Thermoplastic adhesive resin composition and laminate

Abstract

To provide a thermoplastic adhesive resin composition with thermal responsiveness for enhanced adhesion in response to heat, and a laminate including the composition.SOLUTION: A thermoplastic adhesive resin composition includes an α-olefin-based graft copolymer including at least one selected from a carboxylic acid anhydride group and a carboxyl group, and a nitrile-based copolymer including at least one nitrile-based functional group selected from a nitrile group, an acrylonitrile group and a methacrylonitrile group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic adhesive resin composition and a laminate using said composition. [Background technology]

[0002] Laminated films, which have an outer layer made of a resin film with excellent mechanical properties such as tensile strength, an intermediate layer made of a polyamide resin or ethylene-vinyl alcohol copolymer, etc., and an inner layer made of a resin film with excellent heat-sealing properties, have traditionally been widely used as packaging materials, and various studies have been conducted on the adhesive resin compositions (adhesive resin compositions) used to bond the layers together.

[0003] In recent years, there has been an increasing demand for packaging materials to have a reduced environmental impact, and therefore active research has been conducted into adhesive resin compositions that can change the peel strength (particularly reduce the peel strength) in response to an external stimulus, thereby making it easier to peel the layers that make up the laminated film and thereby facilitating recycling.

[0004] As a technology for changing peel strength in response to an external stimulus, Patent Document 1 discloses a pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer and a release sheet are laminated in this order on a base sheet, and the release sheet is configured as a laminate of the release agent layer and a support from the pressure-sensitive adhesive layer side, and the release agent layer is formed so that the release force of the release sheet relative to the pressure-sensitive adhesive layer is reduced when the release agent layer is exposed to an external stimulus such as heat. Furthermore, Patent Document 2 discloses a heat-peelable film that adheres to an adherend with high adhesive strength and easily and selectively peels off the adherend by heating. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5063016 [Patent Document 2] Patent No. 3405576 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the conventional sheets and films described in the above patent documents relate to sheets and films that become easily peeled (weakened adhesive strength) by an external stimulus. On the other hand, there are cases where it is necessary to increase adhesive strength by applying an external stimulus, which is the exact opposite of this idea. However, until now, no compositions (adhesives or pressure-sensitive adhesives) have been known that can increase adhesive strength by applying an external stimulus and bond each layer more firmly.

[0007] The present invention has been made in view of the above, and an object of the present invention is to provide a thermoresponsive thermoplastic adhesive resin composition that increases adhesive strength in response to heat, and a laminate using the composition. [Means for solving the problem]

[0008] As a result of extensive research into methods for solving the above problems, the present invention has been completed with the following configuration. An example of the configuration of the present invention is as follows.

[0009] [1] An α-olefin graft copolymer containing at least one selected from a carboxylic anhydride group and a carboxyl group; a nitrile copolymer containing at least one nitrile functional group selected from a nitrile group, an acrylonitrile group, and a methacrylonitrile group; A thermoplastic adhesive resin composition comprising:

[0010] [2] The nitrile copolymer contains thermally expandable microcapsules, The thermally expandable microcapsules have a core-shell structure, and the shell contains the nitrile functional group. [1] The thermoplastic adhesive resin composition according to [1].

[0011] [3] The thermoplastic adhesive resin composition according to [2], wherein the content of the thermally expandable microcapsules is 1 to 25 parts by mass per 100 parts by mass of the α-olefin graft copolymer.

[0012] [4] The shell of the thermally expandable microcapsule is a shell obtained using a nitrile-based functional group-containing monomer containing the nitrile-based functional group, the content of the structural unit derived from the nitrile functional group-containing monomer in the shell is 40 to 95% by mass; The thermoplastic adhesive resin composition according to [2] or [3].

[0013] [5] The thermoplastic adhesive resin composition according to any one of [2] to [4], wherein the thermally expandable microcapsules have an expansion starting temperature of 130 to 200°C.

[0014] [6] The thermoplastic adhesive resin composition according to any one of [1] to [5], wherein the α-olefin graft copolymer has a carboxylic anhydride group and a carboxyl group content of 0.5 to 15 mass %.

[0015] [7] A film containing the thermoplastic adhesive resin composition according to any one of [1] to [6], a substrate layer; A laminate comprising:

[0016] [8] The laminate according to [7], wherein the substrate layer contains a resin having a hydroxy group. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a thermoresponsive thermoplastic adhesive resin composition that increases adhesive strength in response to heat, and a laminate using the composition. DETAILED DESCRIPTION OF THE INVENTION

[0018] In this specification, unless otherwise specified, the expression "XX to YY" representing a numerical range means a numerical range including the lower and upper limits, which are the endpoints. Furthermore, when numerical ranges are described in stages, the upper and lower limits of each numerical range can be combined in any way. Furthermore, the description "A and / or B" is a concept that includes the case of A, the case of B, and the case of both A and B.

[0019] ≪Thermoplastic adhesive resin composition≫ The thermoplastic adhesive resin composition according to the present invention (hereinafter also referred to as "the composition") contains an α-olefin graft copolymer containing at least one selected from a carboxylic anhydride group and a carboxyl group, and a nitrile copolymer containing at least one nitrile functional group selected from a nitrile group, an acrylonitrile group, and a methacrylonitrile group.

[0020] <α-olefin graft copolymer> The composition contains an α-olefin graft copolymer containing at least one group selected from a carboxylic anhydride group and a carboxyl group (hereinafter simply referred to as "α-olefin graft copolymer"). The α-olefin graft copolymer is a copolymer having at least one group selected from a carboxylic anhydride group and a carboxyl group as a modifying group, and having an olefin polymer main chain. The α-olefin graft copolymer used in the present composition may be one type or two or more types.

[0021] The MFR (JIS K 7210, temperature: 190° C., load: 2.16 kg) of the α-olefin graft copolymer is preferably 0.1 to 50 g / 10 min, more preferably 0.5 to 20 g / 10 min.

[0022] The density of the α-olefin graft copolymer is preferably 900 to 980 kg / m 3 , more preferably 910 to 970 kg / m 3 , more preferably 910 to 950 kg / m 3 is.

[0023] The olefin polymer main chain preferably has structural units derived from an α-olefin, and examples of the α-olefin include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, and 1-octene, with ethylene being preferred. The α-olefin may be two or more types.

[0024] The olefin polymer main chain is preferably an ethylene polymer. Examples of the ethylene polymer include ethylene homopolymers and copolymers of ethylene with an α-olefin having 3 or more carbon atoms, specifically, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, and 1-eicosene. Examples of the ethylene polymer include (linear) low density polyethylene, medium density polyethylene, and high density polyethylene, and any of these may be used.

[0025] The density of the ethylene polymer is usually 900 to 980 kg / m 3 , preferably 900 to 955 kg / m 3 , more preferably 900 to 930 kg / m 3 is. The melt flow rate (MFR) of the ethylene polymer measured in accordance with JIS K 7210 under conditions of 190° C. and a load of 2.16 kg (kgf) is usually 0.1 to 20 g / 10 min, and preferably 0.1 to 15.0 g / 10 min.

[0026] The modifying group is at least one selected from a carboxylic acid anhydride group and a carboxyl group. The modifying group is introduced into the olefin polymer by, for example, using at least one compound selected from unsaturated carboxylic acids and unsaturated carboxylic acid anhydrides and the olefin polymer, and graft-modifying the olefin polymer with the compound. Examples of unsaturated carboxylic acids and unsaturated carboxylic acid anhydrides include maleic acid, fumaric acid, (meth)acrylic acid, crotonic acid, itaconic acid, and the anhydrides of these acids. Of these, maleic anhydride is particularly preferred.

[0027] The content of carboxylic anhydride groups and carboxyl groups in the α-olefin graft copolymer (graft modification amount) is preferably 0.5 to 15 mass %, more preferably 0.5 to 5 mass %, from the viewpoints of ease of synthesis of the α-olefin graft copolymer and ease of obtaining the present composition having superior adhesiveness. The graft modification amount is the mass of the carboxylic anhydride group and the carboxyl group in the graft copolymer, measured by the following method using FT-IR. The graft copolymer was heat-pressed at 250°C for 3 minutes to produce a sheet, and the infrared absorption spectrum of the sheet was measured using an infrared spectrophotometer (JASCO Corporation, FT-IR410 model) with a resolution of 2 cm. -1 The measurement was performed by the transmission method under the condition of 32 accumulations. In the measured spectrum, the peaks of the carboxylic acid anhydride group and the carboxyl group (1790 cm when maleic anhydride was used as the grafting raw material) were -1 The peak intensity of the peak (peak near the peak) is measured and quantified using a calibration curve prepared in advance.

[0028] <Method for producing α-olefin graft copolymer> The α-olefin graft copolymer can be produced by graft-modifying the olefin polymer with at least one selected from the unsaturated carboxylic acid and the unsaturated carboxylic anhydride. Specific examples include a method of melting the olefin polymer using an extruder, adding the unsaturated carboxylic acid and / or the unsaturated carboxylic anhydride thereto for graft reaction, and a method of dissolving the olefin polymer in a solvent to prepare a solution, adding the unsaturated carboxylic acid and / or the unsaturated carboxylic anhydride thereto for graft reaction. The grafting reaction is usually carried out at a temperature of 60 to 350°C. Here, the olefin polymer used may be one type or two or more types, the unsaturated carboxylic acid may be one type or two or more types, and the unsaturated carboxylic acid anhydride may be one type or two or more types.

[0029] In order to efficiently graft copolymerize the unsaturated carboxylic acid and / or unsaturated carboxylic anhydride, it is preferable to carry out the graft reaction in the presence of a radical initiator. The radical initiator is usually used in an amount of 0.001 to 1 part by mass per 100 parts by mass of the olefin polymer before modification.

[0030] The radical initiator is preferably an organic peroxide, such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxidebenzoate)hexyne-3, 1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, tert-butyl peracetate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2.5-di(tert-butylperoxy)hexane, tert-butyl perbenzoate, tert-butyl perphenyl acetate, tert-butyl perisobutyrate, tert-butyl per-sec-octoate, tert-butyl perpivalate, cumyl perpivalate, and tert-butyl perdiethyl acetate. Examples of radical initiators other than organic peroxides include azo compounds, and specific examples thereof include azobisisobutyronitrile and dimethylazoisobutyrate.

[0031] <Nitrile copolymer> The present composition contains a nitrile copolymer (hereinafter also simply referred to as "nitrile copolymer") containing at least one nitrile functional group selected from a nitrile group, an acrylonitrile group, and a methacrylonitrile group. The nitrile copolymer used in the present composition may be one type or two or more types.

[0032] The present inventors consider the reason why the present composition exhibits thermal responsiveness, in which adhesive strength increases in response to heat, when it contains the α-olefin-based graft copolymer and the nitrile-based copolymer (particularly thermally expandable microcapsules), as follows. Usually, when a laminate is produced using a substrate and an adhesive resin composition, a process called heat sealing is performed. In this heat sealing process, the laminate is usually hot-pressed under high temperature and pressure, and the heat generated during this process causes the nitrile functional groups in the nitrile copolymer to react with the functional groups on the surface of the substrate, thereby improving the adhesive strength. This effect is remarkable when the substrate contains a resin having a hydroxy group or when the nitrile copolymer is a thermally expandable microcapsule. The inventors speculate that this is because the microcapsules expand due to the heat during heat sealing, causing the microcapsules and the substrate to press against each other, accelerating the reaction of the nitrile functional groups with the functional groups (particularly hydroxy groups) on the surface of the substrate.

[0033] The nitrile copolymer is not particularly limited, but preferably contains thermally expandable microcapsules, since this composition can be easily obtained with thermal responsiveness that increases adhesive strength in response to heat, etc. In other words, the composition preferably contains the α-olefin graft copolymer and thermally expandable microcapsules. The thermally expandable microcapsules are preferably those having a core-shell structure, the shell of which contains the nitrile functional group. Thermally expandable microcapsules having such a core-shell structure and containing the nitrile functional group may be produced by a conventional method such as those described in International Publication Nos. 2003 / 099955, 2007 / 072769, and 2021 / 172062, or may be commercially available products. Examples of commercially available products include the Matsumoto Microsphere F and FN series manufactured by Matsumoto Yushi Seiyaku Co., Ltd.

[0034] The shell of the thermally expandable microcapsules is preferably a shell obtained using a nitrile-based functional group-containing monomer containing the nitrile-based functional group, and the content of the structural unit derived from the nitrile-based functional group-containing monomer in the shell is preferably 40 to 95% by mass, more preferably 40 to 60% by mass.

[0035] Examples of the nitrile functional group-containing monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, and fumaronitrile. The nitrile-based functional group-containing monomer may be used alone or in combination of two or more kinds.

[0036] In addition to the structural units derived from the nitrile-based functional group-containing monomer, the shell may also contain structural units derived from other monomers, such as a carboxyl group-containing monomer, a vinyl halide monomer, a vinylidene halide monomer, a vinyl ester monomer, a (meth)acrylic acid ester monomer, a (meth)acrylamide monomer, a maleimide monomer, a styrene monomer, an olefin monomer, a vinyl ether monomer, a vinyl ketone monomer, an N-vinyl monomer, or a monomer having two or more polymerizable double bonds in the molecule (a crosslinkable monomer). Specific examples of the other monomers include those described in WO 2003 / 099955, WO 2007 / 072769, WO 2021 / 172062, etc.

[0037] The thermally expandable microcapsules having a core-shell structure preferably contain one or more foaming agents as the core. The blowing agent is preferably a substance that vaporizes when heated, and examples thereof include hydrocarbons having 1 to 13 carbon atoms, such as methane, ethane, propane, (iso)butane, (iso- or neo)pentane, (iso)hexane, (iso)heptane, (iso)octane, (iso)nonane, (iso)decane, (iso)undecane, (iso)dodecane, and (iso)tridecane; hydrocarbons having more than 13 but not more than 20 carbon atoms, such as (iso)hexadecane and (iso)eicosane; 1,2,4-trimethylbenzene, petroleum ether, and normal paraffin having an initial boiling point of 150 to 260°C and / or a distillation range of 70 to 360°C. Examples of such compounds include hydrocarbons such as petroleum fractions, such as raffin and isoparaffin; halogenated hydrocarbons having 1 to 12 carbon atoms, such as methyl chloride, methylene chloride, chloroform, and carbon tetrachloride; fluorine-containing compounds such as hydrofluoroethers; silanes having an alkyl group having 1 to 5 carbon atoms, such as tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, and trimethyl-n-propylsilane; and compounds that undergo thermal decomposition to generate gas when heated, such as azodicarbonamide, N,N'-dinitrosopentamethylenetetramine, and 4,4'-oxybis(benzenesulfonylhydrazide).

[0038] The expansion starting temperature of the thermally expandable microcapsules is preferably 130 to 200° C., more preferably 130 to 175° C. When the expansion starting temperature is within the above range, the adhesive strength of the microcapsules after thermal expansion is increased.

[0039] The content of the nitrile copolymer per 100 parts by mass of the α-olefin graft copolymer is preferably 1 to 25 parts by mass, more preferably 4 to 22 parts by mass, from the viewpoint that the present composition having higher adhesive strength in response to heat can be easily obtained, etc. The content of the thermally expandable microcapsules per 100 parts by mass of the α-olefin graft copolymer is preferably 1 to 25 parts by mass, more preferably 4 to 22 parts by mass, from the viewpoint that the present composition having higher adhesive strength in response to heat can be easily obtained, etc.

[0040] <Other ingredients> The present composition may contain components other than the α-olefin graft copolymer and the nitrile copolymer as long as the effects of the present invention are not impaired. Examples of such other components include weather resistance stabilizers, heat resistance stabilizers, antistatic agents, slip agents, antiblocking agents, antifogging agents, nucleating agents, decomposing agents, pigments, dyes, plasticizers, hydrochloric acid absorbers, antioxidants, crosslinking agents, crosslinking accelerators, reinforcing agents, fillers, softeners, processing aids, activators, moisture absorbents, adhesives, flame retardants, and mold release agents. The other components may each be used alone or in combination of two or more.

[0041] The present resin composition may also contain other resins, such as polyolefins, in addition to the α-olefin graft copolymer and the nitrile copolymer. Examples of the polyolefin include polymers similar to the olefin polymer that is the main chain of the α-olefin graft copolymer, and polyethylene is preferred, for example. Examples of the polyethylene include polymers similar to the ethylene polymer that is the main chain of the α-olefin graft copolymer.

[0042] When the present composition contains the other resin, the content of the other resin is preferably 750 parts by mass or less, more preferably 735 parts by mass or less, per 100 parts by mass of the α-olefin graft copolymer.

[0043] <Laminate> The laminate according to the present invention (hereinafter also referred to as "the present laminate") comprises a film containing the present composition (hereinafter also referred to as "the present film") and a substrate layer. The present laminate may have two or more layers of the present film, and may have two or more base layers. When the present laminate has two or more layers of the present film, these two or more layers of the present film may be the same film or different films. Furthermore, when the present laminate has two or more base layers, these two or more base layers may be the same layer or different layers. In this specification, no particular distinction is made between films and sheets, and the term film is used to represent plate-like bodies.

[0044] Examples of the structure of the present laminate, from the viewpoint of better exerting the effects of the present invention, include substrate layer / present film; substrate layer / present film / substrate layer; and substrate layer / present film / substrate layer / present film / substrate layer. The present laminate may also be a laminate that constitutes a packaging material or the like, and preferably has a configuration of substrate layer (outer layer) / the present film / substrate layer (inner layer) or substrate layer (outer layer) / the present film / substrate layer (intermediate layer) / the present film / substrate layer (outer layer or inner layer).

[0045] The method for producing the present laminate is not particularly limited, and it can be produced by a conventionally known lamination method. When producing the present laminate, it is preferable to apply heat. However, when using the present film obtained from the present composition containing thermally expandable microcapsules, it is desirable to produce the present laminate at a temperature equal to or higher than the expansion initiation temperature of the thermally expandable microcapsules, preferably at a temperature equal to or higher than the expansion initiation temperature of the thermally expandable microcapsules and equal to or lower than 200°C, since this makes it easier to obtain a present laminate with higher adhesive strength.

[0046] <This film> The present film is not particularly limited as long as it contains the present composition, and can be produced by forming the present composition into a film by a conventionally known method. When producing this film, heat is usually applied, but when producing this film from this composition containing thermally expandable microcapsules, it is desirable to produce this film at a temperature below the expansion initiation temperature of the thermally expandable microcapsules, preferably a temperature above the melting temperature of the α-olefin graft copolymer and below the expansion initiation temperature of the thermally expandable microcapsules, more preferably a temperature above the melting temperature of the α-olefin graft copolymer and below the expansion initiation temperature of the thermally expandable microcapsules, from the viewpoint that it is easy to obtain a composition with thermal responsiveness that increases adhesive strength in response to heat.

[0047] The thickness of the present film is not particularly limited, but is preferably 50 to 1000 μm, more preferably 200 to 400 μm, in order to obtain a present laminate having sufficient adhesive strength.

[0048] <Base material layer> The substrate layer may be any of various known substrate layers. Examples of materials for forming the substrate layer include any polymer capable of being formed into a film, paper, and aluminum foil. Examples of the polymer include ethylene polymers such as high density polyethylene (HDPE), medium density polyethylene (MDPE), linear low density polyethylene (LLDPE), high pressure low density polyethylene (HP-LDPE), ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-acrylic acid ester copolymer, and ionomer; propylene polymers such as propylene homopolymer, propylene random copolymer, and propylene block copolymer; olefin polymers such as poly-1-butene and poly-4-methyl-1-pentene; polystyrene, polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, poly Examples of suitable resins include vinyl polymers such as polyvinyl butyral and polyvinylpyrrolidone; polyamides such as nylon 6, nylon 66, nylon 7, nylon 10, nylon 11, nylon 12, nylon 610, and polymetaxylene adipamide; polyesters such as polyethylene terephthalate, polyethylene terephthalate / isophthalate, polybutylene terephthalate, polylactic acid, polycaprolactone, polyglycolic acid, polybutylene succinate, and polyethylene succinate; cellulose resins such as cellophane, cellulose acetate, nitrocellulose, cellulose acetate propionate, and cellulose acetate butyrate; and polycarbonates. Among these, it is preferable to use a substrate layer containing a resin having a hydroxy group as at least one of the substrate layers constituting the present laminate, as this will enable the effects of the present invention to be more effectively exhibited. The material for forming the substrate layer as the outer layer or inner layer is preferably the olefin polymer, and the material for forming the substrate layer as the intermediate layer is preferably the polyamide or ethylene-vinyl alcohol copolymer.

[0049] The thickness of the substrate layer is not particularly limited, but is usually 10 to 1000 μm. [Example]

[0050] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0051] [Example 1] In a 100 mL glass container, α-olefin graft copolymer 1 (acid anhydride-modified polyethylene, manufactured by Mitsui Chemicals, Inc., acid anhydride group content: 1.0 mass%, density: 920 kg / m 3 14.0 g of a nitrile copolymer (MFR: 1.0 g / 10 min (190°C, 2.16 kgf)) and 80 mL of toluene were added, and the vessel was purged with nitrogen. The internal temperature was raised to 110°C, and α-olefin graft copolymer 1 was dissolved. Next, 700 mg (5 parts by mass per 100 parts by mass of α-olefin graft copolymer 1) of nitrile copolymer 1 (Matsumoto Microsphere FN-180SSD, thermally expandable microcapsules manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., having a core-shell structure, the content of structural units derived from nitrile functional group-containing monomers in the shell: 88% by mass, expansion onset temperature: 135°C) suspended in 4 mL of toluene was added to the resulting solution, and the mixture was stirred at 400 rpm for 5 minutes. The mixture was then allowed to cool while stirring for 5 minutes, the toluene was allowed to evaporate, and the mixture was vacuum-dried at 90°C for 12 hours. Resin composition 1 was obtained through the above procedure.

[0052] [Example 2] A 100 mL glass container was charged with 14.0 g of α-olefin graft copolymer 1 and 80 mL of toluene, and the container was purged with nitrogen. The internal temperature was raised to 110°C, and α-olefin graft copolymer 1 was dissolved. Next, 700 mg (5 parts by mass per 100 parts by mass of α-olefin graft copolymer 1) of nitrile copolymer 2 (Matsumoto Microsphere F-190D, a thermally expandable microcapsule manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., with a core-shell structure, containing 54% by mass of structural units derived from nitrile functional group-containing monomers in the shell, and an expansion initiation temperature of 160°C) suspended in 4 mL of toluene was added to the resulting solution, and the mixture was stirred at 400 rpm for 5 minutes. The mixture was then allowed to cool while stirring for 5 minutes, the toluene was allowed to evaporate, and the mixture was vacuum-dried at 90°C for 12 hours. Resin composition 2 was obtained through the above procedure.

[0053] [Example 3] A 100 mL glass container was charged with 14.0 g of α-olefin graft copolymer 1 and 80 mL of toluene, and the container was purged with nitrogen. The internal temperature was raised to 110°C, and α-olefin graft copolymer 1 was dissolved. Next, 700 mg (5 parts by mass per 100 parts by mass of α-olefin graft copolymer 1) of nitrile copolymer 3 (Matsumoto Microsphere F-260D, a thermally expandable microcapsule manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., with a core-shell structure, containing 45% by mass of structural units derived from nitrile functional group-containing monomers in the shell, and an expansion initiation temperature of 190°C) suspended in 4 mL of toluene was added to the resulting solution, and the mixture was stirred at 400 rpm for 5 minutes. The mixture was then allowed to cool while stirring for 5 minutes, the toluene was allowed to evaporate, and the mixture was vacuum-dried at 90°C for 12 hours. Resin composition 3 was obtained through the above procedure.

[0054] [Example 4] A 100 mL glass container was charged with 14.0 g of α-olefin graft copolymer 1 and 80 mL of toluene, and the container was purged with nitrogen. The internal temperature was raised to 110°C, and the α-olefin graft copolymer 1 was dissolved. Next, 2.94 g of nitrile copolymer 2 (21 parts by mass per 100 parts by mass of α-olefin graft copolymer 1) suspended in 4 mL of toluene was added to the resulting solution, and the mixture was stirred at 400 rpm for 5 minutes. The mixture was then allowed to cool and stirred for 5 minutes, the toluene was allowed to evaporate naturally, and the mixture was vacuum-dried at 90°C for 12 hours. A composition was obtained by the above procedure. The obtained composition was placed in a Labo Plastomill heated to 160°C, and 3.4 g of polyethylene (ethylene-hexene copolymer, Evolue SP-1540 manufactured by Prime Polymer Co., Ltd., density: 913 kg / m 3 20.6 g of a mixture of 20.6 g of a copolymer of 2.16 kgf / 10 min (MFR: 3.8 g / 10 min (190° C., 2.16 kgf)) was charged and kneaded for 10 minutes at a rotation speed of 60 rpm, to obtain resin composition 4.

[0055] [Comparative Example 1] Resin composition 5 was obtained in the same manner as in Example 1, except that nitrile copolymer 1 was not used.

[0056] Comparative Example 2 In a Labo Plastomill heated to 160°C, 3.4 g of α-olefin graft copolymer 1 and polyethylene (ethylene-hexene copolymer, Evolue SP-1540 manufactured by Prime Polymer Co., Ltd., density: 913 kg / m) were added. 3 25.6 g of a mixture of 25.6 g of a copolymer of 2.16 kgf, MFR: 3.8 g / 10 min (190° C., 2.16 kgf) was charged and kneaded for 10 minutes at a rotation speed of 60 rpm, to obtain resin composition 6.

[0057] <Peel test> The resin composition was press-molded at a temperature of 160°C, a pressure of 100 kPa, a preheating time of 7 minutes, and a pressure time of 4 minutes, and then quenched in a press molding machine set to 20°C to obtain a pressed sheet having a thickness of 300 μm, a length of 80 mm, and a width of 80 mm. The obtained pressed sheet was cut to a width of 20 mm to obtain an adhesive sheet (L).

[0058] The substrate layer was an EVOH sheet (Q) made of ethylene-vinyl alcohol copolymer (EVOH) resin (manufactured by Kuraray Co., Ltd.) with a thickness of 100 μm, a length of 80 mm, and a width of 20 mm. The surface layer is made of polyethylene (density: 918 kg / m) with a thickness of 500 μm, length of 80 mm, and width of 20 mm. 3 A PE resin sheet (S) having a MFR of 3.8 g / 10 min (190° C., 2.16 kgf) was used.

[0059] The PE resin sheet (S), adhesive sheet (L), EVOH sheet (Q), adhesive sheet (L), and PE sheet (S) were stacked in this order, and the five-layer laminate was sandwiched between Teflon (registered trademark) sheets. Heat sealing was performed for 7 seconds at a pressure of 0.3 MPa using a heat seal tester with a press plate (lower) temperature set to 160°C and a press plate (upper) temperature set to 160°C, to produce a five-layer laminate.

[0060] The 20 mm wide laminate was punched out to a width of 15 mm, and the average peel strength between the upper PE resin sheet (S) and adhesive sheet (L) and the EVOH sheet (Q) was measured by T-peel at a peel speed of 300 mm / min and a peel width of 15 mm. The average values ​​(n=4) are shown in Tables 1 and 2.

[0061] [Table 1]

[0062] [Table 2]

Claims

1. an α-olefin graft copolymer containing at least one selected from a carboxylic anhydride group and a carboxyl group; and a thermally expandable microcapsule having a core-shell structure, the shell contains a nitrile copolymer containing at least one nitrile functional group selected from a nitrile group, an acrylonitrile group, and a methacrylonitrile group; Thermoplastic adhesive resin composition.

2. 2. The thermoplastic adhesive resin composition according to claim 1, wherein the content of the thermally expandable microcapsules is 1 to 25 parts by mass per 100 parts by mass of the α-olefin graft copolymer.

3. the shell of the thermally expandable microcapsules is a shell containing a nitrile copolymer obtained by using a nitrile functional group-containing monomer containing the nitrile functional group, the content of the structural unit derived from the nitrile functional group-containing monomer in the shell is 40 to 95% by mass; The thermoplastic adhesive resin composition according to claim 1 or 2.

4. The thermoplastic adhesive resin composition according to any one of claims 1 to 3, wherein the thermally expandable microcapsules have an expansion initiation temperature of 130 to 200°C.

5. The thermoplastic adhesive resin composition according to any one of claims 1 to 4, wherein the α-olefin graft copolymer has a content of carboxylic anhydride groups and carboxyl groups of 0.5 to 15 mass%.

6. A film comprising the thermoplastic adhesive resin composition according to any one of claims 1 to 5; a substrate layer; A laminate comprising:

7. The laminate according to claim 6 , wherein the substrate layer comprises a resin having a hydroxy group.

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