KR101828931B1 - Acrylic Emulsion Adhesive with Excellent Polyethylene Adhesion and Emulsion Polymerization Stability, and Preparation Method Thereof - Google Patents

Abstract

The present invention relates to an acrylic emulsion pressure-sensitive adhesive excellent in peelability and process stability against polyethylene and a process for producing the same, and a process for producing the acrylic pressure-sensitive adhesive, which comprises: (i) Unsaturated nitrile, iii) at least one monomer selected from the group consisting of an unsaturated carboxylic acid, and iv) an acrylic emulsion resin produced by polymerization of a mixture comprising a crosslinking agent, v) 2-hydroxyethyl methacrylate monomer in an amount of 1 to 4% by weight based on the total weight of the mixture, and a process for producing the acrylic pressure-sensitive adhesive.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic emulsion pressure-sensitive adhesive excellent in polyethylene peel strength and polymerization stability, and a method for producing the same. 2. Description of the Related Art Acrylic Emulsion Adhesive with Excellent Polyethylene Adhesion and Emulsion Polymerization Stability,

The present invention relates to an acrylic emulsion pressure-sensitive adhesive excellent in peelability and polymerization stability to polyethylene and a method for producing the same.

Recently, the use of sticker-type surface finishing materials such as interior / exterior materials, interior materials, and advertisement materials of a building to which a pressure-sensitive adhesive is applied has been greatly increased. Conventional oil-based pressure-sensitive adhesives, as the pressure-sensitive adhesive, have a problem of causing headache, irritation of the eyes, cough, itching, dizziness, fatigue, loss of concentration, etc. due to the residual solvent being discharged into the air for a long time after the construction And exposure to long-term exposure causes problems with Sick House Syndrome, which causes respiratory diseases, heart disease, cancer, and the like.

For this reason, water-based emulsion pressure sensitive adhesives that are environmentally friendly and do not emit harmful substances to the human body have been focused and replaced rapidly by using water as a dispersion medium. The aqueous emulsion pressure-sensitive adhesive can use a polymer having a higher molecular weight than the solvent-based polymer because the viscosity of the pressure-sensitive adhesive and the molecular weight of the dispersion polymer are independent of each other, and the concentration range of the solid content can be widely obtained and the aging resistance is low, It has good adhesiveness in a solid content region and has good compatibility with other polymers.

However, since water is used as a solvent, there is a problem that the drying speed is slow, the adhesiveness to the hydrophobic adhesive surface and the non-porous adhesive agent is low, the selection range of the curing agent is narrow and the initial adhesive force is low, And a dispersant, and therefore, it has a low water resistance and can not reach the physical properties as the oil-based pressure-sensitive adhesive.

On the other hand, pressure sensitive adhesives (PSA) generally have excellent initial adhesion, adhesion and cohesion and should be well balanced, and cause surface damage and contamination of adherend when peeling off after long term adhesion It is required that characteristics should not be done.

In recent years, as the use environment of the pressure sensitive adhesive has been various, the demand for the pressure sensitive adhesive excellent in the peeling force in addition to the above general pressure sensitive property has been increased. For example, in a battery device such as a smart phone or a notebook computer, a pressure-sensitive adhesive is used to fix parts inside the case or improve the sealability of the case. In this case, a pressure- In many cases.

On the other hand, during the manufacturing process of the water-based emulsion pressure-sensitive adhesive, agglomerates having a particle size of a certain level or more are generated for other reasons, and the agglomerates are discarded as impurities, leading to reduction in process yield and cost increase. The process stability is low when a large amount of agglomerates larger than a certain size is produced, and studies on a water-based emulsion pressure-sensitive adhesive excellent in process stability for reducing process yield and cost have been actively conducted.

Conventional techniques solve some problems of initial adhesion, cohesion and cohesion of water-based emulsion pressure-sensitive adhesives, but at the same time, they do not provide a pressure-sensitive adhesive excellent in peel strength against polymeric resins and excellent in process stability.

Therefore, there is a high need for a technique of a pressure-sensitive adhesive which is environmentally friendly, and has excellent peelability and process stability against a polymer resin.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

The inventors of the present application have conducted intensive research and various experiments and have found that when the acrylic emulsion pressure-sensitive adhesive contains 1 to 4% by weight of 2-hydroxyethyl methacrylate monomer based on the total weight of the mixture, And process stability are improved, and the present invention has been accomplished.

Accordingly, the acrylic emulsion pressure-sensitive adhesive according to the present invention is a pressure-sensitive adhesive composition comprising i) a (meth) acrylic acid ester monomer having an alkyl group having 1 to 14 carbon atoms, ii) at least one monomer selected from the group consisting of allyl esters, vinyl esters, unsaturated acetates and unsaturated nitriles , iii) at least one monomer selected from the group consisting of unsaturated carboxylic acids, and iv) an acrylic emulsion resin produced by polymerization of a mixture comprising a crosslinking agent, said mixture comprising: v) 2-hydroxyethyl methacrylate monomer By weight based on the total weight of the mixture.

In the present specification, the term " mixture " as used herein refers to a mixture of monomers, crosslinking agents and the like, which will be described below, based on acrylic monomers and may be prepared by mixing these monomers and crosslinking agents sequentially And so on.

The 2-hydroxyethyl methacrylate monomer of the above v) may be contained in an amount of 2 to 4% by weight based on the total weight of the mixture, specifically, 2 to 3% by weight.

As described above, when the hydroxyethyl methacrylate monomer is contained in an appropriate amount, there is an effect of increasing the peeling force and the process stability to polyethylene, and this effect can be achieved by the hydrogen bonding of the hydroxyl group present in the 2-hydroxyethyl methacrylate monomer and Dipole-dipole attraction, and increased cohesion through self-cross-linking of hydroxyl groups with hydroxyl groups or hydroxyl groups and polar functional groups in the polymer.

If the content of the 2-hydroxyethyl methacrylate monomer is out of the above range, if it is less than 1% by weight, the adhesive force to the adherend decreases, resulting in a decrease in peelability to polyethylene, and more than 4% The self-crosslinking is too much formed in the polymer to increase the peeling force, but the production of the agglomerates in the manufacturing process is increased, so that the process stability is deteriorated.

In one specific example, the acrylic emulsion pressure-sensitive adhesive may have a peel force with respect to polyethylene of 7.5 N / inch or more, more specifically 8.0 N / inch or more, and more specifically 8.5 N / inch or more. The larger the peeling force on polyethylene, the stronger adhesion of the adhesive to the adherend of the polymeric material.

On the other hand, the acryl-based emulsion pressure-sensitive adhesive may have a content of aggregate filtered by a standard of 74 탆 based on the total weight of the acrylic-based emulsion pressure-sensitive adhesive of 500 ppm or less, specifically 200 ppm or less, have. The higher the content of the agglomerate in the acrylic emulsion pressure-sensitive adhesive is, the higher the impurity is. Therefore, the lower the content of the agglomerate, the higher the process stability.

Details of the peeling force and the aggregate content with respect to the polyethylene will be described later.

Hereinafter, the acrylic emulsion pressure-sensitive adhesive according to the present invention will be described in detail.

In one specific example, the monomer of i) is selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (Meth) acrylate, isodecyl acrylate, decyl (meth) acrylate, isopropyl (meth) acrylate, t-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl acrylate, isooctyl acrylate, octyl methacrylate, (Meth) acrylate, and more specifically from 60 to 90% by weight, based on the total weight of the mixture, of at least one member selected from the group consisting of methacrylate, dodecyl methacrylate, isobornyl methacrylate, .

As described above, the monomer of i) may be contained in an amount of 60 to 90% by weight based on the total weight of the emulsion resin. When the amount of the monomer is less than 60% by weight, the initial adhesion of the acrylic emulsion pressure- %, The transfer of the adhesive to the adherend is largely undesirably caused at the time of removal after use.

The number of carbon atoms of the alkyl group in i) may be from 1 to 14, more specifically from 2 to 14, and if it is less than 1, the cohesive force of the acrylic emulsion pressure- By weight, the acrylic emulsion pressure-sensitive adhesive becomes too soft and the adhesive property deteriorates, which is not preferable.

In one specific example, the monomer of ii) may be at least one selected from the group consisting of vinyl acetate, vinyl butanoate, vinyl propionate, vinyl laurate, vinyl pyrrolidone, acrylonitrile and methacrylonitrile , Specifically, vinyl acetate, vinyl butyrate, or acrylonitrile.

The monomer of ii) may be contained in an amount of 1 to 35% by weight, more specifically 7 to 25% by weight based on the total weight of the mixture. If the amount of the monomer is less than 1% by weight, the acrylic emulsion pressure- It is not possible to secure sufficient adhesive property. When the content exceeds 35% by weight, the acrylic emulsion pressure-sensitive adhesive becomes excessively firm, resulting in a remarkable deterioration in adhesive strength.

In one specific example, the monomer of iii) may be at least one selected from the group consisting of acrylic acid, itaconic acid, maleic anhydride, fumaric acid, crotonic acid, methacrylic acid, and ethyl methacrylic acid.

The monomer of iii) may be contained in an amount of 0.5 to 5% by weight based on the total weight of the mixture. When the acrylic emulsion pressure-sensitive adhesive is contained in an amount of less than 0.5% by weight, the acrylic emulsion pressure- %, The acrylic emulsion pressure-sensitive adhesive becomes excessively stiff, resulting in a remarkable deterioration in the adhesive strength.

In one specific example, the crosslinking agent in vi) for reinforcing the cohesive force may be contained in an amount of 0.1 to 3% by weight based on the total weight of the mixture, and the acrylic emulsion pressure-sensitive adhesive has sufficient cohesion within the above range.

The cross-linking agent is added to reinforce the cohesive force. In one specific example, the cross-linking agent may be a compound having 5 to 15 alkylene oxide groups and having an acrylate group or a vinyl group, specifically, an alkylene oxide group of 6 To 12, and may be a compound having an acrylate group or a vinyl group. Within this range, there is an effect of excellent room temperature, aging tackiness, and stability.

For reference, the number of alkylene oxide groups means the average number of alkylene oxide groups contained in the cross-linking agent used, and when the number of alkylene oxide groups is less than 5 in the cross-linking agent, the pressure- And when the number of alkylene oxide groups is more than 15, the pressure-sensitive adhesives to be produced tend to be more flexible than necessary, resulting in deteriorated adhesive properties.

In one specific example, the crosslinking agent is an organic crosslinking agent such as polyethylene glycol diacrylate, polypropylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylpropane triacrylate, Trimethylolpropyl methacrylate, vinyltrimethoxysilane and divinylbenzene, and the like, and an inorganic crosslinking agent such as aluminum acetyl (meth) acrylate such as tripropylene glycol diacrylate, 1,3-butanediol diacrylate, pentatrytol triacrylate, Acetone, zinc acetate, zirconium carbonate and the like, and specifically may be at least one selected from the group consisting of polyethylene glycol diacrylate and polypropylene glycol diacrylate.

On the other hand, in one specific example, the mixture may further contain an epoxy group-containing unsaturated monomer, and the epoxy group-containing unsaturated monomer specifically includes glycidyl (meth) acrylate, alpha methyl glycidyl (meth) (Meth) acrylate, allyl glycidyl ether, oxocyclohexyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, and more specifically, glycidyl Or an allyl glycidyl ether.

The epoxy group-containing unsaturated monomer may be contained in an amount of 0.1 to 3% by weight based on the total weight of the mixture, and the pressure-sensitive adhesive composition has sufficient cohesive strength within the above range.

The present invention also discloses a process for producing the above acrylic emulsion pressure-sensitive adhesive.

The method for producing the acrylic emulsion pressure-sensitive adhesive is not particularly limited when emulsion polymerization is used, but a monomer addition method or a seed polymerization method which can easily control the reaction heat can be used.

Specifically, the method for producing the acrylic emulsion pressure-

(A) a copolymer comprising (i) a (meth) acrylic acid ester monomer having an alkyl group of 1 to 14 carbon atoms, ii) at least one monomer selected from the group consisting of allyl esters, vinyl esters, unsaturated acetates and unsaturated nitriles, Iv) a crosslinking agent, and v) 2-hydroxyethyl methacrylate monomer in an amount of 1 to 4% by weight based on the total weight of the mixture;

(B) adding a surfactant, an electrolyte and water to the mixture to prepare an emulsion;

(C) adding an initiator to the emulsion followed by emulsion polymerization;

And a control unit.

The method for producing an acrylic emulsion pressure-

(D) adding an acidity adjusting agent to the acrylic emulsion adhesive to adjust the acidity of the acrylic emulsion adhesive to 6 to 9.

The surfactant (B) is used for emulsion polymerization to produce initial particles, to control the size of generated particles, and to stabilize the particles. The surfactant is composed of a hydrophilic group and a lipophilic group, and is anionic, cationic and nonionic surfactant. It is divided. It mainly uses anionic and nonionic surfactants, and is mixed with other surfactants to compensate for mechanical stability and chemical stability.

Such an anionic surfactant may be an anionic surfactant and / or a nonionic surfactant, and specifically, an anionic surfactant may include sodium alkyldiphenyl oxide disulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene lauryl ether sulfate , And sodium dialkyl sulfosuccinate, and the nonionic surfactant may be at least one selected from the group consisting of polyethylene oxide alkyl aryl ether, polyethylene oxide alkyl amine, and polyethylene oxide alkyl ester have.

The electrolyte used in the polymerization reaction is selected from the group consisting of sodium bicarbonate, sodium carbonate, sodium phosphate, sodium sulfate, and sodium chloride, and the like. And specifically may be sodium carbonate, and may be 0.1 to 2 parts by weight, more specifically 0.3 to 1 part by weight, based on 100 parts by weight of the mixture.

In one specific example, the initiator may be a water-soluble initiator, such as a persulfate of ammonium or alkali metal, a hydrogen peroxide, a peroxide, a hydroperoxide, and the like. In order to carry out an emulsion polymerization reaction at a low temperature, It can also be used with species. The reducing agent may be sodium bisulfite, sodium metabisulfite, sodium hydrosulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid, and the like.

The temperature of the emulsion polymerization reaction may be in the range of 0 to 100 ° C, more specifically 40 to 90 ° C. The initiator may be used singly or in combination with at least one of the initiator and the reducing agent Method and the like.

The acidity of the acrylic emulsion pressure-sensitive adhesive can be controlled by adding a pH adjusting agent to the acrylic emulsion pressure-sensitive adhesive, wherein the acidity of the acrylic emulsion pressure-sensitive adhesive can be adjusted in detail to 6 to 9, more specifically, , The acidity regulator is an alkaline substance, and may be an inorganic substance such as hydroxide, chloride, carbonate of monovalent metal or divalent metal, ammonia or organic amine, and the like.

Furthermore, the acrylic emulsion pressure sensitive adhesive according to the present invention may further include a thickening agent and a wetting agent in order to prevent shrinkage of the acrylic emulsion pressure-sensitive adhesive which is generated when coating the surface of the silicone release paper.

The thickening agent may be CMC (Carboxyl Methyl Cellulose), acrylic sol, polyvinyl alcohol, starch, alginate, dextrin and the like, and more specifically polyvinyl alcohol.

The wetting agent may be a surfactant mixture, and may further include a glycol or an alcohol. The hydrophilic adhesive may be hydrophobic to closely adhere the adhesive to the surface of the hydrophobic silicone release paper.

The present invention also provides a pressure-sensitive adhesive sheet in which an acrylic emulsion pressure-sensitive adhesive is applied on an ink film or sheet to form a pressure-sensitive adhesive layer.

The pressure-sensitive adhesive sheet may be a building interior and exterior material, an interior material, an advertising film, a label, or a pointing film or sheet of a label. The pressure-sensitive adhesive layer may have a thickness of 10 to 100 탆, specifically 20 to 30 탆, And has sufficient adhesive property.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, when the acrylic emulsion pressure-sensitive adhesive contains 1 to 4% by weight of 2-hydroxyethyl methacrylate monomer based on the total weight of the mixture, the peeling force and the process stability on polyethylene are significantly .

Hereinafter, the present invention will be described with reference to Examples. However, the following Examples are intended to illustrate the present invention and the scope of the present invention is not limited thereto.

≪ Example 1 >

A glass reactor having a capacity of 2 L equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser was charged with 154 g of water and 30% sodium polyoxyethylene alkyl ether sulfate, The temperature was raised to 80 DEG C in an atmosphere and maintained for 60 minutes.

Separately, for the preparation of the pre-emulsion, 140 g of butyl acrylate, 390 g of 2-ethylhexyl acrylate, 21 g of 2-hydroxyethyl methacrylate, 70 g of vinyl acetate, 70 g of meta methyl acrylate, 1 g of polyethylene glycol diacrylate, and 0.3 g of normal dodecyl mercaptan were charged and mixed for 30 minutes to prepare a mixture.

To the mixture was added 11 g of 30% sodium polyoxyethylene alkyl ether sulfate, 7 g of 50% alkyldiphenyl oxide disulfonate, 2 g of sodium carbonate, 2 g of sodium methyl allylsulfonate and 175 g of water, And the mixture was stirred for one minute to prepare a cloudy emulsion.

The glass reactor was charged with 3.5 g of a 10% ammonium persulfate solution and dissolved by stirring for 10 minutes.

The above emulsion and 90% of the 10% antacid ammonium solution were continuously and continuously added to the glass reactor for 4 hours. Thereafter, 10% ammonium persulfate solution (2 g) was further added, and then the temperature was raised to 80 ° C for 30 minutes and maintained at this temperature for 1 hour and then cooled to room temperature to prepare an acrylic emulsion pressure-sensitive adhesive.

A 28% aqueous ammonia solution was added to the acrylic emulsion pressure-sensitive adhesive to adjust the pH to 7 to 8.

≪ Example 2 >

An acryl-based emulsion pressure-sensitive adhesive was prepared in the same manner as in Example 1, except that 14 g of 2-hydroxyethylmaleate was added during the preparation of the pre-emulsion.

≪ Example 3 >

An acryl-based emulsion pressure-sensitive adhesive was prepared in the same manner as in Example 1, except that 7 g of 2-hydroxyethyl methacrylate was added during the preparation of the pre-emulsion.

<Example 4>

An acryl-based emulsion pressure-sensitive adhesive was prepared in the same manner as in Example 1, except that 28 g of 2-hydroxyethyl methacrylate was added during the preparation of the pre-emulsion.

&Lt; Comparative Example 1 &

An acrylic emulsion pressure-sensitive adhesive was prepared in the same manner as in Example 1, except that 2-hydroxyethyl methacrylate was not added during the preparation of the pre-emulsion.

&Lt; Comparative Example 2 &

An acryl-based emulsion pressure-sensitive adhesive was prepared in the same manner as in Example 1, except that 5 g of 2-hydroxyethyl methacrylate was added during the preparation of the pre-emulsion.

&Lt; Comparative Example 3 &

An acryl-based emulsion pressure-sensitive adhesive was prepared in the same manner as in Example 1, except that 40 g of 2-hydroxyethyl methacrylate was added during the preparation of the pre-emulsion.

&Lt; Comparative Example 4 &

An acryl-based emulsion pressure-sensitive adhesive was prepared in the same manner as in Example 1, except that 21 g of 3-acryloyloxypropionic acid was used instead of 2-hydroxyethyl methacrylate in the preparation of the pre-emulsion.

&Lt; Comparative Example 5 &

An acryl-based emulsion pressure-sensitive adhesive was prepared in the same manner as in Example 1, except that 21 g of ethyl acrylate was added instead of 2-hydroxyethyl methacrylate in the preparation of the pre-emulsion.

<Experimental Example 1>

Adhesive coated adhesive sample

The pressure sensitive adhesive prepared in Examples 1 to 4 and Comparative Examples 1 to 3 was coated on a 39 占 퐉 PET film and dried in an oven at 120 占 폚 for 1 minute and laminated on an art paper to produce an adhesive tape and cut in a size of 1 inch x 200 mm To prepare an adhesive sample.

The adhesive properties of the pressure-sensitive adhesives prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were tested by the following methods, and the results are shown in Table 1 below.

* Initial Adhesion Test : Test Method FINAT TEST METHOD NO. 9, the acrylic-based emulsion pressure-sensitive adhesive was made into an annular shape. The pressure was not applied to the surface of the glass, and after 5 seconds, the pressure was measured at 300 mm / min using a TA Texture Analyzer.

* Peel strength test : Test method FINAT TEST METHOD NO. 2, the acrylic emulsion spot test specimen was reciprocated twice at a speed of 2 kg roller 300 mm / min and attached on polyethylene (HDPE, high density polyethylene) or glass plate, aged at room temperature for 20 minutes, and then transferred to a TA (Texture Analyzer) At a rate of 300 mm / min.

* Retention test : Test method FINAT TEST METHOD NO. 8, attach the acrylic emulsion pressure-sensitive adhesive specimen to the stainless steel surface (SUS 304) so that the attachment surface is 1 inch x 1 inch, then add 1 kg weight to the end of the sheet and measure the time for further drop.

Measurement of aggregate content : 100 g of acrylic emulsion pressure-sensitive adhesive was filtered through a mesh having a scale size of 74 탆 according to the process standard, distilled water was flowed through the agglomerate filtered by the standard, washed until the distilled water became transparent, The liquid is dried at a temperature below 110 ° C. The weight of the acrylic emulsion pressure-sensitive adhesive before sieving is passed through a sieve, the weight of the dried acrylic emulsion pressure-sensitive adhesive is subtracted, and the weight of the aggregate filtered by the sieve is obtained and converted into ppm based on the total weight of the acrylic emulsion pressure-sensitive adhesive.

<Table 1>

Referring to Table 1, it can be seen that the acrylic emulsion pressure-sensitive adhesives of Examples 1 to 4 have improved peel strength and process stability for polyethylene due to the action of 2-hydroxyethyl methacrylate in the polymer, The acrylic emulsion pressure-sensitive adhesives of 1 to 5 do not contain a proper amount of 2-hydroxyethyl methacrylate, so that it is possible to confirm that the peeling force and process stability against polyethylene are insufficient.

Specifically, the acrylic emulsion pressure-sensitive adhesives of Examples 1 to 4 exhibited superior or similar levels to those of Comparative Examples 1 to 5 in general adhesive properties such as initial adhesion and retention, The peeling force against polyethylene is remarkably different from that of Comparative Examples 1 to 2 and Comparative Examples 4 to 5 in the case of peeling force against polyethylene. can confirm.

In the case of Comparative Example 3, the peeling force to polyethylene was similar to that of the examples because 2-hydroxyethyl methacrylate was contained in an excess amount, but the content of the aggregate was more than 2 times that in Examples and the process stability was very low , It is inadequate because the process efficiency is too low to be applied to actual production processes.

Therefore, in the case of the acrylic emulsion pressure-sensitive adhesive comprising 2-hydroxyethyl methacrylate monomer in an amount of 1 to 4% by weight based on the total weight of the mixture, peeling force and process stability to polyethylene are remarkably reduced Can be ascertained.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (22)

(i) a (meth) acrylic acid ester monomer having an alkyl group of 1 to 14 carbon atoms, ii) at least one monomer selected from the group consisting of allyl esters, vinyl esters, unsaturated acetates and unsaturated nitriles, iii) unsaturated carboxylic acids And iv) an acrylic emulsion resin produced by polymerization of a mixture comprising a crosslinking agent,
Said mixture comprising v) 2-hydroxyethyl methacrylate monomer in an amount of 1 to 4% by weight based on the total weight of the mixture,
Wherein the acrylic emulsion pressure-sensitive adhesive has a peel force against polyethylene of 7.5 N / inch or more. The acrylic emulsion resin according to claim 1, wherein the acrylic emulsion resin comprises i) 60 to 90% by weight of a (meth) acrylic acid ester monomer having an alkyl group having 1 to 14 carbon atoms, ii) an allyl ester, a vinyl ester, From 1 to 35% by weight of at least one monomer selected from the group consisting of unsaturated nitriles, iii) from 0.5 to 5% by weight of at least one monomer selected from the group consisting of unsaturated carboxylic acids, iv) from 0.1 to 3% by weight of crosslinking agents, -Hydroxyethyl methacrylate monomer in an amount of 1 to 4% by weight based on the total weight of the acrylic emulsion adhesive. The acrylic emulsion pressure-sensitive adhesive according to claim 1, wherein the 2-hydroxyethyl methacrylate monomer in v) is contained in an amount of 2 to 4% by weight based on the total weight of the mixture. 4. The acrylic emulsion pressure-sensitive adhesive according to claim 3, wherein the 2-hydroxyethyl methacrylate monomer is contained in an amount of 2 to 3% by weight based on the total weight of the mixture. The method of claim 1, wherein the monomer of i) is selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) (Meth) acrylate, isodecyl acrylate, decyl (meth) acrylate, isopropyl (meth) acrylate, t-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl acrylate, isooctyl acrylate, octyl methacrylate, Wherein the acrylic emulsion pressure-sensitive adhesive is at least one selected from the group consisting of methacrylate, dodecyl methacrylate, isobornyl methacrylate, and lauryl (meth) acrylate. The method according to claim 1, wherein the monomer of ii) is one or more selected from the group consisting of vinyl acetate, vinyl butanoate, vinyl propionate, vinyl laurate, vinyl pyrrolidone, acrylonitrile, and methacrylonitrile Features acrylic emulsion adhesive. The acrylic emulsion pressure-sensitive adhesive of claim 1, wherein the monomer of iii) is at least one selected from the group consisting of acrylic acid, itaconic acid, maleic anhydride, fumaric acid, crotonic acid, methacrylic acid, and ethylmethacrylic acid. delete The acrylic emulsion pressure-sensitive adhesive according to claim 1, wherein the acryl-based emulsion pressure-sensitive adhesive has an aggregate content of not more than 500 ppm filtered by a standard of 74 탆. The acrylic emulsion pressure-sensitive adhesive according to claim 1, wherein the crosslinking agent in iv) contains 5 to 15 alkylene oxide groups and is a compound having an acrylate group or a vinyl group. The acrylic emulsion pressure-sensitive adhesive according to claim 10, wherein the cross-linking agent is at least one selected from the group consisting of polyethylene glycol diacrylate and polypropylene glycol diacrylate. The acrylic emulsion pressure-sensitive adhesive according to claim 1, wherein the mixture further comprises an epoxy group-containing unsaturated monomer. The acrylic emulsion pressure-sensitive adhesive according to claim 12, wherein the epoxy group-containing unsaturated monomer is contained in an amount of 0.1 to 3% by weight based on the total weight of the mixture. 13. The acrylic emulsion pressure-sensitive adhesive according to claim 12, wherein the epoxy group-containing unsaturated monomer is glycidyl (meth) acrylate or allyl glycidyl ether. A method for producing an acrylic emulsion pressure-sensitive adhesive according to claim 1,
(A) a copolymer comprising (i) a (meth) acrylic acid ester monomer having an alkyl group having 1 to 14 carbon atoms, ii) at least one monomer selected from the group consisting of allyl esters, vinyl esters, unsaturated acetates and unsaturated nitriles, Iv) a crosslinking agent, and v) 2-hydroxyethyl methacrylate monomer in an amount of 1 to 4% by weight based on the total weight of the mixture;
(B) adding a surfactant, an electrolyte and water to the mixture to prepare an emulsion;
(C) adding an initiator to the emulsion followed by emulsion polymerization;
Wherein the acrylic emulsion pressure-sensitive adhesive is prepared by a method comprising the steps of: 16. The method according to claim 15,
(D) adding an acidity adjusting agent to the acryl-based emulsion pressure-sensitive adhesive prepared by the emulsion polymerization to adjust the acidity of the acrylic-based emulsion pressure-sensitive adhesive to 6 to 9. 16. The process for producing an acrylic emulsion pressure-sensitive adhesive according to claim 15, wherein the surfactant (B) is an anionic surfactant and / or a nonionic surfactant. 18. The composition of claim 17, wherein the anionic surfactant is selected from the group consisting of sodium alkyldiphenyl oxide disulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene lauryl ether sulfate, and sodium dialkyl sulfosuccinate. Wherein the acrylic emulsion pressure-sensitive adhesive is one or more of the following. 18. The method of claim 17, wherein the nonionic surfactant is at least one selected from the group consisting of polyethylene oxide alkyl aryl ether, polyethylene oxide alkylamine, and polyethylene oxide alkyl ester. 16. The method of claim 15, wherein the electrolyte of (B) is at least one selected from the group consisting of sodium bicarbonate, sodium carbonate, sodium phosphate, sodium sulfate, and sodium chloride. The method of claim 15, wherein the initiator (C) is at least one selected from the group consisting of persulfates of ammonium or alkali metals, hydrogen peroxide, peroxide, and hydroxoxide. A pressure-sensitive adhesive sheet for forming an adhesive layer by applying the acrylic emulsion pressure-sensitive adhesive according to claim 1 onto a pressure-sensitive adhesive film or sheet.