JP2021004327A - Adhesive resin composition, sheet, lid material, member set for hermetic vessel and vessel - Google Patents

Abstract

To provide an adhesive resin composition having excellent vessel adhesion resistance without generating resin residue or cobwebbing even in a flange of the vessel, also even under normal temperature or under freezing, in particular, when an adherend is a polyester-based vessel, showing excellent easy opening property, and having excellent film forming property during coating, a sheet using the composition, a lid material, a member set for hermetic vessel and a vessel.SOLUTION: The above-described problem can be solved by an adhesive resin composition containing 10 to 25 mass% of (A) an ethylene-α olefin copolymer having density of 0.88 to 0.93 g/cm3, 20 to 45 mass% of (B) an ethylene-vinyl acetate copolymer having a vinyl acetate content of 5% or larger and smaller than 18%, 10 to 35 mass% of (C) an ethylene-vinyl acetate copolymer having a vinyl acetate content of 18% or larger and smaller than 30%, and 25 to 35 mass% of (D) a tackifier resin, an adhesive resin composition, a sheet with the adhesive resin composition, a lid member, a member set for hermetic vessels and vessels.SELECTED DRAWING: None

Description

The present invention is for an adhesive resin composition which exhibits easy-opening property by peeling off the interface at the time of opening and has excellent container adhesiveness and film-forming property, and for sheets, lid materials, and sealed containers using the adhesive resin composition. It relates to a member set and a container.

In the field of food packaging, contents such as cup ramen, yogurt, and jelly have been filled in a paper container coated with a polyethylene resin, and a lid having a heat-sealing layer with excellent sealing properties at the opening of the container. A packaging form in which materials are bonded has been widely used.

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

Conventionally, as an easy-to-open adhesive for paper containers mainly coated with a polyethylene resin, for example, a homopolymer or copolymer of 1-butene having an average molecular weight of at least 500,000 of 8 to 49% by mass has been used. Compositions containing coalesced and modified or non-modified low density polyethylene having a density of 92 to 51% by mass of 930 kg / m ³ or less have been proposed (see Patent Document 1).

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

As yet another example, it contains at least one resin A of an ethylene polymer and an ethylene-vinyl acetate copolymer, a resin B incompatible with the resin A, and a tackifier resin, and has a tensile strength at break of 2 MPa or more. A composition having a tensile elongation 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).

Japanese Unexamined Patent Publication No. 1-315443 Japanese Unexamined Patent Publication No. 2000-302990 Japanese Unexamined Patent Publication No. 2016-148003

The compositions proposed in Patent Documents 1 to 3 are characterized in that they are coagulated and broken at the time of opening by using two kinds of resins having different compatibility. As a result, the contents can be tightly sealed. However, on the other hand, since resin residue and stringing are generated on the flange of the container, not only the appearance is poor, but also there is a possibility of accidental ingestion when eating with the container in the mouth.

The problem to be solved by the present invention is that the adherend is a polyester-based container, and even at room temperature and freezing, no resin residue or stringing occurs on the flange of the container, and the container has excellent adhesion resistance. It is an object of the present invention to provide an adhesive resin composition which is easy to open and has excellent film forming property at the time of coating, a sheet, a lid material, a member set for a sealed container, and a container using the composition.

As a result of diligent studies to solve the above problems, the present inventor has 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. A specific range of ethylene-vinyl acetate copolymer (B) of% or more and less than 18%, ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30%, and tackifier resin (D). It was found that the above-mentioned problem can be solved by containing the content in the ratio of.
The ethylene-vinyl acetate copolymer (B) having a special 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 forming properties. It has the effect of improving.
Based on the above, an adhesive resin composition in which the adherend is excellent in easy-opening property and container adhesion resistance at room temperature and freezing, and also excellent in film-forming property at the time of coating, particularly with respect to a polyester-based container, and an adhesive resin composition thereof. It is possible to provide a sheet in which a coating film of an adhesive resin composition is laminated.
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 by 10 to 25% by mass, and an ethylene-vinyl acetate copolymer having a vinyl acetate content of 5% or more and less than 18%. 20 to 45% by mass of the coalescence (B), 10 to 35% by mass of the 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 the tackifier resin (D). Adhesive resin composition to be contained.

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

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

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

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

[6] The adhesive resin composition according to any one of [1] to [5], wherein the melt flow rate of the adhesive resin composition is 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 base material.

[9] A lid material formed of the sheet according to [8].

[10] A set of members for a sealed container that can be opened, comprising a container body made of polyester resin or a container body whose inner surface is covered with polyester resin, and a lid material according to [9].

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

According to the present invention, 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 and freezing, and the container has excellent adhesion resistance and good easy-opening property. Moreover, it is possible to provide an adhesive resin composition having excellent film forming property at the time of coating, a sheet using the composition, a lid material, a member set for a sealed container, and a container.

The adhesive resin composition of the present invention has an ethylene-α olefin copolymer (A) having a density of 0.88 to 0.93 g / cm ^{3 in} an amount of 10 to 25% by mass and a vinyl acetate content of 5% or more and less than 18%. Ethylene-vinyl acetate copolymer (B) 20-45% by mass, ethylene-vinyl acetate copolymer (C) 10-35% by mass with vinyl acetate content of 18% or more and less than 30%, tackifier resin (D) ) 25-35% 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 >
The ethylene-α-olefin copolymer (A) having a density of 0.88 to 0.93 g / cm ³ constituting the adhesive composition of the present invention includes ethylene and propylene, butene, penten, hexene and higher carbons. A copolymer obtained by polymerizing at least one selected from the group consisting of long-chain olefins at an arbitrary ratio can be used.
From the viewpoint of blocking resistance, the ethylene-α-olefin copolymer (A) is preferably propylene or butene, and more preferably butene. The shorter the carbon chain of the olefin, the better the blocking resistance.
The density in the present application is defined as JIS. It is a measured value by the pycnometer method in K7112.

The ethylene-α-olefin copolymer (A) is 10 to 25% by mass, preferably 10 to 20% by mass in the adhesive resin composition.
When the ethylene-α-olefin copolymer (A) is 10% by mass or more, it sufficiently adheres to the polyester resin container under freezing without impairing the opening strength. Further, when the content is 25% by mass or less, the container is sufficiently adhered to the polyester resin container under freezing and at room temperature without impairing the opening strength.

The ethylene-α-olefin copolymer (A) preferably has a melting point (hereinafter referred to as DSC melting point) measured by a differential scanning calorimeter of 80 to 140 ° C, more preferably 90 to 130 ° C. Yes, particularly preferably in the range of 100 to 120 ° C. When it is 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%>
The ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 5% or more and less than 18% constituting the adhesive composition in the present invention contains vinyl acetate at a ratio of 5% or more and less than 18% with respect to ethylene. A polymerized copolymer can be used.

The ethylene-vinyl acetate copolymer (B) is in the range of 20 to 45% by mass, preferably 25 to 40% by mass in the adhesive resin composition.
When the ethylene-vinyl acetate copolymer (B) is 20% by mass or more, it sufficiently adheres to the polyester resin container under freezing and at room temperature without impairing the opening strength. Further, when it is 45% by mass or less, not only the coating processability and the adhesiveness can be balanced, but also resin residue and stringing do not occur on the flange of the container even at room temperature and 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. When it is within the above range, the ethylene-α-olefin copolymer (A) and the ethylene-vinyl acetate copolymer (C) are compatible with each other to improve the coating processability and sufficiently without impairing the opening strength. It is preferable because it can be bonded.

<Ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30%>
The ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30% constituting the adhesive composition in the present invention contains vinyl acetate at a ratio of 18% or more and less than 30% with respect to ethylene. A polymerized copolymer can be used.

The ethylene-vinyl acetate copolymer (C) is in the range of 10 to 35% by mass, preferably 10 to 30% by mass, and 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 opening strength can be suppressed under freezing. Further, when it is 35% by mass or less, it is possible to balance the film forming property and the adhesiveness 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. When it is within the above range, it is preferable in that the adhesiveness under freezing can be improved.

<Adhesive-imparting resin (D)>
Examples of the tackifier resin (D) constituting the adhesive composition of the present invention include aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins, polyterpene resins, rosins and the like in the field of sealant adhesion. A known tackifier resin used in the above can be used. The tackifier resin (D) can be used alone or in combination of two or more.
The tackifier resin (D) is in the range of 25 to 35% by mass in the adhesive composition. When the tackifying resin is 25% by mass or more, it sufficiently adheres to the polyester resin container under freezing and at room temperature without impairing the opening strength. Further, when it is 35% by mass or less, the film forming property becomes good. Among them, the tackifier resin (D) preferably contains at least one selected from the group consisting of an alicyclic hydrocarbon resin and an aromatic hydrocarbon resin, and more preferably contains an alicyclic hydrocarbon resin. The resin may be partially hydrogenated or completely hydrogenated.

The tackifier resin (D) preferably has a softening point of 120 ° C. or lower from the viewpoint of adhesiveness at the time of heat sealing, that is, opening strength (easy opening property). The softening point in the present invention is a temperature determined by the method specified in JIS K 6863. That is, when a resin filled in a specified ring and allowed to stand for 12 hours or more is placed in a heat medium and a specified ball is placed and the temperature of the heat medium is raised at a constant rate, the ball sinks due to the softening of the resin. This is the temperature when the bottom plate of the annulus is touched.
The DSC melting point of the tackifier resin (D) is preferably 65 to 95 ° C, more preferably 65 to 80 ° C.

<Adhesive resin composition>
Contains 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%, and vinyl acetate. Ethylene-vinyl acetate copolymer (C) and tackifier resin (D) having a ratio of 18% or more and less than 30% can be used from (A) / (B) / (C) / (D) = 10 to 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%), and more preferably. , 10 to 20/25 to 40/10 to 25/25 to 35 (mass%). However, the total of (A), (B), (C) and (D) is 100% by mass.

The total amount of the ethylene-α olefin copolymer (A), the ethylene-vinyl acetate copolymer (B), the ethylene-vinyl acetate copolymer (C) and the tackifier resin (D) is the adhesive resin composition 100. Of the mass%, 90% by mass or more is preferable, 95% by mass or more is more preferable, and 98% by mass or more is further preferable.

The MFR of the adhesive resin composition is preferably 1 to 50 g / 10 minutes, more preferably 10 to 25 g / 10 minutes. When it is within the above range, it is preferable in terms of film forming property at the time of coating. The MFR in the present application is defined as JIS. It is an MFR value at 190 ° C. and 21.168N according to K7210.

Further, in the adhesive resin composition, the ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 5% or more and less than 18% and the ethylene-vinyl acetate copolymer having a vinyl acetate content of 18% or more and less than 30% have a common weight. The vinyl acetate content with respect to the total of the coalescence (C) is preferably 8% or more and less than 9.5%, and more preferably 8.5% or more and less than 9.0%. The above range is preferable from the viewpoint of excellent balance between film forming property and easy opening property at room temperature and freezing, and both physical properties are compatible.

The resin composition of the present invention has a range not contrary to the object of the present invention, that is, a range that does not impair the film-forming property, the easy-opening property under freezing and at room temperature, and the adhesiveness to the PET container. A resin other than the ethylene-α olefin copolymer (A), the ethylene-vinyl acetate copolymer (B), the ethylene-vinyl acetate copolymer (C) and the tackifier resin (D) may be blended.

Specific examples of such resins include known polyolefin resins such as high-density polyethylene and polypropylene, oxides thereof, maleic acid-modified products, ethylene-acrylic acid copolymers, and ethylene- (meth) acrylic acid copolymers. Various elastomers such as ethylene-unsaturated monocarboxylic acid copolymers and metal salts thereof, styrene-butadiene copolymer elastomers and hydrogen adducts thereof, or high-density polyethylene wax, polypropylene wax, ethylene-vinyl acetate copolymer weight. Known waxes such as coalesced wax, Fishertroph wax, paraffin wax, oxide wax, maleic acid-modified wax, and polyethylene wax grafted with styrene monomer can be mentioned. Further, these resins may be used alone or in combination of two or more.

The adhesive resin composition of the present invention is used to prevent thermal deterioration, thermal decomposition, blocking, etc., and to ensure processing suitability such as film processing, extrusion laminating processing, etc., as long as the object of the present invention is not impaired. , Further additives and the like may be used. Examples of additives include organic lubricants such as erucic acid amide, inorganic lubricants such as calcium carbonate, antioxidants such as hindered phenol, other antiblocking agents, antistatic agents, fillers, pigments, antifogging agents and the like. Can be mentioned. These additives are added at the time of blending the ethylene-α olefin copolymer (A), the ethylene-vinyl acetate copolymer (B), the ethylene-vinyl acetate copolymer (C) and the tackifier resin (D). Alternatively, it may be kneaded in advance with any one of ethylene-α olefin copolymer (A), ethylene-vinyl acetate copolymer (B), ethylene-vinyl acetate copolymer (C) or tackifier resin (D). After being mixed, it may be blended by kneading with other ingredients.

The formulation of ethylene-α olefin copolymer (A), ethylene-vinyl acetate copolymer (B), ethylene-vinyl acetate copolymer (C), tackifier resin (D) and additives used as necessary For example, each of these components is put into a mixing device such as a Henschel mixer or a tumbler mixer, mixed for a blending time of 5 to 20 minutes, placed in an extruder, heat-kneaded, and then extruded. The extruded product is usually in pellet form and is used in a later process. Examples of the extruder include, but are not limited to, a twin-screw extruder. Further, extrusion is usually performed at 140 to 200 ° C.

<Sheet>
Next, a sheet in which a coating film of the adhesive resin composition of the present invention is laminated on a base material will be described. As a method for laminating the adhesive resin composition of the present invention on a base material, for example, the resin composition pelletized as described above is used to form a single-layer film by an inflation method or a casting method, and this film is used as a base material. And if necessary, a method of laminating via another adhesive layer can be mentioned. Alternatively, the kneaded resin composition may be directly coated on the base material, or another method may be adopted.

In order to improve the adhesiveness of the laminated surface, the surface of the base material may be treated with a flame treatment, an ozone treatment, a corona discharge treatment or an anchor coating agent. It is also possible to directly extrude and laminate a base material on which a polyethylene resin is laminated in advance. In addition, a multilayer film is formed by co-extrusion with polyethylene, polypropylene, etc., and then laminated by drying or sand lamination with a stretched or unstretched film such as a polyester film, a polyamide film, or a polypropylene film as a base material. You can also get the finished sheet. In this case as well, in order to improve the adhesiveness of the laminated surface, the surface of the base material may be treated with a flame treatment, an ozone treatment, a corona discharge treatment, an anchor coating agent, or the like, if necessary. The thickness of the adhesive resin composition layer of the present invention is preferably 5 μm or more, more preferably 10 μm or more.
The "base material" in the present invention is used to include long and cut short films and sheets, and the "base material" is a single layer or a laminate composed of a plurality of layers. Also includes. Further, the sheet on which the adhesive resin composition of the present invention is laminated can be used as a lid material as described later, and can also be used as a sealant film for a bag-making product in which a film of the adhesive resin composition is sealed as an inner surface. Can be suitably used.

<Lid material>
The sheet of the present invention in which the adhesive resin composition is laminated on the base material is cut according to the opening shape 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 base materials can be used as the base material. Examples of the base material used include paper, aluminum, polyester, polyethylene, polypropylene, polystyrene, aluminum vapor-deposited polyester, aluminum-deposited polypropylene, and silica-deposited polyester. Such a base material does not have to be a single layer, and may be a laminated body having two or more layers.
When the lid material is formed from the sheet of the present invention, the base material is preferably a laminate of, for example, 5 to 20 μm PET and 5 to 30 μm polyethylene, and the polyethylene surface of the laminate is covered with the present invention. A laminated film having a thickness of 5 to 40 μm formed from the adhesive resin composition is preferable.

<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 polyester resin and a container body whose inner surface is covered with polyester resin are preferable.

<Openable sealed container>
The openable sealed container of the present invention is one in which the opening of the container body is sealed by a lid material cut according to the opening shape of the container body. That is, the adhesive resin composition of the present invention disposed on one surface of the lid material 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 the two. .. The bonding conditions are preferably 100 to 180 ° C.
When the container body is a PET container, it is preferable to heat-bond the container body and the lid material at a heat bonding temperature of 100 to 180 ° C., the opening strength at room temperature is in the range of 7 to 15 N, and at the time of peeling. It is preferable that the thermal adhesive layer is interfacially peeled off. For example, jelly, pudding, yogurt, frozen dessert, dried confectionery, cup noodles, etc. can be wrapped in the openable seal of the present invention.

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

<Manufacturing method of adhesive resin composition>
[Examples 1 to 9 and Comparative Examples 1 to 8]
(Production of Adhesive Resin Compositions (S-1) to (S-17))
The ethylene-α olefin copolymer (A) having a density of 0.88 to 0.93 g / cm ^{3 and} the ethylene-vinyl acetate copolymer having a vinyl acetate content of 5% or more and less than 18% (A) shown in Table 1 ( B), an ethylene-vinyl acetate copolymer (C) having a vinyl acetate content of 18% or more and less than 30%, a tackifier resin (D), an antioxidant and an antioxidant were pre-blended with a Henschel mixer for 5 minutes. .. The preblended product 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 if not shown.

≪Extruder conditions≫
Extruder: IKG Co., Ltd. Same-direction rotating twin-screw extruder PMT32-40.5
Barrel temperature: 180 ° C (supply port 160 ° C)
Screw rotation speed: 200 rpm
Supply speed: 10 kg / hr

<Evaluation of adhesive resin composition>
The MFR and film forming property of the obtained adhesive resin composition were evaluated. In addition, a sheet (lid material) laminated according to the following is prepared, and the sheet is used to determine the opening strength (easy opening property) and container adhesion (thread pulling) under freezing and at room temperature by the following methods and. Evaluated based on criteria. The results are shown in Table 1.

[MFR]
The MFR of the adhesive resin composition is JIS. A plan with a weight of 2160 g and a diameter of 9.48 mm after filling a sample in a cylinder of melt indexer L244 (manufactured by Takara Kogyo Co., Ltd.) with an inner diameter of 9.55 mm and a length of 162 mm and melting it at 190 ° C. in accordance with K7210. A load was evenly applied using a jar, and the amount was determined from the amount of resin (g / 10 minutes) extruded per unit time from an orifice having a diameter of 2.1 mm provided in the center of the cylinder.

[Film film property]
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 from the obtained coated product, at 10 locations at random using a film thickness meter. From the numerical value when the film thickness was measured, it was evaluated according to the following criteria.
≪Processing conditions≫
Extruded laminator: Made by Musashinokikai 400M / M test EXT laminator Die direct resin temperature: 200-250 ℃
Processing speed: 30 m / min T die width: 400 mm
Cooling roll surface temperature: 20 ° C
Base material: PET 12 μm / PE 25 μm Coating on the PE surface of the base material ○: Can be applied and the film thickness is 20 ± 3 μm: Good Δ: Can be applied and the film thickness is 20 ± 6 μm: Use Possible ×: Either film cracking or film breakage occurs and coating is not possible, or coating is possible but the film thickness exceeds 20 ± 6 μm: Defective

[Method of manufacturing sheet (lid material)]
The obtained adhesive resin composition was laminated on the PE surface of a base material of PET 12 μm / PE 25 μm using an extruded laminator to prepare a sheet. The thickness of the adhesive layer was 20 μm. The processing conditions are shown below.
Extruded laminator: 400M / M test EXT laminator manufactured by Musashinokikai Resin temperature directly under the die: 200 ° C to 250 ° C (adjusted appropriately by MFR or the like of the adhesive resin composition).
Processing speed: 30 m / min T die width: 400 mm
Cooling roll surface temperature: 20 ° C

[Easy to open (normal temperature)]
The obtained laminated sheet (lid material) is cut into a size of 90 mm × 90 mm, and then the adhesive resin composition surface is heat-bonded to a 71Φ PET container at a gauge pressure of 0.3 MPa, 150 ° C., and 1 second to seal it. It was. It was left in a constant temperature and humidity chamber at a temperature of 23 ° C. and a humidity of 65% for 24 hours, and the peel strength was measured under the conditions of 90 ° square peeling and a tensile speed of 200 mm / min in the same 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.
〇: Peeling strength is 7N or more and less than 15N: Good Δ: Peeling strength is 5N or more and less than 7N, or 15N or more and less than 17N: Usable ×: Peeling strength is less than 5N or 17N or more: Defective

[Easy to open (frozen)]
The obtained laminated sheet (lid material) is cut into a size of 90 mm × 90 mm, and then the adhesive resin composition surface is heat-bonded to a 71Φ PET container at a gauge pressure of 0.3 MPa, 150 ° C., and 1 second to seal it. It was. It was left in a constant temperature bath at a temperature of −20 ° C. for 24 hours, and the peel strength was measured under the conditions of 90 ° square peeling and a tensile speed of 200 mm / min in the same constant temperature bath. The maximum value was taken as the opening strength, and the ease of opening was evaluated according to the following criteria.
〇: Peeling strength is 7N or more and less than 15N: Good Δ: Peeling strength is 5N or more and less than 7N, or 15N or more and less than 17N: Usable ×: Peeling strength is less than 5N or 17N or more: Defective

[Container adhesion resistance at room temperature and freezing]
The presence or absence of the adhesive resin composition on the flange of the PET container at the time of measuring the opening strength at room temperature and freezing was visually confirmed and evaluated according to the following criteria.
〇: No adhesion of the adhesive resin composition to the flange at both normal temperature and freezing: Good Δ: Slight adhesion of the adhesive resin composition to the flange at either normal temperature or freezing Specified: Usable ×: Adhesive resin composition adhered to the flange at either normal temperature or 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: Ultrasen 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: Ultrasen 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: Ultrasen 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: Ultrasen 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: Ultrasen 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: Archon M-115 (manufactured by Arakawa Chemical Industries, Ltd., partially hydrogenated alicyclic hydrocarbon resin, softening point 115 ° C)
D2: Archon P-115 (manufactured by Arakawa Chemical Industries, Ltd., completely hydrogenated alicyclic hydrocarbon resin, softening point 115 ° C)

Anti-blocking agent: Incross Lip C (manufactured by Croda, erucic acid amide, DSC melting point 80 ° C)

Antioxidant: IRGANOX 1010 (BASF, hindered phenolic antioxidant)

VA cont. : Vinyl acetate content (%)

The adhesive compositions of Examples 1 to 9 were excellent in film forming property, and showed good easy-opening property and container adhesion resistance to PET containers at room temperature and freezing. Therefore, the adhesive resin composition of the present invention containing the specific resins (A) to (D) in a specific ratio is most suitable for a lid material for containers made of a polyester resin, particularly a polyethylene terephthalate (PET) resin. ..

Claims (11)

Ethylene-α olefin copolymer (A) having a density of 0.88 to 0.93 g / cm ³ by 10 to 25% by mass, and an ethylene-vinyl acetate copolymer (B) having a vinyl acetate content of 5% or more and less than 18%. ) 20 to 45% by mass, 10 to 35% by mass of the 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 the tackifier resin (D). Adhesive resin composition. 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. Sex 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 of 60 to 90 ° C. as measured by a differential scanning calorimeter. The adhesive resin composition according to. The adhesive resin composition according to any one of claims 1 to 4, wherein the tackifier resin (D) contains an alicyclic hydrocarbon resin. The adhesive resin composition according to any one of claims 1 to 5, wherein the melt flow rate of the adhesive resin composition is 10 to 25 g / 10 minutes. Vinyl acetate with respect to the 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 claims 1 to 6, wherein the content is 8% or more and less than 9.5%. A sheet in which a film of the adhesive resin composition according to any one of claims 1 to 7 is laminated on a base material. A lid material formed of the sheet according to claim 8. An openable sealed container member set comprising a container body made of polyester resin or a container body whose inner surface is covered with polyester resin, and the lid material according to claim 9. An openable container in which the opening of the container body made of polyester resin or the container body whose inner surface is covered with polyester resin is sealed by the lid material according to claim 9.