JP6471017B2 - Adhesive resin composition, laminated film, packaging material and packaging container - Google Patents

Description

  The present invention relates to an adhesive resin composition, a laminated film, a packaging material, and a packaging container.

  2. Description of the Related Art Conventionally, as represented by the food packaging field, for example, a packaging material is sealed by thermal bonding (heat sealing) to wrap an inclusion, and the inclusion is protected during storage or transportation. Various studies have been made on the adhesive strength at the time of sealing from the viewpoints of packaging materials, packaging machines, or packaging conditions. For example, from the viewpoint of packaging materials, ethylene polymers such as polyethylene and ethylene-vinyl acetate copolymers are used. The materials used are known.

  And when you want to take out the inclusion from the packaging material while achieving the adhesive strength required for storage or transportation at the time of sealing, apply force to the adhesive part (heat seal part) and peel it off. A packaging material having performance (peelable property) that can be easily opened has also been proposed.

  In recent years, especially in the food packaging field, in consideration of resource saving, waste volume reduction, and recyclability, a container using a polyester resin (for example, a polyester cup, a container having a polyester resin laminated on the innermost layer). Etc.) provide food and drink such as food (eg, salads, prepared dishes, pickles, fermented foods (such as miso), yogurt, pudding, jelly, etc.), beverages (eg, sake, tea, coffee, etc.), or pharmaceuticals. It is widely used as a packaging container.

  In relation to the above, a cover material is disclosed in which a polymer blended with a thermoplastic resin A and a thermoplastic resin B that is incompatible or partially compatible with the thermoplastic resin A is used as a sealant layer. It is said that the occurrence of stringing can be suppressed (for example, see Patent Document 1). As an example of a combination of the thermoplastic resins A and B used for the lid member, when the adherend is a polystyrene resin, a combination of an ethylene / vinyl acetate copolymer and a polybutene resin is considered preferable. Yes.

  Also, a thermoplastic resin B selected from polybutene-1, polypropylene, etc. in the phase of the thermoplastic resin A selected from a base material layer, an intermediate layer, a polyethylene resin and an ethylene / methacrylic acid copolymer resin, etc. An easy-open laminated film obtained by sequentially laminating a sealant layer having a sea-island structure in which domains consisting of the above are dispersed is disclosed (for example, see Patent Document 2). This easy-open laminate film is said to have both good sealing properties and easy-openability in the field of containers that peel and open the seal part of a sealed container.

  From the viewpoint of such sealability and easy-openability, a heat-sealing layer containing an ethylene / vinyl ester copolymer and a butene polymer, and a heat-sealing layer containing an ethylene polymer and / or a propylene polymer, An easy-open packaging body in which the heat seal strength and the easy peel property are balanced by heat fusion with each other is disclosed (for example, see Patent Document 3).

Japanese Patent No. 3835039 JP2013-136151A Japanese Patent No. 4520605

  In storage or transportation of food, etc., tube-shaped or flat film-shaped packaging materials that can be sealed by heat melting have been widely used. In recent years, for example, a lid is attached to the open end of a resin container such as polyester. Packaging materials that can open the sealed container by peeling off the adhesive part are widely used when the container is sealed by heat bonding the material and the container accommodated in the sealed container is taken out. It is coming.

  When opening a sealed container to which the lid material is bonded by heat melting in this way, as a peeling mechanism when peeling the lid material from the container, (1) interface peeling that peels at the interface between the container and the adhesive layer of the lid material There are three forms: (2) delamination between layers of adhesive layers composed of a plurality of layers, and (3) agglomeration delamination where the adhesive layer itself of the lid material is destructively peeled.

  In order to achieve sealing and easy opening simultaneously, there is a demand for a technique that can be easily and smoothly peeled off when the lid member is peeled off while being melted by heat and firmly bonded. Conventional lid materials, packaging bodies, and the like described in Patent Documents 1 to 3 above are considered to have a good balance between adhesive strength and peelability in consideration of hermeticity and easy-openability. When bonded, there are problems such as causing zipping, leaving room for improvement in terms of easy opening.

  The present invention has been made in view of the above. The present invention relates to an adhesive resin composition and a laminated film that achieve at least adhesion to a container whose surface material is a resin, and easy releasability that can be easily and smoothly peeled off after adhesion, and at least the surface material. The sealing property (adhesiveness) required for storage or transportation of the contained object by adhering to a container made of resin, and the easy-opening property (easily peelable) that can be easily and smoothly opened at the time of opening, It is an object to provide a packaging material and a packaging container having both of the above and to achieve this object.

  The container (or storage container) in the present invention may be formed of a resin having a resin in a partial region or the entire region of the outermost surface, such as a resin. Container. Hereinafter, the container (or storage container) in the present invention may be referred to as a “resin container”.

Specific means for solving the problems include the following embodiments.
<1> Contains at least one resin A of ethylene polymer and ethylene / vinyl acetate copolymer, resin B incompatible with resin A, and partially hydrogenated petroleum resin, and conforms to JIS-K6760 The adhesive resin composition has a tensile strength of 2 MPa to 15 MPa measured at a thickness of 2 mm.
<2> The adhesive resin composition according to <1>, wherein the resin A is an ethylene / vinyl acetate copolymer and the resin B is a butene polymer.
<3> A first resin layer containing the adhesive resin composition according to <1> or <2>, a low density polyethylene, an ethylene / α, β-unsaturated carboxylic acid copolymer, and an ethylene / α, β- And a second resin layer containing at least one unsaturated carboxylic acid ester copolymer.
<4> A packaging material having a support and the laminated film according to <3>.
<5> The packaging film according to <4>, wherein the laminated film is formed into a layer on the support by coextrusion.
<6> The packaging material according to <4> or <5>, which is a lid member that adheres to an opening of a storage container whose outermost surface is a resin and closes the opening.
<7> a storage container having an open storage portion, at least the outermost surface being a resin;
A packaging container comprising: a support and a laminated film according to <3>, and a lid member that adheres the first resin layer of the laminated film to the opening of the storage container and closes the opening. is there.
<8> The packaging container according to <7>, wherein the outermost surface of the storage container that is in contact with the lid member is a polyester resin.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive resin composition and laminated | stacking which compatible the adhesiveness with respect to the container (resin container) whose surface material is resin at least, and the easy peelability which can peel easily and smoothly at the time of peeling after adhesion | attachment A film is provided.
In addition, according to the present invention, at least the surface material is adhered to a container (resin container) and the sealing property (adhesiveness) required for storing or transporting the object to be stored is easily achieved at the time of opening. In addition, a packaging material and a packaging container having both easy-openability (easy peelability) that can be smoothly opened are provided.

  Hereinafter, the adhesive resin composition of the present invention, and the laminated film, packaging material, and packaging container using the same will be described in detail.

<Adhesive resin composition>
The adhesive resin composition of the present invention 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 partially hydrogenated petroleum resin. And the tensile strength in 2 mm thickness measured based on JIS-K6760 is 2 MPa or more and 15 MPa or less.
In addition, in this specification, the layer formed using the adhesive resin composition of this invention may be called an "adhesive layer", and the below-mentioned 1st resin layer is an adhesive layer.
The adhesive resin composition of the present invention may further contain other components as necessary.

In a sealed container in which the lid is bonded by heat melting and the container is sealed, and at least the outermost surface is a resin, the adhesive strength of the lid with the adhesive layer is used for compatibility between sealing and easy opening. Various techniques have been conventionally studied in which the lid material can be peeled from the container while increasing the thickness.
However, no technology has yet been established to achieve the balance between sealability and easy-openability. Under such circumstances, when a peeling mechanism by cohesive peeling is employed, it has been found that it can be easily and smoothly peeled while maintaining adhesive strength.
Based on such knowledge, in the present invention, the first resin A is one or both of an ethylene polymer or an ethylene / vinyl acetate copolymer, the second resin B is a resin incompatible with the resin A, and partial water. A layer in which the petroleum resin is added in combination (hereinafter referred to as an adhesive layer or a first resin layer), and the tensile strength at a thickness of 2 mm measured for the layer in accordance with JIS-K6760 is 2 MPa or more and 15 MPa. By being below (preferably 4 MPa or more and 10 MPa or less), it is possible to obtain a layer that cohesively breaks with a force weaker than the adhesive strength while securing the adhesive strength. As a result, when the object is accommodated in the container and sealed, the strong adhesion between the resin container and the lid is ensured, while the lid is peeled off from the resin container and opened. Can easily and smoothly peel off the lid.
By using the adhesive resin composition of the present invention, the sealing property (adhesiveness) required for storing or transporting the object to be stored and the easy opening property (easy peeling) that can be easily and smoothly opened at the time of opening. A packaging material having both of the above properties.

-Resin A (ethylene polymer and ethylene / vinyl acetate copolymer)-
The adhesive resin composition of the present invention contains at least one of an ethylene polymer and an ethylene / vinyl acetate copolymer. The ethylene polymer and the ethylene / vinyl acetate copolymer are not limited to each containing one kind alone, and a plurality of kinds may be used in combination.

  The ethylene polymer is not particularly limited as long as it is a polymer whose main component is a structural unit derived from ethylene, and examples thereof include a homopolymer of ethylene or a copolymer of ethylene and another monomer. . Among them, an ethylene homopolymer (hereinafter also referred to as polyethylene) is preferable, and a resin material (for example, a resin container, specifically, an adherend, for example, polyester (preferably polyethylene terephthalate (hereinafter, abbreviated as PET)). Low density polyethylene is preferred from the standpoint of excellent adhesion strength to the polyester container).

The low-density polyethylene, the density defined by JIS-K6748 (1995 year) refers to a 910 kg / ^{m 3} or more 930 kg / ^{m 3} of less than polyethylene. A preferable low density polyethylene is polyethylene having the density of 910 kg / m ³ or more and 920 kg / m ³ or less.

  Examples of the low density polyethylene include high pressure method low density polyethylene (LDPE) and linear low density polyethylene (LLDPE). Of these, LDPE is preferred. The LLDPE may be any of an LLDPE produced with a heterogeneous olefin polymerization catalyst such as a Ziegler catalyst or a Philips catalyst, or an LLDPE produced with a homogeneous olefin polymerization catalyst such as a metallocene catalyst or a phenoxyimine catalyst.

  The ethylene polymer is a copolymer of ethylene and an α-olefin other than ethylene (eg, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, etc.). You may have done.

The melting point of the ethylene polymer is preferably 90 ° C. or higher and 140 ° C. or lower.
Further, the melt flow rate (MFR; conforming to JIS-K7210 (1999)) at 190 ° C. and a load of 2160 g of the ethylene polymer is determined by molding processability and a resin material (for example, a resin container, specifically, for example, polyester or From the viewpoint of adhesive strength with a polyester container), 0.1 g / 10 min to 100 g / 10 min is preferable, more preferably 1 g / 10 min to 80 g / 10 min, and further preferably 3 g / 10 min. It is 60 g / 10 minutes or less.

The ethylene / vinyl acetate copolymer is a polymer compound in which ethylene and vinyl acetate are copolymerized, and a compound in which ethylene and vinyl acetate are polymerized at an arbitrary ratio can be selected.
In the ethylene / vinyl acetate copolymer, the content ratio of structural units derived from ethylene is preferably 70% by mass or more and 95% by mass or less, and more preferably 85% by mass or more and 95% by mass or less with respect to all the structural units. .
In the ethylene / vinyl acetate copolymer, the content ratio of the structural units derived from vinyl acetate (VA) is preferably 4% by mass or more and 20% by mass or less, and preferably 5% by mass or more and 15% by mass with respect to the total structural units. % Or less is more preferable. When the content ratio of the structural unit derived from VA is 4% by mass or more, it is preferable in terms of low-temperature sealability.

  The melt flow rate (MFR; JIS-K7210 (1999)) at 190 ° C. under a load of 2160 g of the ethylene / vinyl acetate copolymer is a resin material (for example, a resin container, specifically, for example, a polyester or polyester container). In terms of excellent adhesion strength, 0.1 g / 10 min to 50 g / 10 min is preferable, 1 g / 10 min to 40 g / 10 min is more preferable, and 1 g / 10 min to 30 g / 10 min is preferable. More preferred.

The ethylene polymer and the ethylene / vinyl acetate copolymer may be used alone or in combination of two.
The content of the ethylene polymer and the ethylene / vinyl acetate copolymer in the adhesive resin composition is the total of resin A, resin B incompatible with resin A, and partially hydrogenated petroleum resin. On the other hand, 25 mass% or more and 80 mass% or less are preferable, and 35 mass% or more and 55 mass% or less are more preferable.

-Resin B-
The adhesive resin composition of the present invention contains at least one resin B that is incompatible with resin A.
“Incompatible with resin A” means a state in which the boundary between the resin A and the resin B can be confirmed after the resin A and the resin B are mixed. For the boundary between the resin A and the resin B, a lamellar thin piece (thickness: 0.05 μm to 0.1 μm) is prepared using an adhesive resin composition, dyed with osmium or ruthenium, and then a scanning electron microscope or the like. This can be confirmed by observing the morphology (fine structure).

The resin B can be selected without particular limitation from resins that are incompatible with the resin A, and examples thereof include a butene polymer. By containing the resin B, it contributes to lowering the strength of the adhesive resin composition or the molded product thereof. Therefore, when forming the adhesive layer, the adhesive layer exhibits good adhesive strength with the adjacent layer, while the strength of the adhesive layer itself can be suppressed to a certain level, and the aggregation in the first resin layer Peeling can be performed.
In this case, as a combination of the resin A and the resin B in the adhesive layer, the resin A is an ethylene / vinyl acetate copolymer and the resin B is a butene from the viewpoint of more appropriate strength and easy peelability. A polymer is preferred.

  Examples of the butene polymer include a homopolymer of 1-butene, and 1-butene and other α-olefins (for example, ethylene, propylene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene). And the like (1-butene / α-olefin copolymer). The butene polymer is preferably a polymer having crystallinity. Among these, as the butene polymer, a homopolymer is preferable.

  As an example of the homopolymer of 1-butene, as a commercial item, for example, Tuffmer BL4000 (manufactured by Mitsui Chemicals) can be exemplified. Examples of the 1-butene / α-olefin copolymer include commercially available products such as Tuffmer BL3450 and Tuffmer BL2481 (both manufactured by Mitsui Chemicals).

  The melt flow rate (MFR; JIS-K7210 (1999)) at 190 ° C. under a load of 2160 g of the butene polymer is from 0.1 g / 10 min to 5 g / min from the viewpoint of suppressing the strength when the layer is molded. 10 minutes are preferable, 1 g / 10 minutes to 3 g / 10 minutes are more preferable, and 1 g / 10 minutes to 2 g / 10 minutes are more preferable.

Resin B may be used alone or in combination of two or more.
The content of the resin B in the adhesive resin composition is 20% by mass or more and 55% by mass with respect to the total of the resin A, the resin B incompatible with the resin A, and the partially hydrogenated petroleum resin. % Or less, more preferably 25% by mass or more and 45% by mass or less, and particularly preferably 32% by mass or more and 40% by mass or less. If the content of the resin B is 20% by mass or more, the strength of the adhesive resin composition, in particular, the strength of the molded product when the molded product such as a layer is formed is reduced, and cohesive failure is further facilitated. Can be generated. Moreover, when content of resin B is 55 mass% or less, it is advantageous at the point of shaping | molding workability and economical efficiency.

-Partially hydrogenated petroleum resin-
The adhesive resin composition of the present invention contains at least a partially hydrogenated petroleum resin that is one type of tackifying resin. Partially hydrogenated petroleum resin is a kind of hydrogenated petroleum resin, which means an alicyclic hydrocarbon resin in which a part of unsaturated double bond of aromatic petroleum resin is partially hydrogenated. A resin (tackifying resin) having a function of imparting tackiness to the adhesive resin composition. By containing a partially hydrogenated petroleum resin, compared to other tackifying resins other than the partially hydrogenated petroleum resin, a resin material (eg, a resin container, specifically, a polyester (preferably PET, preferably PET) is used. ) Or a polyester container).

Examples of the partially hydrogenated petroleum resin in the alicyclic hydrocarbon resin include, for example, a resin obtained by cyclizing and dimerizing the diene component in the spent C _{4 to} C ₅ fraction, and a cyclic such as cyclopentadiene. Examples include resins obtained by polymerizing monomers, resins obtained by hydrogenating aromatic petroleum resins (so-called hydrogenated petroleum resins), and the like.
Among these, as the partially hydrogenated petroleum resin, those having a softening point of 90 ° C. or higher are preferable from the viewpoint of the use environment of the adhesive resin composition.

The partially hydrogenated petroleum resin is preferably a resin having a softening point of 90 ° C to 150 ° C. The higher softening point is preferable from the viewpoint of adhesiveness, and since the softening point is 90 ° C. or higher, the adhesiveness with a resin or a resin container (preferably a polyester or polyester container) is excellent. Moreover, when the softening point is 150 ° C. or less, it is advantageous in terms of imparting tackiness.
Among these, for the same reason as above, the softening point is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, and particularly preferably 120 ° C. or higher.
As the softening point of the partially hydrogenated petroleum resin, a value measured based on a softening point test method (ring ball method) can be used in accordance with JIS K2207 (2006).

  Specific examples of the above include commercially available products such as Alcon series (alicyclic hydrocarbon resins manufactured by Arakawa Chemical Co .; for example, Alcon M-90, Alcon M-100, Alcon M-115, Alcon M- 135, etc.), Imabe series (hydrogenated petroleum resins manufactured by Idemitsu; for example, partially hydrogenated petroleum resins such as Imabu S-100 and Imabu S-110).

  The adhesive resin composition of the present invention is a completely hydrogenated petroleum resin (of unsaturated double bonds in the resin) as long as the effect of the present invention is not significantly impaired as a resin composition other than the partially hydrogenated petroleum resin. Any one of hydrogenated alicyclic hydrocarbon resins), aromatic hydrocarbon resins, and aliphatic hydrocarbon resins may be further included.

Examples of the aromatic hydrocarbon resin include at least one terpene resin, rosin resin, styrene resin, or vinyl aromatic hydrocarbon having 8 to 10 carbon atoms such as vinyltoluene, indene, and α-methylstyrene. And a resin obtained by copolymerizing these fractions and aliphatic hydrocarbon fractions.
Examples of the terpene resin include a terpene homopolymer (eg, dipentene polymer) and a pinene homopolymer derived from pinene (an organic compound represented by C ₁₀ H ₁₆ ), which is a type of terpene (eg, α-pinene). Polymer, β-pinene polymer), terpene / phenol copolymer (eg, α-pinene / phenol copolymer), and hydrogenated products thereof.
Specific examples of the terpene resin include commercially available products such as YS resin series (for example, terpene polymers such as YS resin PX1250, YS resin PX1150, YS resin PX1000, YS resin PX800, YS resin PX1150N, and YS resin). Pinene polymers such as PX300N, aromatic modified terpene resins such as YS resin TO125, YS resin TO115, and YS resin TO105; manufactured by Yashara Chemical Co., Ltd .; Terpene / phenol resin such as Polystar G and YS Polyster UH; manufactured by Yashara Chemical Co., Ltd., Clearon series (for example, Clearon P150, Clearon P135, Clearon P125, Clearon P115, Riaron M125, Clearon M115, hydrogenated terpene resins such as Clearon K100, manufactured by Yasuhara Chemical Co., Ltd.), Tama-nor series (e.g., TAMANOL 803L, terpene phenolic resins such as Tamanol 901; manufactured by Arakawa Chemical Co., Ltd.).
Examples of rosin resins include rosin, gum rosin, polymerized rosin, hydrogenated rosin, rosin glycerin ester and hydrogenated product or polymer thereof, and rosin pentaerythritol ester and hydrogenated product or polymer thereof. Is mentioned.
Specific examples of rosin resins include commercially available products such as ester gum series (eg, ester gum AA-L, ester gum AAV, ester gum AT, etc .; manufactured by Arakawa Chemical Co., Ltd.), pencel series (eg, Pencel A, Pencel AZ, Pencel C, etc .; manufactured by Arakawa Chemical Co., Ltd.).
Examples of the styrenic resin include low molecular weight resinous polymers obtained by polymerizing styrenic monomers such as styrene, vinyl toluene, α-methyl styrene, and isopropyl toluene.
Specific examples of the styrenic resin include commercially available products such as YS Resin SX (manufactured by Yasuhara Chemical Co., Ltd.).
As the aliphatic hydrocarbon resin, for example, a fraction containing at least one kind of mono- or diolefins having 4 to 5 carbon atoms such as 1-butene, isobutene, butadiene, 1,3-pentadiene, and isoprene is polymerized. Examples of the resin to be obtained include.

  The content of the partially hydrogenated petroleum resin in the adhesive resin composition is 5% by mass based on the total amount of the resin A, the resin B incompatible with the resin A, and the partially hydrogenated petroleum resin. The content is preferably 30% by mass or less and more preferably 8% by mass or more and 25% by mass or less. When the content is 5% by mass or more, it is advantageous in terms of imparting tackiness with the adhesive resin composition, and when the content is 30% by mass or less, it is advantageous in terms of easy peelability.

-Other ingredients-
The adhesive resin composition is a polymer other than the above components, such as an antifogging agent, a lubricant, an antiblocking agent, an antioxidant, a heat stabilizer, a light stabilizer, a weather stabilizer, and an ultraviolet absorber. You may further contain the additive generally used in the field | area.
Another component can be contained in the range which does not impair the effect by an adhesive resin composition.

-Preparation of adhesive resin composition-
The adhesive resin composition can be prepared, for example, by dry blending or melt blending the above components simultaneously or sequentially. There is no restriction | limiting in particular in the mixing order of these components.
Various mixers such as a Henschel mixer and a tumbler mixer can be used for the dry blend.
For the melt blending, a kneading apparatus such as a single-screw or twin-screw extruder, a Banbury mixer, a roll, a kneader can be used. The melt kneading by the kneading apparatus can be performed at a temperature of 160 ° C. to 230 ° C., for example.

<Laminated film>
The laminated film of the present invention comprises at least a first resin layer containing the above-described adhesive resin composition of the present invention, low-density polyethylene, ethylene / α, β-unsaturated carboxylic acid copolymer, and ethylene / α. , Β-unsaturated carboxylic acid ester copolymer (hereinafter also referred to as “ethylene / α, β-unsaturated carboxylic acid copolymer”), and a second resin layer. ing.
The second resin layer in the laminated film of the present invention contains low-density polyethylene or an ethylene / α, β-unsaturated carboxylic acid copolymer, so that it has a higher tensile strength than the first resin layer and is supported. Since it has adhesiveness to the body, as will be described later, for example, when it is a packaging material provided with an aluminum material, it has excellent adhesiveness to the aluminum material, and also adheres to the first resin layer. It will be excellent.

-First resin layer (adhesive layer)-
The first resin layer (adhesive layer) in the present invention is a layer formed using the adhesive resin composition of the present invention described above. As described above, the adhesive layer comprises one or both of an ethylene polymer and an ethylene / vinyl acetate copolymer (resin A), a resin B incompatible with the resin A, a partially hydrogenated petroleum resin, And a resin material that is an adherend by including a resin composition having a tensile strength at 2 mm thickness of 2 MPa to 15 MPa (preferably 4 MPa to 10 MPa) measured according to JIS-K6760 (For example, at least the outermost surface is a resin, specifically, for example, a polyester resin (preferably PET) or a polyester resin container) is excellent in adhesiveness.

In addition to one or both of an ethylene polymer and an ethylene / vinyl acetate copolymer (resin A), a resin B incompatible with resin A, and a partially hydrogenated petroleum resin, the adhesive layer contains other components. May be included.
The details of the ethylene polymer, the ethylene / vinyl acetate copolymer (resin A), the resin B incompatible with the resin A, and the tackifier resin in the adhesive layer have already been described in the description of the adhesive resin composition. The preferred embodiment is also the same.

The elongation of the adhesive layer is preferably adjusted in the range of 20% to 500% in terms of the elongation from the normal state where the elongation at 2 mm measured according to JIS-K6760 does not give a tensile force. . More preferably, they are 30% or more and 300% or less, More preferably, they are 30% or more and 200% or less, Most preferably, they are 30% or more and 70% or less.
If the elongation is 20% or more, it is advantageous in terms of adhesion reliability, and if the elongation is 500% or less, it is advantageous in terms of cohesive failure and peeling feeling.
The elongation (%) is measured by a method based on JIS-K6760 by pressing a predetermined amount of the adhesive resin composition to produce a 2 mm thick press sheet.

The tensile strength of the adhesive layer is in the range of 2 MPa to 15 MPa, preferably 4 MPa to 10 MPa, from the viewpoint of cohesive failure during peeling.
In addition, the tensile strength (MPa) is measured by a method according to JIS-K6760 by pressing a predetermined amount of the adhesive resin composition to produce a 2 mm-thick press sheet, similarly to elongation (%). Value.

The thickness of the adhesive layer is preferably in the range of 3 μm or more and 20 μm or less, more preferably in the range of 5 μm or more and 15 μm or less from the viewpoints of adhesiveness and easy peelability.
The thickness of the adhesive layer is determined by observing and measuring a cut surface obtained by cutting the laminated film in parallel with the lamination direction with an optical microscope or the like.

  The adhesive layer can be formed by a known method such as a coating method, a casting method, an inflation molding method, or an extrusion molding method using the adhesive resin composition of the present invention described above.

  Examples of the polyester resin include a crystalline, low crystalline, or amorphous polyester resin, or a polyester resin in which three phases of crystalline, low crystalline, and amorphous are mixed. The polyester-based resin includes a resin obtained by reacting one or more diol components with one or more dicarboxylic acid components. Moreover, not only one type of polyester resin but also a mixture of two or more types may be used.

Examples of the monomer constituting the polyester resin include dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, succinic acid, maleic acid, and sebacic acid. Of these, terephthalic acid and isophthalic acid are common.
Examples of the diol component include ethylene glycol, propylene glycol, butylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, and the like. Ethylene glycol or butylene glycol is common.
-Second resin layer-
The second resin layer contains at least one of low-density polyethylene, an ethylene / α, β-unsaturated carboxylic acid copolymer, and an ethylene / α, β-unsaturated carboxylic acid ester copolymer, an aluminum material, etc. It has adhesiveness to the support. Among them, the case of containing an ethylene / α, β-unsaturated carboxylic acid copolymer or an ethylene / α, β-unsaturated carboxylic acid ester copolymer is particularly preferable. Moreover, the aspect in which a 2nd resin layer contains another component as needed is also preferable.

  For the low density polyethylene, the low density polyethylene exemplified in the above-described resin A can be used.

  The ethylene / α, β-unsaturated carboxylic acid copolymer is a polymer obtained by copolymerizing ethylene and a monomer selected from α, β-unsaturated carboxylic acid as at least a copolymerization component. Monomers other than α, β-unsaturated carboxylic acid may be copolymerized. From the viewpoint of excellent adhesion to a support, particularly an aluminum material, and ensuring higher adhesive strength, the ethylene / α, β-unsaturated carboxylic acid copolymer includes ethylene and α, β-unsaturated carboxylic acid. A binary random copolymer obtained by copolymerizing is preferred. Examples of monomers other than α, β-unsaturated carboxylic acid include α, β-unsaturated carboxylic acid esters.

Examples of α, β-unsaturated carboxylic acids include acrylic acid, methacrylic acid, ethacrylic acid, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, maleic acid, maleic anhydride, maleic acid monoester (monomethyl maleate , Monoethyl maleate, etc.), unsaturated carboxylic acids having 4 to 8 carbon atoms such as maleic anhydride monoester (monomethyl maleate, monoethyl maleate anhydride, etc.), and the like. Of these, acrylic acid and methacrylic acid are preferred.
The same applies to the α, β-unsaturated carboxylic acid of the following α, β-unsaturated carboxylic acid ester.

  The content ratio of the structural unit derived from the α, β-unsaturated carboxylic acid in the ethylene / α, β-unsaturated carboxylic acid copolymer is preferably 1% by mass or more and 25% by mass or less, more preferably 2% by mass. % To 20% by mass.

  The ethylene / α, β-unsaturated carboxylic acid ester copolymer is a polymer obtained by copolymerizing ethylene and a monomer selected from α, β-unsaturated carboxylic acid esters as at least a copolymerization component. In addition, monomers other than the unsaturated carboxylic acid ester may be copolymerized. From the viewpoint of excellent adhesion to a support, particularly an aluminum material, and ensuring higher adhesive strength, ethylene / α, β-unsaturated carboxylic acid ester copolymers include ethylene and α, β-unsaturated carboxylic acid. A binary random copolymer obtained by copolymerization with an ester is preferred. Examples of monomers other than the α, β-unsaturated carboxylic acid ester include α, β-unsaturated carboxylic acid.

Preferred examples of the α, β-unsaturated carboxylic acid ester include α, β-unsaturated carboxylic acid alkyl esters, and among them, an α, β-unsaturated carboxylic acid having 1 to 8 carbon atoms in the alkyl moiety. Acid alkyl esters are preferred, and (meth) acrylic acid alkyl esters having 1 to 8 carbon atoms in the alkyl moiety are more preferred. As for carbon number of an alkyl site | part, 1-4 are more preferable.
Examples of α, β-unsaturated carboxylic acid esters include acrylic acid alkyl esters (eg, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, normal butyl acrylate, 2-ethylhexyl acrylate, etc.), Examples thereof include alkyl methacrylate (for example, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, 2-ethylhexyl methacrylate, etc.).

In the ethylene / α, β-unsaturated carboxylic acid copolymer and ethylene / α, β-unsaturated carboxylic acid ester copolymer, carbon monoxide, glycidyl acrylate, glycidyl methacrylate, etc. can be copolymerized as monomers other than the above. Examples of such monomers.
These monomers may be copolymerized singly or in combination of two or more.

  The content ratio of the structural unit derived from the α, β-unsaturated carboxylic acid ester in the ethylene / α, β-unsaturated carboxylic acid ester copolymer is preferably 1% by mass or more and 25% by mass or less, more preferably. It is 2 mass% or more and 20 mass% or less.

  Melt flow rate of an ethylene / α, β-unsaturated carboxylic acid copolymer and an ethylene / α, β-unsaturated carboxylic acid ester copolymer at 190 ° C. under a load of 2160 g (MFR; JIS-K7210 (1999)) Is preferably 0.1 g / 10 min to 30 g / 10 min in terms of excellent adhesive strength with a resin material (for example, a resin container, specifically, a polyester or polyester container, for example). / 10 min to 20 g / 10 min is more preferable, and 3 g / 10 min to 15 g / 10 min is more preferable.

The strength of the second resin layer can be expressed by tensile strength. The tensile strength of the second resin layer is preferably larger than the tensile strength of the first resin layer from the viewpoint of causing the above described first resin layer to undergo cohesive peeling at the time of peeling. Among them, the tensile strength of the second resin layer is more preferably in the range of 10 MPa to 35 MPa, and further preferably in the range of 10 MPa to 30 MPa.
This tensile strength is measured by a method in accordance with JIS-K6760 by pressing a predetermined amount of the adhesive resin composition to produce a press sheet.

The thickness of the second resin layer is preferably in the range of 15 μm to 50 μm, and more preferably in the range of 15 μm to 45 μm.
The thickness of the 2nd resin layer is calculated | required by expanding and observing the cut surface which cut the laminated | multilayer film in parallel with the lamination direction with an optical microscope etc., and measuring it.

  The second resin layer can be formed by a known method such as a coating method, a casting method, an inflation molding method, and an extrusion molding method using the resin composition for forming the second resin layer.

  The total thickness of the laminated film is not particularly limited, but the adhesive point with a resin material as an adherend, particularly polyester (preferably polyethylene terephthalate (hereinafter abbreviated as PET) or its container). It is preferably in the range of 10 μm to 100 μm, more preferably 20 μm to 70 μm.

  In this laminate, the range of the peel strength (adhesive strength) for the resin material that is the adherend is preferably 8 N / 15 mm or more and 25 N / 15 mm or less, and more preferably 10 N / 15 mm or more and 20 N / 15 mm or less. More preferred.

<Packaging materials>
The packaging material of the present invention includes a support and the laminated film of the present invention described above, and the second resin layer of the laminated film is disposed on the support directly or via another layer. Composed.

As an example of the structure of the packaging material of the present invention, a laminated structure including a laminated structure of support / second resin layer / first resin layer (adhesive layer) may be used.
The support is not particularly limited, and paper, aluminum plate (for example, aluminum foil), polyester (for example, polyethylene terephthalate) plate material (sheet or film), aluminum-deposited polyester (for example, aluminum-deposited polyethylene terephthalate) plate-like material. (Sheet or film), plate material (sheet or film) of silica-deposited polyester (for example, silica-deposited polyethylene terephthalate), plate member (sheet or film) of polyolefin (for example, polyethylene, polypropylene, polystyrene), aluminum-deposited polyolefin ( For example, a plate-like material (sheet or film) of aluminum vapor-deposited polypropylene) can be used. These support bases may have not only a single layer structure but also a laminated structure of two or more layers.
As a specific example, the laminated film may have a structure such as paper / polyolefin layer / aluminum foil / second resin layer / first resin layer (adhesive layer).

As described above, as a method of providing a laminated film on a support, a method of applying a coating solution for forming each layer constituting the laminated film on the support in a multilayer manner, a molten resin for forming each layer constituting the laminated film Any of a method of applying to the support by coextrusion may be used.
In the present invention, a method of forming a laminated film on a support by coextrusion is preferred from the viewpoint of economy.

  As an example of the packaging material, a lid material that adheres to the storage container and closes the opening is preferably exemplified. The storage container here is preferably a container having at least the outermost surface formed of a resin material, and more preferably a polyester container having at least the outermost surface formed of a polyester-based resin. Polyester resins include polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and the like.

A packaging container can be mentioned as an example of the packaging material of this invention.
As a packaging container, it has an opening accommodating part, at least the outermost surface is made of resin, the support and the laminated film of the present invention, and is laminated at least on the opening part of the accommodating container whose outermost surface is resin. It may be a packaging container provided with a lid material that adheres the first resin layer of the film and closes the opening.

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. Unless otherwise specified, “part” is based on mass.
The melt flow rate (MFR) was measured at 190 ° C. under a load of 2160 g in accordance with JIS K-7210 (1999).

-Raw material-
The following materials were prepared as raw materials.

[Ethylene / vinyl acetate copolymer]
-Ethylene / vinyl acetate copolymer: 10% by mass of vinyl acetate, MFR (190 ° C., 2160 g load): 9 g / 10 min (hereinafter abbreviated as EVA)

[Butene polymer]
Polybutene: homotype, MFR (190 ° C., 2160 g load): 1.8 g / 10 min (hereinafter abbreviated as PB)

[Ethylene / α, β-unsaturated carboxylic acid copolymer]
-Ethylene / methacrylic acid / butyl acrylate copolymer: acid content: 4% by mass, butyl acrylate: 8% by mass, MFR (190 ° C., 2160 g load): 14 g / 10 min (hereinafter abbreviated as acid polymer)

[Tackifying resin]
-Partially hydrogenated petroleum resin (1): Partially hydrogenated aromatic hydrocarbon resin (ring and ball method softening point: 135 ° C, manufactured by Arakawa Chemical Co., Ltd.)
・ Partially hydrogenated petroleum resin (2): Partially hydrogenated aromatic hydrocarbon resin (ring and ball method softening point: 90 ° C., manufactured by Arakawa Chemical Co., Ltd.)
Fully hydrogenated petroleum resin: Fully hydrogenated aromatic hydrocarbon resin (Ring and ball method softening point: 115 ° C, manufactured by Arakawa Chemical Co., Ltd.)
-Terpene resin: Pinene polymer (ring and ball method softening point: 115 ° C, manufactured by Yasuhara Chemical Co., Ltd.)

Example 1
-Preparation of resin composition for forming first resin layer (adhesive layer)-
In accordance with the formulation shown in Table 1, the raw materials were weighed (the amount charged was 10 kg), and a melt extruder (tip dull image flight screw, screw diameter: φ65 mm, L / D (= screw length / screw diameter): 28) It was thrown into the inlet. Pellets were used for each resin. Then, the processing temperature of the melt extruder was adjusted to 180 ° C. and melt-kneaded to prepare a resin composition for forming an adhesive layer.

<Tensile strength / elongation>
The tensile strength (MPa) and elongation (%) were measured by the following methods.
About 60 g of each prepared resin composition for forming the first resin layer was weighed, and a press sheet having a thickness of 2 mm was prepared by a pressure press method. And the tensile strength (MPa) and elongation (%) were measured by the method based on JIS-K6760. The measurement results are shown in Table 1.

-Preparation of resin for forming second resin layer-
The acid polymer (ethylene / methacrylic acid copolymer) was prepared as a resin for forming the second resin layer (ethylene / α, β-unsaturated carboxylic acid copolymer).

-Preparation of sample for evaluation-
Using a 65 mmφ laminator (die width: 900 mm width), a low-density polyethylene (1 μm) having a thickness of 15 μm between 79.1 g / m ² piece of art paper (Mitsubishi Paper Industries) and aluminum foil (UACJ 1N30) ) Was sandwiched at a processing temperature of 320 ° C. to prepare a support having a laminated structure of piece art paper / low density polyethylene (15 μm) / aluminum foil.

Next, a 40 mmφ coextrusion molding machine (feed block type, feed block type, so as to have a two-layer structure of the second resin layer (10 μm thick) and the first resin layer (adhesive layer (35 μm thick)) shown in Table 2 Die width: 450 mm), the resin for forming the second resin layer and the resin composition for forming the first resin layer are formed on the surface of the aluminum foil of the support from the aluminum foil under the following conditions. An evaluation sample was produced by co-extrusion in a layered manner so as to be sequentially laminated. The sample for evaluation is formed in a laminated structure of piece art paper / low density polyethylene / aluminum foil / second resin layer / first resin layer.
<Melt extrusion conditions>
-Melt extrusion temperature of each layer: 260 ° C. (second resin layer), 240 ° C. (first resin layer)
・ Adapter temperature: 250 ℃
-Die temperature: 250 ° C
・ Line speed: 30m / min

-Evaluation-
The following evaluation was performed for each of the evaluation samples prepared above. The evaluation results are shown in Table 2.

(1) Peel strength, fracture mode, and stringiness Each evaluation sample prepared above is placed on an A-PET support (PR Topura Co., Ltd., thickness: 500 μm) so as to be in contact with the first resin layer. The heat sealing was performed under the following conditions.
<Sealing conditions>
・ Seal device: Heat seal bar (10mm width)
・ Seal temperature: 130 ℃
・ Sealing time: 1 second ・ Sealing pressure: 0.2 MPa (actual pressure)

Next, the strip was cut into 15 mm width strips, and the evaluation sample was peeled off from the A-PET support under peeling conditions of a peeling speed of 300 mm / min and a peeling angle of 80 ° using an autograph, and the peeling strength at the time of peeling was measured. . Here, the target value of the peel strength is 8 N / 15 mm or more and 25 N / 15 mm or less.
Furthermore, the 1st resin layer was observed at the time of peeling, and the peeling form was evaluated according to the following reference | standard 1.
<Standard 1>
A: Peeled due to cohesive failure.
B: Peeling was caused by cohesion failure and interfacial failure.
C: Peeled by interfacial peeling.
Moreover, the presence or absence of stringing was evaluated during the measurement. The stringing was evaluated according to the following criterion 2.
<Standard 2>
A: No stringing is observed.
B: Occurrence of stringing and fluffing is slight.
C: The occurrence of stringing is clearly recognized.

(Example 2)
In Example 1, except that the blending of the first resin (adhesive layer) was replaced with the blending 2, an evaluation sample was prepared, measured and evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Example 3)
In Example 1, except that the blending of the first resin (adhesive layer) was replaced with the blending 3, an evaluation sample was prepared, measured and evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 1)
In Example 1, except that the blending of the first resin (adhesive layer) was replaced with the blending 4, an evaluation sample was prepared, measured and evaluated in the same manner as in Example 1. The results are shown in Table 2.

As shown in Table 2, in Examples 1 to 3 including the partially hydrogenated petroleum resin in the adhesive layer, the first resin (adhesive layer) can cause the cohesive failure to be peeled off (cohesive peeling). Further, while securing the sealing strength (peeling strength) necessary for adhesion, the stringing phenomenon that tends to occur at the time of peeling was not observed.
On the other hand, in Comparative Example 1 not including the partially hydrogenated petroleum resin, cohesive failure was caused in the adhesive layer, and peeling could not be performed, and interface peeling occurred, and sealing strength (peeling strength) was ensured. I couldn't do that either.

  The present invention is suitable as a lid for a packaging container that can take out the encapsulated material enclosed in the container by sealing the container by thermally fusing the lid material to the resin container and opening the container as necessary. In particular, it can be preferably applied to the food packaging field.

Claims (8)

  Contains at least one resin A of ethylene polymer and ethylene / vinyl acetate copolymer, resin B incompatible with resin A, and partially hydrogenated petroleum resin, measured in accordance with JIS-K6760 An adhesive resin composition having a tensile strength of 2 MPa to 15 MPa at a thickness of 2 mm.   The adhesive resin composition according to claim 1, wherein the resin A is an ethylene / vinyl acetate copolymer and the resin B is a butene polymer.   A first resin layer comprising the adhesive resin composition according to claim 1 or 2, a low density polyethylene, an ethylene / α, β-unsaturated carboxylic acid copolymer, and an ethylene / α, β-unsaturated carboxylic acid And a second resin layer containing at least one acid ester copolymer.   The packaging material which has a support body and the laminated | multilayer film of Claim 3.   The packaging material according to claim 4, wherein the laminated film is formed into a layer on the support by coextrusion.   The packaging material according to claim 4 or 5, wherein the packaging material is a lid member that is adhered to an opening of a storage container having at least an outermost surface made of resin to close the opening. A storage container having an open storage part and at least the outermost surface being a resin;
A packaging container comprising a support and the laminated film according to claim 3, and a lid member that closes the opening by adhering a first resin layer of the laminated film to the opening of the storage container.   The packaging container according to claim 7, wherein at least an outermost surface in contact with the lid member of the storage container is a polyester resin.