JP2020152826A - Aqueous dispersion and laminate - Google Patents

Abstract

To provide an aqueous dispersion capable of obtaining a laminate which can suppress repelling property to a base material and is excellent in appearance, and a laminate obtained using the aqueous dispersion.SOLUTION: An aqueous dispersion contains a resin component, water-soluble cellulose ether, and water, in which the resin component contains at least one polymer selected from the group consisting of an ethylene-unsaturated carboxylic acid copolymer (A), a polymer (B) having an acrylic acid ester unit as a polymerization unit and an ethylene-vinyl acetate-based copolymer (C), and viscosity at 20°C of 2 mass% aqueous solution of the water-soluble cellulose ether is 5 mPa s or more and 90 mPa s or less.SELECTED DRAWING: None

Description

The present invention relates to an aqueous dispersion and a laminate, and more particularly to an aqueous dispersion and a laminate obtained by using the aqueous dispersion.

Conventionally, in various industrial fields, it is known that substrates such as plastic films, vapor-deposited films, metal foils, papers, and non-woven fabrics are bonded (that is, heat-sealed) by heat and pressure. In heat sealing, usually, an adhesive layer is formed on the base material in advance, and the base materials or the base material and other adherends are bonded to each other via the adhesive layer.

The adhesive used for such a thermal seal contains, for example, a resin component and water, and the resin component is a polymerization unit of an ethylene / unsaturated carboxylic acid copolymer (A) and an acrylic acid ester unit. An aqueous dispersion containing the polymer (B) and the ethylene / vinyl acetate copolymer (C) has been proposed, and a laminate obtained by applying the aqueous dispersion to a substrate and drying it. Has also been proposed. (See, for example, Patent Document 1).

WO 2018/142997 Pamphlet

On the other hand, in the laminated body, in order to obtain an excellent appearance, it is required to suppress the resilience (water repellency) of the adhesive (aqueous dispersion) to the base material and to blend the base material and the adhesive layer. ..

The present invention is an aqueous dispersion capable of suppressing resilience to a base material and obtaining a laminated body having an excellent appearance, and a laminated body obtained by using the aqueous dispersion.

The present invention [1] is an aqueous dispersion containing a resin component, a water-soluble cellulose ether, and water, wherein the resin component is an ethylene / unsaturated carboxylic acid copolymer (A), an acrylic acid ester. It contains at least one polymer selected from the group consisting of a polymer (B) having a unit as a polymerization unit and an ethylene / vinyl acetate copolymer (C), and 2% by mass of the water-soluble cellulose ether. It contains an aqueous dispersion having an aqueous solution having a viscosity at 20 ° C. of 5 mPa · s or more and 90 mPa · s or less.

In the present invention [2], the resin component is a composite particle (D) having the ethylene / unsaturated carboxylic acid copolymer (A) and the polymer (B) having the acrylic acid ester unit as a polymerization unit. The aqueous dispersion according to the above [1], which comprises the ethylene / unsaturated carboxylic acid copolymer (A) and the composite particles (E) having the ethylene / vinyl acetate-based copolymer (C). Contains the body.

The present invention [3] includes a base material and an adhesive layer laminated on at least one surface of the base material, and the adhesive layer is the aqueous dispersion according to the above [1] or [2]. Contains a laminate, which is a dried product of.

The present invention [4] further includes the laminate according to the above [3], which further includes an adherend layer laminated on one side surface of the adhesive layer.

The present invention [5] includes the laminate according to the above [4], wherein the adherend layer comprises polyvinyl chloride and / or polyvinylidene chloride.

The present invention [6] includes the laminate according to any one of the above [3] to [5], wherein the base material is made of aluminum.

The aqueous dispersion of the present invention contains a water-soluble cellulose ether having a viscosity of a 2% by mass aqueous solution at 20 ° C. of 5 mPa · s or more and 90 mPa · s or less.

Therefore, according to the aqueous dispersion of the present invention, the resilience to the base material can be suppressed, and a laminated body having an excellent appearance can be obtained.

Further, since the laminate of the present invention is obtained by using the above-mentioned aqueous dispersion, the repulsability of the aqueous dispersion with respect to the base material is suppressed, and the appearance is excellent.

FIG. 1 is a schematic view showing an embodiment of the laminate of the present invention.

In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. Good.

The aqueous dispersion of the present invention contains a resin component, a water-soluble cellulose ether, and water for dispersing the resin component and the water-soluble cellulose ether.

The resin component is composed of an ethylene / unsaturated carboxylic acid copolymer (A), a polymer (B) having a (meth) acrylic acid ester unit as a polymerization unit, and an ethylene / vinyl acetate copolymer (C). Contains at least one polymer selected from the group.

<Ethylene / unsaturated carboxylic acid copolymer (A)>
The ethylene / unsaturated carboxylic acid copolymer (A) is obtained by copolymerizing the first monomer component.

The first monomer component contains ethylene and an unsaturated carboxylic acid.

An unsaturated carboxylic acid is a monomer having at least one ethylenically unsaturated bond and a carboxy group, and is a monobasic acid such as acrylic acid, methacrylic acid, or crotonic acid, such as maleic acid or fumaric acid. Examples thereof include dibasic acids such as itaconic acid.

These unsaturated carboxylic acids can be used alone or in combination of two or more.

As the unsaturated carboxylic acid, monobasic acid is preferably used from the viewpoint of water resistance, and acrylic acid and methacrylic acid are more preferable.

Regarding the content ratio of ethylene and unsaturated carboxylic acid in the first monomer component, ethylene is, for example, 75% by mass or more, preferably 78% by mass or more, and for example, 90% by mass or less, based on the total amount thereof. , Preferably 88% by mass or less. The unsaturated carboxylic acid is, for example, 10% by mass or more, preferably 12% by mass or more, and 25% by mass or less, preferably 22% by mass or less.

When the content ratio of ethylene and unsaturated carboxylic acid is in the above range, excellent adhesive strength and blocking resistance can be obtained.

The polymerization of the first monomer component is not particularly limited, and a known polymerization method is adopted. For example, a method of contacting the above-mentioned first monomer component with a known polymerization initiator such as a peroxide under high temperature and high pressure conditions can be mentioned.

Further, the ethylene / unsaturated carboxylic acid copolymer (A) can be obtained as a dispersion (aqueous dispersion) in which the single particles (hereinafter, resin particles (I)) are dispersed in water. In such a case, for example, Tokuho 7-0008933, Tokuho 5-039975, Tokuho 4-030970, Tokukou 42-000275, Tokukou 42-023085, Tokukou 45-029909, Japanese Patent Application Laid-Open No. The first monomer component can be polymerized by the method described in 1976-062890 or the like. The ethylene / unsaturated carboxylic acid copolymer (A) has self-emulsifying properties.

Further, in the production of the ethylene / unsaturated carboxylic acid copolymer (A), an emulsifier (surfactant) described later can be blended, if necessary, from the viewpoint of improving production stability. The blending ratio of the emulsifier is appropriately set according to the purpose and application.

Further, in the production of the ethylene / unsaturated carboxylic acid copolymer (A), from the viewpoint of improving the production stability, for example, a pH adjuster, for example, a metal ion encapsulant such as ethylenediaminetetraacetic acid and a salt thereof. For example, known additives such as molecular weight regulators (chain transfer agents) such as mercaptans and low molecular weight halogen compounds can be blended in an appropriate ratio.

Further, the ethylene / unsaturated carboxylic acid copolymer (A) is preferably neutralized from the viewpoint of improving dispersion stability and printability of the laminate (described later).

In neutralization, for example, a basic compound as a neutralizing agent is added to a dispersion of an ethylene / unsaturated carboxylic acid copolymer (A), specifically, an ethylene / unsaturated carboxylic acid copolymer (A). Is added.

Examples of the basic compound include inorganic basic compounds such as sodium hydroxide and potassium hydroxide, and organic basic compounds such as amines such as ammonia, triethylamine, triethanolamine and dimethylethanolamine.

These basic compounds can be used alone or in combination of two or more.

As the basic compound, an inorganic basic compound is preferably mentioned, and sodium hydroxide is more preferable.

The amount of the basic compound added is, for example, relative to 100 mol of the carboxy group in the ethylene / unsaturated carboxylic acid copolymer (A) from the viewpoint of improving dispersion stability and printability of the laminate (described later). It is 5 mol or more, preferably 30 mol or more, more preferably 50 mol or more, and for example, 200 mol or less, preferably 150 mol or less.

If the amount of the basic compound added is less than the above range, the dispersion stability may be lowered and the printability may be lowered. Further, when the addition amount of the basic compound exceeds the above range, the viscosity of the aqueous dispersion may be increased and the workability may be lowered.

Further, after the addition of the neutralizing agent, it is preferably held at a predetermined temperature for a predetermined time.

As the holding conditions, the holding temperature is, for example, 40 ° C. or higher, preferably 50 ° C. or higher, and for example, 190 ° C. or lower, preferably 180 ° C. or lower. The holding time is, for example, 30 minutes or more, preferably 1 hour or more, and for example, 12 hours or less, preferably 10 hours or less.

By holding under the above conditions, the carboxy group is neutralized, and dispersion stability and printability of the laminate (described later) can be improved.

When the ethylene / unsaturated carboxylic acid copolymer (A) is neutralized, the degree of neutralization is, for example, 30% or more, preferably 50% or more, for example, 200% or less, preferably 150. % Or less.

When the degree of neutralization is within the above range, excellent adhesive strength and blocking resistance can be obtained. The degree of neutralization is calculated according to the examples described later.

The weight average molecular weight of the ethylene / unsaturated carboxylic acid copolymer (A) is, for example, 10,000 or more, preferably 30,000 or more, for example, 20 in terms of standard polystyrene measured by gel permeation chromatography (GPC). It is 10,000 or less, preferably 150,000 or less.

The melting point of the ethylene / unsaturated carboxylic acid copolymer (A) is, for example, 55 ° C. or higher, preferably 65 ° C. or higher, and for example, 110 ° C. or lower, preferably 100 ° C. or lower. The melting point can be determined by DSC (Differential Scanning Calorimetry).

The weight average particle diameter (measurement method: light scattering measurement) of the resin particles (I) made of the ethylene / unsaturated carboxylic acid copolymer (A) is, for example, 0.01 μm or more, preferably 0.02 μm or more. For example, it is 10 μm or less, preferably 1 μm or less.

The solid content concentration of the ethylene / unsaturated carboxylic acid copolymer (A) in the dispersion of the ethylene / unsaturated carboxylic acid copolymer (A) is, for example, 10% by mass or more, preferably 20% by mass or more. For example, it is 60% by mass or less, preferably 50% by mass or less.

These ethylene / unsaturated carboxylic acid copolymers (A) can be used alone or in combination of two or more.

<Polymer (B)>
The polymer (B) is a polymer obtained by polymerizing the second monomer component, and at least the (meth) acrylic acid ester unit obtained from the (meth) acrylic acid ester ((meth) acrylic acid ester monomer) is used. It has as a polymerization unit. That is, the second monomer component contains (meth) acrylic acid ester as an essential component, and the polymer (B) obtained by the polymerization thereof is an acrylic polymer.

The (meth) acrylic acid ester is defined as an acrylic acid ester and / or a methacrylic acid ester.

Examples of the (meth) acrylic acid ester include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, propyl (meth) acrylic acid, n-butyl (meth) acrylic acid, and iso-butyl (meth) acrylic acid. It has an alkyl moiety having 1 to 12 carbon atoms, such as s-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth) acrylate. ) Acrylic acid ester can be mentioned.

These (meth) acrylic acid esters can be used alone or in combination of two or more.

The (meth) acrylic acid ester is preferably methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, t-butyl (meth) acrylate. Butyl and 2-ethylhexyl (meth) acrylate can be mentioned, more preferably methyl (meth) acrylate and n-butyl (meth) acrylate can be mentioned, and more preferably methyl methacrylate and n methacrylate. -Butyl, butyl acrylate can be mentioned.

Further, the polymer (B) can contain, as an optional component, a polymerization unit obtained from a copolymerizable monomer copolymerizable with the (meth) acrylic acid ester.

Examples of the copolymerizable monomer include a functional group-containing vinyl monomer, an aromatic vinyl monomer, an N-substituted unsaturated carboxylic acid amide, a heterocyclic vinyl compound, a vinylidene halide compound, α-olefins, and dienes. Be done.

Examples of the functional group-containing vinyl monomer include a carboxy group-containing vinyl monomer, a hydroxyl group-containing vinyl monomer, an amino group-containing vinyl monomer, a glycidyl group-containing vinyl monomer, a cyano group-containing vinyl monomer, a sulfonic acid group-containing vinyl monomer and a salt thereof, and an aceto. Examples thereof include an acetoxy group-containing vinyl monomer, a phosphoric acid group-containing compound, an amide group-containing vinyl monomer, and vinyl esters.

Examples of the carboxy group-containing vinyl monomer include (meth) acrylic acid, maleic anhydride, maleic acid, fumaric acid, itaconic acid, and crotonic acid.

Examples of the hydroxyl group-containing vinyl monomer include 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate.

Examples of the amino group-containing vinyl monomer include 2-aminoethyl (meth) acrylate, 2- (N-methylamino) ethyl (meth) acrylate, and 2- (N, N-dimethylamino) (meth) acrylate. Ethyl and the like can be mentioned.

Examples of the glycidyl group-containing vinyl monomer include glycidyl (meth) acrylate.

Examples of the cyano group-containing vinyl monomer include (meth) acrylonitrile.

Examples of the sulfonic acid group-containing vinyl monomer include allyl sulfonic acid and metallic sulfonic acid. Examples of the salt include alkali metal salts such as sodium salt and potassium salt of the sulfonic acid group-containing vinyl monomer, for example, ammonium salt and the like. Specific examples thereof include sodium allyl sulfonate, sodium methallyl sulfonate, ammonium metharyl sulfonate and the like.

Examples of the acetoxy group-containing vinyl monomer include acetoxyethyl (meth) acrylate.

Examples of the phosphoric acid group-containing compound include 2-methacryloxyethyl acid phosphate and the like.

Examples of the amide group-containing vinyl monomer include (meth) acrylamide and the like.

Examples of vinyl esters include vinyl propionate (excluding vinyl acetate).

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, divinylbenzene and the like.

Examples of the N-substituted unsaturated carboxylic acid amide include N-methylol (meth) acrylamide.

Examples of the heterocyclic vinyl compound include vinylpyrrolidone and the like.

Examples of the halogenated vinylidene compound include vinylidene chloride and vinylidene fluoride.

Examples of α-olefins include ethylene and propylene.

Examples of the diene include butadiene and the like.

Further, as the copolymerizable monomer, a crosslinkable vinyl monomer can be mentioned.

Examples of the crosslinkable vinyl monomer include compounds containing two or more vinyl groups, such as methylenebis (meth) acrylamide, divinylbenzene, and polyethylene glycol chain-containing di (meth) acrylate.

These copolymerizable monomers can be used alone or in combination of two or more.

As the copolymerizable monomer, a functional group-containing vinyl monomer is preferably used.

Further, as described above, the (meth) acrylic acid ester includes an acrylic acid ester and a methacrylic acid ester, and from the viewpoint of water resistance, a methacrylic acid ester is preferable.

In the polymer (B), the content ratio of the (meth) acrylic acid ester and the copolymerizable monomer is such that the (meth) acrylic acid ester is, for example, 50% by mass or more, preferably 50% by mass or more, based on the total amount of the monomer components. It is 70% by mass or more, more preferably 77% by mass or more. The copolymerizable monomer is 50% by mass or less, preferably 30% by mass or less, and more preferably 23% by mass or less.

When the content ratio of the (meth) acrylic acid ester and the copolymerizable monomer is within the above range, excellent adhesive strength and blocking resistance can be obtained.

That is, the second monomer component may be only the (meth) acrylic acid ester without containing the copolymerizable monomer, and the (meth) acrylic acid ester and the copolymerizable monomer are contained in the above proportions. It may be used in combination. Preferably, only the (meth) acrylic acid ester is used, or the (meth) acrylic acid ester and the copolymerizable monomer are used in combination in the above proportions.

When the second monomer component is only a (meth) acrylic acid ester, the second monomer component is more preferably composed only of a (meth) acrylic acid ester having an alkyl moiety having 4 carbon atoms, or has 1 carbon atom. Examples thereof include a combination of a (meth) acrylic acid ester having an alkyl moiety of the above and a (meth) acrylic acid ester having an alkyl moiety having 4 carbon atoms.

When the second monomer component consists only of a (meth) acrylic acid ester having an alkyl moiety having 4 carbon atoms, it is particularly preferable that the second monomer component consists of only n-butyl methacrylate, or n-butyl methacrylate and acrylic acid. Examples include a combination with n-butyl.

Further, when the second monomer component is a combination of a (meth) acrylic acid ester having an alkyl moiety having 1 carbon atom and a (meth) acrylic acid ester having an alkyl moiety having 4 carbon atoms, methacrylic acid is particularly preferable. Examples thereof include a combination of methyl methacrylate and n-butyl methacrylate, and a combination of methyl methacrylate and n-butyl acrylate.

According to such a second monomer component, the glass transition temperature of the polymer (B) can be adjusted within the range described later.

When a carboxy group-containing vinyl monomer is used as the copolymerizable monomer, the content ratio thereof is, for example, 5% by mass or less, preferably 5% by mass or less, based on the total amount of the second monomer component from the viewpoint of production stability. It is 3% by mass or less. It should be noted that preferably, the second monomer component does not contain a carboxy group-containing vinyl monomer.

The polymerization of the second monomer component is not particularly limited, and a known polymerization method is adopted. For example, water, a second monomer component and a polymerization initiator are blended, and the second monomer component is polymerized in water.

The polymerization initiator is not particularly limited, but is, for example, hydrogen peroxide, for example, persulfates such as ammonium persulfate, potassium persulfate, sodium persulfate, for example, cumene hydroperoxide, t-butyl hydroperoxide, benzoyl. Organic peroxides such as peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, lauroyl peroxide, for example, azo compounds such as azobisisobutyronitrile, or with these. Examples thereof include metal ions such as iron ions and redox initiators in combination with reducing agents such as sodium sulfoxylate, formaldehyde, sodium pyrosulfate, sodium hydrogen peroxide, L-ascorbic acid, and longalit. These polymerization initiators can be used alone or in combination of two or more.

The blending ratio of the polymerization initiator is appropriately set according to the purpose and application, but is, for example, 0.1% by mass or more, for example, 5% by mass or less, based on the total amount of the second monomer component. Is.

Further, in the polymerization, a molecular weight modifier can be added, if necessary.

Examples of the molecular weight modifier include mercaptans such as t-dodecyl mercaptan and n-dodecyl mercaptan, and allyl compounds such as allyl sulfonic acid, metaallyl sulfonic acid and soda salts thereof. These molecular weight modifiers can be used alone or in combination of two or more. The blending ratio of the molecular weight adjusting agent is appropriately set according to the purpose and application.

As the polymerization conditions, the polymerization temperature is, for example, 30 ° C. or higher, preferably 50 ° C. or higher, and for example, 95 ° C. or lower, preferably 85 ° C. or lower under normal pressure. The polymerization time is, for example, 1 hour or more, preferably 2 hours or more, and for example, 30 hours or less, preferably 20 hours or less.

Further, in the production of the polymer (B), an emulsifier (surfactant) can be added, if necessary, from the viewpoint of improving the production stability.

Examples of the emulsifier (surfactant) include anionic surfactants, nonionic surfactants, cationic surfactants and the like.

Examples of anionic surfactants include sodium dodecylbenzene sulfonate, sodium lauryl sulfate, sodium alkyldiphenyl ether disulfonate, sodium alkylnaphthalene sulfonate, sodium dialkyl sulfosuccinate, sodium stearate, potassium oleate, and sodium dioctyl sulfosuccinate. , Sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, sodium dialkyl sulfosuccinate, sodium stearate, sodium oleate, sodium t-octylphenoxyethoxypolyethoxyethyl sulfate, etc. Can be mentioned.

Examples of the nonionic surfactant include polyoxyethylene lauryl ether, polyoxyethylene octylphenyl ether, polyoxyethylene oleylphenyl ether, polyoxyethylene nonylphenyl ether, oxyethylene / oxypropylene block copolymer, and t-octylphenoxy. Examples thereof include ethyl polyethoxyethanol and nonylphenoxy ethyl polyethoxyethanol.

Examples of the cationic surfactant include lauryltrimethylammonium chloride and stearyltrimethylammonium chloride.

These emulsifiers (surfactants) can be used alone or in combination of two or more.

As the emulsifier (surfactant), an anionic surfactant is preferable, and sodium dodecylbenzenesulfonate is more preferable.

The blending ratio of the emulsifier (surfactant) is not particularly limited, but from the viewpoint of production stability, it is, for example, 0.02% by mass or more, for example, 5% by mass or less with respect to the total amount of the second monomer component. ..

Further, in the production of the polymer (B), from the viewpoint of improving the production stability, for example, a pH adjuster, for example, a metal ion encapsulant such as ethylenediaminetetraacetic acid and a salt thereof, for example, mercaptans, low. Known additives such as a molecular weight regulator (chain transfer agent) such as a molecular halogen compound can be blended in an appropriate ratio.

The weight average molecular weight of the polymer (B) is, for example, 5,000 or more, preferably 10,000 or more, preferably 1 million or less, preferably 1 million or less, in terms of standard polystyrene measured by gel permeation chromatography (GPC). , 500,000 or less.

The glass transition temperature of the polymer (B) is, for example, −28 ° C. or higher, preferably −10 ° C. or higher, and for example, 80 ° C. or lower, preferably 60 ° C. or lower.

When the glass transition temperature of the polymer (B) is in the above range, excellent adhesive strength and blocking resistance can be obtained.

In particular, from the viewpoint of improving the adhesive strength, the glass transition temperature of the polymer (B) is preferably 20 ° C. or lower, more preferably 10 ° C. or lower.

Further, from the viewpoint of improving the blocking resistance, the glass transition temperature of the polymer (B) preferably exceeds 0 ° C., and more preferably 10 ° C. or higher. <Ethylene-vinyl acetate copolymer (C)>
The ethylene-vinyl acetate-based copolymer (C) is obtained by copolymerizing ethylene and vinyl acetate. Among the ethylene-vinyl acetate-based copolymers (C), ethylene is preferably 50% by mass or more and 95% by mass or less, and vinyl acetate is preferably 5% by mass, as the copolymerization ratio of ethylene and vinyl acetate. % Or more and 50% by mass or less.

In the copolymer (C), ethylene is preferably 52% by mass or more, more preferably 54% by mass or more, preferably 90% by mass or less, more preferably 85% by mass or less, and has an adhesive strength. From the viewpoint of improvement, it is more preferably 80% by mass or less. The vinyl acetate is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more, and preferably 48% by mass or less from the viewpoint of improving the adhesive strength. , More preferably 46% by mass or less.

When the copolymerization ratio of ethylene and vinyl acetate is in the above range, a heat-sealing material having excellent low-temperature heat-sealing properties can be obtained.

The ethylene-vinyl acetate-based copolymer (C) may contain carbon monoxide as a polymerization unit. The carbon monoxide unit is, for example, 2% by mass or more, preferably 5% by mass or more, and for example, 40% by mass or less, preferably 30% by mass or less, based on the copolymer.

The MFR (Melt flow rate) of the ethylene-vinyl acetate copolymer (C) is, for example, 2 g / 10 min or more, preferably 5 g / 10 min or more, and for example, 1000 g / 10 min or less, preferably 500 g / 10 min or more. It is as follows.

<Resin component>
As described above, the resin component is at least one polymer selected from the group consisting of the ethylene / unsaturated carboxylic acid copolymer (A), the polymer (B) and the ethylene / vinyl acetate copolymer (C). Should be included.

That is, as the resin component, the ethylene / unsaturated carboxylic acid copolymer (A) can be used alone, the polymer (B) can be used alone, and the ethylene / vinyl acetate copolymer can be used alone. The coalescence (C) can be used alone.

Further, the ethylene / unsaturated carboxylic acid copolymer (A) and the polymer (B) can be used in combination, and the polymer (B) and the ethylene / vinyl acetate-based copolymer (C) can be used in combination. In addition, an ethylene / vinyl acetate copolymer (C) and an ethylene / unsaturated carboxylic acid copolymer (A) can be used in combination.

Further, an ethylene / unsaturated carboxylic acid copolymer (A), a polymer (B) and an ethylene / vinyl acetate copolymer (C) can also be used in combination.

From the viewpoint of improving the adhesive strength, the ethylene / unsaturated carboxylic acid copolymer (A), the polymer (B) and the ethylene / vinyl acetate copolymer (C) are preferably used in combination.

When the ethylene / unsaturated carboxylic acid copolymer (A), the polymer (B) and the ethylene / vinyl acetate copolymer (C) are used in combination, the content ratio thereof is appropriately determined according to the purpose and application. Set.

For example, the content of the ethylene / unsaturated carboxylic acid copolymer (A) is, for example, 35% by mass or more, preferably 40% by mass or more, and more preferably 45% by mass or more with respect to 100% by mass of the resin component. For example, it is 70% by mass or less, preferably 68% by mass or less, and more preferably 67% by mass or less.

When the content ratio of the ethylene / unsaturated carboxylic acid copolymer (A) to the total amount of the resin components is in the above range, excellent adhesive strength can be obtained.

The content ratio of the ethylene / unsaturated carboxylic acid copolymer (A) in the resin component can be calculated from the charging ratio of the raw material component.

The content of the polymer (B) having an acrylic acid ester unit as a polymerization unit is, for example, 25% by mass or more, preferably 27% by mass or more, more preferably 28% by mass or more, for example, 64.5%. It is mass% or less, preferably 55% by mass or less, and more preferably 50% by mass or less.

The content of the ethylene-vinyl acetate copolymer (C) is, for example, 0.5% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, and for example, 20% by mass or less. It is preferably 15% by mass or less, and more preferably 10% by mass or less.
(However, the total amount of (A), (B) and (C) is 100%)
Further, the aqueous dispersion may contain the above resin component as a non-particulate resin, or may be contained as a particulate resin. Preferably, the resin component is contained as a particulate resin.

When the resin component is contained in the aqueous dispersion as a particulate resin, the resin component may be a single particle of each polymer or a composite particle composed of two or more kinds of polymers. Good.

Preferably, the ethylene / unsaturated carboxylic acid copolymer (A) and the polymer (B) having a (meth) acrylic acid ester unit as a polymerization unit form composite particles (D).

Further, preferably, the ethylene / unsaturated carboxylic acid copolymer (A) and the ethylene / vinyl acetate-based copolymer (C) form composite particles (E).

The aqueous dispersion preferably contains the composite particles (D) having (A) and (B) and the composite particles (E) having (A) and (C) as resin components.

<Composite particle (D)>
The ethylene / unsaturated carboxylic acid copolymer (A) and the polymer (B) form composite particles (D).

The form of the composite particle (D) is not particularly limited as long as it contains the above-mentioned ethylene / unsaturated carboxylic acid copolymer (A) and polymer (B), and for example, a core / shell structure or a composite structure. , Localized structure, Dull-like structure, Iddle-like structure, Raspberry-like structure, Multi-particle composite structure, IPN structure and the like.

In particular, a structure in which the polymer (B) is dispersed in the continuous phase of the ethylene / unsaturated carboxylic acid copolymer (A) is preferable.

The method for producing such a composite particle (D) is not particularly limited, and a known method can be adopted.

For example, composite particles (D) having a structure in which the polymer (B) is dispersed in the continuous phase of the ethylene / unsaturated carboxylic acid copolymer (A) can be obtained by the following method.

First, an ethylene / unsaturated carboxylic acid copolymer (A) is produced by the above method, and in the presence of the obtained ethylene / unsaturated carboxylic acid copolymer (A), the polymer (B) is produced by the above method. The composite particle (D) can be obtained by producing the above. Alternatively, after emulsifying the ethylene / unsaturated carboxylic acid copolymer (A) in the presence of water to obtain a dispersion liquid containing the resin particles (I) composed of the ethylene / unsaturated carboxylic acid copolymer (A). , A (meth) acrylic acid ester monomer is added to the dispersion liquid to polymerize the polymer (B) to produce a composite particle (D) having the copolymer (A) and the polymer (B). Can be done.

Further, for example, first, the polymer (B) is produced by the above method, and in the presence of the obtained polymer (B) (for example, in a dispersion), the ethylene / unsaturated carboxylic acid copolymer weight is obtained by the above method. The composite particle (D) can be obtained by producing the coalescence (A).

Preferably, the ethylene / unsaturated carboxylic acid copolymer (A) is emulsified in the presence of water to obtain a dispersion liquid containing the resin particles (I) composed of the ethylene / unsaturated carboxylic acid copolymer (A). To the dispersion liquid, a (meth) acrylic acid ester monomer is added to polymerize the polymer (B) to obtain a composite particle (D) having the copolymer (A) and the polymer (B). Since the ethylene / unsaturated carboxylic acid copolymer (A) has a self-emulsifying property, the amount of the emulsifier (surfactant) to be blended can be reduced. If the amount of the emulsifier is large, the adhesiveness may be affected. As the ethylene / unsaturated carboxylic acid copolymer (A), a commercially available product can be used as described above.

In the composite particles (D), the content ratio of the ethylene / unsaturated carboxylic acid copolymer (A) and the polymer (B) is the ethylene / unsaturated carboxylic acid copolymer (A) with respect to the total amount thereof. However, for example, 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, for example, 95% by mass or less, preferably 70% by mass or less, more preferably less than 50% by mass. is there. Further, the polymer (B) is, for example, 5% by mass or more, preferably 30% by mass or more, more preferably more than 50% by mass, for example, 99% by mass or less, preferably 95% by mass or less. More preferably, it is 90% by mass or less.

When the content ratio of the ethylene / unsaturated carboxylic acid copolymer (A) and the polymer (B) is in the above range, excellent adhesive strength can be obtained.

The content ratio of the ethylene / unsaturated carboxylic acid copolymer (A) and the polymer (B) in the composite particles (D) can be calculated from the charging ratio of the raw material components.

The weight average particle diameter (measurement method: light scattering measurement) of the composite particle (D) is, for example, 10 nm or more, for example, 10 μm or less, preferably 1 μm or less.

The average particle size of the composite particles (D) observed by an electron microscope is, for example, 50 nm or more, preferably 60 nm or more, more preferably 80 nm or more, and for example, 300 nm or less, more preferably 200 nm or less. More preferably, it is 120 nm or less.

When the average particle size is within the above range, the storage stability of the aqueous dispersion of the composite particles (D) can be improved, and the transparency and water resistance of the laminate (described later) can be improved. it can.

<Composite particle (E)>
The ethylene-unsaturated carboxylic acid copolymer (A) and the ethylene-vinyl acetate-based copolymer (C) form composite particles (E).

The form of the composite particle (E) is not particularly limited as long as it contains the above-mentioned ethylene / unsaturated carboxylic acid copolymer (A) and ethylene / vinyl acetate-based copolymer (C), and for example, the core. / Shell structure, composite structure, localized structure, dull structure, squid-like structure, raspberry-like structure, multi-particle composite structure, IPN structure and the like.

In particular, a structure in which the ethylene-unsaturated carboxylic acid copolymer (A) is dispersed in the continuous phase of the ethylene-vinyl acetate-based copolymer (C) is preferable. The weight average particle diameter of the composite particle (E) is, for example, 50 nm or more, preferably 60 nm or more, more preferably 80 nm or more, and for example, 300 nm or less, preferably 200 nm or less, more preferably 120 nm or less. is there.

The method for producing such a composite particle (E) is not particularly limited, and a known method can be adopted.

For example, composite particles (E) having a structure in which the ethylene-unsaturated carboxylic acid copolymer (A) is dispersed in the continuous phase of the ethylene-vinyl acetate-based copolymer (C) can be obtained by the following method.

First, an ethylene / unsaturated carboxylic acid copolymer (A) and an ethylene / vinyl acetate-based copolymer (C) are produced by the above method, respectively, and the ethylene / unsaturated carboxylic acid copolymer (A) and ethylene are produced. -Composite particles (E) can be obtained by combining with the vinyl acetate-based copolymer (C) and emulsifying at the same time. Since the ethylene / unsaturated carboxylic acid copolymer (A) has a self-emulsifying property, the amount of the emulsifier (surfactant) to be blended can be reduced. If the amount of the emulsifier is large, the adhesiveness may be affected. As the ethylene / unsaturated carboxylic acid copolymer (A), a commercially available product can be used as described above.

In the composite particle (E), the content ratio of the ethylene / unsaturated carboxylic acid copolymer (A) and the ethylene / vinyl acetate copolymer (C) is the same as that of the ethylene / vinyl acetate copolymer with respect to their total amount. The polymer (C) is, for example, 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, for example, 95% by mass or less, preferably 70% by mass or less, more preferably. It is less than 50% by mass. Further, the ethylene / unsaturated carboxylic acid copolymer (A) is, for example, 5% by mass or more, preferably 30% by mass or more, more preferably more than 50% by mass, for example, 99% by mass or less, preferably 99% by mass or less. Is 95% by mass or less, more preferably 90% by mass or less.

When the content ratio of the ethylene / unsaturated carboxylic acid copolymer (A) and the ethylene / vinyl acetate-based copolymer (C) is within the above range, excellent adhesive strength can be obtained.

The content ratio of the ethylene / unsaturated carboxylic acid copolymer (A) and the ethylene / vinyl acetate-based copolymer (C) in the composite particles (E) can be calculated from the charging ratio of the raw material components.

The weight average particle diameter (measurement method: light scattering measurement) of the composite particle (E) is, for example, 10 nm or more, for example, 10 μm or less, preferably 1 μm or less.

When the weight average particle size is within the above range, the storage stability of the aqueous dispersion of the composite particles (E) can be improved, and the transparency and water resistance of the laminate (described later) can be improved. Can be done.

<Water-soluble cellulose ether>
The water-soluble cellulose ether is an additive (water repellent inhibitor) that suppresses the resilience of the aqueous dispersion to the substrate.

Examples of the water-soluble cellulose ether include alkyl cellulose, hydroxyalkyl cellulose, hydroxyalkyl alkyl cellulose, and carboxyalkyl cellulose.

Examples of the alkyl cellulose include C1-4 alkyl cellulose such as methyl cellulose, ethyl cellulose and propyl cellulose, and these can be used alone or in combination of two or more.

In alkyl cellulose, the degree of substitution of the alkoxy group is, for example, 0.3 or more, preferably 0.5 or more, and for example, 2.5 or less, preferably 2.0 or less.

The degree of substitution indicates the average number of hydroxyl groups substituted with alkoxy groups per glucose ring unit of cellulose (the same applies hereinafter).

Examples of the hydroxyalkyl cellulose include hydroxy C2-4 alkyl cellulose such as hydroxyethyl cellulose and hydroxypropyl cellulose.

In hydroxyalkyl cellulose, the number of substitution moles of the hydroxyalkoxy group is, for example, 0.05 or more, preferably 0.10 or more, and for example, 0.80 or less, preferably 0.50 or less.

The number of moles substituted indicates the average number of moles of functional groups added per glucose ring unit of cellulose (the same applies hereinafter).

Examples of the hydroxyalkylalkyl cellulose include hydroxy C2-4 alkyl C1-4 alkyl cellulose such as hydroxyethyl methyl cellulose, hydroxyethyl ethyl cellulose and hydroxypropyl methyl cellulose.

In hydroxyalkylalkylcellulose, the degree of substitution of the alkoxy group is, for example, 0.3 or more, preferably 0.5 or more, and for example, 2.0 or less, preferably 2.5 or less.

Further, in the hydroxyalkylalkyl cellulose, the number of substitution moles of the hydroxyalkoxy group is, for example, 0.05 or more, preferably 0.10 or more, for example, 0.80 or less, preferably 0.50 or less. ..

Examples of the carboxyalkyl cellulose include carboxy C2-4 alkyl cellulose such as carboxymethyl cellulose.

In carboxyalkyl cellulose, the degree of substitution of the alkoxy group is, for example, 0.3 or more, preferably 0.5 or more, and for example, 2.5 or less, preferably 2.0 or less.

Further, in the carboxyalkyl cellulose, the number of moles of substitution of the carboxy group is, for example, 0.05 or more, preferably 0.10 or more, and for example, 0.80 or less, preferably 0.50 or less.

The water-soluble cellulose ether can also be obtained as a commercially available product, and such commercially available products include, for example, alkyl celluloses such as Metrose SM series and Metrose MCE series (all manufactured by Shin-Etsu Chemical Co., Ltd.), for example, Metrose. Examples thereof include hydroxyalkyl-alkyl celluloses such as 60SH series, Metros 65SH series, Metros 90SH series, Metros SEB series, Metros SNB series, Metros SFE series, and Metros NE series (all manufactured by Shin-Etsu Chemical Co., Ltd.).

These water-soluble cellulose ethers can be used alone or in combination of two or more.

Then, as the water-soluble cellulose ether, a water-soluble cellulose ether having a viscosity in a predetermined range under specific conditions is selected and used.

More specifically, the water-soluble cellulose ether used in the present invention has a viscosity of a 2% by mass aqueous solution of the water-soluble cellulose ether at 20 ° C. of 5 mPa · s or more, preferably 8 mPa · s or more, more preferably. It is 10 mPa · s or more, 90 mPa · s or less, preferably 80 mPa · s or less, more preferably 60 mPa · s or less, still more preferably 50 mPa · s or less, still more preferably 40 mPa · s or less, particularly preferably. , 30 mPa · s or less.

By using a water-soluble cellulose ether having a viscosity of a 2% by mass aqueous solution at 20 ° C. in the above range, the repulsability of the aqueous dispersion with respect to the substrate can be suppressed, and a laminated body (described later) having an excellent appearance can be obtained.

The 2% by mass aqueous solution of the water-soluble cellulose ether can be obtained by dissolving the above-mentioned water-soluble cellulose ether in water so as to be a 2% by mass aqueous solution.

The viscosity of the 2% by mass aqueous solution of the water-soluble cellulose ether is measured by a B-type rotational viscometer at 20 ° C., 60 rpm, and 60 sec.

The viscosity of the 2% by mass aqueous solution of the water-soluble cellulose ether is adjusted by, for example, the degree of substitution of the alkoxy group, the number of substitution moles of the hydroxyalkoxy group, the number of substitution moles of the carboxy group, the number of repeating units (molecular weight) of the glucose ring, and the like. Will be done.

Examples of commercially available water-soluble cellulose ethers satisfying such conditions include Metrose 60SH-15 (2% by mass aqueous solution viscosity (20 ° C.) 15 mPa · s) and Metrose MCE-15 (2% by mass aqueous solution viscosity (20 ° C.)). ) 15 mPa · s), Metrose SE-50 (2 mass% aqueous solution viscosity (20 ° C.) 50 mPa · s) and the like.

These water-soluble cellulose ethers can be used alone or in combination of two or more.

As the water-soluble cellulose ether, preferably, hydroxyalkylalkyl cellulose having a viscosity of a 2% by mass aqueous solution in the above range can be mentioned, and more preferably, hydroxy C2-4alkyl C1- having a viscosity of a 2% by mass aqueous solution in the above range. Examples thereof include 4-alkyl cellulose, and more preferably, hydroxypropyl methyl cellulose having a viscosity of a 2% by mass aqueous solution in the above range.

The content ratio of the water-soluble cellulose ether is, for example, 0.05 parts by mass or more, preferably 0.1 parts by mass or more, based on 100 parts by mass of the total amount of the resin components (total solid content (nonvolatile content)). For example, it is 30 parts by mass or less, preferably 10 parts by mass or less.

<Additives>
The aqueous dispersion may further contain additives in addition to the above resin components and water-soluble cellulose ether.

Examples of the additive include the above-mentioned emulsifier, other curing agent, cross-linking agent, film-forming auxiliary, defoaming agent, anti-repellent agent, leveling agent, tackifier, hardness-imparting agent, preservative, thickener, and the like. Known additives such as antifreeze agents, dispersants, inorganic pigments and organic pigments can be mentioned. These additives can be used alone or in combination of two or more. The blending ratio and blending timing of the additive are appropriately set according to the purpose and application.

The solid content concentration of the aqueous dispersion is, for example, 10% by mass or more, preferably 20% by mass or more, and for example, 60% by mass or less, preferably 50% by mass or less.

The pH of the aqueous dispersion is, for example, 7 or more, preferably 8 or more, and for example, 11 or less, preferably 10 or less.

Such an aqueous dispersion contains a water-soluble cellulose ether having a viscosity of a 2% by mass aqueous solution at 20 ° C. of 5 mPa · s or more and 90 mPa · s or less.

Therefore, according to the above-mentioned aqueous dispersion, the resilience to the base material can be suppressed, and a laminated body having an excellent appearance can be obtained.

Further, if such an aqueous dispersion is used for forming an adhesive layer (heat seal layer) of the laminated body, a laminated body having excellent adhesive strength can be obtained.

Therefore, the aqueous dispersion is suitably used as an adhesive composition for forming an adhesive layer in a laminated body including a base material and an adhesive layer laminated on at least one surface of the base material. be able to.

<Laminated body>
In FIG. 1, the laminated body 1 includes a base material 2 and an adhesive layer 3 laminated on one side surface of the base material 2.

Examples of the base material 2 include a resin base material, a metal base material, and a composite base material.

Examples of the resin base material include cellophane, polyethylene, ethylene / vinyl acetate copolymer, ionomer, polypropylene, polyamide (nylon), polyester, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene / vinyl alcohol copolymer, and the like. Examples thereof include a plastic film made of a plastic material such as polypropylene, polystyrene, and a polyacrylonitrile copolymer.

Examples of the metal base material include a metal plate and a metal foil, and examples of the metal include aluminum, gold, silver, copper, nickel, zinc, titanium, cobalt, indium, and chromium.

As the composite base material, for example, a metal (aluminum, gold, silver, copper, nickel, zinc, titanium, cobalt, indium, chromium, etc.) or an oxide thereof (aluminum oxide, silicon oxide, etc.) is placed on the plastic film. Examples thereof include a vapor-deposited film.

Further, examples of the base material 2 include paper and non-woven fabric.

These base materials 2 can be used alone or in combination of two or more.

As the base material 2, a metal base material is preferably used, a metal base material made of aluminum is more preferable, and a metal foil made of aluminum is more preferable.

Further, the base material 2 may be surface-treated, if necessary. Examples of the surface treatment include ink (solvent-based, water-based) coating treatment, plating treatment, coupling treatment, vacuum plasma treatment, etc., preferably ink coating treatment, and more preferably solvent-based ink coating. Processing can be mentioned.

The adhesive layer 3 is a dried product of the above-mentioned aqueous dispersion, and can be obtained by applying (coating) and drying the above-mentioned aqueous dispersion on one side surface of the base material 2.

The method for applying (coating) the aqueous dispersion is not particularly limited, and for example, known methods such as gravure roll coating, three-roll coating, immersion coating, and spray coating are adopted.

As the drying conditions, the drying temperature is, for example, 100 to 200 ° C., and the drying time is, for example, 10 seconds to 30 minutes.

Further, before coating and drying, a primer (titanate, polyethyleneimine, etc.) can be applied to the base material 2 in order to improve the adhesion between the base material 2 and the adhesive layer 3. In addition, pretreatment such as corona discharge treatment and chemical conversion treatment can be performed.

According to such a laminated body 1, since the above-mentioned aqueous dispersion is used for the adhesive layer 3, excellent adhesive strength and blocking resistance can be obtained. Further, since it is an aqueous dispersion and is not a dispersion in which particles are dispersed in an organic solvent such as ethyl acetate or toluene, the amount of residual organic solvent in the adhesive layer 3 is preferably 100 ppm or less, more preferably 10 ppm. It can be as follows.

Therefore, the laminate 1 is used as a material for heat sealing in various industrial fields.

In the heat seal, as shown in FIG. 1, the base material 2 and the adherend layer 4 (see the broken line in FIG. 1) are attached via the adhesive layer 3.

The adherend layer 4 is a material to which the above-mentioned laminate 1 is adhered, and examples thereof include a resin material, a metal material, and a composite material.

Examples of the resin material include cellophane, polyethylene, ethylene / vinyl acetate copolymer, ionomer, polypropylene, polyamide (nylon), polyester, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene / vinyl alcohol copolymer, and polycarbonate. , Polyester, a plastic film made of a plastic material such as a polyacrylonitrile copolymer, and the like.

Examples of the metal material include a metal plate and a metal foil, and examples of the metal include aluminum, gold, silver, copper, nickel, zinc, titanium, cobalt, indium, and chromium.

As the composite material, for example, a metal (aluminum, gold, silver, copper, nickel, zinc, titanium, cobalt, indium, chromium, etc.) or an oxide thereof (aluminum oxide, silicon oxide, etc.) is deposited on the plastic film. Examples thereof include a vapor-deposited film.

Further, examples of the adherend layer 4 include paper and non-woven fabric.

These adherend layers 4 can be used alone or in combination of two or more.

Further, the adherend layer 4 may be surface-treated, if necessary. Examples of the surface treatment include ink (solvent-based, water-based) coating treatment, plating treatment, coupling treatment, vacuum plasma treatment, etc., preferably ink coating treatment, and more preferably solvent-based ink coating. Processing can be mentioned.

Further, as the adherend layer 4, a laminated body 1 including a base material 2 and an adhesive layer 3 can also be mentioned.

These adherend layers 4 can be used alone or in combination of two or more.

The adherend layer 4 is preferably a plastic film made of polyvinyl chloride or polyvinylidene chloride from the viewpoint of adhesive strength and ease of adhesion.

The method for heat-sealing the base material 2 and the adherend layer 4 is not particularly limited, and a known method is adopted. For example, as shown in FIG. 1, the base material 2 and the adherend layer 4 are laminated via the adhesive layer 3, and then heated and pressurized. When the laminated body 1 is used as the adherend layer 4, the adhesive layers 3 are bonded to each other, and the two base materials 2 are laminated via the two adhesive layers 3 to be heated and applied. Be pressured.

The heating temperature is, for example, 80 ° C. or higher, preferably 100 ° C. or higher, and for example, 250 ° C. or lower, preferably 200 ° C. or lower. The pressure is, for example, 50 kPa or more, preferably 100 kPa or more, and for example, 500 kPa or less, preferably 300 kPa or less.

As a result, the base material 2 and the adherend layer 4 are thermocompression-bonded.

The adhesive strength between the base material 2 and the adherend layer 4 can be measured by the peel strength between the base material 2 and the adherend layer 4. Preferably, the peel strength of 180 degree peeling after thermocompression bonding at a pressure of 2 kg / cm ² for 0.5 seconds at a temperature of 110 ° C. is 900 g / 15 mm or more.

In this way, the laminate 1 in which the adherend layer 4 is laminated on one side surface of the adhesive layer 3 (in other words, the adherend layer 4 laminated on one side surface of the adhesive layer 3). The provided laminate 1) is included in the present invention regardless of its heat-sealed state (that is, before and after the heat-sealing).

Since such a laminate 1 is obtained by using the above-mentioned aqueous dispersion, the repulsability of the aqueous dispersion with respect to the base material 2 is suppressed, and the appearance is excellent.

Further, such a laminate 1 has excellent adhesive strength and blocking resistance.

Therefore, the laminate 1 is suitably used as a packaging material in various industrial fields.

The object to be packaged by the laminate 1 is not particularly limited, and examples thereof include various industrial products such as confectionery, foods, daily necessities, pharmaceuticals, and papers.

In particular, in the fields of pharmaceuticals and food packaging, it is expected to have effects such as suppressing deterioration of packaging materials and objects to be packaged during heat sealing, improving productivity and reducing power consumption by increasing the filling speed. .. Further, since the adhesive composition for forming the adhesive layer 3 is an aqueous dispersion, it has a feature that the burden on the environment is small.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, specific numerical values such as a compounding ratio (content ratio), a physical property value, a parameter, etc. used in the following description are described in the above-mentioned "mode for carrying out the invention", and the compounding ratio corresponding to them ( Substitute the upper limit value (value defined as "less than or equal to" or "less than") or the lower limit value (value defined as "greater than or equal to" or "excess") such as content ratio), physical property value, and parameters. be able to.

<Example 1>
Ethylene content: 85% by mass, methacrylic acid content: 15% by mass, solid content: 27% by mass, 200 parts by mass of neutralized sodium hydroxide of ethylene / unsaturated carboxylic acid copolymer (A), deionized water 27 parts by mass was charged into a reaction vessel, the temperature was raised to 80 ° C. under a nitrogen stream, and 0.3 parts by mass of potassium persulfate was added. The degree of neutralization at this time was measured by the following method.

Separately, 80 parts by mass of n-butyl methacrylate, 20 parts by mass of n-butyl acrylate and 0.2 parts by mass of n-dodecyl mercaptan (molecular weight modifier) are added by 0.4 parts by mass of sodium dodecylbenzene sulfonic acid (emulsifier). The polymerization was completed by emulsifying in 40 parts by mass of deionized water, dropping the obtained emulsified mixture into the above-mentioned reaction vessel in 2 hours, and then holding the mixture at 80 ° C. for 2 hours. As a result, a polymer (B) was formed, and an aqueous dispersion of composite particles (D) having a solid content concentration of 38% by mass was obtained.

Next, the above-mentioned ethylene content: 85% by mass, methacrylic acid content: 15% by mass, ethylene / unsaturated carboxylic acid copolymer (A), and ethylene content: 67% by mass, vinyl acetate content: 33. 100 parts by mass of resin obtained by melt-kneading a mass% ethylene / vinyl acetate copolymer (C) at 150 ° C. using a uniaxial extruder, 5 parts by mass of 48% by mass potassium hydroxide, and deionization. 239 parts by mass of water was charged into a reaction vessel, the temperature was raised to 150 ° C. under a nitrogen stream, and the temperature was maintained at the same temperature for 4 hours. The degree of neutralization at this time was measured by the following method. As a result, an aqueous dispersion of composite particles (E) having a solid content concentration of 42% by mass, containing an ethylene / unsaturated carboxylic acid copolymer (A) and an ethylene / vinyl acetate copolymer (C), was obtained. ..

Then, 31 parts by mass of the aqueous dispersion of the composite particles (E) was added to 100 parts by mass of the aqueous dispersion of the composite particles (D), mixed, and then Metrose 60SH-15 (hydroxypropyl methylcellulose) as a water-soluble cellulose ether was added. , Shin-Etsu Chemical Co., Ltd.) was added in an amount of 0.4 parts by mass.

Then, the obtained mixture was adjusted to a solid content concentration of 40% by mass with deionized water to obtain an aqueous dispersion. Details of the added water-soluble cellulose ether are described below.

Product name: Metrose 60SH-15 (manufactured by Shin-Etsu Chemical)
Chemical name: Hydroxypropyl methylcellulose Degree of substitution of methoxy group: 1.9
Number of moles substituted for hydroxypropoxy group: 0.25
Viscosity (2% by mass solution, 20 ° C): 15 mPa · s
The viscosity is the viscosity of a water-soluble cellulose ether aqueous solution adjusted to 2% by mass with ion-exchanged water at 20 ° C. The measurement conditions are as follows (the same applies hereinafter).

Measuring device: B-type rotational viscometer Measuring conditions: 20 ° C, 60 rpm, 60 sec
<Example 2>
An aqueous dispersion was obtained in the same manner as in Example 1 except that Metrose MCE-15 (methyl cellulose, Shin-Etsu Chemical Co., Ltd.) was used as the water-soluble cellulose ether instead of Metrose 60SH-15. Details of the added water-soluble cellulose ether are described below.

Product name: Metrose MCE-15 (manufactured by Shin-Etsu Chemical)
Chemical name: Methyl cellulose Degree of substitution of methoxy group: 0.75-0.99
Viscosity (2% by mass solution, 20 ° C): Viscosity: 15 mPa · s
<Example 3>
An aqueous dispersion was obtained in the same manner as in Example 1 except that Metrose SE-50 (hydroxypropyl methylcellulose, Shin-Etsu Chemical Co., Ltd.) was used as the water-soluble cellulose ether instead of Metrose 60SH-15. Details of the added water-soluble cellulose ether are described below.

Product name: Metrose SE-50 (manufactured by Shin-Etsu Chemical)
Chemical name: Hydroxypropyl methylcellulose Degree of substitution of methoxy group: 0.81-0.90
Degree of Substitution of Hydroxypropoxy Group: 0.21-0.36
Viscosity (2% by mass solution, 20 ° C): 50 mPa · s
<Comparative example 1>
An aqueous dispersion was obtained in the same manner as in Example 1 except that Metrose SE-03 (hydroxypropyl methylcellulose, Shin-Etsu Chemical Co., Ltd.) was used instead of Metrose 60SH-15 as the water-soluble cellulose ether. Details of the added water-soluble cellulose ether are described below.

Product name: Metrose SE-03 (manufactured by Shin-Etsu Chemical)
Chemical name: Hydroxypropyl methylcellulose Degree of substitution of methoxy group: 0.81-0.90
Degree of Substitution of Hydroxypropoxy Group: 0.21-0.36
Viscosity (2% by mass solution, 20 ° C): 3 mPa · s
<Comparative example 2>
An aqueous dispersion was obtained in the same manner as in Example 1 except that Metrose NE-100 (hydroxypropyl methylcellulose, Shin-Etsu Chemical Co., Ltd.) was used as the water-soluble cellulose ether instead of Metrose 60SH-15. Details of the added water-soluble cellulose ether are described below.

Product name: Metros NE-100 (manufactured by Shin-Etsu Chemical)
Chemical name: Hydroxypropyl methylcellulose Degree of substitution of methoxy group: 0.57-0.72
Degree of Substitution of Hydroxypropoxy Group: 0.12-0.36
Viscosity (2% by mass solution, 20 ° C): 100 mPa · s
<Measurement method>
1) Degree of neutralization The infrared absorption spectrum of the sample is measured, and the peak height of absorption of 1700 cm ^-1 corresponding to the carboxy group is determined (the peak height is a).

Further, the sample is brought into contact with hydrochloric acid to remove metal ions in the resin (demetallation) to obtain an acid copolymer having no ionic bond (intramolecular cross-linking). The infrared absorption spectrum of the sample of this acid copolymer is measured, and the peak height of absorption of 1700 cm ^-1 is obtained (the peak height is b).

The peak height a corresponds to the number of union-bonded carboxy groups in the resin.

Further, the peak height b corresponds to the number of all carboxy groups in the resin.

Therefore, the degree of neutralization (%) is calculated by the following formula.

Neutralization degree (%) = 100-100 × a / b
2) Glass transition temperature (Tg)
The glass transition temperature is determined by the method described in Computational Materials Science of Polymers (AA Askadskii, Cambridge Science Pub (2005/12/30)) Chapter XII. Here, the glass transition temperature is determined using the calculation software CHEOPS (version 4.0, Million Zillion Software) in which the above method is adopted.

3) Appearance evaluation The solid content concentration of the aqueous dispersion was adjusted to 37% with deionized water.

The obtained aqueous dispersion was applied to a hard aluminum foil (20 μm) coated with a solvent-based ink with a wire bar so that the coating amount was 3 g / m ^2, and dried at 180 ° C. for 10 seconds. A laminate composed of a hard aluminum foil and a dry coating film of an aqueous dispersion was obtained.

Then, in the obtained laminate, the coating appearance of the aqueous dispersion was observed.

In addition, the appearance evaluation of the one in which the playing was observed was evaluated as x.

In addition, the appearance evaluation was ○ for those for which no playing was observed.

4) Thermal sealability The solid content concentration of the aqueous dispersion of Example 1 was adjusted to 37% with deionized water.

The obtained aqueous dispersion was applied to a hard aluminum foil (20 μm) coated with a solvent-based ink with a wire bar so that the coating amount was 3 g / m ^2, and dried at 180 ° C. for 10 seconds. A laminate composed of a hard aluminum foil and a dry coating film of an aqueous dispersion was obtained.

The resulting laminate was overnight left at room temperature, cut into strips of 15mm width, overlay coating surface and PVC sheet (200 [mu] m) between, at 110 ° C., 0.5 sec heat sealed at a pressure 2 kg / cm ² did. Using the obtained test piece, the peel strength was measured at 180 degrees under the condition of a tensile speed of 200 mm / min. As a result, it was 1670 g / 15 mm.

Claims (6)

An aqueous dispersion containing a resin component, a water-soluble cellulose ether, and water.
The resin component consists of a group consisting of an ethylene / unsaturated carboxylic acid copolymer (A), a polymer (B) having an acrylic acid ester unit as a polymerization unit, and an ethylene / vinyl acetate-based copolymer (C). Contains at least one polymer of choice,
An aqueous dispersion having a viscosity of a 2% by mass aqueous solution of the water-soluble cellulose ether at 20 ° C. of 5 mPa · s or more and 90 mPa · s or less. The resin component is
A composite particle (D) having the ethylene / unsaturated carboxylic acid copolymer (A) and the polymer (B) having the acrylic acid ester unit as a polymerization unit.
The first aspect of claim 1, wherein the ethylene / unsaturated carboxylic acid copolymer (A) and the composite particles (E) having the ethylene / vinyl acetate copolymer (C) are contained. Water dispersion. A base material and an adhesive layer laminated on at least one surface of the base material are provided.
A laminate, wherein the adhesive layer is a dried product of the aqueous dispersion according to claim 1 or 2. The laminate according to claim 3, further comprising an adherend layer laminated on one side surface of the adhesive layer. The laminate according to claim 4, wherein the adherend layer comprises polyvinyl chloride and / or polyvinylidene chloride. The laminate according to any one of claims 3 to 5, wherein the base material is made of aluminum.

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