Adhesive resin composition, laminated sheet using the same

Abstract

The present invention provides an adhesive resin composition that exhibits excellent peel stability due to a high cohesive failure rate, a superior peel appearance, and good low-temperature heat sealability and easy opening properties, as well as a laminated sheet made using the composition. [Solution] An adhesive resin composition comprising resin (A), resin (B), and inorganic filler (C), wherein resin (A) is present in 50-85% by mass and resin (B) in 100% by mass of the total of resin (A) and resin (B), resin (A) is at least one selected from polyethylene and ethylene-vinyl acetate copolymer with a vinyl acetate content of 7% by mass or less, resin (B) is ethylene-vinyl acetate copolymer with a vinyl acetate content of 25-42% by mass, the difference in vinyl acetate content between resin (A) and resin (B) is 20% by mass or more, and inorganic filler (C) is present in 1-40 parts by mass per 100 parts by mass of the total of resin (A) and resin (B).

Description

[Technical Field]

[0001] The present invention relates to an adhesive resin composition and a laminated sheet using the same. [Background technology]

[0002] In the field of product packaging, a method is used in which a lid material is bonded to the opening of a container via a heat-seal layer with excellent sealing properties in order to protect and preserve the contents.

[0003] In a method of sealing paper containers coated with polyethylene resin, or containers obtained by vacuum molding thermoplastic resin sheets such as high-impact polystyrene, polypropylene, and polyethylene terephthalate (PET), with lid materials made from sheets of aluminum foil, polypropylene, polyvinyl chloride, polyethylene terephthalate, or molded from these materials, a laminate is used in which adhesive resin compositions that exhibit adhesion to the bonding surface of the lid material by heat sealing are employed.

[0004] In particular, for sealing food containers, adhesive compositions intended solely for bonding require not only basic performance characteristics such as coating suitability, airtightness, water resistance, oil resistance, alkali resistance, non-toxicity, and blocking resistance, but also the following special qualities.

[0005] • The contents must be able to be peeled off smoothly and evenly without spilling or scattering (peel stability). • The adhesive resin composition should not produce any fuzz or strings upon opening, and the peel-off appearance should be good. • Easy adjustment of adhesive strength. The adhesive strength (opening strength) can be set to 7N to 15N, allowing for easy opening (easy opening). • Adhesion is possible even when the heat seal temperature decreases due to heat being absorbed by the contents adhering to the container flange (low-temperature heat sealability).

[0006] Of these, in order to enable smooth and uniform peeling, a method is used that causes cohesive failure of the adhesive layer rather than interfacial peeling between the adhesive layer and the container. As a method for causing cohesive failure of adhesive resin compositions, as disclosed in Patent Documents 1 to 3, a method is disclosed in which cohesive failure is caused by mixing polyethylene resin or ethylene-vinyl acetate copolymer with polypropylene resin or polybutene resin, which has low compatibility. However, in these methods, the melting point of the added polypropylene resin or polybutene resin is high, which reduces the low-temperature heat sealability of the adhesive resin composition. Furthermore, as a method for improving low-temperature heat sealability, Patent Document 4 discloses an adhesive resin composition comprising low-density polyethylene, ethylene-vinyl acetate copolymer, and a tackifying resin. Although this adhesive resin composition exhibits excellent low-temperature heat sealability, it did not undergo cohesive failure upon opening. Therefore, the methods described in Patent Documents 1 to 4 made it difficult to achieve both stable peeling due to cohesive failure and low-temperature heat sealability. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2002-241716 [Patent Document 2] Japanese Patent Publication No. 2007-112955 [Patent Document 3] Japanese Patent Publication No. 2016-186059 [Patent Document 4] Japanese Patent Publication No. 2014-025047 [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide an adhesive resin composition that, in addition to having good blocking resistance, has excellent peel stability due to a high cohesive breakdown rate, exhibits a good peel appearance, and has good low-temperature heat sealability and easy opening properties. [Means for solving the problem]

[0009] As a result of diligent research by the inventors, we have found that the above problems can be solved by the specific adhesive resin composition defined below, and have completed the present invention.

[0010] An adhesive resin composition according to one aspect of the present invention is an adhesive resin composition comprising resin (A), resin (B), and inorganic filler (C), wherein the total mass of resin (A) and resin (B) contains 50 to 85% by mass of resin (A) and 15 to 50% by mass of resin (B), and resin (A) is at least one selected from polyethylene and ethylene-vinyl acetate copolymer with a vinyl acetate content of 7% by mass or less, and resin (B) is an ethylene-vinyl acetate copolymer with a vinyl acetate content of 25 to 42% by mass, and the difference in vinyl acetate content between resin (A) and resin (B) is 20% by mass or more. The material is characterized by containing 1 to 40 parts by mass of inorganic filler (C) per 100 parts by mass of resin (A) and resin (B).

[0011] An adhesive resin composition according to one aspect of the present invention is characterized in that the melt mass flow rate of resin (B) at 190°C and a load of 2.16 kg is 15 to 2,000 g / 10 min.

[0012] An adhesive resin composition according to one aspect of the present invention is characterized in that the resin (A) contains polyethylene.

[0013] An adhesive resin composition according to one aspect of the present invention is characterized in that the inorganic filler (C) is talc or mica.

[0014] An adhesive resin composition according to one aspect of the present invention is further characterized by containing 5 to 40 parts by mass of tackifying resin (D) with respect to a total of 100 parts by mass of resin (A) and resin (B).

[0015] A laminated sheet according to one aspect of the present invention is characterized in that a film of the adhesive resin composition is laminated on a substrate. [Effects of the Invention]

[0016] According to the present invention, in addition to having good blocking resistance, the adhesive resin composition has excellent peel stability due to a high aggregation breakdown rate, exhibits an excellent peel appearance, and has good low-temperature heat sealability and easy unsealing properties, and a sheet using the same can be provided.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, each component constituting the adhesive resin composition of the present invention will be described in detail. Needless to say, as long as it conforms to the gist of the present invention, other embodiments are also included in the scope of the present invention. The numerical range specified using "~" in this specification includes the numerical values described before and after "~" as the lower limit value and the upper limit value range.

[0018] In this specification, "melt mass flow rate (hereinafter sometimes abbreviated as MFR)" is a measured value at 190°C and a load of 2.16 kg in accordance with JIS K7210 (Flow test method for thermoplastic plastics).

[0019] ≪Adhesive Resin Composition≫ The adhesive resin composition of the present invention contains a resin (A), a resin (B), and an inorganic filler (C), and contains 50 to 85% by mass of the resin (A) and 15 to 50% by mass of the resin (B) in a total of 100% by mass of the resin (A) and the resin (B), and contains 1 to 40 parts by mass of the inorganic filler (C) with respect to 100 parts by mass of the total of the resin (A) and the resin (B). By making such an adhesive resin composition, in addition to having good blocking resistance, it exhibits stable peeling due to aggregation breakdown and an excellent peel appearance, and an adhesive resin composition having good low-temperature heat sealability and easy unsealing properties can be obtained. The adhesive resin composition of the present invention can be suitably used for a lid material.

[0020] <Resin (A)> The resin (A) used in the present invention contains at least one selected from polyethylene and an ethylene-vinyl acetate copolymer having a vinyl acetate content of 7% by mass or less.

[0021] Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. In this specification, high-density polyethylene refers to polyethylene with a density of 0.940 g / cm³. 3 The above refers to polyethylene, and medium-density polyethylene has a density of 0.930 or higher, or 0.940 g / cm³. 3 Low-density polyethylene is polyethylene with a density of 0.910 or higher, or 0.930 g / cm³. 3 This refers to polyethylene with a density of less than 0.910 g / cm³, while ultra-low density polyethylene has a density of 0.910 g / cm³. 3 It is polyethylene with a density of less than 1.0. The density of polyethylene is measured according to Method D (density gradient pipe method, 23°C) of JIS K7112:1999.

[0022] The ethylene-vinyl acetate copolymer used as resin (A) is not particularly limited as long as its vinyl acetate content is 7% by mass or less. If the vinyl acetate content exceeds 7% by mass, the compatibility with resin (B), described later, becomes too high, which reduces the cohesive failure rate. When the cohesive failure rate decreases, the interfacial delamination rate increases accordingly, and since two types of delamination with different delamination strengths coexist, it is thought that the delamination stability and ease of opening decrease.

[0023] These may be used individually or in combination of two or more types. Polyethylene is preferred for resin (A) from the viewpoint of compatibility with resin (B). Among polyethylenes, low-density polyethylene is particularly preferred. Using low-density polyethylene results in good coating suitability and ease of opening of the extruded laminate.

[0024] In this specification, the vinyl acetate content of resin (A) (hereinafter sometimes referred to as VA) is the vinyl acetate content in resin (A), and is calculated from the vinyl acetate content and blending amount of each component constituting resin (A). The vinyl acetate content of polyethylene is calculated as 0% by mass. That is, when resin (A) consists only of polyethylene, the vinyl acetate content of resin (A) is 0% by mass. When it consists only of one type of ethylene-vinyl acetate copolymer, the vinyl acetate content of resin (A) is the vinyl acetate content of the ethylene-vinyl acetate copolymer used. When resin (A) contains polyethylene and an ethylene-vinyl acetate copolymer, or contains two or more types of polyethylene and / or ethylene-vinyl acetate copolymer, the vinyl acetate content (VA) of resin (A) is calculated by the following formula. (Formula) VA = (VA1 × W1 + VA2 × W2 + ··· VA X × W X ) / (W1 + W2 + ··· W X ) VA1: Vinyl acetate amount of the first component VA2: Vinyl acetate amount of the second component VA X : Vinyl acetate amount of the Xth component (X is an integer of 3 or more) W1: Content of the first component W2: Content of the second component W X : Content of the Xth component (X is an integer of 3 or more)

[0025] The melt mass flow rate of resin (A) is preferably 0.1 to 50 g / 10 min, more preferably 0.5 to 40 g / 10 min, and even more preferably 1 to 30 g / 10 min. When within the above range, coating by extrusion lamination can be more stabilized.

[0026] The content of resin (A) in a total of 100% by mass of resin (A) and resin (B) is 50 to 85% by mass, preferably 60 to 85% by mass, and more preferably 65 to 80% by mass. When within the above range, blocking resistance, low-temperature heat sealability, peel stability, and easy opening property are good.

[0027] <Resin (B)> The resin (B) used in the present invention is an ethylene-vinyl acetate copolymer having a vinyl acetate content of 25 to 42% by mass. The vinyl acetate content of resin (B) is preferably 28 to 33% by mass. If it is less than 25% by mass, the low-temperature heat sealability and ease of opening will decrease. If it exceeds 42% by mass, the blocking resistance will decrease. Any ethylene-vinyl acetate copolymer within the above range may be used alone or in combination of two or more types.

[0028] When multiple ethylene-vinyl acetate copolymers are used as resin (B), the vinyl acetate content of resin (B) can be calculated in the same way as resin (A) from the vinyl acetate content and blending amount of each ethylene-vinyl acetate copolymer.

[0029] The difference between the vinyl acetate content of resin (A) and resin (B) is 20% by mass or more, preferably 25% by mass or more, and more preferably 28% by mass or more. If the difference in vinyl acetate content is less than 20% by mass, the compatibility between resin (A) and resin (B) becomes too high, which lowers the cohesive failure rate and reduces peel stability and ease of opening.

[0030] The melt mass flow rate of resin (B) is preferably 15 to 2,000 g / 10 min, more preferably 30 to 1,000 g / 10 min, and even more preferably 60 to 400 g / 10 min. Within the above range, good blocking resistance, cohesive failure rate, and ease of opening are achieved.

[0031] The content of resin (B) in the total mass of resin (A) and resin (B) is 15 to 50% by mass, preferably 15 to 40% by mass, and more preferably 20 to 35% by mass. Within this range, good blocking resistance, low-temperature heat sealability, peel stability, and ease of opening are achieved.

[0032] <Inorganic filler (C)> Examples of inorganic fillers (C) used in the present invention include silica (silicon dioxide), alumina, titania, talc, mica, calcium oxide, calcium carbonate, calcium sulfate, calcium silicate, and magnesium silicate. Among these, talc or mica is preferred from the viewpoint of stabilizing strength by preventing cohesive failure upon opening and suppressing fuzzing. The average particle size (D50) is not particularly limited as long as it is thinner than the thickness of the adhesive resin composition, but 0.1 to 20 μm is preferred. These can be used alone or in combination of two or more. The above average particle size (D50) is determined from the particle size value at a cumulative amount of 50% by weight, read from the cumulative particle size distribution curve measured in accordance with JIS R1629 using a laser particle size distribution analyzer.

[0033] The inorganic filler (C) content is 1 to 40 parts by mass, preferably 3 to 30 parts by mass, and more preferably 5 to 20 parts by mass, per 100 parts by mass of the total of resin (A) and resin (B). Within this range, coating by extrusion lamination is stabilized, and peel stability and peel appearance are good.

[0034] <Tackifying resin (D)> The adhesive resin composition of the present invention preferably further contains a tackifying resin (D). The tackifying resin (D) can be appropriately selected from known resins. Examples include phenolic resins, xylene resins, coumarone-indene resins, petroleum resins, rosin resins, terpene resins, and the like. Examples of phenolic resins include phenolic resins, modified phenolic resins, xylenephenolic resins, and alkylphenolic resins. Examples of xylene-based resins include xylene resin and modified xylene resin. Examples of coumarone-indene resins include coumarone-indene resin and hydrogenated coumarone-indene resin. Examples of petroleum-based resins include aliphatic (C5) petroleum resins, aromatic (C9) petroleum resins, copolymer (C5 / C9) petroleum resins, alicyclic petroleum resins (hydrogenated or dicyclopentadiene (DCPD) petroleum resins), and low molecular weight polystyrene resins. Examples of rosin-based resins include rosin, rosin derivatives (hydrogenated rosin, disproportionated rosin, polymerized rosin, rosin esters (esterified rosins such as alcohol, glycerin, and pentaerythritol)), etc. Examples of terpene resins include α-pinene resin, β-pinene resin, dipentene resin, aromatically modified terpene resin, hydrogenated terpene resin, terpene phenol resin, acid-modified terpene resin, and styrene-modified terpene resin. In particular, from the viewpoint of easy opening, it is preferable to include a petroleum-based resin. Petroleum-based resins may be used in combination with other tackifying resins, but the use of petroleum-based resins alone is more preferable.

[0035] The content of the tackifying resin (D) is preferably 2 to 45 parts by mass, and more preferably 5 to 40 parts by mass, per 100 parts by mass of the total of resin (A) and resin (B). Within this range, good low-temperature heat sealability and blocking resistance are obtained.

[0036] The softening point of the tackifying resin (D) is preferably in the range of 90 to 150°C, and more preferably in the range of 100°C to 140°C. When the softening point is within the above range, low-temperature heat sealability and blocking resistance are good. The softening point of the tackifying resin (D) can be determined in accordance with JIS K 2207. Specifically, after a specified ring filled with the resin composition is left to stand for 12 hours or more, it is placed in a heat transfer medium, a specified sphere is placed on top of the specified ring filled with the resin composition, and the temperature of the heat transfer medium is increased at a constant rate. The softening point is the temperature at which the sphere sinks due to the softening of the resin composition and touches the bottom plate of the ring base. If the tackifying resin (D) contains multiple tackifying resins, the softening point of the tackifying resin (D) can be determined from the softening point of each tackifying resin and their mass ratio.

[0037] <Other ingredients> The adhesive resin composition of the present invention may contain, as optional components, resins other than resin (A) and resin (B), waxes, antioxidants, anti-blocking agents, etc. Each of these other components may be used individually or in combination of two or more.

[0038] Resins other than resins (A) and (B) can be, for example, polyethylene resins, polypropylene resins, polybutene resins, etc. As polyethylene resins, copolymers consisting of monomers obtained by mixing ethylene and at least one selected from the group consisting of propylene, butene, pentene, hexene, or alkenes with a longer carbon chain in any ratio can be used. As polypropylene resins, homopolymers of propylene, or copolymers consisting of monomers obtained by mixing propylene and at least one selected from the group consisting of ethylene, butene, pentene, hexene, or alkenes with a longer carbon chain can be used. As polybutene resins, polymers obtained by homopolymerization or copolymerization of 1-butene, 2-butene, isobutylene (these are sometimes collectively referred to as butene), or copolymers consisting of monomers obtained by mixing butene and at least one selected from the group consisting of ethylene, propylene, pentene, hexene, or alkenes with a longer carbon chain in any ratio can be used. These resins can be used within the limits that do not impair the low-temperature heat sealability and easy opening properties of the adhesive resin composition of the present invention.

[0039] Ethylene-vinyl acetate copolymers with a vinyl acetate content of 8-24% by mass are classified as resins other than resin (A) and resin (B), but it is preferable not to include them in the adhesive resin composition of the present invention. If the above-mentioned ethylene-vinyl acetate copolymer is included, it acts as a compatibilizer between resin (A) and resin (B), and the compatibility becomes too high, which reduces the cohesive breakdown rate and decreases the peel stability and ease of opening.

[0040] The wax can be appropriately selected from known waxes. Examples include paraffin wax, microcrystalline wax, montane wax, Fischer-Tropsch wax, carnauba wax, ethylene wax, polyethylene wax, propylene wax, polypropylene wax, ethylene-propylene wax, polyethylene-polypropylene wax, and modified waxes such as polyethylene-polypropylene copolymers grafted with styrene. These waxes may be used individually or in combination of two or more.

[0041] Antioxidants include, for example, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 4,6-bis(octylthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-t-butyl-4-hydroxy-m-tolyl]propionate, tris(2,4-di-t-butylphenyl)phosphite, and bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite. The preferred phenolic antioxidant is pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], and the preferred phosphorus antioxidant is tris(2,4-di-t-butylphenyl) phosphite. These antioxidants may be used individually or in combination of two or more.

[0042] Anti-blocking agents can include, for example, lubricants and organic fine powders. Examples of lubricants include erucic acid amide and stearic acid amide. Examples of organic fine powders include heat-resistant fillers made from polyethylene, polypropylene, urethane, acrylic, nylon, urea-based resins, styrene cross-linked fillers, benzoguanamine cross-linked fillers, and the like. These blocking inhibitors may be used individually or in combination of two or more types.

[0043] The lower limit of the content of the above optional components cannot be specified because it varies depending on the physical properties. However, the upper limit is preferably 10% by mass or less, and more preferably 8% by mass or less, of 100% by mass of the adhesive resin composition. When the blending amount is 10% by mass or less, the influence of the optional components on the adhesion and coating suitability can be suppressed.

[0044] <Method for producing adhesive resin composition> The adhesive resin composition of the present invention can be manufactured by conventionally known methods. Resin (A), resin (B), inorganic filler (C), tackifying resin (D) used as needed, and optional 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, then placed in an extruder, heated and kneaded, and extruded to obtain the adhesive resin composition. The adhesive resin composition is usually processed into pellet form and used in a later process. A twin-screw extruder is preferred as the extruder, but is not limited to this. The extrusion is usually carried out at 140 to 200°C.

[0045] The adhesive resin composition of the present invention preferably has a melt mass flow rate of 1 to 100 g / 10 min, more preferably 3 to 50 g / 10 min, and even more preferably 5 to 40 g / 10 min. Within this range, coating by an extrusion laminator is stable. The melt mass flow rate of the adhesive resin composition can be adjusted by the melt mass flow rates of resin (A) and resin (B) used and their respective proportions.

[0046] <Laminated sheet> The laminated sheet of the present invention is a sheet in which a film of the adhesive resin composition is laminated on a substrate. Examples of substrates that can be used include paper, aluminum, polyester, polyethylene, polypropylene, polystyrene, aluminum-deposited polyester, aluminum-deposited polypropylene, and silica-deposited polyester. The substrate does not need to be a single layer; it may be a laminate of two or more layers. There are no particular restrictions on the thickness of the substrate, but 1 to 300 μm is preferred. As a method for laminating the adhesive resin composition onto a substrate, for example, a pelletized adhesive resin composition as described above is used, formed into a single-layer film by an inflation method or a casting method, and this film is laminated to the substrate (with an adhesive layer if necessary). Alternatively, the kneaded composition may be directly coated onto the substrate, or other methods may be employed.

[0047] To improve the adhesion between the substrate and the adhesive resin composition, the substrate surface may be treated with flame treatment, ozone treatment, corona discharge treatment, or an anchor coating agent. For substrates that have been pre-laminated with polyethylene resin, direct extrusion lamination is also possible. Alternatively, a multilayer film can be formed by co-extrusion with polyethylene or polypropylene, and then laminated with stretched or unstretched films such as polyester film, polyamide film, or polypropylene film by dry lamination or sand lamination to obtain a laminated sheet. In this case as well, to improve the adhesion between the substrate and the adhesive resin composition, the substrate surface may be treated with flame treatment, ozone treatment, corona discharge treatment, or an anchor coating agent if necessary. Furthermore, the thickness of the adhesive resin composition film in the laminated sheet of the present invention is usually 5 μm or more, and preferably 10 μm or more. Furthermore, the laminated sheets in this invention include long and cut short films and sheets. The substrate also includes single-layer and multi-layer laminates.

[0048] The laminated sheet of the present invention can be widely used in packaging materials and containers made from thermoplastic resins for foods, beverages, pharmaceuticals, and the like. In particular, it can be suitably used for sealing food containers. [Examples]

[0049] The present invention will be described in detail below with reference to examples, but these examples represent only one aspect of the present invention and are not limited to these examples. In the examples, "parts" refers to "parts by mass," and "%" refers to "mass%."

[0050] <Manufacturing of adhesive resin compositions> (Example 1) 70 parts of resin (A) A1, 30 parts of resin (B) B1, 20 parts of inorganic filler (C) C1, 0.1 parts of Incrosslip C (manufactured by Croda, erucic acid amide) as an anti-blocking agent, and 0.1 parts of IRGANOX 1010 (manufactured by BASF, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]) as an antioxidant were weighed out and pre-blended in a Henschel mixer for 5 minutes. The pre-blended material was put into a hopper and supplied to the extruder described below using a screw feeder to obtain the adhesive resin composition of Example 1. Extruder Conditions Extruder: IKG Corporation co-rotating twin-screw extruder PMT32-40.5 Barrel temperature: 130~160℃ Screw rotation speed: 80 rpm Feeding rate: 15kg / hr

[0051] (Examples 2-25, Comparative Examples 1-10) An adhesive resin composition was obtained in the same manner as in Example 1, except that the amount of material and the mixing ratio (mass) were changed as shown in Tables 1 to 3.

[0052] (Example 26) 70 parts of resin (A) A1, 30 parts of resin (B) B6, 20 parts of inorganic filler (C) C1, 10 parts of tackifying resin (D) D1, 0.1 parts of Incrosslip C (manufactured by Croda, erucic acid amide) as an antiblocking agent, and 0.1 parts of IRGANOX 1010 (manufactured by BASF, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]) as an antioxidant were weighed out and pre-blended in a Henschel mixer for 5 minutes. The pre-blended material was put into a hopper and supplied to the extruder described below using a screw feeder to obtain the adhesive resin composition of Example 26.

[0053] (Examples 27-32) An adhesive resin composition was obtained in the same manner as in Example 26, except that the amount of material and the mixing ratio (mass) were changed as shown in Tables 1-3.

[0054] The abbreviations listed in Tables 1-3 are as follows: <Resin (A)> A1: Petrocene 170 (manufactured by Tosoh Corporation, low-density polyethylene, MFR: 1g / 10 min) A2: Lumitac 43-1 (manufactured by Tosoh Corporation, ultra-low density polyethylene (ethylene-butene copolymer), MFR: 8g / 10 min) A3: UltraCen 515 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content: 6%, MFR: 2.5g / 10min) A4: UltraCen 526 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content: 7%, MFR: 25g / 10 min) <Resin (B)> • B1: Evaflex 310 (manufactured by Mitsui Dow Polychemicals, ethylene-vinyl acetate copolymer, vinyl acetate content: 25%, MFR: 400g / 10 min) • B2: UltraCen 751 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content: 28%, MFR: 5.7g / 10 min) • B3: UltraCen 710 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content: 28%, MFR: 18g / 10 min) • B4: UltraCen 735 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content: 28%, MFR: 1000g / 10 min) B5: UltraCen 750 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content: 32%, MFR: 30g / 10 min) • B6: UltraCen 0B54A-6 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content: 33%, MFR: 400g / 10 min) • B7: UltraCen 760 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content: 42%, MFR: 70g / 10 min) <Other resins (R)> • R1: UltraCen 541 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content: 10%, MFR: 8g / 10 min) • R2: UltraCen 633 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content: 20%, MFR: 20g / 10 min) • R3: Levaprene 500 (manufactured by Lanxess, ethylene-vinyl acetate copolymer, vinyl acetate content: 50%, MFR: 5g / 10 min)

[0055] <Inorganic filler (C)> • C1: MS-K (manufactured by Nippon Talc Co., Ltd., talc, average particle size (D50): 16 μm) • C2: NK-8 (manufactured by Nippon Koken Kogyo Co., Ltd., mica, average particle size (D50): 8 μm) • C3: NS#100 (manufactured by Nitto Funka Kogyo Co., Ltd., calcium carbonate, average particle size (D50): 2 μm)

[0056] <Tackifying resin (D)> • D1: Alcon P-90 (manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point: 90℃) • D2: Alcon P-125 (manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point: 125℃) • D3: Haritack FK125 (manufactured by Harima Chemicals, rosin ester, softening point: 125℃)

[0057] <Manufacturing of laminated sheets (lid material)> The obtained adhesive resin composition was laminated to a thickness of 20 μm onto the PE side (underlayment) of a PET 12 μm / PE 25 μm substrate sheet using an extrusion laminator to produce a laminated sheet. In Comparative Example 10, the adhesive resin composition contained too much inorganic filler, making uniform coating impossible. The coating conditions are shown below. Extrusion Laminator: Musashino Kikai 400M / M Test EXT Laminator Resin temperature directly beneath the die: 130℃~270℃ Machining speed: 20m / min T-die width: 300mm Cooling roll surface temperature: 20~25℃

[0058] <Rating> The following evaluations were performed on the blockage resistance, peel stability, peel appearance, low-temperature heat sealability, and ease of opening of the laminated sheets manufactured as described above.

[0059] [Blocking resistance] Five 4cm x 5cm pieces of laminated sheet were cut and stacked so that the PET surface of the laminate was in contact with the adhesive resin composition surface. The stacked samples were subjected to a load of 10kg at 40°C for 24 hours. After removing the samples and leaving them in an atmosphere of 23°C and 65% relative humidity for 2 hours, the stacked samples were peeled off by hand. The state at the time of peeling was evaluated according to the following criteria. ○: Peels off easily without resistance. (Good) △: Slight resistance (usable) ×: High resistance during peeling, or impossible to peel (unusable).

[0060] [Peeling stability] The obtained laminated sheet was cut to a size of 70 mm x 70 mm, and a paper container with a polyethylene film laminated on the inside and an opening of 52 mmΦ was heat-sealed under the conditions of gauge pressure 0.3 MPa, 150°C, and 1.0 second to obtain a container. The obtained container was left to stand for 24 hours in a constant temperature and humidity chamber at 23°C and 65% relative humidity, and then peeled off at a speed of 200 mm / min by 45-degree angle peeling in the same chamber. The ratio of the area of ​​cohesive failure to the heat-sealed area was observed. Since a larger area of ​​cohesive failure indicates better peel stability, the peel stability was evaluated according to the following criteria. ○: Percentage of area with cohesive failure is 90% or more (good) △: Percentage of area with cohesive failure is between 50% and 90% (usable) ×: Percentage of area where cohesive failure occurred is less than 50% (unusable)

[0061] [Peeling appearance] Test containers were obtained in the same manner as for peel stability. The obtained containers were left undisturbed for 24 hours in a constant temperature and humidity chamber at 23°C and 65% relative humidity. Then, in the same chamber, the containers were peeled off at a speed of 200 mm / min by 45-degree angle peeling. The peeled surface of the containers was visually observed, and the peeled appearance was evaluated according to the following criteria. ○: No fibrous resin was observed (good) △: Slight fibrous resin is observed (usable) ×: Fibrous resin stretched across the entire surface is observed (unusable).

[0062] [Low-temperature heat sealability] The obtained laminated sheet was cut to a size of 70 mm x 70 mm, and a paper container with a polyethylene film laminated on the inside and an opening of 52 mmΦ was heat-sealed under the conditions of gauge pressure 0.3 MPa, 110°C, and 1.0 second to obtain a container. The obtained container was left to stand for 24 hours in a constant temperature and humidity chamber at 23°C and 65% relative humidity, and then the peel strength was measured in the same chamber by peeling at a speed of 200 mm / min at a 45-degree angle. The measurement was performed 5 times, and the average value of the maximum load (N) at the time of opening was used as the opening strength, and the low-temperature heat sealability was evaluated according to the following criteria. ◎: Opening strength of 7N or higher (very good) ○: Opening strength is 5N or more but less than 7N (good) △: Opening strength is 3N or more but less than 5N (usable) ×: Opening strength less than 3N (unusable)

[0063] [Easy to open] Test containers were obtained in the same manner as for peel stability. The obtained containers were left undisturbed for 24 hours in a constant temperature and humidity chamber at 23°C and 65% relative humidity. Then, the peel strength was measured in the same chamber by peeling at a speed of 200 mm / min at a 45-degree angle. Five measurements were taken, and the average of the maximum load (N) at the time of opening was defined as the opening strength. Ease of opening was evaluated according to the following criteria. ○: Opening strength is between 8N and 15N (good) △: Opening strength of 4N or more but less than 8N, or 15N or more but less than 20N (usable) ×: Opening strength less than 4N or 20N or more (not usable)

[0064] [Table 1]

[0065] [Table 2]

[0066] [Table 3]

[0067] According to the evaluation results, the adhesive resin composition of the present invention, which contains at least one resin (A) selected from polyethylene and an ethylene-vinyl acetate copolymer with a vinyl acetate content of 7% by mass or less, and a resin (B) which is an ethylene-vinyl acetate copolymer with a vinyl acetate content of 25 to 42% by mass, in addition to a specific amount of inorganic filler (C), and in which the difference in vinyl acetate content between resin (A) and resin (B) is 20% by mass or more, was shown to have good blocking resistance, excellent peel stability due to a high cohesive breakdown rate, excellent peel appearance, good low-temperature heat sealability and easy opening, and is useful as an adhesive resin composition for sealing. On the other hand, comparative examples with vinyl acetate content outside the above range showed a decrease in cohesive breakdown rate and could not obtain stable peeling. Furthermore, comparative examples without inorganic filler showed deterioration in peel appearance due to the occurrence of fuzzing when opened.

Claims

1. An adhesive resin composition comprising resin (A), resin (B), and inorganic filler (C), The total mass of resin (A) and resin (B) is 100% by mass, and contains 50 to 85% by mass of resin (A) and 15 to 50% by mass of resin (B). Resin (A) is at least one selected from polyethylene and an ethylene-vinyl acetate copolymer having a vinyl acetate content of 7% by mass or less. Resin (B) is an ethylene-vinyl acetate copolymer with a vinyl acetate content of 25 to 42% by mass. The difference in vinyl acetate content between resin (A) and resin (B) is 20% by mass or more. An adhesive resin composition comprising 1 to 40 parts by mass of an inorganic filler (C) per 100 parts by mass of resin (A) and resin (B).

2. The adhesive resin composition according to claim 1, wherein the melt mass flow rate of resin (B) at 190°C and a load of 2.16 kg is 15 to 2,000 g / 10 min.

3. The adhesive resin composition according to claim 1, wherein resin (A) contains polyethylene.

4. The adhesive resin composition according to claim 1, wherein the inorganic filler (C) is talc or mica.

5. Furthermore, the adhesive resin composition according to claim 1, comprising 5 to 40 parts by mass of tackifying resin (D) with respect to a total of 100 parts by mass of resin (A) and resin (B).

6. A laminated sheet in which a film of the adhesive resin composition according to any one of claims 1 to 5 is laminated on a substrate.

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