KR20210089101A - Acrylic emulsion pressure snsitive adhesive composition - Google Patents

Abstract

The present invention relates to an acrylic emulsion adhesive composition, and more specifically, to an acrylic emulsion adhesive composition which can implement excellent adhesive properties, and thus can be usefully used for a bottle label and the like since it is possible to maintain excellent adhesive strength even after aging in particular, when applied to a substrate attached to a curved surface.

Description

Acrylic emulsion adhesive composition {ACRYLIC EMULSION PRESSURE SNSITIVE ADHESIVE COMPOSITION}

The present invention relates to an acrylic emulsion pressure-sensitive adhesive composition.

An adhesive (Pressure-Sensitive Adhesive, PSA) is a material that has the property of adhering to an adherend with a small pressure. It is a viscoelastic material different from adhesives and has basic properties of initial adhesion, adhesion, and cohesion, and is used in various industries such as printing, chemistry, pharmaceuticals, home appliances, automobiles, and stationery.

Among them, adhesive labels called labels or label stickers are used in almost all industrial fields such as printing, chemicals, pharmaceuticals, cosmetics, food industries, home appliances, automobiles, and stationery, as well as trademarks and advertisements of products. The adherend used as an adhesive label is paper such as art paper, imitation paper, mirage paper, gold and silver paper, thermal paper, kraft paper, fluorescent paper, sterile paper, photo paper, or PET, PVC, PE, PP, PS, PI, etc. Polymer films are mainly used, and they are usually applied to final products through constant printing on the surface.

The strength of the adhesive force is determined according to the purpose of the adhesive used in the adhesive label.

For example, a permanent adhesive shows a strong adhesive force of about 8 N/in or more based on a 180 degree peel strength using a standard adherend, but when paper is used as an adherend, when peeling, the adherend can be destroyed

On the other hand, a removable pressure-sensitive adhesive exhibits an adhesive force of about 5 to 8 N/in based on a 180 degree peel strength using a standard adherend. This is a level of adhesion that can be peeled off if necessary, and can usually be used for temporary labeling applications.

However, in the case of a generally used acrylic emulsion pressure-sensitive adhesive, when the adhesive force (tack properties) is improved, the shear resistance is reduced, and the change with time proceeds after aging, which may cause a problem in that the adhesion to a curved surface is greatly reduced.

An object of the present specification is to provide an acrylic emulsion pressure-sensitive adhesive composition that can implement excellent adhesive strength, and can maintain excellent adhesive strength even after aging, particularly when applied to a curved surface to be attached to a substrate.

The present specification, (A) (A1) an alkyl (meth) acrylate-based monomer-derived first repeating unit; (A2) a second repeating unit derived from a hydroxyalkyl (meth)acrylate-based monomer; (A3) a third repeating unit derived from an unsaturated carboxylic acid-based monomer; and (A4) an emulsion polymer particle (A) comprising a fourth repeating unit derived from a vinyl-based monomer; And (B) provides an acrylic emulsion pressure-sensitive adhesive composition comprising an aluminum-based surface curing agent.

The alkyl (meth) acrylate-based monomer is, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl ( Meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, isobornyl (meth)acrylate, and lauryl (meth)acrylate It may include one or more selected from the group consisting of.

And, the alkyl (meth) acrylate-based monomer, (a11) an alkyl (meth) acrylate-based monomer having 1 to 3 carbon atoms in the alkyl group; (a12) an alkyl (meth)acrylate-based monomer having 4 to 6 carbon atoms in the alkyl group; and (a13) an alkyl (meth)acrylate-based monomer having 7 to 10 carbon atoms in the alkyl group.

And, the hydroxy alkyl (meth) acrylate-based monomer is at least one selected from the group consisting of hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate may include

In addition, the unsaturated carboxylic acid-based monomer is acrylic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid (mesaconic acid), glutaconic acid, and allylmalonic acid may include at least one selected from the group consisting of.

In addition, the vinyl-based monomer may include at least one selected from the group consisting of a vinyl ether-based monomer, a vinyl ester-based monomer, a vinyl amide-based monomer, and an aromatic vinyl-based monomer.

According to an embodiment of the present invention, the aluminum-based surface curing agent may include an aluminum salt of an organic acid containing both a hydroxy group and a carboxy group in a molecule.

At this time, the aluminum-based surface curing agent, based on 100 parts by weight of the emulsion polymer particles, may be included in an amount of about 0.1 to about 1.0 jungang.

According to another embodiment of the present invention, the emulsion polymer comprises, based on the total weight of the emulsion polymer, (A1) about 60 to about 90 wt% of a first repeating unit derived from an alkyl (meth)acrylate-based monomer; (A2) about 0.1 to about 10 wt% of a second repeating unit derived from a hydroxyalkyl (meth)acrylate-based monomer; (A3) about 0.1 to about 10 wt% of a third repeating unit derived from an unsaturated carboxylic acid-based monomer; and (A4) about 5 to about 20 wt% of a fourth repeating unit derived from a vinyl-based monomer, and more preferably, (A1) about 80 to about 20 wt% of a first repeating unit derived from an alkyl (meth)acrylate-based monomer. 90 wt %; (A2) about 1 to about 10 wt% of a second repeating unit derived from a hydroxyalkyl (meth)acrylate-based monomer; (A3) about 0.1 to about 5 wt% of a third repeating unit derived from an unsaturated carboxylic acid-based monomer; and (A4) about 5 to about 15 wt% of a fourth repeating unit derived from a vinyl-based monomer.

In this case, the first repeating unit is (a13) based on 100 parts by weight of the repeating unit derived from the alkyl (meth)acrylate-based monomer having 7 to 10 carbon atoms in the alkyl group, (a11) 1 to 3 carbon atoms in the alkyl group. About 100 to about 150 parts by weight, or about 120 to about 150 parts by weight of a repeating unit derived from an alkyl (meth)acrylate-based monomer, and (a12) an alkyl (meth)acrylate-based monomer having 4 to 6 carbon atoms in the alkyl group It may include from about 10 to about 50 parts by weight of the repeating unit, or from about 20 to about 30 parts by weight.

According to an embodiment of the invention, the surface of the emulsion polymer particles may include a surface cross-linkage formed by the aluminum-based surface curing agent.

On the other hand, the present specification, the description; and an adhesive layer formed on at least one surface on the substrate, wherein the adhesive layer is formed by the acrylic emulsion adhesive composition according to claim 1, and provides an adhesive member.

In the present invention, terms such as first, second, etc. are used to describe various components, and the terms are used only for the purpose of distinguishing one component from other components.

In addition, the terminology used herein is only used to describe exemplary embodiments, and is not intended to limit the present invention.

The singular expression includes the plural expression unless the context clearly dictates otherwise.

In this specification, terms such as "comprises", "comprises" or "have" are intended to describe embodied features, numbers, steps, components, or combinations thereof, and include one or more other features, numbers, or steps. , components, combinations or additions thereof are not excluded.

Also in this specification, when it is said that each layer or element is formed "on" or "on" each layer or element, it means that each layer or element is formed directly on each layer or element, or other It means that a layer or element may additionally be formed between each layer, on the object, on the substrate.

Since the present invention may have various changes and may have various forms, specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to the specific disclosed form, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Hereinafter, the present invention will be described in detail.

According to an aspect of the present invention, (A) (A1) an alkyl (meth) acrylate-based monomer-derived first repeating unit; (A2) a second repeating unit derived from a hydroxyalkyl (meth)acrylate-based monomer; (A3) a third repeating unit derived from an unsaturated carboxylic acid-based monomer; and (A4) an emulsion polymer particle (A) comprising a fourth repeating unit derived from a vinyl-based monomer; and (B) an aluminum-based surface curing agent;

The alkyl (meth) acrylate-based monomer includes (a11) an alkyl (meth) acrylate-based monomer having 1 to 3 carbon atoms in the alkyl group; (a12) an alkyl (meth)acrylate-based monomer having 4 to 6 carbon atoms in the alkyl group; and (a13) an alkyl (meth)acrylate-based monomer having 7 to 10 carbon atoms in the alkyl group, an acrylic emulsion pressure-sensitive adhesive composition is provided.

The inventors of the present invention, in an acrylic emulsion pressure-sensitive adhesive composition, including an emulsion of latex particles prepared by emulsion polymerization of an acrylate-based monomer, etc., combine a specific monomer, and use an aluminum-based curing agent as an external curing agent for the latex particles In this case, it was found that an adhesive having excellent adhesion, little change in the viscosity of the adhesive component after adhesion, and excellent adhesion to a curved surface even after aging can be prepared, and the present invention was completed.

First, the acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention includes an emulsion polymer of a specific monomer, that is, latex particles, and each monomer is present in the latex particle in the form of a repeating unit derived from the monomer. can

monomer

First, in the emulsion polymerization for producing the latex particles, an alkyl (meth) acrylate-based monomer may be used, which may be referred to as a first monomer. Accordingly, the latex particles may include a repeating unit derived from an alkyl (meth)acrylate-based monomer, which may be referred to as a first repeating unit.

The alkyl (meth) acrylate-based monomer is, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl ( Meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, isobornyl (meth)acrylate, and lauryl (meth)acrylate It may be one or more selected from the group consisting of, and these may be used alone or in a mixture of two or more.

These alkyl (meth) acrylate-based monomers include, depending on the number of carbon atoms in the alkyl group, (a11) an alkyl (meth) acrylate-based monomer having 1 to 3 carbon atoms in the alkyl group; (a12) an alkyl (meth)acrylate-based monomer having 4 to 6 carbon atoms in the alkyl group; and (a13) an alkyl (meth)acrylate-based monomer having 7 to 10 carbon atoms in the alkyl group, and in the present invention, repeating units derived from these three types of alkyl (meth)acrylate-based monomers include at the same time

In addition, in the emulsion polymerization for producing the latex particles, a hydroxy alkyl (meth) acrylate-based monomer may be used in addition to the above-described alkyl (meth) acrylate, which may be referred to as a second monomer. Accordingly, the latex particles may include a repeating unit derived from a hydroxyalkyl (meth)acrylate-based monomer, which may be referred to as a second repeating unit.

The hydroxyalkyl (meth)acrylate-based monomer includes at least one selected from the group consisting of hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate can do.

And, in the emulsion polymerization for producing the latex particles, an unsaturated carboxylic acid-based monomer may be used, which may be referred to as a third monomer. Accordingly, the latex particles may include a repeating unit derived from an unsaturated carboxylic acid-based monomer, which may be referred to as a third repeating unit.

In addition, the unsaturated carboxylic acid-based monomer is acrylic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid (mesaconic acid), glutaconic acid, and allylmalonic acid may include at least one selected from the group consisting of.

And, in the emulsion polymerization for producing the latex particles, a vinyl-based monomer may be used, which may be referred to as a fourth monomer. Accordingly, the latex particles may include a repeating unit derived from a vinyl-based monomer, which may be referred to as a fourth repeating unit.

In addition, the vinyl-based monomer may include at least one selected from the group consisting of a vinyl ether-based monomer, a vinyl ester-based monomer, a vinyl amide-based monomer, and an aromatic vinyl-based monomer.

Specifically, the vinyl ether-based monomer includes, for example, at least one selected from the group consisting of ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, and 2-ethylhexyl vinyl ether. can do. Among these, ethyl vinyl ether, 2-ethylhexyl vinyl ether, etc. may be mentioned, but the present invention is not necessarily limited thereto.

And, the vinyl ester-based monomer is, specifically, for example, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, vinyl caproate, vinyl heptylate, vinyl caprylate, vinyl ferragonate, vinyl laurel Late, vinyl stearate, vinyl benzoate, vinyl pivalate, vinyl neo-nanoate, vinyl neodecanoate, vinyl neoundecanoate, and can be at least one selected from the group consisting of vinyl-2-ethylhexanoate have. Among them, vinyl acetate, vinyl propionate, or vinyl benzoate may be mentioned, but the present invention is not necessarily limited thereto.

And, the vinyl amide-based monomer may be one represented by the following formula (1).

[Formula 1]

In Formula 1, R1 and R2 are each independently alkyl having 1 to 10 carbons, aryl having 6 to 20 carbons, arylalkyl having 7 to 20 carbons, or alkylaryl having 7 to 20 carbons; , R3 is a single bond, alkylene having 1 to 10 carbons, arylene having 6 to 20 carbons, arylalkylene having 7 to 20 carbons, or alkylarylene having 7 to 20 carbons.

And, in Formula 1, R1 and R2 may each independently be methyl, ethyl, or propyl, and R3 may be preferably a single bond, methylene, ethylene, or propylene. The compound represented by 1 may be specifically, for example, vinyl methyl acetamide, but the present invention is not necessarily limited thereto.

In addition, the aromatic vinyl-based monomer may be at least one selected from the group consisting of styrene, methylstyrene, ethylstyrene, butylstyrene, chlorostyrene, methyl vinylbenzoate, vinylnaphthalene, chloromethylstyrene, and divinylbenzene. Among them, styrene and divinylbenzene may be mentioned, but the present invention is not necessarily limited thereto.

According to another embodiment of the present invention, the emulsion polymer comprises, based on the total weight of the emulsion polymer, (A1) about 60 to about 90 wt% of a first repeating unit derived from an alkyl (meth)acrylate-based monomer; (A2) about 0.1 to about 10 wt% of a second repeating unit derived from a hydroxyalkyl (meth)acrylate-based monomer; (A3) about 0.1 to about 10 wt% of a third repeating unit derived from an unsaturated carboxylic acid-based monomer; and (A4) about 5 to about 20 wt% of a fourth repeating unit derived from a vinyl-based monomer, and more preferably, (A1) about 80 to about 20 wt% of a first repeating unit derived from an alkyl (meth)acrylate-based monomer. 90 wt %; (A2) about 1 to about 10 wt% of a second repeating unit derived from a hydroxyalkyl (meth)acrylate-based monomer; (A3) about 0.1 to about 5 wt% of a third repeating unit derived from an unsaturated carboxylic acid-based monomer; and (A4) about 5 to about 15 wt% of a fourth repeating unit derived from a vinyl-based monomer.

The acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention can exhibit excellent adhesion due to the characteristic content range as described above, and, in particular, when used on a substrate to be adhered in a curved shape, has excellent adhesion even after aging has the advantage of being maintained

And, the first repeating unit, the alkyl (meth) acrylate-based monomer, (a11) a short-chain alkyl (meth) acrylate-based monomer having 1 to 3 carbon atoms in the alkyl group; (a12) a medium-chain alkyl (meth)acrylate monomer having 4 to 6 carbon atoms in the alkyl group; and (a13) repeating units derived from long-chain alkyl (meth)acrylate-based monomers having 7 to 10 carbon atoms in the alkyl group.

As the long-chain alkyl (meth) acrylate monomer, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth)acrylate, and the like, among which it may be preferable to use 2-ethylhexyl acrylate.

And, as the medium-chain alkyl (meth) acrylate-based monomer, butyl (meth) acrylate, pentyl (meth) acrylate, or hexyl (meth) acrylate may be used, of which butyl acrylate is used It may be desirable to

In addition, the short-chain alkyl (meth) acrylate-based monomer may include methyl (meth) acrylate or ethyl (meth) acrylate, among which it may be preferable to use methyl (meth) acrylate. have.

In this case, the first repeating unit is (a13) based on 100 parts by weight of the repeating unit derived from the alkyl (meth)acrylate-based monomer having 7 to 10 carbon atoms in the alkyl group, (a11) 1 to 3 carbon atoms in the alkyl group. About 100 to about 150 parts by weight, or about 120 to about 150 parts by weight of a repeating unit derived from an alkyl (meth)acrylate-based monomer, and (a12) an alkyl (meth)acrylate-based monomer having 4 to 6 carbon atoms in the alkyl group It may include from about 10 to about 50 parts by weight of the repeating unit, or from about 20 to about 30 parts by weight.

Long-chain alkyl (meth)acrylate monomers such as 2-ethylhexyl acrylate form the main chain of the polymer and may act as a monomer to increase the molecular weight of the emulsified polymer particles, and in particular, 2-ethylhexyl acrylate et al., may allow the polymerized latex particles to have a long chain length and branched chain structure, thereby lowering the glass transition temperature value. Therefore, the acrylic emulsion pressure-sensitive adhesive composition including these latex particles, the flexibility of the adhesive surface can be improved, and accordingly, various physical properties related to points and adhesion can be improved.

Medium-chain alkyl (meth) acrylate-based monomers such as butyl acrylate have a high probability of participating in polymerization during polymerization and can act as a monomer to increase the molecular weight of the emulsified polymer particles, and the acrylic emulsion pressure-sensitive adhesive composition prepared from such latex particles Silver, adhesion durability may be improved.

Short-chain alkyl (meth) acrylate monomers such as methyl (meth) acrylate change the glass transition temperature and coating properties of the polymer to increase hardness in the acrylic emulsion pressure-sensitive adhesive composition, thereby reducing residues during peeling and can improve the transparency of the adhesive surface.

emulsion polymerization

The emulsion polymer included in the composition according to an embodiment of the present invention, that is, latex particles, comprises the step of emulsion polymerization of a polymerization composition comprising a monomer mixture comprising the above-described monomer component, a polymerization initiator, and an emulsifier, It can be prepared by emulsion polymerization.

In this case, the polymerization temperature and polymerization time may be appropriately determined depending on the case. For example, the polymerization temperature may be from about 50 °C to about 200 °C, and the polymerization time may be from about 0.5 hours to about 20 hours.

As the polymerization initiator usable during the emulsion polymerization, an inorganic or organic peroxide may be used, for example, a water-soluble polymerization initiator containing potassium persulfate, sodium persulfate, ammonium persulfate, etc., cumene hydroperoxide, Oil-soluble polymerization initiators containing benzoyl peroxide and the like can be used.

In addition, an activator may be further included to promote the initiation of the reaction of the peroxide together with the polymerization initiator, and such activators include sodium formaldehyde sulfoxylate, sodium ethylenediaminetetraacetate, ferrous sulfate, and dextrose. At least one selected from the group consisting of may be used.

The polymerization initiator may be included in an amount of from about 0.1 to about 10 parts by weight, preferably from about 0.1 to about 5 parts by weight, based on 100 parts by weight of the monomer mixture on a dry weight basis.

According to an embodiment of the present invention, the acrylic emulsion pressure-sensitive adhesive composition may include, in addition to the above-described components, other additives within a range that does not reduce the desired effect of the invention without any particular limitation.

Specifically, it may further include an electrolyte to adjust the pH in the polymerization reaction and impart polymerization stability, for example, sodium hydroxide, sodium bicarbonate, sodium carbonate, sodium phosphate, sodium sulfate, sodium chloride, etc. may be mentioned, but is not limited thereto. In addition, these may be used alone or in combination of two or more.

Emulsion polymerization may be specifically carried out through the following steps.

Dispersing the emulsifier in a solvent to prepare an emulsion, a first step;

A second step of preparing a pre-emulsion by mixing a monomer mixture including each monomer component and an emulsifier, etc.;

A third step of mixing the emulsion of the first step and the pre-emulsion of the second step in the presence of a polymerization initiator, and proceeding with emulsion polymerization.

In a specific embodiment of the present invention, the above-described acrylic emulsion pressure-sensitive adhesive composition, specifically, may be prepared by the following method, but is not necessarily limited thereto.

First, as a first step, an emulsion containing an emulsifier is prepared. This is separate from the following pre-emulsion preparation process. The emulsifier may be an anionic emulsifier alone, or an anionic emulsifier, a cationic emulsifier and the above-mentioned nonionic emulsifier may be used together, and the emulsifier component and a solvent such as water may be mixed to prepare an emulsion. .

During the emulsion preparation process, micelles having a size of several nanometers may be stably formed.

And, as a second step, in the process of preparing a pre-emulsion, including the above-described monomer mixture, each of the above-described monomers, emulsifiers, etc. are mixed with water to prepare a pre-emulsion.

In this case, too, as the emulsifier, an anionic emulsifier may be used alone, or an anionic emulsifier and the above-described nonionic emulsifier may be used together. In this process, in the pre-emulsion, nano-sized latex particles may be formed.

That is, the above-mentioned emulsifier may be used in any one or more of the emulsion preparation step and the pre-emulsion preparation step.

And, as a third step, after the polymerization initiator is added to the emulsion prepared above, the pre-emulsion and the polymerization initiator are continuously added at an equal ratio for a predetermined time.

In a non-limiting embodiment of the present invention, the content of the polymerization initiator added to the emulsion may be about 0 to about 1 part by weight based on 100 parts by weight of the monomer mixture, and the content of the polymerization initiator added together with the pre-emulsion is, It may be about 0.1 to about 2 parts by weight based on 100 parts by weight of the monomer mixture, and the continuous input time may be about 3 hours to about 7 hours.

Through this process, suspended monomers or polymers in the pre-emulsion can be introduced into the initial particles produced in the emulsion.

The results of this reaction may then be subjected to a process of heating polymerization in the presence of an additional polymerization initiator, through which polymerization of the remaining monomers takes place.

At this time, the polymerization initiator may be added in an amount of about 0.1 to about 10 parts by weight based on 100 parts by weight of the monomer mixture, and the warming polymerization may be performed at a temperature of about 75 to about 85 ° C., for about 40 minutes to about 80 minutes. .

The production method of such an acrylic emulsion pressure-sensitive adhesive composition is divided into an emulsion production process and a pre-emulsion production process, and thereafter, it can be carried out by a simple method of mixing the pre-emulsion with the emulsion. Process stability and productivity can be improved compared to methods for preparing the emulsion pressure-sensitive adhesive composition.

On the other hand, in the pre-emulsion preparation process, it may be preferable not to use an internal cross-linking agent.

These internal cross-linking agents may serve to form a cross-linking bond linking each monomer in the process of forming a polymer by the unsaturated bond possessed by each monomer. The cohesive force inside the acrylic polymer may be increased by such cross-linking, and accordingly, the acrylic emulsion pressure-sensitive adhesive composition of the present invention may realize excellent adhesion and adhesion durability (shear).

However, in the case of an acrylic emulsion adhesive using these conventional internal crosslinking agents, the adhesive strength is significantly reduced after being adhered to the substrate to be adhered to the curved surface and aging after a certain period of time, causing a lifting phenomenon from the edge of the adhesive surface. There is this.

Therefore, when preparing the latex particles of the acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention, it may be preferable not to use a conventionally known internal crosslinking agent, and accordingly, the latex particles (emulsified polymer particles) are It may not contain internal cross-links formed by cross-linking agents.

And, in one embodiment of the present invention, after the polymerization step, the step of adjusting the pH may be further performed.

The pH of the acrylic emulsion resin may be adjusted by a method commonly used in the art without any particular limitation, for example, inorganic substances such as hydroxides, chlorides, and carbonates of monovalent or divalent metals, which are alkaline substances, Ammonia or organic amines and the like can be used.

emulsifier

And, the emulsifier used in the emulsion polymerization may include at least one selected from the group consisting of anionic emulsifiers, cationic emulsifiers, and nonionic emulsifiers.

Such an emulsifier is a material having a hydrophilic group and a hydrophobic group at the same time, and during the emulsion polymerization process, a micelle structure is formed, and polymerization of each monomer can occur inside the micellar structure.

Emulsifiers commonly used in emulsion polymerization may be divided into anionic emulsifiers, cationic emulsifiers, and nonionic emulsifiers, and two or more types may be mixed and used in terms of polymerization stability in emulsion polymerization.

Specifically, the nonionic emulsifier may include at least one selected from the group consisting of polyethylene oxide alkyl aryl ethers, polyethylene oxide alkyl amines, and polyethylene oxide alkyl esters.

And, the anionic emulsifier is sodium alkyl diphenyl ether disulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene aryl ether sulfate, sodium alkyl sulfate, sodium alkyl benzene sulfonate, and dialkyl sodium sulfosuccinate. It may include one or more selected from the group consisting of nates.

These may be used alone or in combination of two or more types, and may be more effective when an anionic emulsifier and a nonionic emulsifier are mixed and used, but the present invention is not necessarily limited to the type of these emulsifiers.

And, the emulsifier, for example, with respect to a total of 100 parts by weight of the monomer component used in the preparation of the latex particles, about 0.1 to about 10 parts by weight, or, about 1 to about 5 parts by weight may be used.

When the amount of the emulsifier used is too large, the particle diameter of the latex particles becomes small, and there may be problems that points and adhesion are lowered, and when the emulsifier is used too little, the stability of polymerization in the emulsion polymerization reaction is lowered, The stability of the generated latex particles may also be deteriorated.

menstruum

According to an embodiment of the present invention, the polymerization composition may further include an aqueous solvent such as water in addition to the above-described emulsifier or monomer component.

At this time, the aqueous solvent may be used in an amount of about 10 to about 1,000 parts by weight, based on 100 parts by weight of the latex particles, in terms of stability and viscosity control of the latex particles, for example, based on the total amount of the composition, the total It can be used so that the total solid content (TSC) is adjusted to about 10 to about 60% by weight.

When the solvent is used too little, the viscosity rises in the acrylic emulsion pressure-sensitive adhesive composition, and during emulsion polymerization, there may be problems that the stability of the latex particles is lowered, and when the solvent is used too much, the viscosity decreases due to the coating There may be problems with performance degradation.

hardener

In addition, the acrylic pressure-sensitive adhesive composition according to an aspect of the present invention further includes an aluminum-based surface curing agent in addition to the above-described emulsified polymer particles.

The aluminum-based surface curing agent may include an aluminum salt of an organic acid containing both a hydroxy group and a carboxy group in a molecule.

Specifically, the surface of an aluminum-based curing agent, Al ^- the (O- (C = O) -R -OH) and displayed in the form of _three, and R represents a single bond, or a 1 to 5 carbon alkylene, a compound of It may be desirable to use

This aluminum-based surface curing agent is a functional group distributed on the surface of the emulsion polymer particles, specifically, the monomer used for preparing the above-mentioned emulsion polymer, or by interaction with the functional group present in the repeating unit contained in the emulsion polymer particles, the surface can form cross-links.

Accordingly, the surface of the emulsion polymer particles may include a surface cross-linkage formed by the aluminum-based surface curing agent.

These aluminum-based surface curing agents can be dispersed in water and have a relatively slow curing rate, so they can maintain the adhesive properties before aging for a certain period of time, and have a high reactive valence, so the cohesiveness of the acrylic emulsion pressure-sensitive adhesive after aging is also high. can be improved

Accordingly, the adhesive member in which the acrylic emulsion pressure-sensitive adhesive composition is used can implement an effect of improving adhesion to a curved target substrate after aging as well as excellent initial adhesion.

The aluminum-based surface curing agent is, based on 100 parts by weight of the emulsion polymer particles, about 0.1 to about 1.0 parts by weight, or about 0.1 parts by weight or more, preferably about 0.2 parts by weight or more, or less than about 1.0 parts by weight, preferably may be included in less than about 0.7 parts by weight.

When the curing agent is used too much, the increase in viscosity increases over time, and compatibility with latex particles in the emulsion may cause a problem in that the adhesive strength decreases. When the curing agent is used too little, it is difficult to realize the advantages of using the curing agent described above, and thus adhesive durability (shear properties) may be deteriorated.

adhesive member

The acrylic emulsion pressure-sensitive adhesive composition of the present invention prepared according to the above-described method may be applied to an adhesive member such as an adhesive sheet, and may be an interior material, an advertisement film, or an adhesive film or sheet of a label for clothing, but the present invention It is not necessarily limited only to these.

However, considering that the acrylic pressure-sensitive adhesive composition according to an embodiment of the present invention has a great effect of improving residues upon peeling, it may be most preferable to apply it to a label for clothing.

Such a sheet may include a substrate; and an adhesive layer formed on one or both surfaces of the substrate, wherein the adhesive layer may be formed by the above-described acrylic emulsion pressure-sensitive adhesive composition.

The substrate may be paper such as art paper, imitation paper, mirage paper, gold and silver paper, thermal paper, kraft paper, fluorescent paper, sterile paper, photo paper, or polymer films such as PET, PVC, PE, PP, PS, PI. have.

As described above, the acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention can implement excellent adhesion, and in particular, when attached to a curved substrate to be adhered to, excellent adhesion can be maintained even after aging. It can be usefully used as a label for bottles or PET bottles.

Hereinafter, through specific examples of the invention, the operation and effect of the invention will be described in more detail. However, these embodiments are merely presented as an example of the invention, and the scope of the invention is not defined thereby.

<Example>

Preparation Example: Preparation of Emulsified Polymer Particles

220 g of water and 10 g of sodium polyoxyethylene aryl ether sulfate having a concentration of 26% by weight were placed in a 3 L glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen gas inlet tube and a reflux condenser and stirred. After replacing the inside of the reactor with nitrogen, the temperature was raised to 85° C. under a nitrogen atmosphere and maintained for 60 minutes.

Separately, a monomer according to the following composition ratio was added to a 2 L beaker and stirred for 30 minutes to prepare a monomer mixture. (Total weight of the monomer mixture: about 1126 g)

Herein, 35 g of sodium polyoxyethylene lauryl ethersulfate at a concentration of 26% by weight, 10 g of a sodium alkyldiphenyloxide disulfonate solution at a concentration of 45% by weight, 2.2 g of NaOH, sodium dioctyl sulfosite at a concentration of 50% by weight A solution consisting of 8.8 g of cinate solution and 44.8 g of water was added and stirred to prepare a cloudy free emulsion.

5.6 g of ammonium persulfate having a concentration of 30 wt% was added to the glass reactor and dissolved by stirring for 10 minutes.

The pre-emulsion and 150 g of 3 wt% ammonium persulfate were evenly and continuously added to the glass reactor for 5.5 hours, and polymerization was carried out at 85 ° C. After the addition was completed, stirring was carried out at the same temperature for 1 hour. did.

This was cooled to room temperature, and an emulsion containing emulsified polymer particles was prepared by adding an aqueous sodium hydroxide solution having a concentration of 5% by weight to adjust the pH to 5-7. (Solid content: about 56%)

Composition weight ratio (total sum: 100): 2-ethylhexyl acrylate 33.5; butyl acrylate: 46; methyl methacrylate 8; vinyl acetate 8; styrene 2; hydroxyethyl acrylate 2; acrylic acid 0.5;

Example 1

About 0.3 parts by weight of an aluminum-based surface curing agent was added with respect to 100 parts by weight of the emulsion polymer particles prepared above (based on solid content), and the mixture was stirred at room temperature for about 30 minutes to prepare a pressure-sensitive adhesive.

(Aluminum-based surface curing agent: Al ³⁺ ( ^- O-(C=O)-CH ₂ -OH) ₃ )

Additional Example 2

About 0.5 parts by weight of an aluminum-based surface curing agent was added with respect to 100 parts by weight of the emulsion polymer particles prepared above (based on solid content), and the mixture was stirred at room temperature for about 30 minutes to prepare a pressure-sensitive adhesive.

(Aluminum-based surface curing agent: Al ³⁺ ( ^- O-(C=O)-CH ₂ -OH) ₃ )

Additional Example 3

About 0.8 parts by weight of an aluminum-based surface curing agent was added with respect to 100 parts by weight of the emulsion polymer particles prepared above (based on solid content), and the mixture was stirred at room temperature for about 30 minutes to prepare a pressure-sensitive adhesive.

(Aluminum-based surface curing agent: Al ³⁺ ( ^- O-(C=O)-CH ₂ -OH) ₃ )

Additional Example 4

About 0.5 parts by weight of an aluminum-based surface curing agent was added with respect to 100 parts by weight of the emulsion polymer particles prepared above (based on solid content), and the mixture was stirred at room temperature for about 30 minutes to prepare a pressure-sensitive adhesive.

(Aluminum-based surface hardener: aluminum acetylacetonate)

Comparative Example 1

Without adding an aluminum-based surface curing agent, the emulsion polymer particle emulsion prepared above was used as it is.

Comparative Example 2

In the preparation of the emulsion polymer particles, 0.1 parts by weight of the internal crosslinking agent WAM II (manufactured by Solvay) was introduced and polymerization was performed in the same manner as in Example 1 based on 100 parts by weight of the total monomer.

Comparative Example 3

With respect to 100 parts by weight of the emulsion polymer particles prepared above, instead of the aluminum-based curing agent, about 0.5 parts by weight of an aziridine-based curing agent was added, and the same as in Example 1, except that the mixture was mixed with stirring at room temperature for about 30 minutes was prepared.

(Aziridine-based curing agent: CL-467, manufactured by Menadiona SL)

Comparative Example 4

When the emulsion polymer particles were prepared, 0.1 parts by weight of aluminum acetylacetonate was introduced as an internal crosslinking agent for 100 parts by weight of the total monomer to proceed with polymerization, and the preparation was carried out in the same manner as in Example 1, except that a surface crosslinking agent was not used. did.

Adhesive member manufacturing

The acrylic emulsion pressure-sensitive adhesive composition prepared above is coated on a release paper to ^{a thickness that can be an areal density of about 19 g/m 2} , dried at 120° C. for 1 minute, and laminated on a release paper made of paper to prepare an adhesive member did.

Viscosity measurement

Using the #63 spindle of the Brookfield viscometer, the viscosity of the pressure-sensitive adhesives prepared in Examples and Comparative Examples at room temperature and 30 rpm were measured.

After exposure to this at room temperature for 1 day, the viscosity was again measured by the same method.

Adhesive properties measurement

Measurement of loop tack

After aging the adhesive member prepared above at room temperature for 3 days, it was measured according to FTM 9 of the FINAT test method.

A specimen having a size of 12.5 mm × 35 mm was prepared in a ring shape, and contacted for 5 seconds without applying pressure to the surface of stainless steel (SUS304).

The initial adhesive strength was measured while peeling at a rate of 300 mm/min for 5 seconds.

Five measurement specimens were prepared and measured to obtain an average value.

(Measuring equipment: TA Texture Analyzer, Manufacturer: Stable Micro Systems; Measurement conditions: 23℃ humidity 50%)

90 degree peel strength measurement

After the adhesive member prepared above was aged at room temperature for 3 days, adhesion to the curved surface was measured according to FTM 2 of the FINAT test method.

A specimen having a size of 12.5 mm × 35 mm was prepared, attached to a stainless steel (SUS304) surface, and compressed by reciprocating twice at a speed of 300 mm/min with a 2 kg roller.

After aging at room temperature for 20 minutes, peel strength values were measured while peeling at a rate of 300 mm/min for 5 seconds.

Five measurement specimens were prepared and measured to obtain an average value.

(Measuring equipment: TA Texture Analyzer, Manufacturer: Stable Micro Systems; Measurement conditions: 23℃ humidity 50%)

Shear measurement

After aging the adhesive member prepared above at room temperature for 3 days, it was measured according to FTM 8 of the FINAT test method.

A specimen having a size of 12.5 mm × 35 mm was prepared and attached so that the stainless steel (SUS304) surface and the attachment surface were 0.5 inch x 0.5 inch, and then pressed by reciprocating twice at a speed of 300 mm/min with a 2 kg roller.

After 20 minutes, the attached sheet was attached to the wall inclined by about 2 degrees, a weight of 500 g was applied to the bottom, and the time for the sheet to fall from the attachment surface was measured.

Five measurement specimens were prepared and measured to obtain an average value.

(Measuring equipment: TA Texture Analyzer, Manufacturer: Stable Micro Systems; Measurement conditions: 23℃ humidity 50%)

Measurement of adhesion to curved surfaces (HDPE cylinders with a diameter of 15 mm)

The adhesive member specimen having a size of 12.5 mm × 35 mm prepared above was aged for 4 days at a temperature of about 66° C. and a humidity of about 80 RH%, and then attached to a 15 mm diameter HDPE cylinder.

This was left at room temperature for 7 days, and the length of the exfoliated part of the length of the entire specimen was measured.

The measurement results are summarized in Table 1 below.

viscosity change
(cP) pre-aging after aging immediately after manufacturing after 1 day Loop Tack
(N/in) 90 degree peel strength
(N/in) Shear
(min) surface adhesion
(mm) Example 1 324.0 330.0 20.7 9.1 112 3.6 Example 2 302 314 16.4 8.6 153 4.6 Example 3 298 320 12.2 6.1 298 7.9 Example 4 337 344 22 10.3 97 3.9 Comparative Example 1 360.0 392.0 20.2 8.3 32 3.4 Comparative Example 2 620.0 670.0 14.3 6.8 126 12 Comparative Example 3 430.0 1620.0 8.3 6.1 545 24 Comparative Example 4 724 766 12.8 5.5 228 21

Referring to Table 1, the acrylic emulsion pressure-sensitive adhesive composition prepared according to an embodiment of the present invention has excellent adhesive strength and adhesive durability, and at the same time, the viscosity change is not large even when exposed to an external environment. It can be seen that the adhesion to the attachment target substrate is excellently maintained.

In contrast, in the case of Comparative Example 1 in which no separate curing agent or internal crosslinking agent was used, the cohesive force of the latex particles was lowered, and it was confirmed that the adhesion durability (Shear property) was significantly reduced compared to the Example of the present application. . In addition, in the case of Comparative Example 2 in which an internal crosslinking agent was introduced to form crosslinks in the latex particles, Comparative Example 3 in which an aziridine-based curing agent was introduced, or Comparative Example 4 in which only an aluminum-based internal crosslinking agent was used in the preparation of the emulsified polymer particles , adhesion durability, etc. can be improved, but the viscosity change is large, and after aging, it can be seen that the adhesive force of the curved surface to the attachment target substrate is greatly reduced.

This is compared to the conventional internal crosslinking agent or curing agent, which excessively increases the cohesiveness of the latex particles, and thus reduces the adhesive force of the adhesive to the curved surface, in the case of the aluminum-based surface curing agent according to an example of the present invention, the curing rate is relatively slow, so it is possible to maintain the adhesive properties before aging for a certain period of time, but it is thought that it is due to improving the cohesiveness after aging.

Accordingly, the acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention, particularly, when applied to a substrate attached to a curved surface, can maintain excellent adhesion even after aging, so it is thought that it can be usefully used for a label for use in combination. .

Claims (13)

(A)
(A1) a first repeating unit derived from an alkyl (meth)acrylate-based monomer;
(A2) a second repeating unit derived from a hydroxyalkyl (meth)acrylate-based monomer;
(A3) a third repeating unit derived from an unsaturated carboxylic acid-based monomer; and
(A4) comprising a fourth repeating unit derived from a vinyl-based monomer,
emulsified polymer particles (A); and
(B) comprising an aluminum-based surface hardener,
Acrylic emulsion adhesive composition.
According to claim 1,
The alkyl (meth) acrylate-based monomer is methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl ( Meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, isobornyl (meth) acrylate, and lauryl (meth) acrylate Containing one or more selected from the group consisting of,
Acrylic emulsion adhesive composition.
According to claim 1, wherein the alkyl (meth) acrylate-based monomer, (a11) an alkyl (meth) acrylate-based monomer having 1 to 3 carbon atoms in the alkyl group; (a12) an alkyl (meth)acrylate-based monomer having 4 to 6 carbon atoms in the alkyl group; and (a13) an alkyl (meth)acrylate-based monomer having 7 to 10 carbon atoms in the alkyl group,
Acrylic emulsion adhesive composition.
According to claim 1,
The hydroxy alkyl (meth) acrylate-based monomer comprises at least one selected from the group consisting of hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate ,
Acrylic emulsion adhesive composition.
According to claim 1,
The unsaturated carboxylic acid-based monomer is acrylic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid (mesaconic) acid), including at least one selected from the group consisting of glutaconic acid, and allylmalonic acid,
Acrylic emulsion adhesive composition.
According to claim 1,
The vinyl-based monomer,
An acrylic emulsion pressure-sensitive adhesive composition comprising at least one selected from the group consisting of a vinyl ether-based monomer, a vinyl ester-based monomer, a vinyl amide-based monomer, and an aromatic vinyl-based monomer.
According to claim 1,
The aluminum-based surface curing agent, an acrylic emulsion pressure-sensitive adhesive composition comprising an aluminum salt of an organic acid containing both a hydroxy group and a carboxy group in a molecule.
According to claim 1,
The aluminum-based surface curing agent is, based on 100 parts by weight of the emulsion polymer particles, 0.1 to 1.0 parts by weight, acrylic emulsion pressure-sensitive adhesive composition.
According to claim 1,
The emulsion polymer, based on the total weight of the emulsion polymer,
(A1) 60 to 90 wt% of a first repeating unit derived from an alkyl (meth)acrylate-based monomer;
(A2) 0.1 to 10 wt% of a second repeating unit derived from a hydroxyalkyl (meth)acrylate-based monomer;
(A3) 0.1 to 10 wt% of a third repeating unit derived from an unsaturated carboxylic acid-based monomer; and
(A4) comprising 5 to 20 wt% of a fourth repeating unit derived from a vinyl-based monomer,
Acrylic emulsion adhesive composition.
According to claim 1,
The first repeating unit is (a13) based on 100 parts by weight of a repeating unit derived from an alkyl (meth)acrylate-based monomer having 7 to 10 carbon atoms in the alkyl group, (a11) an alkyl group having 1 to 3 carbon atoms ( An acrylic emulsion comprising 100 to 150 parts by weight of a repeating unit derived from a meth)acrylate-based monomer, and 10 to 50 parts by weight of a repeating unit derived from an alkyl (meth)acrylate-based monomer having 4 to 6 carbon atoms in the (a12) alkyl group. Adhesive composition.
According to claim 1,
The surface of the emulsion polymer particles, the acrylic emulsion pressure-sensitive adhesive composition comprising a surface cross-linkage formed by the aluminum-based surface curing agent.
According to claim 1,
The emulsion polymer does not include an internal cross-linking by an internal cross-linking agent, the acrylic emulsion pressure-sensitive adhesive composition.
materials; and
A pressure-sensitive adhesive layer formed on at least one surface of the substrate,
The pressure-sensitive adhesive layer is formed by the acrylic emulsion pressure-sensitive adhesive composition according to claim 1,
no adhesive.