JP7240067B2 - Adhesive resin composition, sheet, lid material, member set for sealed container and container - Google Patents

Description

The present invention provides an adhesive resin composition that exhibits easy-openability by interfacial peeling at the time of opening, and has excellent container adhesion resistance and film-forming properties, a sheet, a lid material, and a sealed container using the adhesive resin composition. It relates to a member set and a container.

In the field of food packaging, until now, contents such as cup noodles, yogurt, and jelly have been filled in a paper container coated with polyethylene resin, and the opening of the container has a heat-sealing layer with excellent sealing properties. A form of packaging in which materials are glued together has been actively used.

However, in recent years, the use of containers made of polyester-based resins, particularly polyethylene terephthalate (hereinafter referred to as PET)-based resins, has increased because of their superior physical properties such as strength, transparency, and heat resistance.

Conventionally, as an easy-open adhesive mainly intended for paper containers coated with polyethylene resin, for example, 1-butene homopolymer or copolymer having an average molecular weight of 8 to 49% by mass of at least 500,000 A composition comprising coalescence and 92-51% by weight of modified or unmodified low density polyethylene having a density of 930 kg/m ³ or less has been proposed (see US Pat.

Further, a thermoplastic resin A having a melt index of 0.1 to 100 and a thermoplastic resin B that is incompatible or partially compatible with the thermoplastic resin A, and the melt index is specified as the thermoplastic resin A A composition containing a specific proportion of a thermoplastic resin B having a relationship of is proposed (see Patent Document 2).

As still another example, a resin containing at least one of an ethylene polymer and an ethylene/vinyl acetate copolymer, a resin B incompatible with the resin A, and a tackifying resin, and having a tensile strength at break of 2 MPa or more A composition having a tensile strength of 15 MPa or less and a tensile elongation strength of 50% or more and 500% or less has been proposed (see Patent Document 3).

JP-A-1-315443 JP-A-2000-302990 JP 2016-148003 A

The compositions proposed in Patent Documents 1 to 3 are characterized by cohesive failure when unsealed due to the use of two types of resins having different compatibility. This allows the contents to be tightly sealed. On the other hand, however, resin residue and stringiness occur on the flange of the container, which not only results in poor appearance, but also the possibility of accidental ingestion when the container is put into the mouth and eaten.

The problem to be solved by the present invention is that, especially when the adherend is a polyester-based container, resin residue and stringing do not occur on the flange of the container even at room temperature or under freezing, and the container has excellent adhesion resistance and good adhesion. An object of the present invention is to provide an adhesive resin composition exhibiting easy openability and excellent film-forming properties during coating, a sheet, a lid material, a member set for a sealed container, and a container using the composition.

As a result of intensive studies to solve the above problems, the present inventors have found that an ethylene-α-olefin copolymer (A) having a density of 0.88 to 0.93 g/cm ³ and a vinyl acetate content of 5 % or more and less than 18% of ethylene-vinyl acetate copolymer (B), vinyl acetate content of 18% or more and less than 30% of ethylene-vinyl acetate copolymer (C), and tackifier resin (D) within specific ranges It was found that the above problem was solved by containing at a ratio of
The ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 5% or more and less than 18% is an ethylene-α-olefin having a density of 0.88 to 0.93 g/cm ³ that imparts adhesion to PET. It acts as a compatibilizer between the copolymer (A) and the ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30%, which develops adhesive strength under freezing, and improves film formability. have the effect of improving
By the above, the adhesive resin composition has excellent easy-openability and adhesion resistance to containers at room temperature and freezing, and has excellent film-forming properties during coating, especially for polyester-based containers. It is possible to provide a sheet laminated with a film of the adhesive resin composition.
That is, the present invention relates to the following inventions [1] to [11].

[1] Ethylene-α olefin copolymer (A) having a density of 0.88 to 0.93 g/cm ³ 10 to 25% by mass and an ethylene-vinyl acetate copolymer having a vinyl acetate content of 5% to less than 18% Combined (B) 20 to 45% by mass, ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30% (C) 10 to 35% by mass, and tackifying resin (D) 25 to 35% by mass Adhesive resin composition containing.

[2] The adhesive resin composition according to [1], wherein the ethylene-α-olefin copolymer (A) has a melting point measured by a differential scanning calorimeter of 100 to 120°C.

[3] The ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 5% or more and less than 18% has a melting point of 80 to 100°C as measured by a differential scanning calorimeter, [1] or [2] ].

[4] The ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30% has a melting point of 60 to 90°C as measured by a differential scanning calorimeter, [1] to [3]. ] The adhesive resin composition according to any one of the above items.

[5] The adhesive resin composition according to any one of [1] to [4], wherein the tackifying resin (D) contains an alicyclic hydrocarbon resin.

[6] The adhesive resin composition according to any one of [1] to [5], which has a melt flow rate of 10 to 25 g/10 minutes.

[7] Total of ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 5% or more and less than 18% and ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30% The adhesive resin composition according to any one of [1] to [6], wherein the vinyl acetate content is 8% or more and less than 9.5%.

[8] A sheet in which a film of the adhesive resin composition according to any one of [1] to [7] is laminated on a substrate.

[9] A lid material formed of the sheet described in [8].

[10] A member set for an openable sealed container, comprising a container body made of a polyester resin or a container body whose inner surface is covered with a polyester resin, and the cover member according to [9].

[11] An openable container in which the opening of a container body made of a polyester resin or a container body whose inner surface is covered with a polyester resin is sealed with the cover material according to [9].

According to the present invention, especially when the adherend is a polyester-based container, resin residue and stringiness do not occur on the flange of the container even at normal temperature or freezing, and it has excellent container adhesion resistance and exhibits good easy-opening properties. In addition, it is possible to provide an adhesive resin composition excellent in film-forming properties during coating, a sheet, a lid material, a sealed container member set, and a container using the composition.

The adhesive resin composition of the present invention contains 10 to 25% by mass of an ethylene-α-olefin copolymer (A) having a density of 0.88 to 0.93 g/cm ³ and a vinyl acetate content of 5% to less than 18%. 20 to 45% by mass of ethylene-vinyl acetate copolymer (B), 10 to 35% by mass of ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30%, tackifying resin (D ) containing 25 to 35% by mass.
The present invention will be described in detail below.

<Ethylene-α-olefin copolymer (A) having a density of 0.88 to 0.93 g/cm ³ >
As the ethylene-α-olefin copolymer (A) having a density of 0.88 to 0.93 g/cm ³ and constituting the adhesive composition of the present invention, ethylene and propylene, butene, pentene, hexene and higher carbon A copolymer obtained by polymerizing at least one selected from the group consisting of long-chain olefins in an arbitrary ratio can be used.
From the viewpoint of blocking resistance, the ethylene-α-olefin copolymer (A) is preferably propylene or butene, more preferably butene. The shorter the carbon chain of the olefin, the better the blocking resistance.
It should be noted that the density in the present application refers to JIS. It is a measured value by the pycnometer method for K7112.

The ethylene-α-olefin copolymer (A) accounts for 10 to 25% by mass, preferably 10 to 20% by mass, in the adhesive resin composition.
Since the ethylene-α-olefin copolymer (A) is 10% by mass or more, it can be sufficiently adhered to a polyester-based resin container without impairing the opening strength under freezing. Moreover, since it is 25 mass % or less, it adheres sufficiently to the polyester-based resin container without impairing the opening strength under freezing and at room temperature.

The ethylene-α-olefin copolymer (A) preferably has a melting point measured by a differential scanning calorimeter (hereinafter referred to as DSC melting point) of 80 to 140°C, more preferably 90 to 130°C. and particularly preferably within the range of 100 to 120°C. Within the above range, it is preferable in that the adhesion to PET can be improved.

<Ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 5% or more and less than 18%>
As the ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 5% or more and less than 18%, which constitutes the adhesive composition in the present invention, vinyl acetate is added to ethylene at a ratio of 5% or more and less than 18%. Polymerized copolymers can be used.

The ethylene-vinyl acetate copolymer (B) accounts for 20 to 45% by mass, preferably 25 to 40% by mass, in the adhesive resin composition.
Since the ethylene-vinyl acetate copolymer (B) is 20% by mass or more, it adheres well to the polyester-based resin container under freezing conditions and at room temperature without impairing the opening strength. Moreover, since the content is 45% by mass or less, not only is it possible to achieve a balance between coating suitability and adhesiveness, but resin residue and stringiness do not occur on the flange of the container even at room temperature or under freezing.

The ethylene-vinyl acetate copolymer (B) preferably has a DSC melting point of 80° C. or higher and lower than 100° C., preferably 85° C. or higher and lower than 95° C. Within the above range, the ethylene-α-olefin copolymer (A) and the ethylene-vinyl acetate copolymer (C) are compatible with each other, improving the coating suitability and sufficiently without impairing the opening strength. It is preferable in that it can be adhered.

<Ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30%>
As the ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30%, which constitutes the adhesive composition of the present invention, vinyl acetate is added to ethylene at a ratio of 18% or more and less than 30%. Polymerized copolymers can be used.

The ethylene-vinyl acetate copolymer (C) accounts for 10 to 35% by mass, preferably 10 to 30% by mass, particularly preferably 10 to 25% by mass, in the adhesive resin composition.
When the ethylene-vinyl acetate copolymer (B) is 10% by mass or more, the unsealing strength under freezing can be suppressed. In addition, when the content is 35% by mass or less, it is possible to balance the film-forming property and the adhesion property under freezing and at room temperature.

The ethylene-vinyl acetate copolymer (C) preferably has a DSC melting point of 60°C or higher and lower than 90°C, preferably 65°C or higher and lower than 85°C. It is preferable that it is within the above range because the adhesiveness under freezing can be improved.

<Tackifying resin (D)>
The tackifier resin (D) constituting the adhesive composition of the present invention includes aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins, polyterpene resins, rosins, etc., and sealant adhesives. can be used known tackifying resins used in. The tackifying resin (D) can be used alone or in combination of two or more.
The tackifying resin (D) ranges from 25 to 35% by weight in the adhesive composition. When the tackifying resin is 25% by mass or more, it can be sufficiently adhered to a polyester-based resin container under freezing conditions and at room temperature without impairing the opening strength. Moreover, when it is 35% by mass or less, the film formability is improved. Among them, the tackifier resin (D) preferably contains at least one selected from the group consisting of alicyclic hydrocarbon resins and aromatic hydrocarbon resins, and more preferably contains alicyclic hydrocarbon resins. The above resin may be partially hydrogenated or completely hydrogenated.

The tackifying resin (D) preferably has a softening point of 120° C. or lower from the viewpoint of adhesiveness during heat sealing, that is, opening strength (easiness to open). The softening point in the present invention is the temperature determined by the method specified in JIS K6863. That is, when the resin filled in a specified ring and allowed to stand still for 12 hours or longer is placed in a heat medium and the temperature of the heat medium is raised at a constant rate by placing a specified ball, the ball sinks due to the softening of the resin. It is the temperature when the bottom plate of the ring base is touched.
The DSC melting point of the tackifying resin (D) is preferably 65-95°C, more preferably 65-80°C.

<Adhesive resin composition>
Ethylene-α-olefin copolymer (A) having a density of 0.88 to 0.93 g/cm ³ , Ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 5% or more and less than 18%, vinyl acetate-containing Ethylene-vinyl acetate copolymer (C) with a ratio of 18% or more and less than 30% and a tackifying resin (D), (A) / (B) / (C) / (D) = 10 ~ 25 / 20 ~ It is contained in a composition of 45/10 to 35/25 to 35 (mass%), preferably 10 to 20/25 to 40/10 to 30/25 to 35 (mass%), more preferably , 10 to 20/25 to 40/10 to 25/25 to 35 (% by mass). However, the sum of (A), (B), (C) and (D) shall be 100% by mass.

The total amount of ethylene-α-olefin copolymer (A), ethylene-vinyl acetate copolymer (B), ethylene-vinyl acetate copolymer (C) and tackifying resin (D) is the adhesive resin composition 100 In mass %, it is preferably 90 mass % or more, more preferably 95 mass % or more, and still more preferably 98 mass % or more.

The MFR of the adhesive resin composition is preferably 1 to 50 g/10 minutes, more preferably 10 to 25 g/10 minutes. Within the above range, it is preferable from the viewpoint of film-forming properties during coating. MFR in the present application means JIS. It is the MFR value at 190° C. and 21.168 N according to K7210.

Further, in the adhesive resin composition, an ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 5% or more and less than 18% and an ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 18% or more and less than 30% The vinyl acetate content with respect to the total of coalescence (C) is preferably 8% or more and less than 9.5%, more preferably 8.5% or more and less than 9.0%. Within the above range, it is preferable from the viewpoint of excellent balance between film formability and easy-openability at room temperature and under freezing, and from the viewpoint of achieving both physical properties.

In the resin composition of the present invention, within a range that does not contradict the object of the present invention, that is, within a range that does not impair film-forming properties, easy-openability under freezing and normal temperature, and resistance to container adhesion to PET containers, Resins other than the ethylene-α-olefin copolymer (A), the ethylene-vinyl acetate copolymer (B), the ethylene-vinyl acetate copolymer (C) and the tackifying resin (D) may be blended.

Specific examples of such resins include known polyolefin resins such as high-density polyethylene and polypropylene, their oxides and maleic acid-modified products, ethylene-acrylic acid copolymers, and ethylene-(meth)acrylic acid copolymers. Various elastomers such as ethylene-unsaturated monocarboxylic acid copolymers such as coalescence and metal salts thereof, styrene-butadiene copolymer elastomers and hydrogenated products thereof, or high-density polyethylene wax, polypropylene wax, ethylene-vinyl acetate copolymer Known waxes such as coalescent wax, Fischer-Tropsch wax, paraffin wax, oxidized wax, maleic acid-modified wax, and polyethylene wax grafted with styrene monomer can be used. Moreover, these resins may be used alone or in combination of two or more.

In the adhesive resin composition of the present invention, in order to prevent thermal deterioration, thermal decomposition, blocking, etc., and to ensure processing suitability such as film processing and extrusion lamination processing, within a range that does not impair the purpose of the present invention. , and further additives and the like may be used. Examples of additives include organic lubricants such as erucamide, inorganic lubricants such as calcium carbonate, antioxidants such as hindered phenol, other antiblocking agents, antistatic agents, fillers, pigments, and antifogging agents. are mentioned. These additives are added when blending the ethylene-α-olefin copolymer (A), the ethylene-vinyl acetate copolymer (B), the ethylene-vinyl acetate copolymer (C) and the tackifying resin (D). Alternatively, the ethylene-α-olefin copolymer (A), ethylene-vinyl acetate copolymer (B), ethylene-vinyl acetate copolymer (C) or tackifier resin (D) may be kneaded in advance. After being mixed, it may be blended by kneading with other ingredients.

Ethylene-α-olefin copolymer (A), ethylene-vinyl acetate copolymer (B), ethylene-vinyl acetate copolymer (C), tackifier resin (D) and optional additives are mixed. For example, these components are put into a mixing device such as a Henschel mixer or a tumbler mixer, mixed for a blending time of 5 to 20 minutes, put into an extruder, heated and kneaded, and then extruded. The extrudate is usually pelletized for use in subsequent steps. Preferred examples of the extruder include, but are not limited to, a twin-screw extruder. Extrusion is also usually carried out at 140-200°C.

<Seat>
Next, a sheet in which a film of the adhesive resin composition of the present invention is laminated on a substrate will be described. As a method for laminating the adhesive resin composition of the present invention on a substrate, for example, the resin composition pelletized as described above is used, and a single layer film is formed by an inflation method or a casting method, and this film is used as a substrate. and a method of laminating via another adhesive layer if necessary. Alternatively, the kneaded resin composition may be directly coated on the substrate, or another method may be employed.

In order to improve the adhesion of the lamination surface, the substrate surface may be subjected to flame treatment, ozone treatment, corona discharge treatment or treatment with an anchor coating agent. It is also possible to perform extrusion lamination directly on a substrate that has been laminated with a polyethylene-based resin in advance. In addition, a multilayer film is formed by co-extrusion with polyethylene, polypropylene, etc., and by dry lamination or sand lamination, it is laminated with stretched or unstretched films such as polyester film, polyamide film, polypropylene film, etc. as a base material. You can also get a printed sheet. Also in this case, in order to improve the adhesion of the laminated surface, if necessary, the substrate surface may be subjected to flame treatment, ozone treatment, corona discharge treatment, treatment with an anchor coating agent, or the like. Moreover, the thickness of the adhesive resin composition layer of the present invention is preferably 5 μm or more, more preferably 10 μm or more.
In addition, the "base material" in the present invention is used to include long and cut short films and sheets. It also includes In addition, the sheet laminated with the adhesive resin composition of the present invention can be used as a lid material as described later, and can also be used as a sealant film for bag products in which the coating of the adhesive resin composition is sealed as the inner surface. It can be used preferably.

<Lid material>
The sheet of the present invention, in which the adhesive resin composition is laminated on the substrate, is cut according to the shape of the opening of the container body to be sealed, and is suitably used as a lid material.
When the sheet of the present invention is used as a lid material, various substrates can be used as the substrate. Substrates used include paper, aluminum, polyester, polyethylene, polypropylene, polystyrene, aluminum-deposited polyester, aluminum-deposited polypropylene, silica-deposited polyester, and the like. Such a substrate need not be a single layer, and may be a laminate of two or more layers.
When the sheet of the present invention is used to form a cover material, the substrate is preferably a laminate of PET having a thickness of 5 to 20 μm and polyethylene having a thickness of 5 to 30 μm. A laminate of films having a thickness of 5 to 40 μm formed from an adhesive resin composition is preferred.

<Container body>
Examples of the container body include a container body made of polyester resin, a container body whose inner surface is covered with polyester resin, a container body made of polyethylene resin, and a container body whose inner surface is covered with polyethylene resin. In particular, a container body made of a polyester-based resin, and a container body whose inner surface is covered with a polyester-based resin are preferable.

<Openable sealed container>
In the openable sealed container of the present invention, the opening of the container body is sealed with a cover member cut to match the shape of the opening of the container body. That is, the adhesive resin composition of the present invention provided on one surface of the lid member and the adhesive surface (also referred to as a flange) of the opening of the sealed container are brought into contact with each other and heated to bond them together. . The bonding conditions are preferably 100 to 180°C.
When the container body is a PET container, the container body and the lid material are preferably thermally bonded at a thermal bonding temperature of 100 to 180° C., and the opening strength at room temperature is in the range of 7 to 15 N. It is preferred that the thermal adhesive layer exhibits interfacial peeling. The openable seal of the present invention can be used to package, for example, jellies, puddings, yoghurts, frozen desserts, dry sweets, cup noodles, and the like.

EXAMPLES The present invention will be described below based on examples, but the present invention is not limited by these. In the examples, "parts" and "%" represent "mass parts" and "mass%", respectively.

<Method for producing adhesive resin composition>
[Examples 1 to 9 and Comparative Examples 1 to 8]
(Production of adhesive resin compositions (S-1) to (S-17))
Ethylene-α olefin copolymer (A) having a density of 0.88 to 0.93 g/cm ³ and ethylene-vinyl acetate copolymer having a vinyl acetate content of 5% or more and less than 18% ( B), an ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30%, a tackifying resin (D), an antiblocking agent and an antioxidant were preblended for 5 minutes in a Henschel mixer. . The pre-blend was put into a hopper and supplied to the following extruder using a screw feeder to produce adhesive resin compositions (S-1) to (S-17). Units of numerical values in Table 1 represent parts unless otherwise indicated.

≪Extruder conditions≫
Extruder: Co-rotating twin-screw extruder PMT32-40.5 manufactured by IKG
Barrel temperature: 180°C (supply port 160°C)
Screw rotation speed: 200 rpm
Feed rate: 10kg/hr

<Evaluation of adhesive resin composition>
The obtained adhesive resin composition was evaluated for MFR and film formability. In addition, a laminated sheet (lid material) was prepared according to the following, and using the sheet, the opening strength (easy opening property) under freezing and at room temperature, and the container adhesion resistance (stringing) were measured by the following methods and Evaluated based on criteria. Table 1 shows the results.

[MFR]
The MFR of the adhesive resin composition is JIS. In accordance with K7210, a cylinder with an inner diameter of 9.55 mm and a length of 162 mm of a melt indexer L244 (manufactured by Takara Kogyo Co., Ltd.) is filled with a sample, melted at 190 ° C., and then weighed 2160 g and a plan with a diameter of 9.48 mm It was determined from the amount of resin extruded per unit time (g/10 minutes) from an orifice with a diameter of 2.1 mm provided in the center of the cylinder while applying a uniform load using a jar.

[Film formability]
The film-forming property of the adhesive resin composition is determined by whether or not it can be coated at any temperature of 200 to 250 ° C. under the following processing conditions, and by using a film thickness meter from the resulting coated product. Evaluation was made according to the following criteria based on the values obtained when the film thickness was measured.
≪Processing conditions≫
Extrusion laminator: 400M/M Test EXT laminator manufactured by Musashino Kikai Resin temperature directly below the die: 200-250°C
Processing speed: 30m/min T die width: 400mm
Cooling roll surface temperature: 20°C
Substrate: PET 12 μm / PE 25 μm Coated on the PE surface of the substrate ○: Coatable and film thickness 20 ± 3 μm: good △: Coatable and film thickness 20 ± 6 μm: used Possible ×: Either film cracking or film breakage occurs and coating is impossible, or coating is possible but the film thickness exceeds 20 ± 6 µm: Poor

[Method for producing sheet (lid material)]
The obtained adhesive resin composition was laminated on the PE surface of a PET 12 μm/PE 25 μm substrate using an extrusion laminator to prepare a sheet. The thickness of the adhesive layer was 20 μm. Processing conditions are shown below.
Extrusion laminator: 400M/M Test EXT laminator manufactured by Musashino Kikai Resin temperature directly below the die: 200° C. to 250° C. (adjusted appropriately according to the MFR of the adhesive resin composition, etc.).
Processing speed: 30m/min T die width: 400mm
Cooling roll surface temperature: 20°C

[Ease of opening (room temperature)]
After cutting the obtained laminated sheet (lid material) into a size of 90 mm × 90 mm, the adhesive resin composition surface was heat-bonded to a 71Φ PET container at a gauge pressure of 0.3 MPa, 150 ° C., and 1 second, and sealed. rice field. It was left for 24 hours in a constant temperature and humidity chamber at a temperature of 23° C. and a humidity of 65%, and the peel strength was measured under the conditions of 90° angle peeling and tensile speed of 200 mm/min in the constant temperature and humidity chamber. The maximum value was taken as the opening strength, and the ease of opening was evaluated according to the following criteria.
○: Peel strength is 7 N or more and less than 15 N: Good △: Peel strength is 5 N or more and less than 7 N, or 15 N or more and less than 17 N: Usable ×: Peel strength is less than 5 N or 17 N or more: Poor

[Ease of opening (freezing)]
After cutting the obtained laminated sheet (lid material) into a size of 90 mm × 90 mm, the adhesive resin composition surface was heat-bonded to a 71Φ PET container at a gauge pressure of 0.3 MPa, 150 ° C., and 1 second, and sealed. rice field. It was left for 24 hours in a constant temperature bath at a temperature of −20° C., and the peel strength was measured in the same constant temperature bath under the conditions of 90° angle peeling and tensile speed of 200 mm/min. The maximum value was taken as the opening strength, and the ease of opening was evaluated according to the following criteria.
○: Peel strength is 7 N or more and less than 15 N: Good △: Peel strength is 5 N or more and less than 7 N, or 15 N or more and less than 17 N: Usable ×: Peel strength is less than 5 N or 17 N or more: Poor

[Resistant adhesion to container under normal temperature and freezing]
The presence or absence of the adhesive resin composition on the flange portion of the PET container during the measurement of the opening strength at room temperature and under freezing was visually confirmed and evaluated according to the following criteria.
○: No adhesive resin composition adheres to the flange at room temperature or frozen: Good △: Adhesive resin composition slightly adheres to the flange at room temperature or frozen Observed: Usable ×: Adhesion of the adhesive resin composition to the flange portion was observed either at room temperature or under freezing: Defective

The raw material abbreviations used in Table 1 are shown below.
A1: Lumitac 22-7 (manufactured by Tosoh Corporation, ethylene-butene copolymer, density 0.900 g/cm ³ , DSC melting point 113° C., MFR 2 g/10 minutes)
A2: Lumitac 43-1 (manufactured by Tosoh Corporation, ethylene-butene copolymer, density 0.910 g/cm ³ , DSC melting point 113° C., MFR 20 g/10 minutes)

B1: Ultrathen 540 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer (vinyl acetate content: 10%), density: 0.929 g/cm ³ , DSC melting point: 94°C, MFR: 3 g/10 minutes)
B2: Ultrathene 626 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer (vinyl acetate content: 15%), density: 0.936 g/cm ³ , DSC melting point: 88°C, MFR: 3 g/10 minutes)

C1: Ultrathene 627 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer (vinyl acetate content: 20%), density: 0.941 g/cm ³ , DSC melting point: 83°C, MFR: 1 g/10 minutes)
C2: Ultrathen 751 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer (vinyl acetate content: 28%), density: 0.952 g/cm ³ , DSC melting point: 70°C, MFR: 6 g/10 minutes)
C3: Ultrathene 634 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer (vinyl acetate content: 26%), density: 0.949 g/cm ³ , DSC melting point: 74°C, MFR: 4 g/10 minutes)

D1: Alcon M-115 (manufactured by Arakawa Chemical Industries, Ltd., partially hydrogenated alicyclic hydrocarbon resin, softening point 115 ° C.)
D2: Alcon P-115 (manufactured by Arakawa Chemical Industries, fully hydrogenated alicyclic hydrocarbon resin, softening point 115 ° C.)

Anti-blocking agent: Incroslip C (manufactured by Croda, erucamide, DSC melting point 80°C)

Antioxidant: IRGANOX 1010 (manufactured by BASF, hindered phenolic antioxidant)

VA cont. : Vinyl acetate content (%)

The adhesive compositions of Examples 1 to 9 were excellent in film-forming properties, and exhibited good easy-to-open properties and resistance to adhesion to PET containers at room temperature and under freezing. Therefore, the adhesive resin composition of the present invention containing specific resins (A) to (D) in specific ratios is optimal for container lids made of polyester resins, particularly polyethylene terephthalate (PET) resins. .

Claims (10)

Ethylene-α olefin copolymer (A) having a density of 0.88 to 0.93 g/cm ³ 10 to 25% by mass, and an ethylene-vinyl acetate copolymer (B ) 20 to 45% by mass, 10 to 35% by mass of an ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30%, and 25 to 35% by mass of a tackifying resin (D), Adhesive resin composition. 2. The adhesive resin composition according to claim 1, wherein the ethylene-α-olefin copolymer (A) has a melting point of 100 to 120° C. as measured by a differential scanning calorimeter. The adhesion according to claim 1 or 2, wherein the ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 5% or more and less than 18% has a melting point of 80 to 100°C as measured by a differential scanning calorimeter. elastic resin composition. Any one of claims 1 to 3, wherein the ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30% has a melting point measured by a differential scanning calorimeter of 60 to 90°C. The adhesive resin composition according to . The adhesive resin composition according to any one of claims 1 to 4, wherein the tackifying resin (D) comprises an alicyclic hydrocarbon resin. The adhesive resin composition according to any one of claims 1 to 5, wherein the adhesive resin composition has a melt flow rate of 10 to 25 g/10 minutes. A sheet in which a film of the adhesive resin composition according to any one of claims 1 to 6 is laminated on a substrate. A lid material formed from the sheet according to claim 7 . A member set for an openable sealed container, comprising a container body made of a polyester resin or a container body whose inner surface is covered with a polyester resin, and the lid material according to claim 8 . An openable container, wherein the opening of the container body made of polyester resin or the inner surface of the container body covered with polyester resin is sealed with the cover material according to claim 8 .