JP6604830B2 - Ethylene polymer composition and use thereof - Google Patents

Description

  The present disclosure relates to an ethylene-based polymer composition and an easily openable sealing material comprising the ethylene-based polymer composition.

  As containers for various foods and beverages and pharmaceuticals, plastic containers equipped with easy-open lids are widely used. The easy-open sealing material used for the sealing layer of such a lid material is required to have a wide temperature range of heat sealing temperature, to obtain a stable sealing strength and to be easily opened. Since the required seal strength differs depending on the material and size of the container, various easily openable seal materials have been proposed and used.

  Conventionally, polyolefins such as polypropylene, polyvinyl chloride, polystyrene, and the like have been widely used as container materials, and many easily openable materials suitable for containers of these materials are already known (for example, Patent Document 1). ~ 2).

Japanese Patent Publication No. 05-6513 Japanese Patent Laid-Open No. 02-185547

However, in recent years, no material has been found that has practically excellent easy-opening properties for amorphous polyester containers that are attracting attention as highly transparent containers.
Among the easily-openable sealing materials that have been proposed in the past, there are many materials that exhibit a wide heat-sealing temperature range and an appropriate sealing strength with respect to amorphous polyester. The seal strength is not obtained. That is, the sealing surface of the amorphous polyester container may be crystallized at the time of sealing or due to other thermal history, and when crystallization is caused, the conventional easy-open sealing material has to be sealed. It was found that the strength decreased significantly. Moreover, the roll-off property was bad at the time of sealing material shaping | molding, and the subject with respect to blocking property also became clear. For this reason, the seal strength varies, or the adhesion during transportation and storage remains uneasy.
This point is similarly concerned when a resin other than amorphous polyester is crystallized.

  On the other hand, stretched polyethylene terephthalate (O-PET), which has excellent heat resistance and strength, is used as a packaging substrate and molded container, and crystalline polyethylene, which is excellent in heat resistance and used in containers for microwave ovens, etc. Excellent terephthalate (C-PET), heat resistance, gas barrier properties, polyethylene naphthalate used for semi-retort foods, impact resistant polystyrene (HIPS), etc. Excellent gas barrier properties, used for miso containers, etc. As for acrylonitrile-based polymers, an excellent easy-opening sealing material is not provided other than a hot-melt adhesive having a low softening point.

  Based on the above situation, the present disclosure is easy to mold, exhibits excellent blocking resistance when formed into a molded product, and has an adhesive strength (especially an adhesive strength against amorphous polyester) when used as a heat seal material. An object of the present invention is to provide an ethylene polymer composition and an easily openable sealing material that are high and easily peeled (opened after sealing) at the time of peeling.

The inventor is suitable as a sealing material for resins such as polyester, acrylonitrile-based polymer, styrene-based polymer, polyvinyl chloride, etc., and has a wide heat-sealing temperature range with respect to the resin and an appropriate sealing strength ( That is, it has the sealing strength necessary for the sealing state and the sealing strength that is easy to peel at the time of peeling), even if the resin (for example, amorphous polyester) is crystallized, The sealing material which showed the characteristic and was excellent in moldability and blocking resistance was examined.
As a result, the following ethylene polymer composition was found to have such characteristics, and the present invention was completed.

Specific means for achieving the object includes the following aspects.
<1> The content ratio of the structural unit derived from the polar monomer is 7% by mass to 18% by mass, and the melt flow rate (may be abbreviated as “MFR” (hereinafter the same)), conforms to JIS K7210-1999. , 190 ° C., 2160 g load) of 40 to 95 parts by mass of an ethylene / polar monomer copolymer having 1 g / 10 min to 7 g / 10 min;
1 to 40 parts by mass of an A-B-A type block copolymer (A represents a polystyrene block and B represents an alkylene copolymer block);
3 to 25 parts by weight of tackifying resin;
(However, the total of the ethylene / polar monomer copolymer, the ABA type block copolymer, and the tackifying resin is 100 parts by mass),
An ethylene polymer composition having a melt flow rate (MFR, JIS K7210-1999 compliant, 190 ° C., 2160 g load) of 20 g / 10 min or less.

  <2> The ethylene-based polymer composition according to <1>, wherein the ethylene / polar monomer copolymer is an ethylene / vinyl acetate copolymer.

  <3> The ethylene polymer composition according to <1> or <2>, wherein the tackifying resin is a hydrocarbon resin.

  <4> An easily openable sealing material comprising the ethylene polymer composition according to any one of <1> to <3>.

  <5> The easily openable sealing material according to <4>, which is used for an adherend including a resin selected from polyester, acrylonitrile-based polymer, styrene-based polymer, and polyvinyl chloride.

  <6> The easy-open sealing material according to <4> or <5>, which is used by being laminated on a base material.

  According to the present disclosure, it is easy to mold, exhibits excellent blocking resistance when used as a molded product, has high adhesive strength when used as a heat seal material (particularly, adhesive strength against amorphous polyester), and An ethylene polymer composition and an easily openable sealing material that are easily peeled (opened after sealing) at the time of peeling are provided.

  Hereinafter, the ethylene polymer composition of the present disclosure and the easy-open sealing material using the same will be described in detail.

<Ethylene polymer composition>
The ethylene polymer composition has at least the following components (1) 40 parts by mass to 95 parts by mass, components (2) 1 part by mass to 40 parts by mass, and component (3) 3 parts by mass to 25 parts by mass. The MFR (conforming to JIS K7210-1999, 190 ° C., 2160 g load) is set to 20 g / 10 min or less.
(1) The content ratio of the structural unit derived from the polar monomer is 7% by mass to 18% by mass, and MFR (based on JIS K7210-1999, 190 ° C., 2160 g load) is 1 g / 10 min to 7 g / 10. (2) ABA type block copolymer (A represents a polystyrene block and B represents an alkylene copolymer block).
(3) Tackifying resin The total of the ethylene / polar monomer copolymer, the ABA block copolymer, and the tackifying resin is 100 parts by mass.

  In the ethylene-based polymer composition of the present disclosure, in particular, the MFR of the ethylene / polar monomer copolymer that is the component (1) includes the components (1) to (3), and is 1 g / 10 min to 7 g / 10. The content ratio of the structural unit derived from the polar monomer constituting the component (1) is in the range of 7% by mass to 18% by mass, and the MFR of the ethylene polymer composition itself is 20 g / 10. By suppressing to less than or equal to minutes, it is easy to mold, shows excellent blocking resistance when made into a molded product, has high adhesive strength when used as a heat seal material (especially adhesive strength against amorphous polyester), and When peeling, it becomes easy to peel (open after sealing).

-(1) Ethylene / polar monomer copolymer-
The ethylene-based polymer composition contains at least one ethylene / polar monomer copolymer. The ethylene / polar monomer copolymer, which is a component constituting the ethylene polymer composition, is a binary or multi-component copolymer of ethylene and a polar monomer.

The ethylene / polar monomer copolymer obtained by copolymerizing ethylene and a polar monomer has a polar monomer content (content ratio of structural units derived from the polar monomer) of 18% by mass or less, and a range of 15% by mass or less. preferable. When the polar monomer content exceeds 18% by mass, when the composition is used as a resin heat seal material (eg, polyester heat seal material), the resin (eg, polyester) is amorphous or crystalline. This is not preferable because there is a tendency for a large difference in seal strength.
Moreover, polar monomer content (content ratio of the structural unit derived from a polar monomer) is 7 mass% or more, Preferably it is 8 mass% or more. When the polar monomer content is 7% by mass or more, the heat sealability is excellent, and both the adhesive strength by heat sealing and the ease of peeling at the time of peeling (easy to open after sealing) can be achieved.

Examples of polar monomers include vinyl esters such as vinyl acetate; unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, isobutyl acrylate, nbutyl acrylate, isooctyl acrylate, and methyl methacrylate; acrylic acid, methacrylic acid, Examples thereof include unsaturated carboxylic acids such as maleic anhydride; carbon monoxide and the like. Of these, vinyl acetate is most preferred.
From the above, the ethylene / polar monomer copolymer is preferably an ethylene / vinyl acetate copolymer.

The ethylene polymer composition may contain two or more different types of ethylene / polar monomer copolymers. Further, two or more of the same type of ethylene / polar monomer copolymers having different compositions may be included. In this case, it is preferable that the total amount of the polar monomers contained satisfies the above range.
Further, the ethylene / polar monomer copolymer may contain two or more polar monomers. In this case, it is preferable that the total amount of polar monomers satisfy the above range.

The ethylene / polar monomer copolymer has a melt flow rate (MFR) at 190 ° C. under a load of 2160 g and a range of 1 g / 10 min to 7 g / 10 min from the viewpoint of molding processability and heat-sealing adhesive strength. The range is preferably 2 g / 10 min to 7 g / 10 min.
When the melt flow rate is 1 g / 10 min or more, the adhesive strength by heat sealing is better, and when the melt flow rate is 7 g / 10 min or less, the moldability is good. When two or more types of ethylene / polar monomer copolymers are included, it is preferable that a mixture of two or more types of ethylene / polar monomer copolymers satisfy the melt flow rate.
The melt flow rate of the ethylene / polar monomer copolymer is a value measured under the above temperature and load in accordance with JIS K7210-1999.

-A-B-A type block copolymer-
The ethylene-based polymer composition contains at least one type of ABA block copolymer. In the ABA type block copolymer, A represents a styrene polymer block, and B represents an alkylene copolymer block. The styrene polymer block refers to a polystyrene moiety, and the alkylene copolymer block refers to an alkylene copolymer moiety obtained by copolymerizing two or more alkenes.
Examples of the alkylene copolymer block include an ethylene / butene copolymer block and an ethylene / propylene copolymer block.
Such a block copolymer is obtained by hydrogenating a butadiene polymer unit or an isoprene polymer unit of a polystyrene-polybutadiene-polystyrene block copolymer or a polystyrene-polyisoprene-polystyrene block copolymer. Generally, for example, what is called SEBS or SEPS.
For example, SEBS is a polymer (polystyrene-poly (ethylene-butylene) -polystyrene) obtained by hydrogenating a double bond portion of a polystyrene-polybutadiene-polystyrene block copolymer comprising styrene and butadiene, and SEPS is styrene and isoprene. It is a polymer (polystyrene-poly (ethylene-propylene) -polystyrene) obtained by hydrogenating a double bond portion of a polystyrene-polyisoprene-polystyrene block copolymer.

  Here, the content of the styrene polymer block is preferably 1% by mass to 40% by mass, more preferably 5% by mass to 30% by mass with respect to the total mass of the ABA type block copolymer. is there.

Moreover, as a melt flow rate (MFR) in 230 degreeC and a 2160g load of an ABA type | mold block copolymer, 0.1g / 10min-500g / 10min are preferable, More preferably, it is 1g / 10min. ~ 100 g / 10 min.
The MFR of the ABA type block copolymer is a value measured at 230 ° C. and a load of 5000 g by a method based on JIS K7210-1999.

  Specific examples of the ABA type block copolymer include Clayton G1657 manufactured by Kraton Japan, Tuftec H1221 manufactured by Asahi Kasei Chemicals, and the like.

-Tackifying resin-
The ethylene-based polymer composition contains at least one tackifying resin in addition to the above-mentioned ethylene / polar monomer copolymer and ABA type block copolymer.
The tackifying resin is a hydrocarbon resin selected from the group consisting of aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins (including styrene resins), coumarone-indene resins, and the like. Or terpene resins are preferably used.

Examples of aliphatic hydrocarbon resins include polymers based on C _{4 to} C ₅ mono or diolefins such as butene-1, isobutylene, butadiene, 1,3-pentadiene, isoprene, piperylene and the like. .
Examples of the alicyclic hydrocarbon resin include a resin obtained by polymerizing a diene component in the fraction of C _{4 to} C ₅ after cyclization and dimerization, a resin obtained by polymerizing a cyclic monomer such as cyclopentadiene, an aromatic Examples include resins obtained by intranuclear hydrogenation of an aromatic hydrocarbon resin. Examples of commercially available products include Alcon AM-1 (C9 hydrogenated aromatic petroleum resin) manufactured by Arakawa Chemical Industries, Ltd., YS Resin PX1150N manufactured by Yashara Chemicals, and the like.
Examples of aromatic hydrocarbon resins, vinyl toluene, indene, alpha-vinyl aromatic hydrocarbons C ₉ -C _10, such as methyl styrene, styrene, a resin mainly composed of isopropenyl toluene and the .

  Examples of terpene resins include α-pinene polymers, β-pinene polymers, dipentene polymers, terpene-phenol copolymers, α-pinene-phenol copolymers, hydrogenated terpene resins (hydrogenated terpene resins). Etc.

  Of these, the use of hydrogenated resins such as hydrogenated aromatic hydrocarbon resins (hydrogenated petroleum resins) and hydrogenated terpene resins is particularly preferred.

In the ethylene-based polymer composition, the blending ratio of the ethylene / polar monomer copolymer, the ABA block copolymer, and the tackifier resin is ethylene when the total amount is 100 parts by mass. -The polar monomer polymer is 40 parts by mass to 95 parts by mass (preferably 50 parts by mass to 85 parts by mass), and the ABA block copolymer is 1 part by mass to 40 parts by mass (preferably 3 parts by mass to 30 parts by mass), and the tackifier resin is in the range of 3 parts by mass to 25 parts by mass (preferably 3 parts by mass to 20 parts by mass).
When the content of the ABA type block copolymer is 1 part by mass or more, it is easy to stably maintain the sealing strength when the resin (particularly amorphous polyester) is crystallized. Moreover, it is easy to apply also to oil-based foodstuffs as content of an ABA type block copolymer is 40 mass parts or less.
Further, when the content of the tackifying resin is 3 parts by mass or more, the sealing strength is improved. Further, when the content of the tackifying resin is 25 parts by mass or less, it is more suitable in terms of oil resistance and workability of the composition.

-Other ingredients-
In addition to the above-mentioned three components (ethylene / polar monomer copolymer, ABA block copolymer, and tackifying resin), an optional additive is blended in the ethylene polymer composition. be able to.
Examples of such additives include antioxidants, heat stabilizers, light stabilizers, antistatic agents, lubricants, and colorants.

In particular, it is desirable to add a lubricant in order to improve the processability of the composition. Examples of such lubricants include fatty acid amides, high molecular weight polyethylene glycols, hydrogenated castor oil, and silica.
The blending amount of the lubricant is about 100 ppm to 10000 ppm in the case of an organic compound lubricant with respect to 100 parts by mass of the total amount of the above three components, and 0.1 in the case of an inorganic compound lubricant such as silica. An amount of about 3% to 3% by mass is effective. The use of a lubricant has the advantage that the ethylene-based polymer composition can be prevented from blocking a film and sticking to a metal roll in an extrusion coating process on a base material, and at the same time, improving workability in subsequent processes such as unwinding. is doing.

The MFR (190 ° C., 2160 g load) of the ethylene polymer composition is 20 g / 10 min or less, particularly 5 g / 10 min to 18 g / 10 min in consideration of molding processability, seal characteristics, and blocking resistance. It is desirable to be adjusted. When the MFR exceeds 20 g / 10 minutes, particularly the molding processability is lowered.
The MFR of the ethylene polymer composition is a value measured under the above temperature and load in accordance with JIS K7210-1999.

<Easy-opening sealing material>
The easily openable sealing material according to the present disclosure is composed of the ethylene-based polymer composition according to the present disclosure described above.
The ethylene-based polymer composition according to the present disclosure has heat sealability with respect to both an amorphous resin and a crystalline resin (for example, an amorphous polyester and a crystalline polyester). The ethylene polymer composition can be used as an easy-open sealing material used for packaging materials. For example, by using it as a sealing layer of a packaging material using amorphous polyester (for example, a lid material or a cover material such as a cup or a tray), it is possible to perform sealing with excellent sealing properties and easy opening properties. And even if polyester crystallizes, stable seal strength can be maintained.

  Ethylene polymer compositions include stretched polyethylene terephthalate, crystalline polyethylene terephthalate, polytetramethylene terephthalate, polyethylene naphthalate, and other polyesters, and acrylonitrile polymers (for example, nitrile rubber grafted with acrylonitrile and acrylic ester, Excellent easy-open seal properties that show moderate seal strength over a wide temperature range, even for styrene polymers such as polystyrene and high-impact polystyrene, and polyvinyl chloride. have.

The easy-open sealing material composed of an ethylene polymer composition can be used as a single layer for packaging materials, and can be used by laminating the ethylene polymer composition as a heat seal layer on a substrate. it can.
Examples of such a substrate include stretched or unstretched films, such as polyesters such as polyethylene terephthalate, polyamides, polypropylene, polyethylene, ethylene / vinyl acetate copolymers, and ethylene / unsaturated carboxylic acid ester copolymers. , Ethylene / unsaturated carboxylic acid copolymer or its ionomer, ethylene / vinyl alcohol copolymer, paper, aluminum foil, film deposited with aluminum, silica, alumina, etc., gas barrier materials such as polyvinylidene chloride and polyvinyl alcohol A coated film or the like can be exemplified. These base materials may be a single layer or a laminate of two or more layers.

  When the substrate is a laminate of two or more layers, in particular, a laminate substrate comprising a polyolefin polymer such as polyethylene, polypropylene, ethylene / unsaturated carboxylic acid copolymer, ionomer and other substrate is preferable, By laminating the above-described ethylene polymer composition on the polyolefin polymer side, a heat seal layer can be easily formed on the surface of various laminated substrates.

The lamination of the ethylene polymer composition and the base material is performed by the tandem extrusion laminating method in which the polyolefin polymer and the ethylene polymer composition are continuously extruded and laminated to the base material, the resin constituting the base material and the ethylene base material. It can be carried out by a known method such as a method of co-extrusion laminating with a polymer composition, a sandwich extrusion lamination method of a polyolefin polymer between a substrate and an ethylene polymer composition film.
In addition, when laminating | stacking a base material and a polyolefin-type polymer, it is effective to use an adhesive agent as needed.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof.
The MFR of the ethylene / polar monomer copolymer is a value measured at 190 ° C. and a load of 2160 g by a method based on JIS K7210-1999. Moreover, MFR of an ABA type block copolymer is the value measured by 230 degreeC and the load 5000g by the method based on JISK7210-1999.

[raw materials]
The composition and physical properties of the resins for preparing the ethylene polymer compositions used in the following examples and comparative examples are as follows. The vinyl acetate unit content in the ethylene / polar monomer copolymer is the content ratio of structural units derived from the polar monomer in the ethylene / polar monomer copolymer.

-Ethylene / polar monomer copolymer-
・ EVA1:
Ethylene / vinyl acetate copolymer (ethylene unit content: 90% by mass, vinyl acetate unit content: 10% by mass, MFR (190 ° C., 2160 g load) 9 g / 10 min)
・ EVA2:
Ethylene / vinyl acetate copolymer (ethylene unit content: 90% by mass, vinyl acetate unit content: 10% by mass, MFR (190 ° C., 2160 g load) 3 g / 10 min)
・ EVA3:
Ethylene / vinyl acetate copolymer (ethylene unit content: 86% by mass, vinyl acetate unit content: 14% by mass, MFR (190 ° C., 2160 g load) 3 g / 10 min)
・ EVA4:
Ethylene / vinyl acetate copolymer (ethylene unit content: 86% by mass, vinyl acetate unit content: 14% by mass, MFR (190 ° C., 2160 g load) 15 g / 10 min)
・ EVA5:
Ethylene / vinyl acetate copolymer (ethylene unit content: 81% by mass, vinyl acetate unit content: 19% by mass, MFR (190 ° C., 2160 g load) 2.5 g / 10 min)

-A-B-A type block copolymer-
・ Clayton G1657 (SEBS, manufactured by Clayton Japan)
(MFR (230 ° C., 5000 g load) 22 g / 10 min, density 900 kg / m ³ )
-Tackifying resin-
・ Alcon AM-1 (alicyclic hydrocarbon resin having a ring-and-ball method softening point of 115 ° C.), manufactured by Arakawa Chemical Industries, Ltd.
Neutron-S (erucic acid amide, hereinafter abbreviated as ELA), manufactured by Nippon Seika Co., Ltd. Polyethylene glycol (hereinafter abbreviated as PEG), manufactured by Nippon Oil & Fats Co., Ltd.

(Examples 1-3 and Comparative Examples 1-2)
The resin is mixed at a blending ratio shown in Table 1 so that the charging amount becomes 10 kg, and the resin is introduced into an extruder (65 mmφ, L / D = 28, tip dull image flight screw), and melt kneaded at a processing temperature of 160 ° C. Thus, a resin composition (ethylene polymer composition) was prepared. The following evaluation was performed with respect to the obtained resin composition. The evaluation results are shown in Table 1 below.

(Evaluation)
-Releasing properties-
A base material having a laminated structure of polyethylene terephthalate (PET, 12 μm) / polyethylene (PE, 15 μm) was prepared in advance. The resin composition obtained as described above is laminated on the base material PET at a thickness of 30 μm by an extrusion laminating method (processing temperature: 230 ° C., processing speed: 30 m / min) to obtain a resin composition layer / base material. A laminate having a laminate structure of (= PET / PE) was obtained. At this time, the peelability from the cooling roll was evaluated according to the following criteria. The evaluation results are shown in Table 1.
<Evaluation criteria>
A: Peelability is particularly good, and there is almost no peeling sound from the cooling roll.
B: Peelability is good, and there is no problem in processing although there is a peeling sound from the cooling roll.
C: Peelability is poor, and peeling failure occurs when peeling from the cooling roll, which hinders processing.

-Adhesive strength (heat sealability for amorphous polyester)-
Using the laminate obtained by the evaluation of the above-mentioned “rolling-off property”, the laminate and a commercially available amorphous polyester sheet having a thickness of 0.4 mm are used, and the resin composition layer of the laminate is an amorphous polyester sheet. And then heat-sealed under the conditions of a pressing force of 0.2 MPa, a heating temperature of 120 ° C., and a heating time of 1.0 second to obtain an adhesive. This adhesive has a laminated structure of amorphous polyester sheet / resin composition layer / base material (= PET / PE).
After heat sealing, it was left at room temperature for 24 hours.
After standing, a test piece having a width of 15 mm was cut out from the adhesive, and both sides of the cut-out test piece were pulled in opposite directions (180 ° C. peeling direction) to determine the maximum stress when the seal part was peeled off. This maximum stress (N / 15 mm) was defined as the adhesive strength (N / 15 mm) for the amorphous polyester resin of the resin composition.
Further, the heating temperature was changed from 120 ° C. to 140 ° C. and 160 ° C., and the adhesive strength of the adhesive after heat sealing was evaluated in the same manner.
The measurement results are shown in Table 1 below. The adhesive strength is preferably in the range of 10 N / 15 mm to 15 N / 15 mm in order to achieve both adhesion by heat sealing and easy releasability when peeling after heat sealing.

-Blocking strength-
Six samples having a width of 50 mm were cut out from the laminate (laminated structure of resin composition layer / base material (= PET / PE)) obtained by the evaluation of the above-mentioned “rolling-off property” and stacked in order, and fixed conditions (20 kgf Aging for 2 days under a load of / cm ^{2 and} an atmosphere of 40 ° C. Thereafter, the peel strength between the six samples was measured with a measuring instrument VG-35 manufactured by Vangard. The obtained peel strength (g / 50 mm) was defined as anti-blocking strength. The measured peel strength (anti-blocking strength) is shown in Table 1 below. The anti-blocking strength is preferably less than 10 g / 50 mm.

  As shown in Table 1, in the examples, the roll release property and the adhesive strength were excellent, and the blocking resistance was also good. On the other hand, in Comparative Example 1 in which the MFR of the ethylene / polar monomer copolymer exceeds 7 g / 10 min, the roll release property is inferior, and in Comparative Example 2 in which the content ratio of the constituent units derived from the polar monomer is too large. Adhesive strength and blocking resistance were significantly reduced.

  The ethylene-based polymer composition of the present disclosure makes use of the properties as described above and is useful as a lid material or cover material for various packaging bodies of amorphous polyester. In addition, the ethylene polymer composition of the present disclosure can be used as an easily openable sealing material such as various other polyester materials, acrylonitrile polymers, styrene polymers, and polyvinyl chloride. Furthermore, the ethylene polymer composition of the present disclosure can also be used as a sealing material such as polyethylene, polypropylene, polyolefin such as poly-4-methyl-1-pentene, and polycarbonate.

Claims (6)

The content ratio of the structural unit derived from the polar monomer is 7% by mass to 18% by mass, and the melt flow rate (according to JIS K7210-1999, 190 ° C., 2160 g load) is 1 g / 10 min to 7 g / 10 min. 40 parts by mass to 95 parts by mass of an ethylene / polar monomer copolymer,
1 to 40 parts by mass of an A-B-A type block copolymer (A represents a polystyrene block and B represents an alkylene copolymer block);
3 to 25 parts by weight of tackifying resin;
(However, the total of the ethylene / polar monomer copolymer, the ABA type block copolymer, and the tackifying resin is 100 parts by mass),
The melt flow rate (according to JIS K7210-1999, 190 ° C., 2160 g load) Ri is 20 g / 10 min der hereinafter, the ethylene-polar monomer copolymer, ethylene-vinyl ester copolymer, and ethylene-unsaturated Ru least 1 Tsudea selected from unsaturated carboxylic acid ester copolymer, ethylene polymer composition.   The ethylene-based polymer composition according to claim 1, wherein the ethylene / polar monomer copolymer is an ethylene / vinyl acetate copolymer.   The ethylene polymer composition according to claim 1 or 2, wherein the tackifying resin is a hydrocarbon resin.   The easily openable sealing material which consists of an ethylene-type polymer composition of any one of Claims 1-3.   The easily openable sealing material according to claim 4, which is used for an adherend containing a resin selected from polyester, acrylonitrile-based polymer, styrene-based polymer, and polyvinyl chloride.   The easily openable sealing material according to claim 4 or 5, which is used by being laminated on a base material.