indicating a numerical range indicates A or more and B or less.

[1] 5 to 30% by mass of a butene polymer (A) that satisfies requirements (a-1), (a-2) and (a-3),
42 to 90% by mass of high-pressure low-density polyethylene (B),
3 to 38% by mass of ethylene/α-olefin copolymer (C) satisfying requirement (c-1) (however, butene polymer (A), high-pressure low-density polyethylene (B) and ethylene/α-olefin The total of the copolymer (C) is 100% by mass)),
A resin characterized in that the mass ratio [(B)/(C)] of the high-pressure low-density polyethylene (B) and the ethylene/α-olefin copolymer (C) is 60/40 to 93/7. Composition.
(a-1): Mw/Mn, which is the ratio of the weight average molecular weight Mw to the number average molecular weight Mn measured by the GPC method, is 5-20.
(a-2): Melting point measured by differential scanning calorimeter is 100 to 130°C.
(a-3): Melt flow rate (190° C., 2.16 kg load) is 0.3 to 10 g/10 minutes.
(c-1): Melt flow rate (190° C., 2.16 kg load) is 0.1 to 16 g/10 minutes.

[2] The resin composition according to [1], wherein the butene-based polymer (A) further satisfies requirement (a-4).
(a-4): The ratio of components having a molecular weight of 10,000 or less determined from an integrated molecular weight distribution curve obtained by measurement by GPC method is 2% or more.

[3] The resin composition according to [1] or [2], wherein the butene polymer (A) further satisfies requirement (a-5).
(a-5): the sum of the structural unit (i) derived from 1-butene and the structural unit (ii) derived from an α-olefin having 2 to 10 carbon atoms (excluding 1-butene); Based on 100 mol %, it consists of 90 to 100 mol % of the structural unit (i) and 0 to 10 mol % of the structural unit (ii).

[4] The resin composition according to any one of [1] to [3], wherein the ethylene/α-olefin copolymer (C) satisfies requirement (c-2).
(c-2): Density is 870 to 936 kg/m ³ .

[5] A film made of the resin composition according to any one of [1] to [4].

[6] A laminated film obtained by laminating the film according to [5] and another layer.

[7] The laminated film of [6], wherein a sealant layer and a substrate layer are laminated, and the sealant layer is the film of [5].

[8] A sealant layer, an intermediate layer and a substrate layer laminated in this order, the sealant layer comprising an ethylene polymer, and the intermediate layer comprising the film of [5]. laminated film.

According to the present invention, a sealant film and a laminate film having a low heat-sealing strength to the extent that the easy peelability required in the market can be exhibited while being able to protect the contents, and a good appearance of the peeling surface, and a material thereof can be provided.

<<Resin composition>>
The resin composition according to the present invention (hereinafter also referred to as "this composition") contains 5 to 30% by mass of a specific butene polymer (A) and 42 to 90% by mass of a high-pressure low-density polyethylene (B). , containing 3 to 38% by mass of a specific ethylene/α-olefin copolymer (C) (where the total of (A), (B), and (C) is 100% by mass), and the following requirement (X) meet.

[Requirement (X)]
The mass ratio [(B)/(C)] between the high-pressure low-density polyethylene (B) and the ethylene/α-olefin copolymer (C) is 60/40 to 93/7, preferably 70/30 to 92/8, more preferably 75/25 to 90/10.
When the mass ratio of the high-pressure low-density polyethylene (B) and the ethylene/α-olefin copolymer (C) is 93/7 or less, when the present composition is used as a sealant film, the release surface of the sealant film It is preferable because the thread-like resin is less likely to remain on the surface and the appearance of the peeled surface is good. The reason why the appearance of the release surface is good when the mass ratio [(B)/(C)] is 93/7 or less is that the interface between the high-pressure low-density polyethylene (B) and the butene polymer (A) It is presumed that this is because the strength is improved. That is, by improving the interfacial strength between the high-pressure low-density polyethylene (B) and the butene-based polymer (A), the butene-based polymer (A) is separated from the high-pressure low-density polyethylene (B) in the vicinity of the peeling surface. As a result, the butene-based polymer (A) is less likely to remain on the peeling surface. On the other hand, when the appearance of the peeling surface is not good, the butene polymer (A) is peeled from the high-pressure low-density polyethylene (B) even in the vicinity of the peeling surface, resulting in a relatively distant position from the peeling surface. It is presumed that the butene-based polymer (A) continues to the butene-based polymer (A) in the vicinity of the release surface and remains on the release surface, causing stringiness on the release surface.
It is preferable that the mass ratio [(B)/(C)] is 60/40 or more because the heat seal strength is low. The reason why the above effect can be obtained when the mass ratio [(B)/(C)] is 60/40 or more is that the material strength is low when the composition adjusted at the mass ratio is used as a sealant. guessed.

The content of the butene-based polymer (A) in the composition is 5 to 30% by mass, preferably 8.5 to 30% by mass, more preferably 10 to 30% by mass (however, the butene-based polymer The total of the coalescence (A), the high-pressure low-density polyethylene (B) and the ethylene/α-olefin copolymer (C) is 100% by mass).
When the content of the butene-based polymer (A) is within the above range, the heat seal strength is lowered, which is preferable.

<Butene polymer (A)>
Examples of the butene-based polymer (A) include homopolymers of 1-butene and copolymers of 1-butene and α-olefins having 2 to 10 carbon atoms excluding 1-butene. The butene-based polymer (A) used in the present composition may be of one type or two or more types.

Examples of the α-olefin include ethylene, propylene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 3-methyl-1-butene, 3-methyl-1-pentene, 4- Methyl-1-pentene, 4-methyl-1-hexene and 4,4-dimethyl-1-hexene, preferably ethylene, propylene, 1-hexene, 4-methyl-1-pentene and 1-octene. and more preferably ethylene and propylene.

If necessary, the butene polymer (A) may be copolymerized with a small amount of another comonomer as long as the effects of the present invention are not impaired. The other comonomer is a monomer other than 1-butene and the α-olefin and is copolymerizable with at least one of 1-butene and the α-olefin. Said other comonomer may be a monomer copolymerizable with both 1-butene and said α-olefin.
The 1-butene content of the butene-based polymer (A) is preferably 90 to 100 mol %, as detailed in requirement (a-5) below. Also, the α-olefin content is usually 0 to 10 mol % (provided that the total of 1-butene content and α-olefin content is 100 mol %).

The butene-based polymer (A) satisfies the following requirements (a-1) to (a-3).

[Requirements (a-1)]
The ratio of the weight average molecular weight Mw to the number average molecular weight Mn measured by the gel permeation (GPC) method (converted to polystyrene) under the conditions employed in the examples described later, that is, Mw/Mn, is 5 to 20. , preferably 5-10, more preferably 6-9.
If the Mw/Mn is in this range, the dispersibility is improved when kneaded with the ethylene polymer, so that the easy peelability is improved.
When adjusting Mw/Mn, for example, two or more butene-based polymers different in one or more of weight average molecular weight Mw, number average molecular weight Mn, or Mw/Mn are prepared and mixed to obtain Mw /Mn can be increased.

[Requirement (a-2)]
It has a melting point of 100 to 130°C, preferably 105 to 130°C, more preferably 110 to 125°C, as measured by a differential scanning calorimeter under the conditions employed in Examples described later.
When the melting point is in this range, the heat resistance of the film is improved, it can be applied to a packaging form in which boiling or retort sterilization is performed, and heat sealing can be performed over a wide range of sealing temperatures.

[Requirement (a-3)]
Melt flow rate (ASTM D-1238, 190° C., 2.16 kg load) is 0.3 to 10 g/10 min, preferably 1.2 to 8 g/10 min, more preferably 2 to 5 g/10 min. 10 minutes.
When the melt flow rate is within this range, it is possible to form a film from the resin composition of the present invention at a high molding speed using an existing molding machine, which is preferable.

The butene-based polymer (A) has a ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn, a melting point, and a melt flow rate within specific ranges. Excellent balance of durability and easy peelability. In other words, by blending the butene-based polymer (A) that satisfies the requirements (a-1) to (a-3), the film obtained from this composition can achieve low heat seal strength over a wide range of sealing temperatures. , is presumed.

The butene polymer (A) may satisfy one or more of the following requirements (a-4) to (a-6), preferably the following requirements (a-4), (a- 5) is satisfied.

[Requirement (a-4)]
The proportion of components having a molecular weight of 10,000 or less, determined from an integral molecular weight distribution curve obtained by a gel permeation (GPC) method (converted to polystyrene), is preferably 2% or more, more preferably 2.5%. That's it. The upper limit of the ratio of components having a molecular weight of 10,000 or less is determined mainly depending on requirements (a-1) and (a-3), but is preferably 5% or less. In addition, the conditions of the measurement by the GPC method are the conditions described in Examples described later.

When the ratio is within this range, the dispersibility is improved when kneaded with the ethylene polymer, so that the easy peeling property is improved.
The proportion can be increased, for example, by polymerizing a low molecular weight butene-based polymer in one step of a multistage polymerization process or by melt-kneading a low molecular weight butene-based polymer.

[Requirements (a-5)]
The 1-butene content of the butene-based polymer (A) is usually 90 to 100 mol%, preferably 95 to 100 mol%, more preferably 98 to 100 mol%, and the α-olefin content is 0 to 10 mol. %, preferably 0 to 5 mol %, more preferably 0 to 2 mol % (provided that the total of 1-butene content and α-olefin content is 100 mol %).

[Requirements (a-6)]
It has a density of 880-925 kg/m ³ , preferably 885-920 kg/m ³ , measured under the conditions employed in the examples below. When the density of the butene polymer (A) is within this range, the coefficient of friction of the surface of the film formed from the resin composition is small, so that when a container is finally produced from the film, the content can be filled at a high filling speed. It is possible to fill.

[Method for producing butene polymer (A)]
Examples of the method for producing the butene polymer (A) include the method described in International Publication No. 2002/002659. On pages 32-33 of this patent document, the following (M1) and (M2) are described as examples of a method for producing a solid titanium catalyst (A') used for producing a butene-based copolymer. .
(M1) contacting a halogen-containing magnesium compound (α) with a solubilizer (β) capable of dissolving the halogen-containing magnesium compound (α) in a solvent (γ) to obtain a solution (I),
A first compound (δ) having two or more ether bonds existing through a plurality of atoms is added to the solution (I) to obtain a solution (II),
A method of contacting the solution (II) with a titanium compound (ε) in a liquid state to obtain a solution (III), or further separating a solid from the solution (III).
(M2) contacting a halogen-containing magnesium compound (α) with a solubilizer (β) capable of dissolving the halogen-containing magnesium compound (α) in a solvent (γ) to obtain a solution (I),
A first compound (δ) having two or more ether bonds existing through a plurality of atoms is added to the solution (I) to obtain a solution (II),
Contacting the solution (II) with a titanium compound (ε) in a liquid state to obtain a solution (III),
A second compound (δ') having two or more ether bonds present via a plurality of atoms is added to the solution (III) to obtain a solution (IV), or a solid is separated from the solution (IV) how to.
In the present invention, from the viewpoint of producing a butene-based polymer (A) having a high proportion of components having a molecular weight of 10,000 or less, the method (M1) (i.e., the solution (III) via a plurality of atoms a second compound (δ') having two or more ether bonds present in the solution (IV) to obtain a solution (IV), or a method that does not include the step of separating a solid from the solution (IV)) 1-Butene is (co)polymerized in the presence of a solid titanium catalyst (A') to produce a butene-based polymer (A).

Also, prepare two or more butene-based polymers (each butene-based polymer may or may not satisfy all of the requirements (a-1) to (a-3)). These may be mixed to prepare the butene polymer (A) so that the mixture as a whole satisfies the requirements (a-1) to (a-3).

<High pressure low density polyethylene (B)>
The melt flow rate (ASTM D-1238, 190° C., 2.16 kg load) of the high-pressure low-density polyethylene (B) is preferably 0.2 to 30 g/10 minutes, more preferably 0.5 to 10 g/10 minutes. , more preferably 0.8 to 8 g/10 minutes. When the melt flow rate is within this range, the present composition can be film-formed at a high molding speed using an existing molding machine.

The density of the high-pressure low-density polyethylene (B) is generally 900-940 kg/m ³ , preferably 910-930 kg/m ³ .

As the high-pressure low-density polyethylene (B), if it is a commercial product, for example, NUC8160 (MFR=2.4 g/10 min, density=922 kg/m ³ , manufactured by ENEOS NUC Co., Ltd.) can be mentioned.

<Ethylene/α-olefin copolymer (C)>
Examples of the ethylene/α-olefin copolymer (C) include ethylene/α-olefin random copolymers. The α-olefin has 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms, and examples thereof include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1 -octene, 1-decene, 1-undecene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene and 4,4-dimethyl-1 - includes hexene. These may be used individually by 1 type, and may use 2 or more types together. In addition, the ethylene/α-olefin copolymer (C) may be obtained by further polymerizing a small amount of comonomers other than ethylene and α-olefin, if necessary.

The α-olefin content of the ethylene/α-olefin copolymer (C) is preferably 0.1 to 15 mol%, more preferably 0.5 to 10 mol%. However, the total of ethylene content and α-olefin content is 100 mol %.

The ethylene/α-olefin copolymer (C) satisfies the following requirements (c-1), preferably the following requirements (c-1) and (c-2).

[Requirement (c-1)]
The melt flow rate (ASTM D-1238, 190° C., 2.16 kg load) of the ethylene/α-olefin copolymer (C) is 0.1 to 16 g/10 min, preferably 0.5 to 9 g/10 min. 10 minutes, more preferably 0.5 to 3.5 g/10 minutes. When the ethylene/α-olefin copolymer (C) having a melt flow rate within the above range is used, the dispersibility of the butene copolymer (A) is improved, and thus the easy peelability is improved. The heat seal strength of the sealant film obtained from the product is low, and the appearance of the release surface is good.

[Requirement (c-2)]
The density of the ethylene/α-olefin copolymer (C) is generally 870-936 kg/m ³ , preferably 885-932 kg/m ³ , more preferably 912-927 kg/m ³ . When the density of the ethylene/α-olefin copolymer (C) is within this range, it is possible to obtain a film having excellent transparency and low-temperature sealability, which is preferable. When the ethylene/α-olefin copolymer (C) having a density within the above range is used, the interfacial strength between the high-pressure low-density polyethylene (B) and the butene polymer (A) is such that the appearance of peeling can be improved. and the seal strength does not become too high. Therefore, the heat seal strength of the sealant film obtained from this composition is low, and the appearance of the release surface is good.

Examples of the ethylene/α-olefin copolymer (C) include Evolue SP2510 (MFR=1.5 g/10 min, density 923 kg/m ³ , manufactured by Prime Polymer Co., Ltd.) and Evolue SP2540, if they are commercially available products. (MFR = 3.8 g/10 min, density 924 kg/m ³ , Prime Polymer Co., Ltd.) and Evolue SP1510 (MFR = 1.0 g/10 min, density 915 kg/m ³ , Prime Polymer Co., Ltd.). mentioned.

<Various additives>
The composition may contain optional additives such as antioxidants, heat stabilizers, weather stabilizers, anti-fogging agents, anti-blocking agents, slip agents, lubricants, crystal nucleating agents, antistatic agents, flame retardants, pigments, Dyes, fillers, and the like may be contained within a range that does not impair the effects of the present invention (for example, a total amount of 1% by mass or less in the present composition).

<Method for producing the present composition>
The present composition is prepared by mixing a butene polymer (A), a high-pressure low-density polyethylene (B), an ethylene/α-olefin copolymer (C), and optionally various additives by a conventionally known method. , can be prepared.

≪Films and laminated films≫
The film according to the present invention comprises the composition and is preferably used as a sealant film for packaging materials.

The thickness of the film is appropriately set according to the use of the film, and is preferably 3 to 100 μm when used as a sealant film, for example.
A film according to the present invention can be produced by molding the resin composition according to the present invention. Examples of film-forming methods include cast-molding and inflation-molding methods. The temperature of the molten resin during film molding is preferably 160 to 260°C.

The laminated film according to the present invention is obtained by laminating the above-described film according to the present invention and another layer. Examples of the laminated film according to the present invention include the following two types.
(i) A laminate film in which a sealant layer and a substrate layer are laminated, and the sealant layer is the film (sealant film) according to the present invention.
(ii) A laminated film comprising a sealant layer, an intermediate layer and a substrate layer laminated in this order, the sealant layer comprising an ethylene-based polymer, and the intermediate layer comprising the film of the present invention.

In the laminated film according to the present invention, when the film according to the present invention is used as an intermediate layer like the laminated film (ii), the peeling start portion of the laminated film is the sealant layer and the laminated film. However, since the breakage between the layers immediately moves between the sealant layer and the intermediate layer, the intermediate layer is substantially peeled off from the sealant layer. In other words, the peeling surface is between the sealant layer and the intermediate layer, and the sealant layer is not substantially peeled from the object to be sealed.

When the adhesive strength between each layer of the laminated film is not sufficient, an adhesive layer may be provided between each layer.
The laminated film is preferably used as a packaging film or packaging sheet, and may also be used as a container material or a container lid material.

Examples of the substrate layer include polyolefin films such as polyethylene or polypropylene, styrene resin films, polyester films such as polyethylene terephthalate or polybutylene terephthalate, polyamide films such as nylon 6 or nylon 6,6, and polyolefins. Laminate films of films and resin films with gas barrier properties such as polyamide resin or ethylene-vinyl alcohol copolymer resin, foils of metals such as aluminum, vapor-deposited films with aluminum, silica, etc. vapor-deposited, paper, etc. be done. The base material layer is appropriately selected according to the purpose of use of the packaging material, etc., and may be used alone or in combination of two or more.

Examples of the method for producing the laminated film include the following (M11) to (M13).
(M11) Raw material resins for the sealant layer, raw material resins for the base material layer, and optionally raw material resins for the intermediate layer are supplied to separate extruders, melted, merged and laminated, and T A method of extruding a sheet from a die (co-extrusion method).
(M12) Raw material resins for the sealant layer are put into an extruder, and melt-extruded and laminated on a pre-manufactured base material layer or on an intermediate layer of a laminate consisting of a pre-manufactured base material layer and an intermediate layer. method (melt lamination method).
(M13) A method in which the sealant layer, the base material layer, and optionally the intermediate layer are prepared from the corresponding raw material resins, and these are thermocompression-bonded by a group of heated rolls or the like (thermal lamination method).
Among these methods, the co-extrusion method (M11) is preferable in that the time required for production is short and the adhesion between layers is good.

The sealing temperature for heat-sealing the film or laminated film of the present invention is generally 100 to 180°C, preferably 140 to 170°C. Also, the sealing pressure is usually 0.1 to 0.5 MPa.

When the sealant films (sealant layers) are stacked on each other and heat-sealed, or when the sealant film (sealant layer) is stacked on another film and heat-sealed, the adhesion of the sealant films (sealant layers) is reduced. The film can be strongly bonded to each other by force, and can be separated from each other by an appropriate force. Therefore, the film and laminated film of the present invention can be used as a film having both heat sealability and easy peelability.

Further, the laminated film according to the present invention is formed by laminating a sealant layer, an intermediate layer and a substrate layer in this order, the sealant layer is made of an ethylene polymer, and the intermediate layer is made of the film according to the present invention. In the case of the laminate film (ii), examples of raw materials for the sealant layer include polyethylene. Examples of polyethylene that can be used as a raw material for the sealant layer include high-pressure low-density polyethylene and a mixture of high-pressure low-density polyethylene and ethylene/α-olefin copolymer. , for example, high-pressure low-density polyethylene: ethylene/α-olefin copolymer = 1:0 to 70:30.

The density of the ethylene/α-olefin copolymer that can be used as a raw material for the sealant layer in the laminated film (ii) is preferably 870-920 kg/m ³ , more preferably 880-905 kg/m ³ . In particular, by blending a low-density ethylene/α-olefin copolymer, the heat-sealing property at low temperatures is improved, and the suitability for high-speed sealing (productivity) is improved. Further, the melt flow rate (190° C., 2.16 kg load) of the ethylene/α-olefin copolymer that can be used as a raw material for the sealant layer in the laminated film (ii) is preferably 0.5 to 7.0 g/10. minutes, more preferably 1.0 to 4.0 g/10 minutes. Examples of ethylene/α-olefin that can be used as raw materials for the sealant layer include copolymers exemplified as ethylene/α-olefin copolymer (C), Toughmer A-1085S (MFR = 1.2 g/10 min, density = 885 kg/m ³ , manufactured by Mitsui Chemicals, Inc.).

Two laminated films according to the present invention are prepared and the sealant layer surfaces face each other, or the laminated film according to the present invention is folded and arranged so that the sealant layers face each other, or the sealant layer of the laminated film according to the present invention A sealed container, for example, a bag-like container can be produced by facing another film and then heat-sealing the periphery from either one of the outer surfaces so as to form the desired container shape. When this process of forming the bag-like container is combined with the process of filling the contents, the content is filled after the bottom and sides of the bag-like container are heat-sealed, and then the top is heat-sealed to automatically form the package. can be completed. Therefore, this laminate film can be used by being supplied to an automatic packaging machine for solids such as snacks, powders, or liquid materials.

Alternatively, the laminated film according to the present invention or other films may be previously formed into a cup-shaped container by means of vacuum forming, deep drawing, or the like, or an ordinary injection-molded container may be prepared and Filling with contents followed by covering with a laminate film or other film as a lidding material and heat sealing along the perimeter of the top or sides of the container yields a package containing the contents. In this case, the sealant film according to the present invention can be used for the sealant layer of the lid member, the sealant layer of the container body, or both. This container can be suitably used for packaging cup noodles, miso, ham, bacon, jelly, pudding, snacks, and the like.

The structure and manufacturing method of the container are not limited to the above description, and can be arbitrarily changed. Other films or containers that can be used in combination with the film or laminated film according to the present invention include packaging materials molded from conventionally used resins such as polyethylene, ethylene-vinyl acetate copolymer, and polypropylene. . For example, such a material is molded into a container-shaped molding having a flange at the opening, and the sealant layer is laminated on the flange of the opening, and the two surfaces are joined by heat-sealing to form a container. It can be used as a package. The sealant film or sealant layer and the packaging material can be heat-sealed with sufficient adhesive strength, and can be easily unsealed due to their easy peelability. Therefore, this container can be suitably used as a sealing and easy peelable packaging container, particularly in the field of food packaging.

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[Molecular weight distribution (Mw/Mn), ratio of components with a molecular weight of 10,000 or less]
Using a gel permeation chromatograph HLC-8321 GPC/HT type manufactured by Tosoh Corporation, measurement was performed as follows. The separation columns were two TSKgel GMH6-HT and two TSKgel GMH6-HTL, each having an inner diameter of 7.5 mm, a length of 300 mm, and a column temperature of 140°C. Ortho-dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd.) was used as a mobile phase, BHT (manufactured by Wako Pure Chemical Industries, Ltd.) was used as an antioxidant at 0.025% by weight, and the flow rate was set to 1.0 mL/min. The sample concentration was 30 mg/20 mL, the sample injection volume was 0.4 mL, and a differential refractometer was used as a detector. As a standard sample, 16 TSK standard polystyrene products manufactured by Tosoh Corporation were used. For molecular weight calculation, data processing software Empower 3 manufactured by Waters was used to calculate weight average molecular weight Mw, number average molecular weight Mn, molecular weight distribution (Mw/Mn), and ratio of components with molecular weights of 10,000 or less.

[Measurement of ethylene content in 1-butene/ethylene copolymer]
Using an AVANCEIII500 (CryoProbe) type NMR spectrometer manufactured by Bruker Biospin Co., Ltd., measurements were made as follows.

60 mg of a sample and 0.5 ml of ortho-dichlorobenzene were placed in an NMR tube with an inner diameter of 5 mm and dissolved by heating. 0.1 ml of deuterated benzene was added to this solution and ¹³ C-NMR measurement was carried out at 120°C. The number of accumulation times was 128 or more. The ¹³ C-NMR spectrum obtained quantified the composition of 1-butene and ethylene.

[Melting point]
A polymer containing a structural unit derived from 1-butene was molded under the following press molding conditions, and the obtained press sheet with a thickness of 1 mm was stored at room temperature for 10 days and used as a sample. Using the sample, the melting point was measured by a differential scanning calorimeter (DSC) under the DSC measurement conditions described below.

[Press molding conditions]
Press machine: manufactured by Kansai Roll Co., Ltd. (model number: PEWE-70/50 35)
Heating time: 5 minutes Heating temperature: 200°C
Pressure during heating: 5 MPa
Cooling rate: 40 ° C./min or more (pressurized at 5 MPa for 4 minutes with another press set at 30 ° C. and cooled to room temperature)

[DSC measurement conditions]
Using PerkinElmer's DSCPyris1 or DSC7, in a nitrogen atmosphere (20 ml/min), about 5 mg of the sample was heated from room temperature to 200°C at 10°C/min. The peak was taken as the melting point.

[density]
A press sheet with a thickness of 1 mm was produced under the same conditions as in the measurement of the melting point, stored at room temperature for 10 days, and then the density was measured according to ASTM D-1505-68.

[Melt flow rate (MFR)]
Measurement was performed at 190° C. under a load of 2.16 kg according to ASTM D-1238.

[Preparation Example] Preparation of butene-based polymer (BER-1) A solid titanium catalyst component was prepared by the production method described in JP-A-2019-123842. Using the obtained solid titanium catalyst component, 1-butene is produced by a method according to the production method described in JP-A-2019-123842, while appropriately changing the amounts of 1-butene, ethylene, and hydrogen supplied. and ethylene to obtain a butene polymer (BER-1). Table 1 shows the physical properties of the polymer BER-1.

<Raw materials>
Raw materials used in the following examples and comparative examples are as follows.

[Butene polymer (A)]
- "BER-1": The polymer BER-1 prepared in the above preparation example was used as the butene-based polymer (A).

[High pressure low density polyethylene (B)]
・"LDPE-1": NUC8160 (manufactured by ENEOS NUC Co., Ltd.), MFR (190°C, 2.16 kg load) = 2.4 g/10 min, density = 922 kg/m ³

[Ethylene/α-olefin copolymer (C)]
・"LLDPE-1": ULTZEX 2022L (manufactured by Prime Polymer Co., Ltd.), MFR (190°C, 2.16 kg load) = 2.0 g/10 min, density 919 kg/m ³
・"LLDPE-2": Evolue SP2510 (manufactured by Prime Polymer Co., Ltd.), MFR (190°C, 2.16 kg load) = 1.5 g/10 min, density 923 kg/m ³
・"LLDPE-3": Evolue SP2540 (manufactured by Prime Polymer Co., Ltd.), MFR (190°C, 2.16 kg load) = 3.8 g/10 min, density 924 kg/m ³
・"LLDPE-4": Evolue SP1510 (manufactured by Prime Polymer Co., Ltd.), MFR (190°C, 2.16 kg load) = 1.0 g/10 min, density 915 kg/m ³
・"LLDPE-5": Evolue SP1540 (manufactured by Prime Polymer Co., Ltd.), MFR (190°C, 2.16 kg load) = 3.8 g/10 min, density 913 kg/m ³
・"LLDPE-6": Evolue SP1071C (manufactured by Prime Polymer Co., Ltd.), MFR (190°C, 2.16 kg load) = 10 g/10 min, density 910 kg/m ³
・"EBR-1": A-1085S (manufactured by Mitsui Chemicals, Inc.), MFR (190°C, 2.16 kg load) = 1.2 g/10 minutes, density 885 kg/m ³
・"EBR-2": A-4085S (manufactured by Mitsui Chemicals, Inc.), MFR (190°C, 2.16 kg load) = 3.6 g/10 minutes, density 885 kg/m ³

[Other copolymers]
・"EBR-3": A-20085S (manufactured by Mitsui Chemicals, Inc.), MFR (190°C, 2.16 kg load) = 18 g/10 min, density 885 kg/m ³

[Example 1]
[Production of laminated film]
Using a two-layer T-die-cast molding machine with a die width of 300 mm, equipped with an extruder with a screw diameter of 40 mm for molding the base layer and an extruder with a diameter of 30 mm for molding the sealant layer, the following resin composition for each layer was used to prepare a film under the following molding conditions. That is, a laminate film was produced by laminating the sealant film formed from the present composition as a sealant layer and the base layer and the sealant layer.

(Resin composition for manufacturing each layer)
・Base layer:
A resin composition obtained by blending 50 parts by mass of each of LDPE-1 and LLDPE-1.
・Sealant layer:
20 parts by mass of BER-1 as the butene polymer (A), 70 parts by mass of LDPE-1 as the high-pressure low-density polyethylene (B), and 10 parts by mass of LLDPE-2 as the ethylene/α-olefin copolymer (C) A resin composition obtained by blending parts by mass.

(Molding condition)
・Film molding temperature: 230°C
・Chill roll temperature: 30°C
・Film composition: base layer/sealant layer (50 μm/20 μm)
・Film forming speed: 10m/min

[Measurement of heat seal strength]
Two laminated films molded in Example 1 are stacked so that the sealant layers face each other, aligning the MD direction (the direction in which the molten resin was flowed during molding) of each sealant layer. A specimen was prepared by sandwiching it between 50 μm Teflon (registered trademark) sheets. Next, a heat seal bar of a heat seal tester (manufactured by Tester Sangyo Co., Ltd., model TP-701-G) was set at a width of 5 mm and a length of 300 mm, and the lower heat seal bar was set to 70°C. The upper heat-seal bar was set to 120° C., and the specimen (Teflon sheet/laminated film/laminated film/Teflon sheet) was sandwiched between the seal bars and heat-sealed at a pressure of 0.2 MPa for 1.0 second. The Teflon sheet was removed, and the heat-sealed film portion was left at about 23° C. for one day. After that, a 15 mm wide slit is made so as to include the heat-sealed portion of the film, and the unsealed portion is fixed to a tensile tester ("EZ-LX, manufactured by Shimadzu Corporation"), and the film is heated at a speed of 300 mm / min. was measured. The above operation was performed 5 times, and the average value was taken as the heat seal strength. The maximum peel strength was used as the peel strength. Table 2 shows the results obtained.
Similar experiments were conducted by changing the set temperature of the upper heat seal bar to 130°C, 140°C, 150°C, 160°C, 170°C, or 180°C. The results obtained at these set temperatures are also shown in Table 2.

[Seal strength evaluation]
The heat seal strength was evaluated according to the following evaluation criteria.
(Evaluation criteria)
○: The heat seal strength is 1 N/15 mm or more when the heat seal temperature is 140°C, and the heat seal strength is 2 N/15 mm or less when the heat seal temperature is 160°C.
Δ: The heat seal strength when the heat seal temperature is 140 ° C. is 1 N / 15 mm or more, and the heat seal strength when the heat seal temperature is 160 ° C. is more than 2 N / 15 mm and 3 N / 15 mm or less. be.
x: The heat seal strength is less than 1 N/15 mm when the heat seal temperature is 140°C, or exceeds 3 N/15 mm when the heat seal temperature is 160°C.

[Evaluation of stringiness]
After measuring the heat seal strength, the sealing surface of the film sample was observed and evaluated according to the following evaluation criteria depending on whether the filamentous resin adhered to the sealing surface and its surroundings. Table 2 shows the results obtained.
(Evaluation criteria)
◯: No filamentous resin was observed on or around the sealing surface.
Δ: Filamentous resin having a length of less than 1 mm adhered to the sealing surface or the periphery of the sealing surface.
x: A filamentous resin with a length of 1 mm or more adhered to the sealing surface or the periphery of the sealing surface.

[Appearance evaluation]
The evaluation result of the stringiness at 160°C was used as the result of the appearance evaluation.

〔Comprehensive evaluation〕
Based on the results of seal strength evaluation and appearance evaluation, evaluation was made according to the following evaluation criteria. Table 2 shows the results obtained.
(Evaluation criteria)
◯: The evaluation was ◯ in both the seal strength evaluation and the appearance evaluation.
Δ: At least one of the seal strength evaluation and appearance evaluation was Δ, and there was no item evaluated as x.
x: At least one of the seal strength evaluation and appearance evaluation was x.

[Examples 2 to 13, Comparative Examples 1 to 5]
A laminated film was produced in the same manner as in Example 1, except that the resin composition shown in Table 2 was used as the resin composition for the sealant layer. Evaluated the pullability. Table 2 shows the results.
In some examples and comparative examples, the heat seal strength was not measured at 130°C, 150°C, and 170°C, so the heat seal strength is shown as "-". Since the stringiness was not evaluated under the conditions where the heat seal strength was not measured, the evaluation result was given as "-".

Claims (8)

5 to 30% by mass of a butene polymer (A) that satisfies requirements (a-1), (a-2) and (a-3),
42 to 90% by mass of high-pressure low-density polyethylene (B),
3 to 38% by mass of ethylene/α-olefin copolymer (C) satisfying requirement (c-1) (however, butene polymer (A), high-pressure low-density polyethylene (B) and ethylene/α-olefin The total of the copolymer (C) is 100% by mass)),
A resin characterized in that the mass ratio [(B)/(C)] of the high-pressure low-density polyethylene (B) and the ethylene/α-olefin copolymer (C) is 60/40 to 93/7. Composition.
(a-1): Mw/Mn, which is the ratio of the weight average molecular weight Mw to the number average molecular weight Mn measured by the GPC method, is 5-20.
(a-2): Melting point measured by differential scanning calorimeter is 100 to 130°C.
(a-3): Melt flow rate (190° C., 2.16 kg load) is 0.3 to 10 g/10 minutes.
(c-1): Melt flow rate (190° C., 2.16 kg load) is 0.1 to 16 g/10 minutes. The resin composition according to claim 1, wherein the butene-based polymer (A) further satisfies requirement (a-4).
(a-4): The ratio of components having a molecular weight of 10,000 or less determined from an integrated molecular weight distribution curve obtained by measurement by GPC method is 2% or more. 3. The resin composition according to claim 1, wherein the butene polymer (A) further satisfies requirement (a-5).
(a-5): the sum of the structural unit (i) derived from 1-butene and the structural unit (ii) derived from an α-olefin having 2 to 10 carbon atoms (excluding 1-butene); Based on 100 mol %, it consists of 90 to 100 mol % of the structural unit (i) and 0 to 10 mol % of the structural unit (ii). The resin composition according to any one of claims 1 to 3, wherein the ethylene/α-olefin copolymer (C) satisfies the requirement (c-2).
(c-2): Density is 870 to 936 kg/m ³ . A film made of the resin composition according to any one of claims 1 to 4. A laminated film obtained by laminating the film according to claim 5 and another layer. 7. The laminate film according to claim 6, wherein a sealant layer and a substrate layer are laminated, and the sealant layer comprises the film according to claim 5. 7. The laminated film according to claim 6, wherein a sealant layer, an intermediate layer and a substrate layer are laminated in this order, the sealant layer comprising an ethylene-based polymer, and the intermediate layer comprising the film according to claim 5.