Dispersion, adhesive composition, laminate, and method for producing dispersion

Abstract

To provide a dispersion having excellent adhesiveness and dispersibility, an adhesive composition containing the dispersion, a laminate obtained using the dispersion, and a method for producing the dispersion.SOLUTION: The dispersion contains an ethylene-(meth)acrylic acid-(meth)acrylate copolymer (A), a basic compound (B), an organic solvent (C), and water (D). The content ratio of a structural unit derived from (meth)acrylic acid is 6 mass% or more and 11 mass% or less based on the total amount of the ethylene-(meth)acrylic acid-(meth)acrylate copolymer (A). The organic solvent (C) has a dielectric constant at 25°C of 7.0 or more and 37.0 or less. The content ratio of the organic solvent (C) is 1 mass% or more and 45 mass% or less based on the total amount of the organic solvent (C) and the water (D).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to dispersions, adhesive compositions, laminates, and methods for making the dispersions. [Background technology]

[0002] Conventionally, ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymers have been known. The ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer is a polyolefin resin obtained by copolymerizing ethylene, an unsaturated carboxylic acid, and an unsaturated carboxylic acid ester. The ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer is prepared, for example, as an oil-based solvent dispersion and used as an adhesive.

[0003] On the other hand, in recent years, from the viewpoint of environmental friendliness, there has been a demand for a reduction in the amount of oil-based solvents used, and therefore, a dispersion in which an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer is dispersed in an aqueous solvent has been investigated.

[0004] For example, the following polyolefin resin aqueous dispersion has been proposed. The polyolefin resin aqueous dispersion contains a polyolefin resin, ethylene glycol-n-butyl ether, N,N-dimethanolamine, and distilled water. The polyolefin resin contains 91% by mass of ethylene, 3% by mass of maleic anhydride, and 6% by mass of ethyl acrylate (see, for example, Patent Document 1 (Example 1)). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-119328 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the dispersibility of the polyolefin resin aqueous dispersion may be insufficient, and there is a demand for the polyolefin resin aqueous dispersion to have better adhesiveness.

[0007] The present invention relates to a dispersion having excellent adhesive properties and dispersibility, an adhesive composition containing the dispersion, a laminate obtained using the dispersion, and a method for producing the dispersion. [Means for solving the problem]

[0008] The present invention [1] comprises a dispersion comprising an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), a basic compound (B), an organic solvent (C), and water (D), wherein the content of structural units derived from (meth)acrylic acid is 6% by mass or more and 11% by mass or less relative to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), the dielectric constant of the organic solvent (C) at 25°C is 7.0 or more and 37.0 or less, and the content of the organic solvent (C) is 1% by mass or more and 45% by mass or less relative to the total amount of the organic solvent (C) and the water (D).

[0009] The present invention [2] includes the dispersion according to the above [1], in which the organic solvent (C) includes an alcohol having 1 to 4 carbon atoms.

[0010] The present invention [3] includes an adhesive composition containing the dispersion described in [1] or [2] above.

[0011] The present invention [4] includes a laminate comprising a substrate and a resin layer disposed on at least one side of the substrate, the resin layer including a dried product of the dispersion described in [1] or [2] above.

[0012] The present invention [5] includes a method for producing a dispersion, the method comprising: a preparation step of preparing an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), a basic compound (B), an organic solvent (C), and water (D); and a mixing step of mixing and heating the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), the basic compound (B), the organic solvent (C), and the water (D), wherein the content of structural units derived from (meth)acrylic acid is 6% by mass or more and 11% by mass or less relative to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), the dielectric constant of the organic solvent (C) at 25°C is 7.0 or more and 37.0 or less, and the content of the organic solvent (C) is 1% by mass or more and 45% by mass or less relative to the total amount of the organic solvent (C) and the water (D). [Effects of the Invention]

[0013] The dispersion of the present invention contains an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), a basic compound (B), an organic solvent (C), and water (D). The content of structural units derived from (meth)acrylic acid is 6% by mass or more and 11% by mass or less, based on the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A). The dielectric constant of the organic solvent (C) at 25°C is 7.0 or more and 37.0 or less. The content of the organic solvent (C) is 1% by mass or more and 45% by mass or less, based on the total amount of the organic solvent (C) and water (D). Therefore, the dispersion of the present invention has excellent dispersibility and adhesiveness.

[0014] The adhesive composition of the present invention contains the above-mentioned dispersion, and therefore has excellent dispersibility and adhesive properties.

[0015] The laminate of the present invention is obtained using the above dispersion, and therefore has excellent adhesiveness.

[0016] According to the method for producing a dispersion of the present invention, the above-mentioned dispersion can be obtained efficiently. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram showing one embodiment of the laminate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] 1. Dispersion The dispersion of the present invention contains an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), a basic compound (B), an organic solvent (C), and water (D).

[0019] (1) Ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) The ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is obtained by copolymerization of raw material monomer components, which contain ethylene, (meth)acrylic acid, and a (meth)acrylic acid ester.

[0020] The (meth)acrylic acid is acrylic acid and / or methacrylic acid. The same applies to (meth)acrylic acid esters described below. As the (meth)acrylic acid, methacrylic acid is preferable.

[0021] Examples of (meth)acrylic acid esters include (meth)acrylic acid alkyl esters, preferably (meth)acrylic acid alkyl esters having an alkyl moiety with 1 to 12 carbon atoms. More specific examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate. These may be used alone or in combination of two or more.

[0022] The (meth)acrylic acid alkyl ester is preferably a (meth)acrylic acid alkyl ester having an alkyl moiety with 1 to 4 carbon atoms. More specifically, examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and isobutyl (meth)acrylate.

[0023] More preferred examples of the (meth)acrylic acid alkyl ester include (meth)acrylic acid alkyl esters having an alkyl moiety with a carbon number of 2 to 4. More specific examples include ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and isobutyl (meth)acrylate.

[0024] More preferred examples of the (meth)acrylic acid alkyl ester include butyl acrylate and isobutyl acrylate, and even more preferred example is isobutyl acrylate.

[0025] The raw material monomer component may contain other copolymerizable monomers as needed. Examples of other copolymerizable monomers include known hydroxyl group-containing vinyl monomers, known amino group-containing vinyl monomers, known glycidyl group-containing vinyl monomers, known cyano group-containing vinyl monomers, known sulfonic acid group-containing vinyl monomers, known acetoacetoxy group-containing vinyl monomers, known phosphoric acid group-containing vinyl monomers, known amide group-containing vinyl monomers, known aromatic vinyl monomers, known N-substituted unsaturated carboxylic acid amides, known heterocyclic vinyl compounds, known vinylidene halide compounds, known α-olefins, known dienes, and known vinyl esters. These may be used alone or in combination of two or more.

[0026] The content of the other copolymerizable monomer in the raw material monomer components is appropriately adjusted within a range that does not impair the excellent effects of the present invention. For example, the content of the other copolymerizable monomer relative to the total amount of the raw material monomer components is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 1% by mass or less, and particularly preferably 0% by mass.

[0027] That is, the raw material monomer component preferably does not contain any other copolymerizable monomers and is composed of ethylene, (meth)acrylic acid, and a (meth)acrylic acid ester.

[0028] The ethylene content relative to the total amount of the raw material monomer components is, for example, 60% by mass or more, preferably 65% ​​by mass or more, more preferably 70% by mass or more, and for example, 90% by mass or less, preferably 80% by mass or less, more preferably 75% by mass or less, relative to the total amount of the raw material monomer components.

[0029] The content of (meth)acrylic acid relative to the total amount of raw material monomer components is 6% by mass or more, preferably 7% by mass or more, more preferably 8% by mass or more, and 11% by mass or less, preferably 10% by mass or less, more preferably 9% by mass or less, relative to the total amount of raw material monomer components.

[0030] The content of the (meth)acrylic acid ester relative to the total amount of the raw material monomer components is, for example, 4% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, and for example, 29% by mass or less, preferably 25% by mass or less, more preferably 20% by mass or less, relative to the total amount of the raw material monomer components.

[0031] The polymerization method of the raw material monomer components is not particularly limited, and known methods can be used. For example, the raw material monomer components are contacted with a known polymerization initiator (such as a peroxide) under high temperature and high pressure conditions. This results in an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) as the polymerization product of the raw material monomer components.

[0032] The ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) contains structural units derived from ethylene, structural units derived from (meth)acrylic acid, and structural units derived from a (meth)acrylic acid ester. Preferably, the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) comprises structural units derived from ethylene, structural units derived from (meth)acrylic acid, and structural units derived from a (meth)acrylic acid ester.

[0033] The content ratio of structural units derived from ethylene to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is calculated as the content ratio of ethylene to the total amount of the raw material monomer components.

[0034] The content of structural units derived from ethylene relative to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is, for example, 60% by mass or more, preferably 65% ​​by mass or more, more preferably 70% by mass or more. The content of structural units derived from ethylene relative to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is, for example, 90% by mass or less, preferably 80% by mass or less, more preferably 75% by mass or less.

[0035] The content ratio of structural units derived from (meth)acrylic acid to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is calculated as the content ratio of (meth)acrylic acid to the total amount of the raw material monomer components.

[0036] The content of structural units derived from (meth)acrylic acid relative to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is 6% by mass or more, preferably 7% by mass or more, more preferably 8% by mass or more. The content of structural units derived from (meth)acrylic acid relative to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is 11% by mass or less, preferably 10% by mass or less, more preferably 9% by mass or less.

[0037] The content ratio of structural units derived from (meth)acrylic acid ester relative to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is calculated as the content ratio of (meth)acrylic acid ester relative to the total amount of raw material monomer components.

[0038] The content of structural units derived from (meth)acrylic acid ester relative to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is, for example, 4% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more. The content of structural units derived from (meth)acrylic acid ester relative to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is, for example, 29% by mass or less, preferably 25% by mass or less, more preferably 20% by mass or less.

[0039] The melt flow rate (MFR; ASTM D1238, 2.16 kg load) of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) at 190°C is, for example, 0.1 g / 10 min or more, preferably 1.0 g / 10 min or more, more preferably 10 g / 10 min or more, even more preferably 30 g / 10 min or more, and particularly preferably 50 g / 10 min or more. The melt flow rate (MFR; ASTM D1238, 2.16 kg load) of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) at 190°C is, for example, 300 g / 10 min or less, preferably 200 g / 10 min or less, more preferably 100 g / 10 min or less, even more preferably 80 g / 10 min or less, and particularly preferably 60 g / 10 min or less.

[0040] The melting point of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is, for example, 100°C or lower, or preferably 90°C or lower.

[0041] The ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is available as a commercial product.

[0042] The ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is not particularly limited as long as the content of structural units derived from (meth)acrylic acid is within the above range. These can be used alone or in combination of two or more kinds.

[0043] The content of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, based on the total amount of the dispersion. The content of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is, for example, 40% by mass or less, preferably 30% by mass or less, more preferably 25% by mass or less, based on the total amount of the dispersion.

[0044] (2) Basic Compound (B) The basic compound (B) is a neutralizing agent for neutralizing the carboxyl groups derived from the (meth)acrylic acid of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A).

[0045] Examples of the basic compound (B) include inorganic basic compounds and organic basic compounds. Examples of inorganic basic compounds include sodium hydroxide and potassium hydroxide. Examples of organic basic compounds include amines. Examples of amines include ammonia, triethylamine, triethanolamine, dimethylethanolamine, diethanolamine, diethylamine (DEA), and N,N-dimethylethanolamine (DMEA). These can be used alone or in combination of two or more.

[0046] The basic compound (B) is preferably an organic basic compound, more preferably an amine, even more preferably diethylamine (DEA) and N,N-dimethylethanolamine (DMEA), and particularly preferably diethylamine (DEA).

[0047] The content of the basic compound (B) is appropriately set depending on the content of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A). The content of the basic compound (B) is also appropriately set depending on the content of structural units derived from (meth)acrylic acid in the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A).

[0048] More specifically, the content of the basic compound (B) is, for example, 0.1 mass% or more, preferably 0.5 mass% or more, more preferably 1.0 mass% or more, relative to the total amount of the dispersion, and for example, 5.0 mass% or less, preferably 3.0 mass% or less, more preferably 1.5 mass% or less, relative to the total amount of the dispersion.

[0049] The content of the basic compound (B) is, for example, 0.5 parts by mass or more, preferably 3.0 parts by mass or more, more preferably 5.0 parts by mass or more, per 100 parts by mass of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A). The content of the basic compound (B) is, for example, 25 parts by mass or less, preferably 15 parts by mass or less, more preferably 10 parts by mass or less, per 100 parts by mass of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A).

[0050] The content of the basic compound (B) is, for example, 0.5 mol or more, preferably 0.6 mol or more, more preferably 0.7 mol or more, relative to 1 mol of carboxy groups in the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A). The content of the basic compound (B) is, for example, 2.0 mol or less, preferably 1.5 mol or less, more preferably 1.2 mol or less, relative to 1 mol of carboxy groups in the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A).

[0051] That is, the degree of neutralization ([equivalent of basic compound / carboxy group equivalent of ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A)]×100) is, for example, 50 mol% or more, preferably 70 mol% or more, and more preferably 80 mol% or more. Also, the degree of neutralization ([equivalent of basic compound / carboxy group equivalent of ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A)]×100) is, for example, 150 mol% or less, preferably 100 mol% or less, and more preferably 90 mol% or less.

[0052] (3) Organic solvent (C) The organic solvent (C) is a dispersion medium for dispersing the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) together with water (D) described below.

[0053] In other words, in the dispersion, the dispersion medium contains the organic solvent (C) and water (D), and preferably consists of the organic solvent (C) and water (D).

[0054] As the organic solvent (C), an organic solvent having a predetermined relative dielectric constant (dimensionless) is selected.

[0055] More specifically, the dielectric constant of the organic solvent (C) at 25° C. is 7.0 or more, preferably 10.0 or more, more preferably 15.0 or more, even more preferably 18.0 or more, and particularly preferably 20.0 or more. When the dielectric constant of the organic solvent (C) is above the lower limit, excellent dispersibility and adhesiveness can be obtained.

[0056] The dielectric constant of the organic solvent (C) at 25°C is 37.0 or less, preferably 34.0 or less, more preferably 28.0 or less, even more preferably 25.0 or less, and particularly preferably 23.0 or less. When the dielectric constant of the organic solvent (C) is below the upper limit, excellent dispersibility and adhesiveness can be obtained.

[0057] The relative dielectric constant is measured by a known method, for example, by a method in accordance with JIS C 2138 (2007).

[0058] More specific examples of the organic solvent (C) having the above-mentioned dielectric constant include alcohols having the above-mentioned dielectric constant, ethers having the above-mentioned dielectric constant, ketones having the above-mentioned dielectric constant, nitriles having the above-mentioned dielectric constant, amines having the above-mentioned dielectric constant, and amides having the above-mentioned dielectric constant.

[0059] Examples of alcohols having the above-mentioned dielectric constant include alcohols having 1 to 4 carbon atoms. Examples of alcohols having 1 to 4 carbon atoms include aliphatic alkyl alcohols having 1 to 4 carbon atoms and ether alcohols having 1 to 4 carbon atoms. Examples of aliphatic alkyl alcohols having 1 to 4 carbon atoms include methanol (dielectric constant (25°C) 33.1), ethanol (dielectric constant (25°C) 23.8), n-propanol (dielectric constant (25°C) 22.2), isopropanol (dielectric constant (25°C) 18.3), and n-butanol (dielectric constant (25°C) 17.1). Examples of ether alcohols having 1 to 4 carbon atoms include methyl cellosolve (dielectric constant (25°C) 16.9).

[0060] Examples of ethers having the above-mentioned dielectric constant include ethers having 1 to 4 carbon atoms. Examples of ethers having 1 to 4 carbon atoms include 1,2-dimethoxyethane (dielectric constant (25°C) 7.2) and tetrahydrofuran (dielectric constant (25°C) 7.6).

[0061] Examples of ketones having the above dielectric constant include acetone (dielectric constant (25° C.) 20.7) and acetylacetone (dielectric constant (25° C.) 27.2).

[0062] An example of a nitrile having the above-mentioned relative dielectric constant is benzonitrile (relative dielectric constant (25° C.) 25.2).

[0063] An example of an amine having the above-mentioned relative dielectric constant is ethylenediamine (relative dielectric constant (25° C.) 12.9).

[0064] Examples of amides having the above dielectric constant include N,N-dimethylformamide (dielectric constant (25°C) 36.7), hexamethylphosphoramide (dielectric constant (25°C) 29.6), and N-methylpyrrolidone (dielectric constant (25°C) 32.0).

[0065] These solvents can be used alone or in combination of two or more. When two or more solvents are used in combination, that is, when the solvent is a mixed solvent, the relative dielectric constant of the mixed solvent is the weighted arithmetic mean of the relative dielectric constants of the individual solvents. The weighted arithmetic mean is calculated based on the mass fraction of each solvent.

[0066] In addition, as long as the relative dielectric constant (weighted arithmetic mean value) of the organic solvent (C) is within the above range, the organic solvent (C) may contain a solvent that does not have the above relative dielectric constant by itself.

[0067] Examples of solvents that do not have the above dielectric constant by themselves include glycerin (dielectric constant (25°C) 42.5) and ethyl acetate (dielectric constant (25°C) 6.0). These can be used alone or in combination of two or more.

[0068] The content of the solvent that does not have the above-mentioned relative dielectric constant by itself is appropriately set within a range that does not impair the excellent effects of the present invention.

[0069] More specifically, the content of the solvent that does not have the above-mentioned relative dielectric constant by itself is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0% by mass, relative to the total amount of the organic solvent (C). That is, the organic solvent (C) preferably consists of a solvent that has the above-mentioned relative dielectric constant by itself.

[0070] In order to achieve both dispersibility and adhesiveness, the organic solvent (C) is preferably an organic solvent having a predetermined solubility parameter (SP value).

[0071] More specifically, from the viewpoint of achieving both dispersibility and adhesiveness, the solubility parameter (SP value) of the organic solvent (C) calculated according to the Fedors method is, for example, 8.00 (cal / cm 3 ) 1 / 2 More than 9.00 (cal / cm 3 ) 1 / 2 More preferably, 10.00 (cal / cm 3 )1 / 2 More preferably, 11.00 (cal / cm 3 ) 1 / 2 More preferably, 11.50 (cal / cm 3 ) 1 / 2 That is all. If the solubility parameter (SP value) of the organic solvent (C) is above the lower limit, better dispersibility and adhesiveness can be obtained.

[0072] In order to achieve both dispersibility and adhesiveness, the solubility parameter (SP value) of the organic solvent (C) calculated according to the Fedors method is, for example, 16.00 (cal / cm 3 ) 1 / 2 Preferably, 15.00 (cal / cm 3 ) 1 / 2 Less than or equal to 14.00 (cal / cm 3 ) 1 / 2 More preferably, 13.00 (cal / cm 3 ) 1 / 2 Particularly preferably, 12.00 (cal / cm 3 ) 1 / 2 If the solubility parameter (SP value) of the organic solvent (C) is below the above upper limit, better dispersibility and adhesiveness can be obtained.

[0073] An example of a solvent having the above solubility parameter is methanol (SP value 13.77 (cal / cm 3 ) 1 / 2 ), ethanol (SP value 12.58 (cal / cm 3 ) 1 / 2 ), n-propanol (SP value 11.84 (cal / cm 3 ) 1 / 2 ), isopropanol (SP value 11.58 (cal / cm 3 ) 1 / 2 ), n-butanol (SP value 11.33 (cal / cm 3 ) 1 / 2 ), and tetrahydrofuran (SP value 9.00 (cal / cm 3 ) 1 / 2 ) are mentioned.

[0074] Solvents having the above solubility parameters can be used alone or in combination of two or more. When two or more solvents are used in combination, i.e., when the solvent is a mixed solvent, the solubility parameter of the mixed solvent is the weighted geometric mean of the solubility parameters of each solvent. The weighted geometric mean is calculated based on the mass fraction of each solvent.

[0075] From the viewpoint of achieving both dispersibility and adhesiveness, the organic solvent (C) is more preferably an alcohol or an ether, more preferably an alcohol having 1 to 4 carbon atoms and an ether having 1 to 4 carbon atoms, even more preferably an alcohol having 1 to 4 carbon atoms, even more preferably an alkyl alcohol having 1 to 4 carbon atoms, and particularly preferably n-propanol.

[0076] The content of the organic solvent (C) relative to the total amount of the dispersion is, for example, 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, and for example, 40% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, relative to the total amount of the dispersion.

[0077] The content of the organic solvent (C) is, for example, 0.5 parts by mass or more, preferably 3 parts by mass or more, more preferably 5 parts by mass or more, per 100 parts by mass of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A). The content of the organic solvent (C) is, for example, 200 parts by mass or less, preferably 150 parts by mass or less, more preferably 100 parts by mass or less, per 100 parts by mass of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A).

[0078] (4) Water (D) Water (D) is a dispersion medium for dispersing the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) together with the organic solvent (C).

[0079] The content of water (D) relative to the total amount of the dispersion is, for example, 40% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, and for example, 80% by mass or less, preferably 75% by mass or less, more preferably 70% by mass or less, relative to the total amount of the dispersion.

[0080] The content of water (D) is, for example, 50 parts by mass or more, preferably 100 parts by mass or more, more preferably 200 parts by mass or more, per 100 parts by mass of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A). The content of water (D) is, for example, 900 parts by mass or less, preferably 700 parts by mass or less, more preferably 500 parts by mass or less, per 100 parts by mass of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A).

[0081] The content of water (D) relative to 100 parts by mass of organic solvent (C) is, for example, 120 parts by mass or more, preferably 150 parts by mass or more, more preferably 185 parts by mass or more, even more preferably 230 parts by mass or more, and particularly preferably 300 parts by mass or more. The content of water (D) relative to 100 parts by mass of organic solvent (C) is, for example, 9900 parts by mass or less, preferably 2000 parts by mass or less, more preferably 900 parts by mass or less, and even more preferably 500 parts by mass or less.

[0082] The content of water (D) relative to the total amount of organic solvent (C) and water (D) is, for example, 55% by mass or more, preferably 60% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, and particularly preferably 75% by mass or more. The content of water (D) relative to the total amount of organic solvent (C) and water (D) is, for example, 99% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

[0083] In other words, the content of organic solvent (C) is 1% by mass or more, preferably 3% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and particularly preferably 15% by mass or more, based on the total amount of organic solvent (C) and water (D). Also, the content of organic solvent (C) is 45% by mass or less, preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less, and particularly preferably 25% by mass or less, based on the total amount of organic solvent (C) and water (D).

[0084] When the content of the organic solvent (C) and the content of the water (D) are within the above ranges, excellent dispersibility and adhesiveness can be obtained.

[0085] 5) Method for producing dispersion The dispersion is produced, for example, by the following method: First, an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), a basic compound (B), an organic solvent (C), and water (D) are prepared (preparation step).

[0086] Next, in this method, the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), the basic compound (B), the organic solvent (C), and the water (D) are mixed in the above-mentioned ratio, and then the mixture is heated (mixing step).

[0087] The ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), the basic compound (B), the organic solvent (C), and the water (D) may be blended sequentially in any order, or may be blended all at once. Preferably, the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), the basic compound (B), the organic solvent (C), and the water (D) are blended all at once.

[0088] The heating conditions for the mixture are set appropriately depending on the purpose and application. For example, the mixture is heated at an appropriate temperature and pressure while stirring under appropriate conditions. The heating temperature is, for example, 80°C or higher, preferably 100°C or higher, and more preferably 120°C or higher. The heating temperature is, for example, 250°C or lower, preferably 200°C or lower, and more preferably 180°C or lower. The pressure condition is, for example, 0.1 MPa or higher. The pressure condition is, for example, 1.0 MPa or lower, preferably 0.5 MPa or lower. The heating time is, for example, 30 minutes or longer, preferably 1 hour or longer. The heating time is, for example, 24 hours or shorter, preferably 12 hours or shorter.

[0089] As a result, the carboxy groups of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) are neutralized by the basic compound (B) in the dispersion medium containing the organic solvent (C) and water (D).

[0090] The neutralized ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is then dispersed in a dispersion medium containing an organic solvent (C) and water (D), thereby obtaining a dispersion.

[0091] The solid content concentration of the dispersion is, for example, 5% by mass or more, or preferably 10% by mass or more, and for example, 40% by mass or less, or preferably 30% by mass or less.

[0092] The average particle size of the dispersion is, for example, 0.01 μm or more, preferably 0.02 μm or more. The average particle size of the dispersion is, for example, 50 μm or less, preferably 30 μm or less, more preferably 10 μm or less, even more preferably 1 μm or less, and particularly preferably 0.1 μm or less. The average particle size is measured in accordance with the examples described below.

[0093] The dispersion may also contain additives as needed. Examples of additives include sizing agents, antistatic agents, lubricants, smoothing agents, antifoaming agents, thickeners, tackifiers, hardening agents, preservatives, antifreezing agents, dispersants, pigments, and dyes. These additives may be used alone or in combination of two or more. The blending ratio and blending timing of the additives are appropriately determined depending on the purpose and application.

[0094] According to the above-mentioned method for producing a dispersion, the above-mentioned dispersion can be obtained efficiently.

[0095] The dispersion contains an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), a basic compound (B), an organic solvent (C), and water (D). The content of structural units derived from (meth)acrylic acid is 6% by mass or more and 11% by mass or less, based on the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A). The dielectric constant of the organic solvent (C) at 25°C is 7.0 or more and 37.0 or less. The content of the organic solvent (C) is 1% by mass or more and 45% by mass or less, based on the total amount of the organic solvent (C) and water (D). Therefore, the dispersion has excellent dispersibility and adhesiveness.

[0096] In particular, in the dispersion, the content of structural units derived from (meth)acrylic acid in the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is relatively low. Therefore, the dispersion has a relatively high affinity even for substrates with relatively low polarity. As a result, the dispersion has excellent adhesiveness.

[0097] In the dispersion, the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) has a relatively low melting point due to the structural units derived from the (meth)acrylic acid ester, and the dispersion containing such an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) has excellent adhesiveness.

[0098] On the other hand, when the content of structural units derived from (meth)acrylic acid in the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is relatively small, the water dispersibility of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) usually decreases.

[0099] In contrast, in the above dispersion, a specific organic solvent (C) is used in combination with water (D) in a predetermined ratio, and therefore, even if the content of structural units derived from (meth)acrylic acid in the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is relatively small, the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is well dispersed in the dispersion medium.

[0100] Therefore, the dispersion is suitably used as an adhesive composition.

[0101] 2. Adhesive composition The adhesive composition comprises the above dispersion, for example, the adhesive composition can consist of the above dispersion.

[0102] The adhesive composition may contain the above dispersion and a diluent. In other words, the adhesive composition may be a diluted solution of the above dispersion.

[0103] The diluent contains, for example, the organic solvent (C) and the water (D), and preferably consists of the organic solvent (C) and the water (D).

[0104] The ratio of the organic solvent (C) to the water (D) in the diluent is preferably the same as the ratio of the organic solvent (C) to the water (D) in the dispersion.

[0105] That is, the content of water (D) relative to the total amount of organic solvent (C) and water (D) in the diluent is, for example, 55% by mass or more, preferably 60% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, and particularly preferably 75% by mass or more. Also, the content of water (D) relative to the total amount of organic solvent (C) and water (D) in the diluent is, for example, 99% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

[0106] The content of the organic solvent (C) relative to the total amount of the organic solvent (C) and water (D) in the diluent is, for example, 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and particularly preferably 20% by mass or more. The content of the organic solvent (C) relative to the total amount of the organic solvent (C) and water (D) in the diluent is, for example, 45% by mass or less, preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less, and particularly preferably 25% by mass or less.

[0107] The blending ratio of the diluent is not particularly limited, and is appropriately set so that the solid content concentration of the adhesive composition falls within a predetermined range.

[0108] The adhesive composition has a solid content concentration of, for example, 5% by mass or more, or preferably 10% by mass or more, and for example, 30% by mass or less, or preferably 20% by mass or less.

[0109] The adhesive composition may also contain additives as needed. Examples of additives include sizing agents, antistatic agents, lubricants, smoothing agents, antifoaming agents, thickeners, tackifiers, hardness-imparting agents, preservatives, antifreeze agents, dispersants, pigments, and dyes. These additives may be used alone or in combination of two or more. The blending ratio and blending timing of the additives are appropriately determined depending on the purpose and application.

[0110] Such adhesive compositions contain the above dispersion, and therefore have excellent dispersibility and adhesive properties.

[0111] Therefore, the dispersion and adhesive composition are preferably used to form a resin layer (described later) in the laminate described below. More specifically, the dispersion and adhesive composition are preferably used to form a heat-seal adhesive layer (described later) as the resin layer (described later). In other words, the dispersion and adhesive composition are preferably heat-seal adhesive compositions for forming a heat-seal adhesive layer (described later).

[0112] 3.Laminate In FIG. 1, the laminate 1 includes a base material 2 and a resin layer 3 disposed on at least one surface of the base material 2.

[0113] Examples of the substrate 2 include resin substrates, metal substrates, composite substrates, and fiber substrates. Examples of resin substrates include plastic films made of resin materials. Examples of resin materials include cellophane, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, polyester, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polycarbonate, polystyrene, and polyacrylonitrile copolymer. Examples of metal substrates include metal plates and metal foils. Examples of metals include aluminum, gold, silver, copper, nickel, zinc, titanium, cobalt, indium, and chromium. Examples of composite substrates include vapor-deposited films (glass vapor-deposited films) in which metal and / or its oxide is vapor-deposited onto a plastic film. Examples of fiber substrates include paper, woven fabric, nonwoven fabric, glass fiber film, and carbon fiber film. These can be used alone or in combination. A preferred substrate is a metal substrate, and more preferably, a metal foil.

[0114] The thickness of the substrate 2 is, for example, 1 μm or more, or preferably 10 μm or more. The thickness of the substrate 2 is, for example, 1000 μm or less, or preferably 100 μm or less.

[0115] The resin layer 3 contains a dried product of the dispersion (preferably an adhesive composition). In other words, the resin layer 3 contains a solid content from which the organic solvent (C) and water (D) have been removed. That is, the resin layer 3 contains the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) and the basic compound (B).

[0116] The resin layer 3 may contain trace amounts of organic solvent (C) and water (D) that inevitably remain after drying. Preferably, the resin layer 3 does not contain the organic solvent (C) and water (D) and is composed of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) and the basic compound (B).

[0117] The resin layer 3 is formed by applying a dispersion (preferably an adhesive composition) to a substrate and drying the dispersion. There are no particular limitations on the method for applying the dispersion (preferably an adhesive composition) to the substrate 2. Examples of application methods include curtain coating, roll coating, blade coating, and bar coating.

[0118] The coating amount of the dispersion (preferably the adhesive composition) is, for example, 1.0 g / m 2 More than 2.0 g / m 2 The amount of the dispersion (preferably the adhesive composition) applied is, for example, 10.0 g / m 2 Preferably, 5.0 g / m or less 2 The following is the result.

[0119] The drying conditions are not particularly limited and are set appropriately. For example, the drying temperature is, for example, 20°C or higher, preferably 40°C or higher. The drying temperature is, for example, 200°C or lower, preferably 150°C or lower, and the drying time is, for example, 10 seconds or longer, preferably 30 seconds or longer. The drying time is, for example, 120 seconds or shorter, preferably 90 seconds or shorter.

[0120] By such drying, the organic solvent (C) and water (D) are removed from the dispersion (preferably the adhesive composition).

[0121] As a result, a resin layer 3 made of a dried dispersion (preferably an adhesive composition) is formed on at least one surface of the substrate 2. If necessary, a resin layer 3 may be formed on the other side of the substrate 2 using the same method as above.

[0122] Such a laminate 1 is obtained using the above dispersion (preferably an adhesive composition), and therefore the above laminate has excellent adhesiveness.

[0123] Therefore, the laminate 1 is suitable for use as a heat-sealing material in various industrial fields.

[0124] 4. Heat-sealed laminate

[0125] When the laminate 1 is used as a heat-sealing material, the resin layer 3 is an adhesive layer. More specifically, the resin layer 3 is a heat-sealing adhesive layer.

[0126] That is, when the laminate 1 is used as a heat-sealing material, the substrate 2 and the adherend layer 4 are heat-sealed via the resin layer 3 (heat-sealing adhesive layer 3) as shown by the imaginary line in FIG.

[0127] The adherend layer 4 is a material to which the resin layer 3 is adhered. Examples of the adherend layer 4 include the resin substrate, metal substrate, composite substrate, and fiber substrate. These may be used alone or in combination of two or more. A preferred example of the adherend layer 4 is a resin substrate, and a preferred example is a plastic film.

[0128] There are no particular limitations on the method for heat-sealing the substrate 2 and the adherend layer 4, and any known method may be used. For example, as shown in Fig. 1, the substrate 2 and the adherend layer 4 are laminated together with the resin layer 3 interposed therebetween, and then heated and pressurized.

[0129] The heating temperature is, for example, 80°C or higher, preferably 100°C or higher. The heating temperature is, for example, 250°C or lower, preferably 200°C or lower. The pressure is, for example, 0.05 MPa or higher, preferably 0.1 MPa or higher. The pressure is, for example, 1.0 MPa or lower, preferably 0.5 MPa or lower.

[0130] This heat seals the substrate 2 and the adherend layer 4. As a result, a heat-sealed laminate 10 is formed.

[0131] In the heat-sealed laminate 10, the resin layer 3 of the laminate 1 is used as a heat-seal adhesive layer. Therefore, in the heat-sealed laminate 10, the substrate 2 and the adherend layer 4 are well bonded to each other.

[0132] Therefore, the laminate 1 and the heat-sealed laminate 10 are suitable for use as packaging materials, and in particular, the laminate 1 and the heat-sealed laminate 10 are suitable for use as laminate packaging materials. [Example]

[0133] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited thereto. Note that specific numerical values ​​of the blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values ​​(numerical values ​​defined as "equal to or less than") or lower limit values ​​(numerical values ​​defined as "equal to or more than" or "exceeding") of the corresponding blending ratios (content ratios), physical property values, parameters, etc. described in the above "Modes for Carrying Out the Invention."

[0134] 1. Ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) Preparation examples A1~A4 The following commercially available ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymers were prepared. Hereinafter, the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymers will be referred to as "resins." The resins of Preparative Examples A1 to A4 will be referred to as "Resins A1 to A4," respectively.

[0135] Resins A1 to A4 were copolymers of ethylene, methacrylic acid, and isobutyl acrylate. The content of structural units derived from ethylene, methacrylic acid, and isobutyl acrylate is shown in Table 1. Table 1 also shows the MFR at 190°C.

[0136] Resin A1: 75% by mass of ethylene, 8% by mass of methacrylic acid, 17% by mass of isobutyl acrylate

[0137] Resin A2: 80% by mass of ethylene, 10% by mass of methacrylic acid, 10% by mass of isobutyl acrylate

[0138] Resin A3: 79% by mass of ethylene, 11% by mass of methacrylic acid, 10% by mass of isobutyl acrylate

[0139] Resin A4: 85% by mass of ethylene, 5% by mass of methacrylic acid, 10% by mass of isobutyl acrylate

[0140] Preparation example A5 The following commercially available ethylene-(meth)acrylic acid copolymer was prepared: The copolymer of Preparative Example A5 is hereinafter referred to as Resin A5.

[0141] Resin A5: 90% by mass of ethylene, 10% by mass of methacrylic acid

[0142] Resin A5 was a copolymer of ethylene and methacrylic acid. The content of structural units derived from ethylene and the content of structural units derived from methacrylic acid are shown in Table 1. Table 1 also shows the MFR at 190°C.

[0143] 2. Basic Compounds (B) Preparation example B1 Diethylamine (DEA) was prepared as the basic compound (neutralizing agent) B1.

[0144] Preparation example B2 As the basic compound (neutralizer) B2, N,N-dimethylethanolamine (DMEA) was prepared.

[0145] 3. Organic solvent (C) Preparation examples C1~C9 The organic solvents shown in Table 2 were prepared as organic solvents C1 to C9. The relative dielectric constant of each organic solvent at 25°C is shown in Table 2. When the organic solvent is a mixed solvent, the weighted arithmetic mean value based on the weight fraction of the relative dielectric constant of each component is shown.

[0146] The solubility parameters (SP values) of each organic solvent calculated by the Fedors method are shown in Table 2. When the organic solvent is a mixed solvent, the weighted geometric mean value of the solubility parameters (SP values) of each component by weight fraction is shown.

[0147] 5. Dispersions and Laminates Examples 1 to 10 and Comparative Examples 1 to 5 The resin, neutralizer, organic solvent, and water were placed in a pressure-resistant stirring vessel (autoclave (volume 1.5 L)) equipped with a heating function, according to the formulations shown in Tables 3 to 5. The vessel was then sealed, and the contents of the vessel were heated while being stirred at a rotation speed of 800 rpm. The contents were then maintained at a rotation speed of 800 rpm and at the temperature shown in Tables 3 to 5 for 4 hours. The vessel was then air-cooled to room temperature, and the contents were removed. This yielded a dispersion. The solids concentration of the dispersion was 20% by mass.

[0148] A diluent was prepared by mixing an organic solvent and water in the same ratio as above. The dispersion was then diluted with the diluent to obtain a diluted solution (adhesive composition) with a solid content of 17% by mass.

[0149] Next, the diluted solution was applied to an aluminum foil (substrate) having a thickness of 50 μm to obtain a coating film (wet coating film). 2 The coating was then dried at 120°C for 30 seconds to remove the organic solvent and water, thereby forming a resin layer on one surface of the substrate.

[0150] 6. Physical properties of dispersion (1) Viscosity The viscosity of the dispersion was measured using a B-type rotational viscometer TVB-10M (manufactured by Toki Sangyo Co., Ltd.) under the following measurement conditions. Measurement temperature: 25°C, rotation speed: 6 rpm

[0151] (2) Particle size The average particle size of the dispersion (measurement method: light scattering measurement) was measured using a particle distribution size measurement device, Microtrac MT3300EXII (manufactured by Microtrac Bell).

[0152] In addition, when the average particle size could not be measured using the above-mentioned device, the average particle size of the dispersion was measured using a nanoparticle size measuring device, Nanotrac Wave II-EX150 (manufactured by Microtrac Bell).

[0153] 7. Evaluation (1) Dispersibility The dispersibility of the dispersion (sample) was evaluated by the following method. That is, the dispersion was left to stand for 24 hours, and the dispersion state after standing was confirmed. In addition, the dispersion was filtered through a wire mesh with a mesh size of 150 μm, and the residue was confirmed.

[0154] The evaluation criteria are as follows: ×: The sample was not a dispersion after standing for 24 hours. ◯: The sample was a dispersion after standing for 24 hours. In addition, the residue after filtration was 750 ppm or more. ⊚: The sample was a dispersion after standing for 24 hours. In addition, the residue after filtration was less than 750 ppm.

[0155] (2) Adhesiveness (a) PP adhesiveness The corona-treated polypropylene (PP) sheet and the resin layer of the laminate were heat-sealed using a heat-sealing machine (Heat Seal Tester TP-701-B, manufactured by Tester Sangyo Co., Ltd.). This resulted in a heat-sealed laminate. The heat-sealing conditions are as follows: Pressure: 0.3 MPa, Temperature: 150°C, Time: 1 second

[0156] The heat-sealed laminate was left standing for 1 day. Thereafter, the heat-sealed laminate was cut into 15 mm wide samples. The adhesive strength between the aluminum foil and the polypropylene (PP) sheet was measured using a tensile tester (Universal Tester 201X, manufactured by Intesco). The tensile test conditions are as follows: Peeling speed: 200 mm / min, Peeling angle: 180°

[0157] The evaluation criteria are as follows: -;Cannot be rated. ×: 0N / 15mm or more but less than 1N / 15mm. △: 1N / 15mm or more but less than 4N / 15mm. ○: 4N / 15mm or more but less than 7N / 15mm. ◎: 7N / 15mm or more.

[0158] (b) EPDM adhesion Instead of the polypropylene (PP) sheet, an ethylene propylene diene rubber (EPDM) sheet was used. The heat sealing temperature was changed to 200°C. Other than this, the adhesive strength between the aluminum foil and the ethylene propylene diene rubber (EPDM) sheet was measured using the same method as above. The evaluation criteria were the same as above.

[0159] [Table 1]

[0160] [Table 2]

[0161] [Table 3]

[0162] [Table 4]

[0163] [Table 5] [Explanation of symbols]

[0164] 1. Laminate 2 Base material 3 Resin layer

Claims

1. an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A); a basic compound (B); an organic solvent (C); and water (D), a content ratio of structural units derived from (meth)acrylic acid relative to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is 6% by mass or more and 11% by mass or less; The (meth)acrylic acid is methacrylic acid, the organic solvent (C) has a relative dielectric constant at 25°C of 7.0 or more and 37.0 or less; a content of the organic solvent (C) relative to the total amount of the organic solvent (C) and the water (D) of 1% by mass or more and 45% by mass or less;

2. The dispersion according to claim 1 , wherein the organic solvent (C) comprises an alcohol having 1 to 4 carbon atoms.

3. An adhesive composition comprising the dispersion of claim 1 or 2.

4. A substrate and a resin layer disposed on at least one surface of the substrate, The resin layer is A laminate comprising a dried dispersion according to claim 1 or 2.

5. a preparation step of preparing an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), a basic compound (B), an organic solvent (C), and water (D); a mixing step of mixing and heating an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A), a basic compound (B), an organic solvent (C), and water (D); Equipped with a content ratio of structural units derived from (meth)acrylic acid relative to the total amount of the ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer (A) is 6% by mass or more and 11% by mass or less; The (meth)acrylic acid is methacrylic acid, the organic solvent (C) has a relative dielectric constant at 25°C of 7.0 or more and 37.0 or less; a content of the organic solvent (C) relative to the total amount of the organic solvent (C) and the water (D) of 1% by mass or more and 45% by mass or less.

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