Laminate, packaging film, and method for manufacturing the laminate

Abstract

This laminate (1) comprises a base material (2) and a heat seal layer (3). The heat seal layer (3) is a dried article of a coating composition. The coating composition contains a resin component comprising a copolymer of 4-methyl-1-pentene and an α-olefin (excluding 4-methyl-1-pentene) and / or a modified form of the copolymer. In the copolymer, the content ratio for constituent units derived from 4-methyl-1-pentene is 50-99 mol% inclusive, and the content ratio for constituent units derived from the α-olefin is 1-50 mol% inclusive, relative to the total amount of constituent units derived from 4-methyl-1-pentene and constituent units derived from the α-olefin. The oxygen transmission coefficient and the carbon dioxide transmission coefficient of the laminate are each 1000 cm3·mm / (m2·24hr·atm) or greater.

Description

[Technical Field]

[0001] The present invention relates to a laminate, a packaging film, and a method for manufacturing a laminate, and more particularly to a laminate, a packaging film comprising the laminate, and a method for manufacturing the laminate. [Background technology]

[0002] Conventionally, films formed from copolymers containing structural units derived from 4-methyl-1-pentene are known to have excellent gas permeability. For this reason, such films are suitably used, for example, as packaging materials for fresh foods.

[0003] As such a film, for example, a film has been proposed that is made by casting a resin composition containing a thermoplastic resin (A) which is a copolymer containing structural units derived from 4-methyl-1-pentene and structural units derived from α-olefins having 2 to 20 carbon atoms, and a thermoplastic resin (B) which is an olefin copolymer other than thermoplastic resin (A) (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2016-121322 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the film requires both gas permeability and heat sealability.

[0006] Patent Document 1 incorporates a polymer other than the polymer containing the structural unit derived from 4-methyl-1-pentene (specifically, thermoplastic resin (B)) from the viewpoint of improving heat sealability. However, incorporating thermoplastic resin (B) has the drawback of reducing gas permeability.

[0007] The present invention provides a laminate with excellent gas permeability and heat sealability, a packaging film comprising the laminate, and a method for manufacturing the laminate. [Means for solving the problem]

[0008] The present invention [1] is a laminate comprising a substrate and a heat-seal layer in order toward one side in the thickness direction, wherein the heat-seal layer is a dried product of a coating composition, the coating composition comprises a resin component, the resin component comprises a copolymer of 4-methyl-1-pentene and an α-olefin having 2 to 20 carbon atoms (excluding 4-methyl-1-pentene), and / or a modified product of the copolymer, wherein the content ratio of constituent units derived from 4-methyl-1-pentene is 50 mol% or more and 99 mol% or less relative to the total amount of constituent units derived from 4-methyl-1-pentene and constituent units derived from the α-olefin, the content ratio of constituent units derived from the α-olefin is 1 mol% or more and 50 mol% or less, and the oxygen permeability coefficient and carbon dioxide permeability coefficient of the laminate are 1000 cm 3 ·mm / (m 2 It is a laminated material with a temperature of 24 hours (atm) or higher.

[0009] The present invention [2] includes the laminate described in [1] above, wherein the substrate is a gas-permeable porous substrate or a substrate made of a polymer of 4-methyl-1-pentene.

[0010] The present invention [3] includes the laminate described in [1] or [2] above, wherein the thickness of the heat seal layer is 1 μm or more and less than 50 μm.

[0011] The present invention [4] includes a laminate according to any one of the above [1] to [3], wherein the peel strength measured by the following test is 2.0 N / 15 mm or more. Test: Prepare two laminates. Stick the two laminates together so that their heat-sealing layers are in contact, and produce a film by heat-sealing at 160 °C, 0.3 MPa, and for 2 seconds. For the film, peel it in the direction of 180° with respect to the heat-sealing surface under the conditions of a tensile speed of 50 mm / min and a temperature of 23 °C, and measure the peel strength.

[0012] The present invention [5] includes a packaging film comprising the laminate according to any one of [1] to [4] above.

[0013] The present invention [6] is a method for manufacturing the laminate according to any one of [1] to [4] above, comprising: a first step of preparing the base material; a second step of dissolving the coating composition in an organic solvent to prepare a varnish; and a third step of disposing a heat-sealing layer by applying the varnish on one surface in the thickness direction of the base material and drying it.

Advantages of the Invention

[0014] In the laminate of the present invention, the heat-sealing layer is a dried product of the coating composition. Therefore, it has excellent heat-sealing properties.

[0015] Also, in this laminate, the coating composition contains a resin component comprising a copolymer of 4-methyl-1-pentene and an α-olefin having 2 or more and 20 or less carbon atoms (excluding 4-methyl-1-pentene), and / or a modified product of the copolymer. Therefore, the gas permeability can be improved.

[0016] The packaging film of the present invention comprises the laminate of the present invention. Therefore, it has excellent gas permeability and heat-sealing properties.

[0017] The present invention provides a method for manufacturing a laminate, comprising a second step of dissolving a coating composition in an organic solvent to prepare a varnish, and a third step of applying the varnish to one side of the substrate in the thickness direction and drying it to form a heat-seal layer. In other words, the second and third steps allow a heat-seal layer, which is a dried coating composition, to be formed on one side of the substrate in the thickness direction. Therefore, this method makes it possible to manufacture a laminate with excellent heat-sealability.

[0018] Furthermore, this method for producing the laminate uses a coating composition containing a resin component consisting of a copolymer of 4-methyl-1-pentene and an α-olefin having 2 to 20 carbon atoms (excluding 4-methyl-1-pentene), and / or a modified version of the copolymer. Therefore, this method makes it possible to produce a laminate with excellent gas permeability. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a schematic diagram showing one embodiment of the laminate of the present invention. [Figure 2] Figure 2 is a schematic diagram showing one embodiment of the method for manufacturing a laminate according to the present invention. Figure 2A shows the first step of preparing the substrate 2. Figure 2B shows the third step of applying a varnish of the coating composition to one side of the substrate in the thickness direction and drying it, thereby arranging a heat seal layer on one side of the substrate in the thickness direction. [Modes for carrying out the invention]

[0020] <Laminate> Referring to Figure 1, one embodiment of the laminate of the present invention will be described in detail.

[0021] In Figure 1, the vertical direction of the paper is the vertical direction (thickness direction). The upper side of the paper is the upper side (one side in the thickness direction). The lower side of the paper is the lower side (the other side in the thickness direction). The horizontal direction and depth direction of the paper are plane directions perpendicular to the vertical direction. Specifically, these correspond to the directional arrows in each figure.

[0022] The laminate 1 has a film shape (including a sheet shape) with a predetermined thickness. The laminate 1 extends in a planar direction perpendicular to the thickness direction.

[0023] As shown in Figure 1, the laminate 1 comprises a base material 2 and a heat-seal layer 3 in order toward one side in the thickness direction.

[0024] Specifically, the laminate 1 comprises a base material 2 and a heat-seal layer 3 disposed on the upper surface (one side in the thickness direction) of the base material 2.

[0025] The thickness of the laminate 1 is, for example, 5 μm or more, and for example, 10,000 μm or less.

[0026] <Base material> The base material 2 extends along the planar direction (a direction perpendicular to the thickness direction) and has a sheet shape with a front surface and a back surface.

[0027] The substrate 2 is preferably selected such that its gas permeability, as described later, is equal to or greater than a predetermined value.

[0028] Examples of such substrate 2 include a gas-permeable porous substrate and a substrate made of a polymer of 4-methyl-1-pentene (preferably a homopolymer of 4-methyl-1-pentene).

[0029] Examples of gas-permeable porous substrates include paper, cloth, knitted fabrics, and nonwoven fabrics. Specifically, such porous substrates are composed of, for example, natural fibers such as polyolefins, polyesters, and cellulose, fluororesins, silicone resins, and urethane resins.

[0030] Preferably, the base material 2 is a gas-permeable porous base material. If the base material 2 is a gas-permeable porous base material, the dried coating composition (described later) can penetrate into the base material 2, and the resulting anchoring effect improves the adhesion between the base material 2 and the heat seal layer 3. As a result, the heat sealability is improved.

[0031] The thickness of the substrate 2 is, for example, 1 μm or more, and for example, 9999 μm or less.

[0032] <Heat seal layer> The heat seal layer 3 extends along the planar direction (a direction perpendicular to the thickness direction) and has a sheet shape with a flat front surface and a flat back surface. The heat seal layer 3 is in contact with one side of the substrate 2 in the thickness direction.

[0033] The heat seal layer 3 is a dried product of the coating composition. Therefore, it exhibits excellent heat sealability.

[0034] The coating composition contains a resin component.

[0035] [Resin components] The resin component consists of a copolymer of 4-methyl-1-pentene and an α-olefin having 2 to 20 carbon atoms (excluding 4-methyl-1-pentene) (hereinafter sometimes referred to as a copolymer of 4-methyl-1-pentene and α-olefin), and / or a modified product of the copolymer of 4-methyl-1-pentene and α-olefin. In other words, the resin component substantially consists only of a copolymer of 4-methyl-1-pentene and α-olefin, and / or a modified product of the copolymer of 4-methyl-1-pentene and α-olefin. The statement that the resin component substantially consists only of a copolymer of 4-methyl-1-pentene and α-olefin, and / or a modified version of the copolymer of 4-methyl-1-pentene and α-olefin, means that the content of the copolymer of 4-methyl-1-pentene and α-olefin, and / or a modified version of the copolymer of 4-methyl-1-pentene and α-olefin, is, for example, 95% by mass or more, preferably 99% by mass or more, more preferably 99.9% by mass or more, and even more preferably 100% by mass, relative to the resin component.

[0036] If the resin component consists of a copolymer of 4-methyl-1-pentene and α-olefin, and / or a modified copolymer of 4-methyl-1-pentene and α-olefin, gas permeability can be improved.

[0037] (Copolymer of 4-methyl-1-pentene and α-olefin) The copolymer of 4-methyl-1-pentene and α-olefin is a polymerization product of 4-methyl-1-pentene and α-olefin having 2 to 20 carbon atoms.

[0038] Examples of α-olefins having 2 to 20 carbon atoms include linear α-olefins having 2 to 20 carbon atoms and branched α-olefins having 2 to 20 carbon atoms.

[0039] Examples of linear α-olefins having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

[0040] Examples of branched α-olefins having 2 to 20 carbon atoms include 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4,4-dimethyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4-ethyl-1-hexene, and 3-ethyl-1-hexene.

[0041] Preferably, the α-olefin having 2 to 20 carbon atoms is a linear α-olefin having 2 to 20 carbon atoms. More preferably, the α-olefin having 2 to 20 carbon atoms is a linear α-olefin having 2 to 4 carbon atoms. Even more preferably, the α-olefin having 2 to 20 carbon atoms is propylene.

[0042] α-olefins with 2 to 20 carbon atoms can be used alone or in combination of two or more types.

[0043] Furthermore, copolymers of 4-methyl-1-pentene and α-olefins are obtained by polymerizing 4-methyl-1-pentene with an α-olefin having 2 to 20 carbon atoms, based on the method described in International Publication No. 2004 / 87775. Specifically, copolymers of 4-methyl-1-pentene and α-olefins are obtained by polymerizing 4-methyl-1-pentene with an α-olefin having 2 to 20 carbon atoms in the presence of a metallocene catalyst.

[0044] This yields a copolymer of 4-methyl-1-pentene and α-olefin (a reaction solution containing the copolymer of 4-methyl-1-pentene and α-olefin).

[0045] In a copolymer of 4-methyl-1-pentene and α-olefin, the content of constituent units derived from 4-methyl-1-pentene is 50 mol% or more, preferably 60 mol% or more, and 99 mol% or less, preferably 90 mol% or less, relative to the total amount of constituent units derived from 4-methyl-1-pentene and constituent units derived from α-olefin.

[0046] If the content of constituent units derived from 4-methyl-1-pentene is above the lower limit mentioned above, gas permeability can be improved.

[0047] On the other hand, if the content of constituent units derived from 4-methyl-1-pentene is below the above lower limit, gas permeability decreases.

[0048] Furthermore, if the content of constituent units derived from 4-methyl-1-pentene is below the above upper limit, heat sealability and film formation properties can be improved.

[0049] On the other hand, if the content of constituent units derived from 4-methyl-1-pentene exceeds the above upper limit, the heat sealability and film-forming properties will decrease.

[0050] Furthermore, the amount of constituent units derived from α-olefins is 1 mol% or more, preferably 10 mol% or more, and 50 mol% or less, preferably 40 mol% or less, relative to the total amount of constituent units derived from 4-methyl-1-pentene and constituent units derived from α-olefins.

[0051] If the number of structural units derived from α-olefins is above the lower limit mentioned above, heat sealability and film formation properties can be improved.

[0052] On the other hand, if the number of constituent units derived from α-olefins is below the above lower limit, the heat sealability and film-forming properties will decrease.

[0053] Furthermore, if the constituent units derived from α-olefins are below the above upper limit, gas permeability can be improved.

[0054] On the other hand, if the constituent units derived from α-olefins exceed the above upper limit, gas permeability decreases.

[0055] Furthermore, the content ratio of constituent units derived from 4-methyl-1-pentene and the content ratio of constituent units derived from α-olefins are, for example, 13 This can be confirmed by known methods such as 13C-NMR measurement.

[0056] Furthermore, the weight-average molecular weight of the copolymer of 4-methyl-1-pentene and α-olefin, measured by GPC (gel permeation chromatography) and converted to standard polystyrene, is, for example, 10,000 or more, preferably 50,000 or more, more preferably 100,000 or more, even more preferably 300,000 or more, and also, for example, 500,000 or less, preferably 400,000 or less.

[0057] Furthermore, the weight-average molecular weight / number-average molecular weight (Mw / Mn) of the copolymer of 4-methyl-1-pentene and α-olefin is, for example, 1.5 or more, preferably 2.0 or more, and also, for example, 4.0 or less, preferably 3.0 or less.

[0058] Furthermore, the melting point of the copolymer of 4-methyl-1-pentene and α-olefin is either not observed, or, if observed, is for example 199°C or lower, preferably 150°C or lower, more preferably 140°C or lower, or for example 80°C or higher, preferably 100°C or higher.

[0059] If the melting point of the copolymer of 4-methyl-1-pentene and α-olefin is not observed, or if the melting point is below the above upper limit, the heat sealability can be further improved.

[0060] The melting point can be measured using a differential scanning calorimeter (the same applies hereafter). Furthermore, the absence of a observed melting point means that, in measurements using a differential scanning calorimeter, no crystal melting peak with a heat of fusion of 1 J / g or more is observed in the range of -150°C to 200°C.

[0061] (Modified copolymer of 4-methyl-1-pentene and α-olefin) Modified copolymers of 4-methyl-1-pentene and α-olefins (hereinafter sometimes referred to as "modified copolymers") are obtained by graft modification of the copolymer of 4-methyl-1-pentene and α-olefins with a graft component.

[0062] Examples of graft components include hydroxyl group-containing ethylenically unsaturated compounds, amino group-containing ethylenically unsaturated compounds, unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, vinyl ester compounds, and thiol group-containing ethylenically unsaturated compounds. Preferably, the graft component is an unsaturated carboxylic acid and / or an unsaturated carboxylic acid anhydride.

[0063] Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, norbornenedicarboxylic acid, and bicyclo[2,2,1]hepto-2-ene-5,6-dicarboxylic acid.

[0064] Examples of unsaturated carboxylic acid anhydrides include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and bicyclo[2,2,1]hepto-2-ene-5,6-dicarboxylic acid anhydride.

[0065] More preferably, unsaturated carboxylic acid anhydrides are used as graft components. Even more preferably, maleic anhydride is used as a graft component.

[0066] Graft components can be used individually or in combination of two or more types.

[0067] The modified product is obtained by graft modification of a copolymer of 4-methyl-1-pentene and α-olefin with a graft component.

[0068] To graft-modify a copolymer of 4-methyl-1-pentene and α-olefin using a graft component, for example, first, the copolymer is dissolved in a known organic solvent (e.g., toluene). Then, the graft component and a radical polymerization initiator are added, mixed, and heated (specifically, melt-mixed).

[0069] The amount of modification (introduction) of the graft component in the modified copolymer of 4-methyl-1-pentene and α-olefin, that is, the content ratio of constituent units derived from the graft component in the modified copolymer of 4-methyl-1-pentene and α-olefin, is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and for example, 10% by mass or less, preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 2.0% by mass or less, relative to the modified copolymer of 4-methyl-1-pentene and α-olefin.

[0070] The above-mentioned amount of modification is, for example, 1 This can be confirmed by known methods such as 1H-NMR measurement.

[0071] Examples of radical polymerization initiators include organic peroxides and organic peresters.

[0072] Examples of organic peroxides include dicumyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxybenzoate)hexine-3, 1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3, 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, tert-butylperoxybenzoate, and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane. Examples of organic peresters include tert-butyl peracetate, tert-butyl perphenyl acetate, tert-butyl perisobutyrate, tert-butyl persec-octoate, tert-butyl perpivalate, cumyl perpivalate, and tert-butyl perdiethyl acetate.

[0073] Preferably, organic peroxides are used as radical polymerization initiators. More preferably, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane is used as a radical polymerization initiator.

[0074] The proportion of the radical polymerization initiator is, for example, 0.001 parts by mass or more, and for example, 10 parts by mass or less, per 100 parts by mass of the copolymer of 4-methyl-1-pentene and α-olefin.

[0075] Radical polymerization initiators can be used alone or in combination of two or more types.

[0076] The heating temperature is, for example, 50°C or higher, preferably 80°C or higher, and also, for example, 250°C or lower. The reaction time is, for example, 1 minute or more, and also 10 hours or less.

[0077] This process involves graft modification of the copolymer of 4-methyl-1-pentene and α-olefin using graft components, yielding a modified product (a varnish of the modified product) of the copolymer of 4-methyl-1-pentene and α-olefin.

[0078] Furthermore, the weight-average molecular weight of the modified product, measured by GPC (gel permeation chromatography) and converted to standard polystyrene, is, for example, 10,000 or more, preferably 50,000 or more, more preferably 100,000 or more, even more preferably 200,000 or more, and also, for example, 500,000 or less, preferably 300,000 or less.

[0079] Furthermore, the weight-average molecular weight / number-average molecular weight (Mw / Mn) of the modified product is, for example, 1.5 or more, preferably 1.9 or more, and for example, 4.0 or less, preferably 3.0 or less.

[0080] Furthermore, the modified material either has no observed melting point, or, if a melting point is observed, its melting point is, for example, 199°C or lower, preferably 150°C or lower, more preferably 140°C or lower, and also, for example, 80°C or higher, preferably 100°C or higher.

[0081] If the modified material has no observed melting point, or if its melting point is below the above upper limit, the heat sealability can be further improved.

[0082] As described above, the resin component consists of a copolymer of 4-methyl-1-pentene and α-olefin, and / or a modified version of the copolymer of 4-methyl-1-pentene and α-olefin. Preferably, the resin component consists of a copolymer of 4-methyl-1-pentene and α-olefin without a modified version of the copolymer of 4-methyl-1-pentene and α-olefin, or it consists of a modified version of the copolymer of 4-methyl-1-pentene and α-olefin without a copolymer of 4-methyl-1-pentene and α-olefin.

[0083] Furthermore, since the resin component consists of a copolymer of 4-methyl-1-pentene and α-olefin, and / or a modified copolymer of 4-methyl-1-pentene and α-olefin, the resin component is substantially free of other thermoplastic resins. The fact that the resin component is substantially free of other thermoplastic resins means that the content of other thermoplastic resins is, for example, 5% by mass or less, preferably 1% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0% by mass, relative to the resin component.

[0084] Other thermoplastic resins include, for example, the thermoplastic resin (B) described in Japanese Patent Publication No. 2016-121322. Specifically, other thermoplastic resins include olefin polymers (polymers of α-olefins (excluding 4-methyl-1-pentene)).

[0085] The resin component can improve gas permeability if it contains virtually no other thermoplastic resins.

[0086] The resin component content is, for example, 80% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, and for example, 100% by mass or less, relative to the coating composition.

[0087] [Additives] The coating composition may also contain additives in appropriate proportions as needed.

[0088] Examples of additives include leveling agents, defoaming agents, antioxidants, heat stabilizers, UV absorbers, plasticizers, surfactants, pigments, thixotropes, thickeners, tackifiers, surface modifiers, anti-settling agents, weathering agents, pigment dispersants, antistatic agents, fillers, fungicides, and silane coupling agents.

[0089] Additives can be used individually or in combination of two or more types.

[0090] [Preparation of coating composition] The coating composition is prepared by mixing a resin component with additives, which are added as needed.

[0091] Furthermore, in the second step described later, the coating composition is dissolved with an organic solvent (described later) to prepare a varnish for the coating composition. The varnish for the coating composition is an organic solvent solution of the coating composition.

[0092] As will be explained in more detail later, the heat seal layer 3 is formed by applying the varnish of the coating composition to one side in the thickness direction of the substrate 2 and drying it.

[0093] The thickness of the heat seal layer 3 is, for example, 1 μm or more, preferably 3 μm or more, from the viewpoint of moldability, and, for example, less than 50 μm, preferably less than 20 μm, and more preferably 19 μm or less, from the viewpoint of improving heat sealability.

[0094] <Method for manufacturing laminates> An embodiment of a method for manufacturing a laminate will be described with reference to Figures 2A and 2B.

[0095] The method for manufacturing the laminate 1 comprises a first step of preparing a substrate 2, a second step of dissolving a coating composition in an organic solvent to prepare a varnish of the coating composition, and a third step of applying the varnish of the coating composition to one side of the substrate 2 in the thickness direction and drying it, thereby arranging a heat seal layer 3 on one side of the substrate 2 in the thickness direction.

[0096] [1st step] In the first step, the base material 2 is prepared as shown in Figure 2A.

[0097] [Second process] In the second step, the coating composition is dissolved in an organic solvent to prepare a varnish for the coating composition.

[0098] Examples of organic solvents include aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, ketones, alkyl esters, glycol ether esters, ethers, and polar aprotons. Examples of aliphatic hydrocarbons include n-hexane, n-heptane, and octane. Examples of alicyclic hydrocarbons include cyclohexane and methylcyclohexane. Examples of aromatic hydrocarbons include toluene and xylene. Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Examples of alkyl esters include methyl acetate, ethyl acetate, butyl acetate, and isobutyl acetate. Examples of glycol ether esters include methyl cellosolve acetate, ethyl cellosolve acetate, methyl carbitol acetate, ethyl carbitol acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, 3-methyl-3-methoxybutyl acetate, and ethyl-3-ethoxypropionate. Examples of ethers include diethyl ether, tetrahydrofuran, and dioxane. Examples of polar aprotons include N-methylpyrrolidone, dimethylformamide, N,N'-dimethylacetamide, dimethyl sulfoxide, and hexamethylphosphonylamide.

[0099] Preferred organic solvents include alicyclic hydrocarbons and / or alkyl esters. More preferably, methylcyclohexane and / or ethyl acetate are used as solvents.

[0100] Organic solvents can be used alone or in combination of two or more. Preferably, methylcyclohexane and ethyl acetate are used together as solvents.

[0101] The proportion of the organic solvent is, for example, 200 parts by mass or more, and for example, 1000 parts by mass or less, per 100 parts by mass of the resin component.

[0102] The solid content concentration of the varnish in the coating composition is, for example, 5% by mass or more, and for example, 70% by mass or less.

[0103] [3rd step] In the third step, as shown in Figure 2B, a varnish of the coating composition is applied to one side of the substrate 2 in the thickness direction and dried, thereby forming a heat seal layer 3 on one side of the substrate 2 in the thickness direction.

[0104] To apply the varnish of the coating composition to one surface in the thickness direction of the substrate 2, first, if necessary, the surface treatment of one surface in the thickness direction of the substrate 2 is performed.

[0105] Examples of surface treatments include corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, and saponification treatment, with corona treatment being preferred.

[0106] Next, the coating composition is applied to one side of the substrate 2 in the thickness direction by a known method, and if necessary, heated and dried.

[0107] The heating temperature is, for example, 50°C or higher, preferably 80°C or higher, and for example, 250°C or lower. The heating time is, for example, 10 seconds or more, and for example, 600 seconds or lower.

[0108] Further, particularly when the base material 2 is a non-woven fabric, after applying the coating composition to one surface in the thickness direction of the base material 2, from the viewpoint of allowing the coating composition to penetrate into the non-woven fabric, for example, it is allowed to stand for 1 hour, and for example, for 50 hours or less, and then heated and dried as necessary.

[0109] Thereby, a heat seal layer 3 which is a dried product of the varnish of the coating composition (that is, a dried product of the coating composition) is disposed (formed) on one surface in the thickness direction of the base material 2. Thus, the laminate 1 is manufactured.

[0110] And, as described above, such a laminate 1 includes a heat seal layer 3 which is a dried product of the coating composition. Therefore, it has excellent heat sealability.

[0111] Specifically, in the laminate 1, the peel strength measured by the following test is, for example, 2.0 N / 15 mm or more, preferably 4.0 N / 15 mm or more.

[0112] In the test, first, two laminates 1 are prepared. Next, the two laminates 1 are bonded together such that their heat seal layers 3 contact each other, and a film is manufactured by heat sealing under the conditions of 160 °C, 0.3 MPa, and 2 seconds. With respect to the film, at a tensile speed of 50 mm / min and a temperature of 23 °C, it is peeled in a direction of 180° with respect to the heat seal surface, and the peel strength is measured.

[0113] Also, the oxygen transmission coefficient and the carbon dioxide transmission coefficient of the laminate 1 are 1000 cm 3 ·mm / (m 2 ·24hr·atm) or more.

[0114] More specifically, the oxygen transmission coefficient is 1000 cm 3 ·mm / (m 2 ·24hr·atm) or more, preferably 1400 cm 3 ·mm / (m 2 ·24hr·atm) or more, and for example, 100000 cm 3 ·mm / (m2 (24hr·atm) or less.

[0115] Furthermore, the carbon dioxide transmission coefficient is 1000 cm 3 ·mm / (m 2 (24hr·atm) or more, preferably 2000cm 3 ·mm / (m 2 (24hr·atm) or more, more preferably 4000cm² 3 ·mm / (m 2 • 24hr·atm) or more, and for example, 200,000cm 3 ·mm / (m 2 (24hr·atm) or less.

[0116] The methods for measuring the oxygen permeability coefficient and carbon dioxide permeability coefficient will be described in detail in the examples described later.

[0117] Furthermore, such a laminate 1 is particularly suitable for use in packaging films because it has excellent gas permeability and heat sealability. Such a packaging film comprises the laminate 1. Therefore, it has excellent gas permeability and heat sealability.

[0118] <Effects and Effects> In this laminate 1, the coating composition includes a resin component consisting of a copolymer of 4-methyl-1-pentene and α-olefin, and / or a modified copolymer of 4-methyl-1-pentene and α-olefin. Therefore, gas permeability can be improved.

[0119] In detail, Patent Document 1 describes how, from the viewpoint of improving heat sealability, a polymer other than the polymer containing a structural unit derived from 4-methyl-1-pentene (specifically, thermoplastic resin (B)) is blended with thermoplastic resin (A). However, blending with thermoplastic resin (B) has the drawback of reducing gas permeability.

[0120] On the other hand, in this laminate 1, the resin component consists of a copolymer of 4-methyl-1-pentene and α-olefin, and / or a modified copolymer of 4-methyl-1-pentene and α-olefin. Therefore, the resin component is substantially free from other thermoplastic resins (specifically, thermoplastic resin (B) of Patent Document 1).

[0121] Therefore, the decrease in gas permeability caused by the incorporation of thermoplastic resin (B) can be suppressed. As a result, gas permeability can be improved.

[0122] Furthermore, in laminate 1, the heat seal layer 3 is a dried product of the coating composition. Therefore, it has excellent heat sealability. Specifically, in laminate 1, even if the base material 2 is a gas-permeable porous base material (preferably paper and nonwoven fabric) and has irregularities on its surface, the thickness of the heat seal layer 3 can be reduced (for example, to less than 50 μm), thereby improving heat sealability. [Examples]

[0123] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" and "%" are based on mass. Furthermore, specific numerical values ​​such as blending ratios (content), physical properties, and parameters used in the following description may be replaced with the corresponding upper limits (numerical values ​​defined as "less than or equal to" or "less than") or lower limits (numerical values ​​defined as "greater than or equal to" or "greater than") of the blending ratios (content), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0124] <Details of ingredients> The product names and abbreviations of the components used in each manufacturing example, each embodiment, and each comparative example are described in detail below. Paper: Product name "OK Blizzard", manufactured by Oji Materia Co., Ltd. Nonwoven fabric: Product name "Syntex PK102", manufactured by Mitsui Chemicals, Inc. TPX: A film made of a polymer of 4-methyl-1-pentene, trade name "Opulan XP-88B", manufactured by Mitsui Chemicals Tohcello Co., Ltd. Propylene-ethylene random copolymer: Prime PolyPro (registered trademark) F327, propylene-ethylene random copolymer, manufactured by Prime Polymer Co., Ltd.

[0125] <Preparation of a copolymer of 4-methyl-1-pentene and propylene> Manufacturing Example 1 In a 1.5 L stainless steel autoclave (capacity) equipped with stirring blades and thoroughly purged with nitrogen, 300 ml of n-hexane (dried on activated alumina under a dry nitrogen atmosphere) and 450 ml of 4-methyl-1-pentene were mixed at 23°C. Next, 0.75 ml of a toluene solution of 1.0 mmol / ml triisobutylaluminum (TIBAL) was added to this autoclave and stirred.

[0126] Next, the autoclave was heated to an internal temperature of 60°C and pressurized with propylene to a total pressure (gauge pressure) of 0.40 MPa.

[0127] Next, 0.34 ml of a toluene solution containing 1 mmol (in terms of Al) of methylaluminoxane and 0.01 mmol of diphenylmethylene (1-ethyl-3-t-butyl-cyclopentadienyl)(2,7-di-t-butyl-fluorenyl)zirconium dichloride, which had been prepared in advance, was injected into an autoclave under nitrogen pressure to initiate the polymerization reaction. During the polymerization reaction, the temperature inside the autoclave was adjusted to 60°C.

[0128] Sixty minutes after the start of polymerization, 5 ml of methanol was injected into the autoclave under pressure with nitrogen to stop the polymerization reaction, and then the autoclave was depressurized to atmospheric pressure. After depressurization, acetone was added to the reaction mixture while stirring. This yielded a reaction solution containing a copolymer of 4-methyl-1-pentene and propylene.

[0129] Next, the reaction solution containing the copolymer of 4-methyl-1-pentene and propylene was dried under reduced pressure at 100°C for 12 hours. This yielded 36.9 g of powdered 4-methyl-1-pentene and propylene copolymer.

[0130] The weight-average molecular weight of this copolymer was 337,000. The weight-average molecular weight / number-average molecular weight (Mw / Mn) of this copolymer was 2.1. The melting point of this copolymer was not observed. Furthermore, in this copolymer, the content of constituent units derived from 4-methyl-1-pentene was 73 mol%, and the content of constituent units derived from propylene was 27 mol%, relative to the total amount of constituent units derived from both methyl-1-pentene and propylene. Note that the above content percentages are... 13 The measurement was performed by 1C-NMR.

[0131] Manufacturing Example 2 Using the same procedure as in Production Example 1, 44.0 g of a copolymer of powdered 4-methyl-1-pentene and propylene was obtained. However, in Production Example 2, the copolymer was pressurized with propylene to a total pressure (gauge pressure) of 0.19 MPa.

[0132] The weight-average molecular weight of this copolymer was 340,000. The weight-average molecular weight / number-average molecular weight (Mw / Mn) of this copolymer was 2.1. The melting point of this copolymer was 132°C. Furthermore, in this copolymer, the content of constituent units derived from 4-methyl-1-pentene was 85 mol%, and the content of constituent units derived from propylene was 15 mol%, relative to the total amount of constituent units derived from both methyl-1-pentene and propylene. Note that the above content percentages are... 13 The measurement was performed by 1C-NMR.

[0133] <Preparation of maleic anhydride-modified copolymer of 4-methyl-1-pentene and propylene> Production Example 3 The copolymer of 4-methyl-1-pentene and propylene from Production Example 1 was charged into the resin charging section of a twin-screw compounding extruder with a vent. Furthermore, as a graft component, maleic anhydride was added at a rate of 2 parts by mass per 100 parts by mass of the copolymer of 4-methyl-1-pentene and propylene, and as a radical polymerization initiator, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane was added at a rate of 0.4 parts by mass per 100 parts by mass of the copolymer of 4-methyl-1-pentene and propylene.

[0134] Next, the copolymer of 4-methyl-1-pentene and propylene, the graft component, and the radical polymerization initiator were melt-kneaded at 190°C. The mixture was then discharged from a kneading extruder and cooled. After cooling, it was pelletized in a pelletizer. This yielded a maleic anhydride-modified copolymer of 4-methyl-1-pentene and propylene.

[0135] The weight-average molecular weight of this modified product was 231,000. The weight-average molecular weight / number-average molecular weight (Mw / Mn) ratio of this modified product was 2.0. The melting point of this modified product was not observed. Furthermore, the amount of modification (introduction) of the graft component in the maleic anhydride-modified copolymer of 4-methyl-1-pentene and propylene was 0.9% by mass. Note that the above modification amount is... 1 The measurement was performed by 1H-NMR.

[0136] Manufacturing Example 4 A maleic anhydride-modified copolymer of 4-methyl-1-pentene and propylene was obtained using the same procedure as in Production Example 3. However, in Production Example 4, the copolymer of 4-methyl-1-pentene and propylene from Production Example 2 was used instead of the copolymer of 4-methyl-1-pentene and propylene from Production Example 1.

[0137] The weight-average molecular weight of this modified product was 208,000. The weight-average molecular weight / number-average molecular weight (Mw / Mn) of this modified product was 2.1. The melting point of this modified product was 132°C. Furthermore, the amount of modification (introduction) of the graft component in the maleic anhydride-modified copolymer of 4-methyl-1-pentene and propylene was 1.8% by mass. Note that the above modification amount is... 1 The measurement was performed by 1H-NMR.

[0138] <Production of maleic anhydride-modified propylene / 1-butene copolymer> Manufacturing Example 5 In a thoroughly nitrogen-purged autoclave (2 L capacity), 900 ml of hexane and 90 g of 1-butene were added, followed by 1 mmol of triisobutylaluminum, and the temperature was raised to 70°C. Then, propylene was supplied to a total pressure of 7 kg / cm². 2 Set to G, add 0.30 mmol of methylaluminoxane and 0.001 mmol of rac-dimethylsilylene-bis{1-(2-methyl-4-phenylindenyl)}zirconium dichloride (calculated as Zr atoms), and continuously supply propylene to a total pressure of 7 kg / cm². 2 The polymerization reaction was carried out for 30 minutes while maintaining a constant temperature of G. After the polymerization reaction, the polymer was degassed and recovered in a large amount of methanol, and dried under reduced pressure at 110°C for 12 hours. This yielded a propylene / 1-butene copolymer.

[0139] The weight-average molecular weight of the propylene / 1-butene copolymer was 300,000. The melting point of the weight-average molecular weight was 78.3°C. Furthermore, in this copolymer, the content of propylene-derived components was 75 mol%, and the content of 1-butene-derived components was 25 mol%, relative to the total amount of propylene-derived components and 1-butene-derived components. Note that the above content ratios are as follows: 13 The measurement was performed by 1C-NMR.

[0140] Next, 3 kg of propylene / 1-butene copolymer was added to 10 L of toluene and heated to 145°C under a nitrogen atmosphere to dissolve the propylene / 1-butene copolymer in toluene. Furthermore, under stirring, 382 g of maleic anhydride and 175 g of di-tert-butyl peroxide as a radical polymerization initiator were added over 4 hours, and the mixture was stirred at 145°C for 2 hours. This yielded maleic anhydride-modified propylene / 1-butene copolymer. After that, the mixture was cooled, a large amount of acetone was added to precipitate the maleic anhydride-modified propylene / 1-butene copolymer, then filtered, washed with acetone, and vacuum dried.

[0141] The weight-average molecular weight (Mw) of the maleic anhydride-modified propylene / 1-butene copolymer was 100,000. The melting point of the maleic anhydride-modified propylene / 1-butene copolymer was 75.8°C. Furthermore, the amount of maleic anhydride modification in the maleic anhydride-modified propylene / 1-butene copolymer was 0.8% by mass. Note that the above modification amount is 1 The measurement was performed by 1H-NMR.

[0142] <Preparation of 4-methyl-1-pentene homopolymer> Manufacturing Example 6 Using the same procedure as in Production Example 1, 36.9 g of powdered 4-methyl-1-pentene homopolymer was obtained. However, in Production Example 6, no pressurization with propylene was performed.

[0143] The weight-average molecular weight of this polymer was 337,000. The weight-average molecular weight / number-average molecular weight ratio (Mw / Mn) of this polymer was 2.1. The melting point of this copolymer was 222°C.

[0144] <Manufacturing of laminates> Example 1 [1st step] Paper was prepared as the base material.

[0145] [Second process] In a 5L flask thoroughly purged with nitrogen, 650 parts by mass of the copolymer from Production Example 1, 1040 parts by mass of ethyl acetate, and 1560 parts by mass of methylcyclohexane were charged. The mixture was heated to 70°C and dissolved for 3 hours. After that, it was cooled to below 60°C. This prepared a varnish for the coating composition. The solid content concentration of the varnish for the coating composition was 20% by mass.

[0146] [3rd step] The varnish of the above coating composition was applied to one side of the substrate in the thickness direction and dried at 100°C for 1 minute. This created a heat-seal layer (film thickness after drying: 19 μm) on one side of the substrate in the thickness direction. A laminate was then manufactured.

[0147] Examples 2-6, Comparative Example 1, Comparative Example 2, and Comparative Example 4 Laminates were manufactured following the same procedure as in Example 1. However, the type of substrate and the composition of the varnish in the coating composition were changed as described in Table 1. In Example 5 and Comparative Example 2, the varnish of the above coating composition was applied to one side in the thickness direction of the substrate, left to stand at room temperature for 5 hours, and then dried at 100°C for 1 minute.

[0148] Comparative Example 3 Sixty parts by mass of the copolymer from Production Example 1 and fourty parts by mass of the propylene-ethylene random copolymer were mixed (dry blended) to obtain a mixture. Next, the mixture was fed into the hopper of a 20 mmφ single-screw extruder (single-screw sheet forming machine, manufactured by Tanaka Iron Works Co., Ltd.) equipped with a T-die with a lip width of 240 mm. The cylinder temperature and die temperature were set to 230°C, and the molten mixture was extruded from the T-die to a thickness of 50 μm, thereby casting it onto one side in the thickness direction of the paper. This produced a laminate.

[0149] <Rating> [Gas permeability] For each example and each comparative example, the oxygen permeability coefficient (unit: cm) is as follows: 3 ·mm / (m 2 (24h·atm) and carbon dioxide transmission coefficient (unit: cm)3 ·mm / (m 2 The temperature (24 hours atm) was measured.

[0150] Specifically, first, the laminates of each example and each comparative example were molded into a shape of 30 mm in width and 30 mm in length.

[0151] Next, in accordance with JIS K7126-1, a differential pressure method gas permeability measuring device (manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used to measure the laminate's surface area at a test temperature of 23°C and a test humidity of 0%RH, with a measurement area of ​​7cm². 2 The measurement was performed using the following method. The measurement area of ​​the laminate was adjusted by preparing two adhesive aluminum masks manufactured by Modern Control, each with a 25 mm diameter hole in the center, and stacking the sample to be measured between these two masks. Specifically, the film was positioned so that the central holes of the two masks overlapped. The results are shown in Table 1.

[0152] [Heat sealability] Two laminates were prepared by cutting the laminates of each example and comparative example into strips measuring 150 mm in width and 50 mm in length. The two laminates were bonded together so that their heat-seal layers were in contact with each other, and a film was manufactured by heat-sealing them using a heat-seal tester (thermal gradient heat-seal tester TP-701-B, manufactured by Tester Sangyo Co., Ltd.) under the conditions of a seal width of 5 mm, a temperature of 160°C, a seal pressure of 0.3 MPa, and a seal time of 2 seconds. The peel strength (unit: N / 15 mm) of the film was measured by peeling it at a 180° angle to the heat-sealed surface using an Intesco precision tester (210N model (manufactured by Intesco Corporation)) at a tensile speed of 50 mm / min and a temperature of 23°C. The test was performed five times, and the average values ​​are shown in Table 1.

[0153] [Table 1]

[0154] The above invention is provided as an illustrative embodiment of the present invention, but this is merely illustrative and should not be interpreted restrictively. Modifications of the present invention that are obvious to those skilled in the art are included in the claims below. [Industrial applicability]

[0155] The laminate, packaging film, and method for manufacturing the laminate of the present invention are suitably used, for example, in packaging materials.

Claims

1. A laminate comprising a base material and a heat-seal layer arranged sequentially toward one side in the thickness direction, The heat seal layer is a dried product of the coating composition. The coating composition comprises a resin component, The resin component consists of a copolymer of 4-methyl-1-pentene and an α-olefin having 2 to 20 carbon atoms (excluding 4-methyl-1-pentene), and / or a modified form of the copolymer. In the copolymer, the content ratio of the constituent units derived from 4-methyl-1-pentene is 50 mol% or more and 99 mol% or less relative to the total amount of constituent units derived from 4-methyl-1-pentene and the constituent units derived from α-olefin, and the content ratio of the constituent units derived from α-olefin is 1 mol% or more and 50 mol% or less. The oxygen permeability coefficient and carbon dioxide permeability coefficient of the aforementioned laminate are 1000 cm². ３ mm / (m) ２ • 24hr·atm) or higher, The content ratio of the resin component is 80% by mass or more relative to the coating composition. A laminate in which the peel strength measured by the following test exceeds 2.0 N / 15 mm. Test: Prepare two laminates. Bond the two laminates together so that their heat-seal layers are in contact, and heat-seal them at 160°C, 0.3 MPa, and for 2 seconds to produce a film. The film is peeled at a 180° angle to the heat-sealed surface under conditions of a tensile speed of 50 mm / min and a temperature of 23°C, and the peel strength is measured.

2. The laminate according to claim 1, wherein the substrate is a gas-permeable porous substrate or a substrate made of a polymer of 4-methyl-1-pentene.

3. The laminate according to claim 1, wherein the thickness of the heat seal layer is 1 μm or more and less than 50 μm.

4. A packaging film comprising the laminate described in claim 1.

5. A method for manufacturing a laminate according to claim 1, The first step is to prepare the aforementioned substrate, The second step involves dissolving the coating composition in an organic solvent to prepare a varnish, A method for manufacturing a laminate, comprising a third step of applying the varnish to one surface in the thickness direction of the substrate and drying it to form a heat seal layer.

Images