KR20210148722A - Acrylic emulsion pressure snsitive adhesive composition - Google Patents

Abstract

The present invention relates to an acrylic emulsion adhesive composition. The acrylic emulsion adhesive composition according to an embodiment of the present invention can implement excellent adhesive force, and at the same time can have excellent coating properties when coating a substrate to be adhered or in a process of manufacturing an adhesive member, thereby being usefully used as a paper or a plastic label.

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 that is different from adhesives and has basic properties of initial adhesion, adhesion, and cohesion, and is used in various industries such as printing, chemicals, 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.

On the other hand, in the case of a generally used acrylic emulsion adhesive, a phenomenon occurs in which a part is not coated due to a coating problem during application to attach to a substrate to be adhered, or during an application process for manufacturing an adhesive member, or after application There is a problem in that the edge of the coated part is contracted, and an uncoated part is also generated.

Therefore, there is a need for research on the development of an adhesive having excellent coating properties during application while being able to implement excellent adhesive strength.

An object of the present specification is to provide an acrylic emulsion pressure-sensitive adhesive composition having excellent coating properties during coating while implementing excellent adhesion.

The present specification, (A) (A1) an alkyl (meth) acrylate-based monomer-derived first repeating unit; (A2) a second repeating unit derived from an unsaturated carboxylic acid-based monomer; And (A3) comprising a third repeating unit derived from a vinyl-based monomer, it provides an acrylic emulsion pressure-sensitive adhesive composition comprising the emulsion polymer particles (A) and the acrylic acid-based copolymer resin (B).

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.

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

The vinyl-based monomer is selected from the group consisting of styrene, methylstyrene, ethylstyrene, butylstyrene, chlorostyrene, methyl vinylbenzoate, vinylnaphthalene, chloromethylstyrene, divinylbenzene, acrylonitrile, vinyl acetate, and vinyl alcohol. It may include one or more types.

And, the emulsion polymer particles, based on the total weight of the first repeating unit, the second repeating unit, and the third repeating unit, from about 50 to about 95% by weight of the first repeating unit; about 0.1 to about 10 weight percent of said second repeating unit; and about 1 to about 40 wt% of the third repeating unit.

The emulsion polymer particles preferably comprise, based on the total weight of the first repeating unit, the second repeating unit, and the third repeating unit, from about 55 to about 95% by weight of the first repeating unit; about 0.2 to about 7 weight percent of said second repeating unit; and about 4 to about 40 wt% of the third repeating unit.

In addition, the emulsion polymer particles (A) may further include a fourth repeating unit derived from an alkyl (meth)acrylate-based monomer including a hydroxy group.

In this case, the alkyl (meth) acrylate-based monomer including the hydroxy group is hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate from the group consisting of It may include one or more selected.

And, the said emulsion polymer particle (A) may contain the crosslinking bond formed by a crosslinking agent.

According to an embodiment of the invention, the acrylic acid-based copolymer resin (B) comprises i) a repeating unit derived from acrylic acid (B1), and ii) acrylamide (B21), acrylonitrile (B22), and a hydroxy group. It may include a repeating unit derived from at least one comonomer (B2) selected from the group consisting of an alkyl (meth)acrylate (B23).

At this time, the acrylic acid-based copolymer resin (B) may be included in an amount of about 0.1 to about 10 parts by weight, or about 0.1 to about 5 parts by weight, or about 0.5 to 5 parts by weight based on 100 parts by weight of the emulsion polymer particles. .

And, the acrylic acid-based copolymer resin (B) has a weight average molecular weight of about 100,000 to about 1,000,000 g/mol, preferably about 300,000 to about 800,000 g/mol, and a molecular weight distribution (PDI) of about 2 to about 12, Preferably it may be about 3 to about 6.

And, the acrylic acid-based copolymer resin (B) may have a viscosity of about 2,000 to about 10,000 cP, preferably about 3,000 to about 7,000 cP.

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 another.

In addition, the terminology used herein is used only 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 used 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 "over" 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 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 an unsaturated carboxylic acid-based monomer; And (A3) comprising a third repeating unit derived from a vinyl-based monomer, the emulsion polymer particles (A) and an acrylic acid-based copolymer resin (B), an acrylic emulsion pressure-sensitive adhesive composition is provided.

The inventors of the present invention, in an acrylic emulsion pressure-sensitive adhesive composition comprising an emulsion of latex particles prepared by emulsion polymerization of acrylate-based monomers, etc., emulsified polymer particles prepared by combining specific monomers, that is, latex particles, and When an acrylic emulsion pressure-sensitive adhesive is prepared by mixing with a separate acrylic acid-based copolymer resin, it was discovered that the coating property can be greatly improved while maintaining excellent adhesiveness, 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.

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 second 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 second repeating unit.

In addition, the unsaturated carboxylic acid-based monomer is acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid (citraconic acid), mesaconic acid (mesaconic acid), glutaconic acid (glutaconic acid), and may be at least one member selected from the group consisting of allylmalonic acid (allylmalonic acid), these may be used alone, or two or more It can be used by mixing.

And, in the emulsion polymerization for producing the latex particles, a vinyl-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 a vinyl-based monomer, which may be referred to as a third repeating unit.

The vinyl-based monomer is selected from the group consisting of styrene, methylstyrene, ethylstyrene, butylstyrene, chlorostyrene, methyl vinylbenzoate, vinylnaphthalene, chloromethylstyrene, divinylbenzene, acrylonitrile, vinyl acetate, and vinyl alcohol. There may be one or more types, and these may be used alone or in combination of two or more types.

And, the emulsion polymer particles, based on the total weight of the first repeating unit, the second repeating unit, and the third repeating unit, from about 50 to about 95% by weight of the first repeating unit; about 0.1 to about 10 weight percent of said second repeating unit; and about 1 to about 40 wt% of the third repeating unit.

The emulsion polymer particles preferably comprise, based on the total weight of the first repeating unit, the second repeating unit, and the third repeating unit, from about 55 to about 95% by weight of the first repeating unit; about 0.2 to about 7 weight percent of said second repeating unit; and about 4 to about 40 wt% of the third repeating unit.

The acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention, due to the content range as described above, can exhibit excellent adhesion and, at the same time, realize excellent coatability during coating.

In addition, the first repeating unit includes a repeating unit derived from a long-chain alkyl (meth)acrylate-based monomer having 6 to 10 carbon atoms in the alkyl group, and a short-chain alkyl (meth)acrylate having 1 or 2 carbon atoms in the alkyl group. A repeating unit derived from a system monomer may be included at the same time.

Examples of the long-chain alkyl (meth) acrylate monomer include hexyl (meth) acrylate, 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.

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.

A long-chain alkyl (meth)acrylate-based monomer such as 2-ethylhexyl acrylate forms the main chain of the polymer and can act as a monomer to increase the molecular weight of the emulsified polymer particles, and in particular, 2-ethylhexyl acrylate and the like, allow the polymerized latex particles to have a branched chain structure, so that the acrylic emulsion pressure-sensitive adhesive composition prepared accordingly can implement better adhesion.

Short-chain alkyl (meth) acrylate-based 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 can do.

Separately, the first repeating unit may further include a repeating unit derived from a medium-chain alkyl (meth)acrylate-based monomer having 3 to 5 carbon atoms in the alkyl group.

Examples of the medium-chain alkyl (meth) acrylate-based monomer include propyl (meth) acrylate, butyl (meth) acrylate, and pentyl (meth) acrylate. Among them, butyl acrylate is preferable. can do.

Butyl acrylate has a high reactivity among monomers used for emulsion polymerization, and can promote a polymerization reaction, and also impart a low glass transition temperature to the polymer, thereby improving adhesion properties of the pressure-sensitive adhesive.

In addition, in the emulsion polymerization for preparing the latex particles, an alkyl (meth)acrylate-based monomer including a hydroxy group may be further used in addition to the above-mentioned monomers. Accordingly, the latex particles may include a repeating unit derived from an alkyl (meth) acrylate-based monomer including a hydroxy group.

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.

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, and the like, cumene hydroperoxide, Oil-soluble polymerization initiators including 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 about 0.1 to about 10 parts by weight, preferably 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-mentioned monomer mixture, each of the above-mentioned monomers, emulsifiers, etc. are mixed with water to prepare a pre-emulsion.

At this time, 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 warming polymerization in the presence of an additional polymerization initiator, through which polymerization of the remaining monomers takes place.

In this case, the polymerization initiator may be added in an amount of about 0 to about 10 parts by weight based on 100 parts by weight of the monomer mixture, and the warming polymerization may proceed for about 40 minutes to about 80 minutes at a temperature of about 70 to about 90 ° C. .

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 an emulsion pressure-sensitive adhesive composition.

Meanwhile, in the preparation of the pre-emulsion, a separate internal crosslinking agent may be used in addition to the above-described monomers. These internal cross-linking agents may serve to form a cross-linkage linking each monomer in the process of forming a polymer by the unsaturated bond possessed by each monomer, and accordingly, the emulsified polymer particle (A) cross-links formed by cross-linking agents. The cohesive force inside the emulsion polymer may be increased by such cross-linking, and accordingly, the acrylic emulsion acrylic emulsion pressure-sensitive adhesive composition of the present invention can implement excellent adhesion and adhesion durability (shear) and excellent coatability.

The crosslinking agent is divinyl benzene, 3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, allyl acrylate, allyl methacryl One or more kinds may be used from the group consisting of lactate, trimethylolpropane triacrylate, tetraethylene glycol diacrylate, and tetraethylene glycol dimethacrylate.

In addition, these internal crosslinking agents may be used in an amount of about 0.05 to about 0.5 parts by weight, or about 0.05 to about 0.2 parts by weight, based on 100 parts by weight of the above-described monomer component.

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, an alkaline material such as a monovalent or divalent metal hydroxide, chloride, carbonate, etc. inorganic materials, Ammonia or organic amines and the like may be used.

The particle diameter of the emulsion polymer particles thus prepared may be from about 100 to about 500 nm, preferably from about 150 to about 400 nm, or from about 200 to about 300 nm.

When the particle size of the emulsion polymer particles is too large, a problem of not reaching the appropriate viscosity may occur, and when the particle size of the emulsion polymer particles is too small, a problem of exceeding the appropriate viscosity may occur.

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 generally 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 mixture of two or more, 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, based on 100 parts by weight of the total 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. 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, in terms of stability and viscosity control of the latex particles, based on 100 parts by weight of the latex particles, may be used in about 10 to about 1,000 parts by weight, 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 increases 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. There may be problems with performance degradation.

Acrylic acid-based copolymer resin

In addition, the acrylic pressure-sensitive adhesive composition according to an aspect of the present invention further comprises an acrylic acid-based copolymer resin (B) in addition to the above-described emulsion polymer, ie, latex particles, in order to improve coating properties. The acrylic acid-based copolymer resin referred to herein is separate from the latex particles described above, that is, the acrylic emulsion copolymer particles, and is in a resin phase rather than a particle (or vehicle).

According to an embodiment of the invention, the acrylic acid-based copolymer resin (B) comprises i) a repeating unit derived from acrylic acid (B1), and ii) acrylamide (B21), acrylonitrile (B22), and a hydroxy group. It may include a repeating unit derived from at least one comonomer (B2) selected from the group consisting of an alkyl (meth)acrylate (B23).

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.

Specifically, the acrylic acid-based copolymer resin (B) contains i) 100 parts by weight of a repeating unit derived from acrylic acid (B1), ii) acrylamide (B21), acrylonitrile (B22), and a hydroxy group. about 10 to about 300 parts by weight, or about 20 to about 250 parts by weight, or about 25 to about 210 parts by weight of a repeating unit derived from at least one comonomer (B2) selected from the group consisting of an alkyl (meth)acrylate (B23) may include wealth.

Since the polymer chains may be linearly dispersed in an aqueous solution, the acrylic acid-based copolymer resin may have relatively superior dispersibility compared to an emulsion including latex particles. Due to these characteristics, when an acrylic acid-based copolymer resin is mixed and used in an acrylic emulsion pressure-sensitive adhesive composition containing latex particles, it is possible to prevent non-uniformity of the coating resulting from the polymer in the form of existing particles.

Specifically, in the case of using the existing latex emulsion as it is, after the solvent is dried, voids are generated between the particles, causing the coating thickness to vary depending on each part, causing non-uniformity of the coating.

However, as in the present invention, when the latex emulsion and the acrylic acid-based copolymer resin are used together, the acrylic acid-based copolymer resin fills the voids between the latex particles generated by solvent drying, which can prevent unevenness of the coating. will be.

In addition, since the acrylic acid-based copolymer resin may have points and adhesive strength by itself, it is possible to implement points and adhesive strength comparable to or superior to that of the existing latex emulsion, and at the same time, it is possible to improve the coating property of the pressure-sensitive adhesive.

In this respect, the acrylic acid-based copolymer resin (B) has a weight average molecular weight of about 100,000 to about 1,000,000 g/mol, or about 300,000 to about 800,000 g/mol, and a molecular weight distribution of about 2 to about 12, or about 3 to It may be desirable to use about six.

And, from a similar viewpoint, the acrylic acid-based copolymer resin (B) may preferably have a viscosity of about 2,000 to about 10,000 cP, or about 3,000 to about 7,000 cP.

When the acrylic acid-based copolymer resin (B) is out of the above range, there may be problems in that the adhesive strength of the acrylic emulsion pressure-sensitive adhesive composition is lowered or the coating property is lowered.

At this time, the acrylic acid-based copolymer resin (B) may be included in an amount of about 0.1 to about 10 parts by weight, or about 0.1 to about 5 parts by weight, or about 0.5 to 5 parts by weight based on 100 parts by weight of the emulsion polymer particles. .

When the acrylic acid-based copolymer resin is used in an excessively small amount compared to the emulsion polymer particles, there may be a problem in that the above-described beneficial effects such as coating properties are not expressed, and the acrylic acid-based copolymer resin is used in an amount compared to the emulsion polymer particles. When used in an excessively large amount, there may be a problem in that adhesive properties are deteriorated.

Such an acrylic acid-based copolymer resin may be prepared by a polymerization method including a step of solution polymerization of the above-described monomer components, a solvent, an initiator, and the like. This polymerization method is different from the emulsion polymerization using an emulsifier, and the above-mentioned resinous acrylic acid-based copolymer can be obtained by solution polymerization or the like.

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 60° C. to about 90° C., and the polymerization time may be from about 0.5 hours to about 20 hours.

As the polymerization initiator that can be used, an inorganic or organic peroxide may be used, and for example, a water-soluble polymerization initiator including potassium persulfate, sodium persulfate, ammonium persulfate, etc. may be mentioned.

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 mixing component on a dry weight basis.

Specifically, solution polymerization may be carried out by replacing the inside of the reactor with nitrogen or the like, and stirring the monomer and the initiator together with water in a constant amount while uniformly inputting.

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.

Such a sheet may include a substrate; and an adhesive layer formed on one side or both sides 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 realize excellent adhesion and, at the same time, have excellent coatability when coated on a substrate to be adhered or when coated in an adhesive member manufacturing process, It can be usefully used as a plastic label or the like.

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 1: Preparation of latex emulsion

300 g of water and 10 g of sodium polyoxyethylene aryl ether sulfate having a concentration of 26% by weight were added to 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 75° C. under a nitrogen atmosphere and maintained for 60 minutes.

Separately, a monomer and a crosslinking agent according to the composition ratio of Table 1 were added to a 2 L beaker, followed by stirring for 30 minutes to prepare a monomer mixture. (Based on the 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 dioctylsulfosite 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. proceeded.

This was cooled to room temperature, and the pH was adjusted to 5.0-9.0 by adding an aqueous sodium hydroxide solution having a concentration of 5 wt%, to obtain a latex emulsion.

The content of solids in all the prepared latex emulsions was about 40 to 60% by weight.

Preparation 1-1 Preparation 1-1 Preparation 1-2 Preparation 1-3 2-EHA 30 20 70 80 MMA 15 EA 70 BA 30 3 sub Total: 60 90 85 83 AA 2 One 2.5 0.5 IA 2.5 sub Total: 2 One 5 0.5 Vac 30 One 5 12 St 6 One 5 4.5 AN 6.9 sub Total: 36 8.9 10 16.5 HEA 2 sub Total: 2 0 0 0 AMA 0.1 sub Total: 0 0.1 0 0

*2-EHA:2-ethylhexyl acrylate; MMA: methyl methacrylate; EA: ethyl acrylate; BA: butyl acrylate; above the first monomer.

*AA: acrylic acid; IA: itaconic acid; above the second monomer.

*Vac: vinyl acetate; St: styrene; AN: acrylonitrile; above third monomer

*HEA: hydroxyethyl acrylate; above fourth monomer

*AMA: allyl methacrylate (crosslinking agent)

Preparation Example 2: Preparation of acrylic acid-based copolymer resin

Molecular weight measurement

For each of the acrylic acid-based copolymers obtained below, molecular weight and molecular weight distribution were measured in the following manner.

The number average molecular weight (Mn) and the weight average molecular weight (Mw) were respectively measured under the following conditions by gel permeation chromatography (GPC: gel permeation chromatography, Agilent GPC (Agulent 1200 series, USA)), and the weight average molecular weight was The molecular weight distribution was calculated by dividing by the number average molecular weight.

- Column: Connect 2 PL Mixed B

- Column temperature: 40℃

- Eluent: Tetrohydrofuran

- Flow rate: 1.0mL/min

- Concentration: ~ 1mg/mL (100μL injection)

viscosity measurement

For each of the acrylic acid-based copolymers obtained below, the viscosity was measured in the following manner.

It was measured according to the following method using a Brookfield RVDV3T viscometer. Specifically, the sample is placed in a 13ml sample chamber, heated using a Brookfield Thermosel, and when the sample is completely melted, lower the viscometer to fix the spindle in the sample chamber, and set the rotation speed of the spindle (SC-29) to 20rpm. After fixation, readings were taken for at least 20 minutes or until the values stabilized and the final values were recorded.

Preparation 2-1

800 g of distilled water was placed in a glass reactor, heated to 80 °C, and then the temperature was maintained. Nitrogen gas was circulated inside the reactor, and the reactor was sealed except that a heat exchanger (condenser) was connected.

Using a pump, 33 g of acrylic acid, 33 g of acrylamide, 33 g of acrylonitrile, and 100 g of an aqueous solution of ammonium persulfate having a concentration of 3 wt. Inside, the agitation was maintained between 200 and 800 rpm at the speed of the impeller.

After the polymerization was carried out at 80 °C for 3 hours, stirring was continued at an impeller speed of 200 to 800 rpm while maintaining 85 °C for 2 hours.

Thereafter, the glass reactor was cooled to room temperature to obtain an acrylic acid-based copolymer resin.

weight average molecular weight: 320,000; PDI: 5.0

Viscosity: 3,100 cP

Preparation 2-2

800 g of distilled water was placed in a glass reactor, heated to 80 °C, and then the temperature was maintained. Nitrogen gas was circulated inside the reactor, and the reactor was sealed except that a heat exchanger (condenser) was connected.

Using a pump, 50 g of acrylic acid, 50 g of hydroxyethyl acrylate, and 100 g of a 3 wt% ammonium persulfate solution were each introduced into the glass reactor in constant amounts for 3 hours, while the inside of the glass reactor was inside of the impeller. Agitation was maintained at a speed between 200 and 800 rpm.

After the polymerization was carried out at 80 °C for 3 hours, stirring was continued at an impeller speed of 200 to 800 rpm while maintaining 85 °C for 2 hours.

Thereafter, the glass reactor was cooled to room temperature to obtain an acrylic acid-based copolymer resin.

weight average molecular weight: 440,000; PDI: 4.2

Viscosity: 4,800 cP

Preparation 2-3

800 g of distilled water was placed in a glass reactor, heated to 80 °C, and then the temperature was maintained. Nitrogen gas was circulated inside the reactor, and the reactor was sealed except that a heat exchanger (condenser) was connected.

Using a pump, 77 g of acrylic acid, 7.7 g of acrylamide, 15.3 g of acrylonitrile, and 100 g of a 3 wt% ammonium persulfate solution were each introduced into the glass reactor in constant amounts for 3 hours, while inside the glass reactor was such that the agitation was maintained between 200 and 800 rpm at the speed of the impeller.

After the polymerization was carried out at 80 °C for 3 hours, stirring was continued at an impeller speed of 200 to 800 rpm while maintaining 85 °C for 2 hours.

Thereafter, the glass reactor was cooled to room temperature to obtain an acrylic acid-based copolymer resin.

weight average molecular weight: 520,000; PDI: 3.0

Viscosity: 6,000 cP

Preparation of acrylic emulsion pressure-sensitive adhesive composition

Comparative Examples 1-4:

The latex emulsions obtained in Preparation Examples 1-1 to 1-4 were used as they were.

Reference Example 5:

7 parts by weight of the acrylic acid copolymer resin obtained in Preparation Example 2-1 was mixed with 100 parts by weight of the latex emulsion obtained in Preparation Example 1-2 (based on solid content) to obtain an acrylic emulsion adhesive composition.

Reference Example 6:

6 parts by weight of the acrylic acid copolymer resin obtained in Preparation Example 2-2 was mixed with 100 parts by weight (based on solid content) of the latex emulsion obtained in Preparation Example 1-3 to obtain an acrylic emulsion adhesive composition.

Reference Example 7:

By mixing 0.05 parts by weight of the acrylic acid copolymer resin obtained in Preparation Example 2-4 with 100 parts by weight (based on solid content) of the latex emulsion obtained in Preparation Example 1-4, an acrylic emulsion pressure-sensitive adhesive composition was obtained.

Example 1:

2 parts by weight of the acrylic acid copolymer resin obtained in Preparation Example 2-1 was mixed with 100 parts by weight of the latex emulsion obtained in Preparation Example 1-2 (based on solid content) to obtain an acrylic emulsion adhesive composition.

Example 2:

By mixing 0.8 parts by weight of the acrylic acid copolymer resin obtained in Preparation Example 2-2 with 100 parts by weight (based on solid content) of the latex emulsion obtained in Preparation Example 1-3, an acrylic emulsion pressure-sensitive adhesive composition was obtained.

Example 3:

3 parts by weight of the acrylic acid copolymer resin obtained in Preparation Example 2-3 was mixed with 100 parts by weight of the latex emulsion obtained in Preparation Example 1-4 (based on solid content) to obtain an acrylic emulsion pressure-sensitive adhesive composition.

Table 2 below summarizes the above manufacturing conditions.

latex emulsion Acrylic acid-based copolymer resin
(content, parts by weight) Comparative Example 1 Preparation 1-1 - Comparative Example 2 Preparation 1-2 - Comparative Example 3 Preparation 1-3 - Comparative Example 4 Preparation Example 1-4 - Reference Example 5 Preparation 1-2 Preparation Example 2-1 (7) Reference Example 6 Preparation 1-3 Preparation Example 2-2 (6) Reference Example 7 Preparation Example 1-4 Preparation 2-3 (0.05) Example 1 Preparation 1-2 Preparation Example 2-1 (2) Example 2 Preparation 1-3 Preparation Example 2-2 (0.8) Example 3 Preparation Example 1-4 Preparation 2-3 (3)

Adhesive member manufacturing

A release paper was laid on the bar coater, and about 5 g of the acrylic emulsion pressure-sensitive adhesive composition prepared above was uniformly applied to the edge, and then the coater was operated to coat it to a thickness of about 20 μm.

After putting it in an oven and drying it at 120° C. for 1 minute, it was laminated on a paper substrate to prepare an adhesive member.

How to measure coating properties

When the adhesive member was manufactured, the area of the uncoated surface was measured from the coated surface, and the ratio of the area of the uncoated surface to the total area to which the coating process was applied was calculated as a %.

Measurement of loop tack

After aging the specimen prepared above at room temperature for 24 hours, it was measured according to FTM 9 of the FINAT test method.

A specimen having a size of 150 mm (length) × 25.4 mm (width, 1 inch) was prepared, attached to a stainless steel (SUS304) surface, and contacted for 5 seconds without applying pressure.

The initial adhesive force 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 aging the specimen prepared above at room temperature for 24 hours, it was measured according to FTM 2 of the FINAT test method.

A specimen having a size of 150 mm (length) × 25.4 mm (width, 1 inch) 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%)

How to measure shear

After aging the specimen prepared above at room temperature for 24 hours, it was measured according to the FTM of the FINAT test method.

Prepare a specimen of 150mm (length) × 25.4mm (width, 1 inch), attach it so that the stainless steel (SUS304) surface and the attachment surface are 1 inch x 0.5 inch, and then use a 2 kg roller, It was compressed by reciprocating twice at a speed.

After 20 minutes, the attached sheet was attached to the wall inclined by about 2 degrees, a weight of 1,000 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%)

The measurement results are summarized in Table 3 below.

uncoated rate
(%) initial adhesion
(N/in) peel strength
(N/in) retention
(h) Comparative Example 1 18 13.1 8.1 4.40 Comparative Example 2 32 11.0 5.5 6.0 Comparative Example 3 28 12.9 7.2 2.4 Comparative Example 4 14 14.2 7.6 4.2 Reference Example 5 0 6.5 6.0 7.1 Reference Example 6 0 6.8 7.7 3.5 Reference Example 7 14 13.9 7.7 4.3 Example 1 0 10.4 5.6 5.5 Example 2 0 12.9 7.2 2.5 Example 3 0 13.1 8.1 4.4

Referring to Table 3, the acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention can maintain excellent adhesion-related physical properties, such as adhesive force and holding power, and there is almost no uncoated portion during coating, so it is clearly evident that the coating property is very excellent. can be checked

On the other hand, in the case of the comparative example or the reference example, when the coating property is very poor or some coating properties are satisfied, it can be seen that the initial adhesive strength is greatly deteriorated.

Claims (13)

(A)
(A1) a first repeating unit derived from an alkyl (meth)acrylate-based monomer;
(A2) a second repeating unit derived from an unsaturated carboxylic acid-based monomer; and
(A3) comprising a third repeating unit derived from a vinyl-based monomer,
emulsified polymer particles (A) and
Containing an acrylic acid-based copolymer resin (B),
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,
The unsaturated carboxylic acid-based monomer is acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid acid), including at least one selected from the group consisting of mesaconic acid, glutaconic acid, and allylmalonic acid,
Acrylic emulsion adhesive composition.
According to claim 1,
The vinyl-based monomer is selected from the group consisting of styrene, methylstyrene, ethylstyrene, butylstyrene, chlorostyrene, methyl vinylbenzoate, vinylnaphthalene, chloromethylstyrene, divinylbenzene, acrylonitrile, vinyl acetate, and vinyl alcohol. comprising at least one,
Acrylic emulsion adhesive composition.
According to claim 1,
The emulsion polymer particles may contain, based on the total weight of the first repeating unit, the second repeating unit, and the third repeating unit,
50 to 95% by weight of the first repeating unit;
0.1 to 10% by weight of the second repeating unit;
1 to 40% by weight of the third repeating unit;
Containing, acrylic emulsion pressure-sensitive adhesive composition.
According to claim 1,
The emulsion polymer particle (A) further comprises a fourth repeating unit derived from an alkyl (meth)acrylate-based monomer containing a hydroxy group,
Acrylic emulsion adhesive composition.
7. The method of claim 6,
The alkyl (meth)acrylate-based monomer including the hydroxy group is one selected from the group consisting of hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate. including more than
Acrylic emulsion adhesive composition.
According to claim 1,
The emulsion polymer particles (A) contain a cross-linkage formed by a cross-linking agent,
Acrylic emulsion adhesive composition.
According to claim 1,
The acrylic acid-based copolymer resin (B) is,
i) a repeating unit derived from acrylic acid (B1), and ii) at least one selected from the group consisting of acrylamide (B21), acrylonitrile (B22), and alkyl (meth)acrylate (B23) containing a hydroxy group comprising repeating units derived from comonomer (B2); Acrylic emulsion adhesive composition.
According to claim 1,
The acrylic acid-based copolymer resin (B) is contained in 0.1 to 10 parts by weight based on 100 parts by weight of the emulsion polymer particles, the acrylic emulsion pressure-sensitive adhesive composition.
According to claim 1,
The acrylic acid-based copolymer resin (B) has a weight average molecular weight of 100,000 to 1,000,000 g/mol, and a molecular weight distribution (PDI) of 2 to 12, an acrylic emulsion pressure-sensitive adhesive composition.
According to claim 1,
The acrylic acid-based copolymer resin (B) has a viscosity of 2,000 to 10,000 cP, an acrylic emulsion pressure-sensitive adhesive composition.
write; 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.