JP4553633B2 - Aqueous dispersion and laminate - Google Patents

Description

  The present invention is obtained by applying an aqueous dispersion of an ethylene / (meth) acrylic acid copolymer excellent in dispersibility and film forming property and capable of forming a low moisture-permeable coating film to a substrate. It is related with the laminated body made. In particular, the present invention relates to an aqueous dispersion useful as a heat seal material for a packaging material or a rust preventive paint for a metal material.

  An aqueous dispersion in which an ethylene / (meth) acrylic acid copolymer is dispersed in water with a base is widely known. This general aqueous dispersion is used by being applied to a metal foil or a polymer film to form a heat seal layer, for example, but depending on the application, higher moisture resistance and heat resistance are required. was there.

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to apply it to a polymer material such as a biaxially oriented polypropylene film (OPP) so as to achieve moisture resistance and heat resistance. An object of the present invention is to provide an aqueous dispersion of an ethylene / (meth) acrylic acid copolymer which is capable of forming an excellent heat seal layer and is excellent in dispersibility and film forming property. Another object of the present invention is to provide an aqueous dispersion of an ethylene / (meth) acrylic acid copolymer which is a rust-preventing paint having excellent moisture resistance for metal materials. Another object of the present invention is to provide a laminate obtained by coating and drying such an aqueous dispersion on a substrate.

That is, according to the present invention, an ethylene / (meth) acrylic acid copolymer (A) having a (meth) acrylic acid content of 3 to 30% by weight and a melt flow rate of 5 to 1500 g / 10 min is obtained by using the copolymer. (a) 0.5 to 10 parts by weight of polyoxyalkylene-based on 100 parts by weight, sulfonate-type, and at least one surfactant selected from sulfuric ester and phosphoric acid ester, the copolymerization An aqueous dispersion is provided which is dispersed in water using 40 to 300 mol% of an alkali metal compound, an alkali metal ion, an alkaline earth metal compound or an alkaline earth metal ion based on the carboxyl group of the union (A). Is done.

  According to the present invention, there is also provided a laminate obtained by applying the aqueous dispersion to a base material such as a polymer material or a metal material and drying.

  ADVANTAGE OF THE INVENTION According to this invention, the aqueous dispersion which can form the coating film excellent in the dispersibility and film forming property, and the low moisture permeability and heat resistance can be provided. Since such an aqueous dispersion can form a coating film having excellent heat sealability, it can be applied to a polymer material such as OPP to form a heat seal layer. Moreover, since it is excellent in metal adhesiveness and moisture resistance, it can be used for forming a rust-proof coating film of a metal material.

  In the present invention, an ethylene / (meth) acrylic acid copolymer having a (meth) acrylic acid content of 3 to 30% by weight, preferably 3 to 15% by weight, more preferably 5 to 13% by weight is used as a raw material for the aqueous dispersion. A polymer (A) is used. Here, (meth) acrylic acid means acrylic acid or methacrylic acid. When a copolymer having a (meth) acrylic acid content less than the above range is used, it is difficult to obtain an aqueous dispersion excellent in dispersibility and metal adhesion, while the copolymer content is more than 30% by weight. When the coalescence is used, it is difficult to obtain an aqueous dispersion capable of forming a coating film having low hygroscopicity and heat resistance.

  Such a copolymer may also be obtained by copolymerizing other monomers in addition to ethylene and (meth) acrylic acid. Examples of such other monomers include vinyl acetate, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, unsaturated esters such as methyl methacrylate, and carbon monoxide. Can do. Such other monomers may be contained, for example, in a proportion of 20% by weight or less, preferably 10% by weight or less.

  As the ethylene / (meth) acrylic acid copolymer, two or more kinds of copolymers having different kinds of acid, (meth) acrylic acid content and / or melt flow rate can be used. In particular, two or more kinds of ethylene / methacrylic acid having different (meth) acrylic acid contents so that the average (meth) acrylic acid content is 3 to 30% by weight, preferably 3 to 15% by weight, and particularly preferably 5 to 13% by weight. When (meth) acrylic acid copolymer is used, it is compared with an aqueous dispersion using one kind of ethylene / (meth) acrylic acid copolymer having the same (meth) acrylic acid content as the average (meth) acrylic acid content. Thus, an aqueous dispersion having a reduced viscosity can be obtained, and thus the solid concentration can be increased, which is preferable. In particular, an ethylene / (meth) acrylic acid copolymer having a (meth) acrylic acid content of 1 to 10% by weight and an ethylene / (meth) acrylic acid copolymer having a (meth) acrylic acid content of 5 to 20% by weight. The coalescence is preferably used in such a proportion that its average (meth) acrylic acid content is 5 to 14% by weight. In this case, the difference between the former and latter (meth) acrylic acid contents is preferably 1% by weight or more, particularly preferably 1 to 18% by weight.

  As the raw material ethylene / (meth) acrylic acid copolymer, considering the ease of production of the aqueous dispersion, the dispersion stability, the physical properties of the coating film obtained from the aqueous dispersion, JIS K7210-1999, 190 ° C. A melt flow rate at a load of 2160 g is 5 to 1500 g / 10 min, particularly 10 to 1000 g / 10 min.

  The aqueous dispersion of the present invention comprises the ethylene / (meth) acrylic acid copolymer (A), a dispersant and / or an emulsifier (B), and an alkali metal compound, an alkali metal ion, an alkaline earth metal compound, or an alkali. It is dispersed in water using a base such as an earth metal ion.

  As said dispersing agent and / or emulsifier, 1 type, 2 types, such as an anionic surfactant generally known as surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, etc. The above can be selected and used.

  Specific examples of the anionic surfactant include, for example, fatty acid salts such as sodium stearate, potassium oleate, and sodium oleate, carboxylates such as polycarboxylic acid salts such as resin acid soap, potassium naphthenate, and sodium polyacrylate. Acid salts; alkyl aryl sulfonates such as sodium dodecylbenzene sulfonate, sodium alkyl naphthalene sulfonate, sodium alkyl diphenyl ether disulfonate, sodium diisobutyl sulfosuccinate, sodium dihexyl sulfosuccinate, sodium dioctyl sulfosuccinate, etc. Sulfonates such as sodium acid, formalin condensates of alkylaryl sulfonates; sodium lauryl sulfate, polyoxyethylene alkyl ether sulfate sodium Sulfates such as sodium polyoxyethylene alkylphenyl ether sulfate, sodium t-octylphenoxyethoxypolyethoxyethyl sulfate; phosphate esters such as alkyl phosphate esters and phosphate esters of polyoxypropylene aryl ethers; anionic Examples thereof include silicone surfactants.

  Specific examples of the cationic surfactant include, for example, polyoxyethylene dodecylamine, polyoxyethylene octadecylamine, stearylamine acetate, lauryldimethylamine oxide, lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, cetyltrimethylammonium chloride, Examples include distearyldimethylammonium chloride, alkylbenzyldimethylammonium chloride, coconutamine acetate, stearylamine acetate, alkylming anidine polyoxyethanol, and alkylpicolinium chloride.

  Specific examples of the nonionic surfactant include, for example, polyoxyethylene lauryl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene oleyl phenyl ether, polyoxyethylene nonyl phenyl ether, oxyethylene / oxypropylene block copolymer, t- Octylphenoxyethyl polyethoxyethanol, nonylphenoxyethyl polyethoxyethanol, polyoxyethylene alkylamine ether, polyoxyethylene fatty acid amide, polyoxyethylene alkyl ester, sorbitan monooleate, sorbitan sesquioleate, sorbitan monostearate, polyoxyethylene sorbitan Monooleate, polyoxyethylene sorbitan stearate, polyether-modified silicone oil It can be mentioned.

  Examples of amphoteric surfactants include lauryl betaine, stearyl betaine, lauryl carboxymethylhydroxyethyl imidazolinium betaine, and alkylalanine.

（式中、Ｒは水素原子又はメチル基、Ｘはメチレン基又はカルボニル基、（ＡＯ）_ｎはエチレンオキサイド０〜３０モル％及び炭素数３以上のアルキレンオキサイド１００〜７０モル％で構成されたポリオキシアルキレン基、Ｍは水素原子、金属原子又はアンモニウムをそれぞれ表し、ｍは１〜２の数、ｎは１以上、好ましくは２〜１００、一層好ましくは〜５０の数を表す）で表されるものを代表例としてあげることができる。このようなリン酸エステルの一例として、商品名アデカリアソーブＰＰ（旭電化工業（株）製）を市場で入手することができる。 Among these surfactants, at least one surfactant selected from the group consisting of polyoxyalkylenes (having polyoxyethylene and polyoxypropylene units), sulfonates, sulfates and phosphates The use of an agent is preferable because an aqueous dispersion capable of forming a coating film having particularly low viscosity and low moisture permeability can be obtained. Use of a reactive surfactant having a polymerizable carbon-carbon double bond is preferable because an aqueous dispersion capable of forming a coating film having excellent low moisture permeability can be obtained. Particularly preferred reactive surfactants are those based on phosphate esters. As a preferable phosphate ester type reactive surfactant, the following formula (1)

(In the formula, R is a hydrogen atom or a methyl group, X is a methylene group or a carbonyl group, (AO) _n is a polyoxyethylene composed of 0 to 30 mol% of ethylene oxide and 100 to 70 mol% of alkylene oxide having 3 or more carbon atoms. An oxyalkylene group, M represents a hydrogen atom, a metal atom, or ammonium, m represents a number of 1 to 2, n represents 1 or more, preferably 2 to 100, and more preferably represents a number of -50. A typical example can be given. As an example of such a phosphoric acid ester, the trade name Adekaria Sorb PP (Asahi Denka Kogyo Co., Ltd.) can be obtained on the market.

  The surfactant as such a dispersant and / or emulsifier is 0.5 to 10 parts by weight, preferably 1 to 8 parts by weight, based on 100 parts by weight of the ethylene / (meth) acrylic acid copolymer (A). Used at a rate of

  Examples of the alkali metal in the alkali metal compound or alkali metal ion used for the preparation of the aqueous dispersion of the present invention include lithium, sodium, potassium, cesium, and rubidium, and sodium or potassium is particularly preferable. Examples of the alkaline earth metal in the alkaline earth metal compound or alkaline earth metal ion include calcium, magnesium, and barium.

  The alkali metal compound or alkali metal ion or alkaline earth metal compound or alkaline earth metal ion is 40 to 300 mol%, preferably 50 to 50% based on the carboxyl group of the ethylene / (meth) acrylic acid copolymer (A). It is used in such a ratio that it becomes 100 mol%. When the alkaline earth metal compound or alkaline earth metal ion is used, it is preferably used in combination with the alkali metal compound or alkali metal ion. In addition, a compound or ion of a polyvalent metal such as zinc can be used in combination as long as the water dispersibility is not significantly impaired.

  The aqueous dispersion of the present invention can be produced by the following method. That is, water, an ethylene / (meth) acrylic acid copolymer (A) having the above-described properties in an amount of 5 to 50% by weight, preferably 10 to 40% by weight, and the copolymer (A ) The above dispersant and / or emulsifier in a ratio of 0.5 to 10 parts by weight with respect to 100 parts by weight, and an alkali having an ion amount as described above based on the carboxyl group of the copolymer (A). In a reaction apparatus capable of applying a shearing force between a metal compound or an alkaline earth metal compound and optionally a compound of the polyvalent metal, for example, in an autoclave equipped with a stirrer, 100 ° C. or higher, preferably 130 to 200 ° C. It can obtain by making it react, applying a shear force at the temperature of. The reaction time varies depending on the reaction temperature and other reaction conditions, but is about 30 to 300 minutes. Examples of the alkali metal compound include hydroxides, carbonates, hydrogen carbonates, carboxylates and the like. As the alkaline earth metal compound or other polyvalent metal compound, use of an oxide, hydroxide, carbonate or the like is preferable.

  In the present invention, in addition to the above-described method, an alkali metal ionomer or an alkaline earth metal ionomer of the ethylene / (meth) acrylic acid copolymer (A) prepared in advance, a dispersant and / or an emulsifier and necessary Accordingly, the aqueous dispersion of the present invention can be produced by a method in which other alkali metal or alkaline earth metal compound is dispersed in water while applying a shearing force.

  The aqueous dispersion of the present invention prepared as described above has an average particle size of 1 to 5000 nm, particularly 5 to 3000 nm, and Brookfield viscosity in consideration of dispersion stability, coatability, coating film uniformity, and the like. It is preferable that the viscosity at 23 ° C. measured by the meter is 1 to 100000 mPa · s, particularly 5 to 5000 mPa · s, and the pH is 8 to 12, preferably 8.5 to 11.5.

  Various additives can be arbitrarily blended in the aqueous dispersion of the present invention. Examples of such additives include antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, plasticizers, pigments, adhesives, dyes, lubricants, antiblocking agents, adhesives, crosslinking agents, and foaming agents. , Viscosity modifiers, writability improvers, inorganic fillers, and the like.

  The aqueous dispersion of the present invention can be applied to various substrates and dried for various purposes such as imparting heat sealing performance and forming a rust-preventive coating film to obtain a laminate having these performances. Can do. Base materials include high, medium and low density polyethylene, ethylene / α-olefin copolymer, ethylene / vinyl acetate copolymer, ethylene / (meth) acrylic acid ester copolymer, ethylene / (meth) acrylic acid copolymer. Polymer or its ionomer, ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer or its ionomer, olefin polymer such as polypropylene, poly-1-butene, poly-4-methyl-1-pentene Or copolymer, polystyrene, high impact polystyrene, ABS type resin, styrene resin such as styrene / butadiene block copolymer or hydrogenated product thereof, polyethylene terephthalate, polyester such as polybutylene terephthalate, nylon 6, nylon 66 Like polyamide, polycarbonate , Thermoplastic polymers such as polyvinyl chloride and mixtures of these in any proportion, rubber materials such as natural rubber, synthetic rubber, thermosetting resins such as phenolic resin, polyurethane, iron, copper, aluminum, stainless steel, etc. Examples thereof include natural materials such as metal, glass, ceramics, wood, paper, rayon and leather. The thermoplastic polymer can be applied to various molded products such as films, sheets, hollow molded products, injection molded products, woven fabrics, nonwoven fabrics, and synthetic leathers. By using a flat substrate such as a film, sheet, woven fabric, nonwoven fabric, synthetic leather, or paper as the substrate, a laminate in which a heat seal layer is formed on the substrate can be easily obtained. The aqueous dispersion of the present invention is excellent in wettability not only with polar materials but also with hydrophobic materials such as olefin polymers and styrene polymers, so that the aqueous dispersion has good coatability. The body can be applied. For example, a film obtained by applying and drying the aqueous dispersion of the present invention on a polyolefin film, typically an OPP film, exhibits good heat seal performance and can be suitably used as various packaging materials. In addition, the laminate obtained by applying the aqueous dispersion of the present invention to a metal material and drying is excellent in rust resistance, in particular moisture and rust resistance, and should be used suitably for applications requiring rust prevention. Can do.

  The aqueous dispersion of the present invention can be modified with other polymer dispersions, or can be blended with other polymer dispersions at an arbitrary ratio for the purpose of modifying other polymer dispersions. In general, it is preferably blended at a ratio of 10/90 to 90/10, particularly 20/80 to 80/20 in terms of solid content (weight ratio).

  Such other polymer aqueous dispersions are those having a pH of 7 or more, or those having a pH of 7 or more with aqueous ammonia, etc., and do not gel when mixed with the aqueous dispersion of the present invention. It is necessary to choose something like this. Further, it is desirable to select those having a solid content concentration of 2 to 60%, preferably about 5 to 50%, and an average particle size of 1 to 10000 nm, preferably 5 to 5000 nm.

  Such other polymer aqueous dispersions include, for example, polyvinyl acetate, ethylene / vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, water-soluble acrylic resin, acrylamide resin, methacrylamide resin, acrylonitrile resin, Methacrylonitrile resin, styrene, acrylic acid copolymer, water-soluble polyurethane resin, water-soluble styrene / maleic acid copolymer, styrene / butadiene copolymer, high impact polystyrene resin, polybutadiene resin, polyester resin, acrylonitrile / butadiene copolymer Polymer, polyethylene, polyethylene oxide, propylene / ethylene copolymer, maleic anhydride grafted polyolefin, chlorinated polyethylene, chlorinated polypropylene, EPDM, phenol resin, silicone resin, epoxy resin It can be mentioned aqueous dispersion. Of course, two or more of these may be used.

  In order to apply the aqueous dispersion of the present invention to a substrate, a known method, for example, a coating method such as roll coating, reverse roll coater, doctor coater, brush coating, spray coating, screen printing, gravure printing, engraving roll printing, Printing methods such as flexographic printing can be adopted. The base material may be coated with a primer for the purpose of improving adhesiveness or the like, or may be subjected to a surface treatment such as corona treatment. Although the thickness of a dry coating film is arbitrary, what is necessary is just to apply | coat so that thickness may become 1-300 micrometers, Preferably it is 5-200 micrometers, and this may be dried.

  EXAMPLES Next, although an Example demonstrates this invention in detail, this invention is not restrained by these Examples. In addition, the raw material used for the Example and the physical-property evaluation method of an aqueous dispersion are shown below.

[Aqueous dispersion material]
(1) Base polymer BP-1: ethylene / methacrylic acid copolymer (methacrylic acid content 11% by weight, melt flow rate (MFR) 100 g / 10 min)
BP-2: ethylene / methacrylic acid copolymer (methacrylic acid content 15% by weight, MFR 600 g / 10 min)
BP-3: Ethylene / methacrylic acid copolymer (methacrylic acid content 20% by weight, MFR 60 g / 10 min)
(2) Ion source potassium hydroxide: purity 86% by weight (manufactured by Kanto Chemical Co., Inc.)
(3) Dispersant The following table 1 was used.

[Method for evaluating properties of aqueous dispersion]
(1) pH
Measured using pH METER F-12 manufactured by Horiba, Ltd.
(2) Viscosity The viscosity was measured at 23 ° C. using a Brookfield viscometer. Unit (mPa · s)
(3) Particle size It measured using LB-500 by Horiba, Ltd. The median diameter was taken as the particle size. Unit (nm)

(4) Moisture resistance evaluation method (a) When the target of the coating thickness is 4 μm, No. The aqueous dispersion is applied to the electrolytic galvanized steel sheet with a 4-bar coater and dried at 100 ° C. for 2 minutes.
(B) Hold in a constant temperature and humidity chamber at a temperature of 50 ° C. and a humidity of 90% for 24 hours.
(C) Lightly apply filter paper to remove moisture from the coating surface and hold for 2 hours.
(D) Use a cutter knife to make a 15 mm gap and a width of 40 mm.
(E) A cellophane adhesive tape is applied, pressed firmly with an eraser, and the adhesive tape is attached to the coated surface.
(F) After holding for about 1 minute, peel off quickly and measure the residual rate (%) of the coating film.
(5) Heat seal performance (HS strength) evaluation: Unit (g / 15mm)
An aqueous dispersion was applied to a 50 μm thick OPP film treated with a corona treatment with a target thickness of 10 μm. It was applied using an 18 bar coater and dried at 100 ° C. for 3 minutes. The two OPP films obtained were overlapped so that the coated surfaces were in contact with each other, heat sealed under conditions of a temperature of 100 to 150 ° C., a pressure of 2 kg / cm ² , and a sealing time of 0.5 seconds, and then heat seal strength Was measured.

(6) Moisture permeability (moisture resistance)
On the OA paper, the aqueous dispersion was No. 1 with a target thickness of 10 μm. It was applied using an 18 bar coater and dried at 100 ° C. for 3 minutes. The moisture permeability of the obtained coating film was evaluated according to JIS K7129.

[Example 1]
70 g of base polymer (BP-1), 280 g of ion-exchanged water, 6.8 g of potassium hydroxide, 3 g of pluronic P85 as a dispersant, 1 g of pluronic L61, and added to the autoclave for 1.5 hours at a temperature of 150 ° C. and a stirring speed of 1200 rpm. Stir. Thereafter, it was cooled with tap water to obtain an aqueous dispersion 1 having a solid concentration of 20% by weight.

[Example 2]
87 g of base polymer (BP-1), 263 g of ion-exchanged water, 4.7 g of potassium hydroxide, 3 g of Evan 785 as a dispersing agent, 1 g of Pluronic L61, added to the autoclave, temperature of 150 ° C., stirring speed of 1200 rpm for 1.5 hours Stir. Thereafter, the mixture was cooled with tap water to obtain an aqueous dispersion 3 having a solid content concentration of 25% by weight.

[Example 3]
87 g of base polymer (BP-1), 263 g of ion-exchanged water, 4.7 g of potassium hydroxide, 3 g of Adekalysorb PP as a dispersant, 1 g of Pluronic L61, added to the autoclave, temperature 150 ° C., stirring speed 1200 rpm for 1.5 hours Stir. Thereafter, the mixture was cooled with tap water to obtain an aqueous dispersion 4 having a solid content concentration of 25% by weight.

[Example 4]
87 g of base polymer (BP-1), 263 g of ion-exchanged water, 4.7 g of potassium hydroxide, 3 g of Monogen Y500 as a dispersing agent, 1 g of Pluronic L61, and added to the autoclave for 1.5 hours at a temperature of 150 ° C. and a stirring speed of 1200 rpm. Stir. Thereafter, the mixture was cooled with tap water to obtain an aqueous dispersion 5 having a solid concentration of 25% by weight.

[Example 5]
94.5 g of base polymer (BP-1), 256 g of ion exchange water, 5.1 g of potassium hydroxide, 3 g of Monogen Y500 as a dispersing agent, 1 g of Pluronic L61, and 1.g at a temperature of 150 ° C. and a stirring speed of 1200 rpm are added to the autoclave. Stir for 5 hours. Thereafter, the mixture was cooled with tap water to obtain an aqueous dispersion 6 having a solid concentration of 27% by weight.

[Example 6]
87 g of base polymer (BP-1), 263 g of ion-exchanged water, 4.7 g of potassium hydroxide, 3 g of monogen Y500 as a dispersant, were added to the autoclave, and stirred for 1.5 hours at a temperature of 150 ° C. and a stirring speed of 1200 rpm. Thereafter, it was cooled with tap water to obtain an aqueous dispersion 7 having a solid concentration of 27% by weight.

[Example 7]
87 g of base polymer (BP-1), 263 g of ion-exchanged water, 4.7 g of potassium hydroxide, 3 g of Adekalysorb PP as a dispersant were added to the autoclave, and the mixture was stirred for 1.5 hours at a temperature of 150 ° C. and a stirring speed of 1200 rpm. Thereafter, it was cooled with tap water to obtain an aqueous dispersion 8 having a solid concentration of 25% by weight.

[Comparative Example 1]
35 g of base polymer (BP-3), 315 g of ion-exchanged water, and 3.4 g of potassium hydroxide were added to the autoclave, and the mixture was stirred for 1.5 hours at a temperature of 150 ° C. and a stirring speed of 1200 rpm. Thereafter, the mixture was cooled with tap water to obtain an aqueous dispersion 9 having a solid concentration of 10% by weight.

[Comparative Example 2]
35 g of base polymer (BP-2), 315 g of ion exchange water, and 2.6 g of potassium hydroxide were added to the autoclave, and the mixture was stirred for 1.5 hours at a temperature of 150 ° C. and a stirring speed of 1200 rpm. Thereafter, the mixture was cooled with tap water to obtain an aqueous dispersion 10 having a solid content concentration of 10% by weight.

[Comparative Example 3]
87 g of base polymer (BP-3), 263 g of ion-exchanged water, and 9.1 g of potassium hydroxide were added to the autoclave, and the mixture was stirred at a temperature of 150 ° C. and a stirring speed of 1200 rpm for 1.5 hours. Thereafter, the mixture was cooled with tap water to obtain an aqueous dispersion 11 having a solid concentration of 27% by weight.

  Table 2 shows the results of measuring the ratio of the raw materials used in the aqueous dispersions 1 to 11 and the physical properties of the aqueous dispersion.

Claims (6)

An ethylene / (meth) acrylic acid copolymer (A) having a (meth) acrylic acid content of 3 to 30% by weight and a melt flow rate of 5 to 1500 g / 10 min is added to 100 parts by weight of the copolymer (A). 0.5 to 10 parts by weight of the polyoxyalkylene against, sulfonic acid salts, at least one surface active agent, a carboxyl group of the copolymer (a) is selected from sulfuric ester and phosphoric acid ester An aqueous dispersion dispersed in water using 40 to 300 mol% of an alkali metal compound, an alkali metal ion, an alkaline earth metal compound or an alkaline earth metal ion based on the above formula. 2. The ethylene / (meth) acrylic acid copolymer comprises two or more kinds of ethylene / (meth) acrylic acid copolymers, and the average (meth) acrylic acid content in the blend is 3 to 30% by weight. the aqueous dispersion according to. The aqueous dispersion according to claim 1 or 2, wherein the surfactant is a reactive surfactant. The coating film formed from the aqueous dispersion in any one of Claims 1-3 . The laminated body formed by apply | coating and drying the aqueous dispersion in any one of Claims 1-4 to a base material. The laminate according to claim 4, wherein the substrate is a polymer material or a metal.