KR102371667B1 - Acrylic emulsion pressure snsitive adhesive composition - Google Patents

Abstract

The present invention relates to an acrylic emulsion pressure-sensitive adhesive composition. According to the present invention, it is possible to provide an acrylic emulsion pressure-sensitive adhesive composition, which uses a relatively small amount of an emulsifier and maintains polymerization stability, reduces the occurrence of aggregates and can implement excellent adhesive properties.

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, chemistry, pharmaceuticals, home appliances, automobiles, and stationery.

Adhesives can be classified into acrylic, rubber, silicone, EVA, and the like according to the monomer used in manufacturing, and can be classified into solvent type, emulsion type, and hot melt type according to the shape.

In the past, most rubber-based adhesives or solvent-type adhesives were used for adhesive tapes and adhesive labels, but as the demand for environmentally friendly adhesives increased, interest in solvent-free adhesives increased, and technology development was progressed. Currently, the use and production of solvent-free adhesives has increased significantly, and is expected to continue to increase in the future.

Solvent-free pressure-sensitive adhesives are typically produced by aqueous emulsion polymerization, and in terms of economic efficiency and processability improvement, it is required to have less agglomerate generation and to stably implement excellent adhesive properties.

An object of the present specification is to provide an acrylic emulsion pressure-sensitive adhesive composition that uses a relatively small amount of an emulsifier, and maintains polymerization stability, reduces the occurrence of agglomerates and implements excellent adhesive properties.

the present invention

A) as a monomer component

a1) a (meth)acrylic acid ester-based first monomer having 1 to 14 carbon atoms;

a2) at least one second monomer selected from the group consisting of an allyl ester-based monomer, a vinyl ester-based monomer, a monomer containing a cyano group, and a monomer containing an amine group

a3) unsaturated carboxylic acid-based third monomer

A monomer mixture comprising;

B) a crosslinking agent; and

C) emulsion polymerization in the presence of a nonionic emulsifier containing a dialkylene glycol alkyl ether compound, comprising copolymer particles,

An acrylic emulsion adhesive composition is provided.

According to the present invention, it is possible to provide an acrylic emulsion pressure-sensitive adhesive composition, which uses a relatively small amount of an emulsifier and maintains polymerization stability, reduces the occurrence of aggregates and can implement excellent adhesive properties.

In the present invention, terms such as first and second 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 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 the present specification, terms such as "comprise", "comprising" or "have" are intended to designate the existence of an embodied feature, number, step, element, or a combination thereof, but one or more other features or It should be understood that the existence or addition of numbers, steps, elements, or combinations thereof, is not precluded in advance.

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, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

According to one aspect of the present invention,

A) as a monomer component

a1) a (meth)acrylic acid ester-based first monomer having 1 to 14 carbon atoms;

a2) at least one second monomer selected from the group consisting of an allyl ester-based monomer, a vinyl ester-based monomer, a monomer containing a cyano group, and a monomer containing an amine group

a3) unsaturated carboxylic acid-based third monomer

A monomer mixture comprising;

B) a crosslinking agent; and

C) emulsion polymerization in the presence of a nonionic emulsifier containing a dialkylene glycol alkyl ether compound, comprising copolymer particles,

An acrylic emulsion pressure-sensitive adhesive composition is provided.

In this case, the number average particle diameter of the copolymer particles may be about 150 to about 400 nm, and the content of aggregates having a particle diameter of about 74 μm or more may be included in less than about 1000 ppm.

And, the acrylic emulsion pressure-sensitive adhesive composition may have a viscosity of about 500 to about 1500 cps.

The nonionic emulsifier may preferably include diethylene glycol dodecyl ether.

In addition, the acrylic emulsion pressure-sensitive adhesive composition may include about 1 to about 20 parts by weight of the second monomer based on 100 parts by weight of the first monomer, and 100 parts by weight of the first monomer, Sanggi's third monomer It may be desirable to include from about 1 to about 5 parts by weight.

In addition, the acrylic emulsion pressure-sensitive adhesive composition, based on 100 parts by weight of the monomer mixture, may include about 0.05 to about 0.5 parts by weight of the nonionic emulsifier.

In this case, the first monomer is methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, t-butyl (meth) ) may be at least one selected from the group consisting of acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, and lauryl (meth) acrylate, and the third monomer is maleic anhydride, fumaric acid , may be at least one selected from the group consisting of crotanic acid, itaconic acid, and (meth)acrylic acid.

And, according to another aspect of the present invention,

write; and

A pressure-sensitive adhesive sheet comprising an adhesive layer formed by the above-described acrylic emulsion pressure-sensitive adhesive composition on at least one surface of the substrate may be provided.

Hereinafter, the present invention will be described in detail.

In the present specification, the "monomer mixture" is not particularly limited as long as it can be used in an emulsion polymerization reaction to make an acrylic emulsion resin based on the monomers. For example, the monomers are polymerized in a mixed state. It may be added to the reaction, and the monomers may be sequentially added to the polymerization reaction.

First, the acrylic emulsion pressure-sensitive adhesive composition according to the present invention,

A) as a monomer component

a1) a (meth)acrylic acid ester-based first monomer having 1 to 14 carbon atoms;

a2) at least one second monomer selected from the group consisting of an allyl ester-based monomer, a vinyl ester-based monomer, a monomer containing a cyano group, and a monomer containing an amine group

a3) unsaturated carboxylic acid-based third monomer

A monomer mixture comprising

B) a crosslinking agent; and

C) copolymer particles produced by emulsion polymerization from a reaction mixture comprising a nonionic emulsifier comprising a dialkylene glycol alkyl ether compound.

According to an embodiment of the present invention, the copolymer particles in the acrylic emulsion pressure-sensitive adhesive composition may have a number average particle diameter of about 150 to about 400 nm, preferably about 150 to about 350 nm. When the particle diameter of the resin is out of the above range, the stability of the pressure-sensitive adhesive may be reduced.

In addition, according to another embodiment of the present invention, in the acrylic emulsion pressure-sensitive adhesive composition, the content of aggregates having a particle diameter of 74 μm or more may be about 1,000 ppm or less. In the present invention, by using a combination of a monomer, a crosslinking agent, and an emulsifier of a specific component, the stability in the polymerization reaction is very excellent, and accordingly, only a small amount of aggregates are generated, so that excellent adhesion properties can be realized. When the content of the above-mentioned aggregates exceeds about 1,000 ppm, it may be difficult to remove the aggregates by filtering, and when an adhesive is used, problems of lowering adhesion and poor appearance of the coated surface may occur.

In addition, the acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention has a viscosity of about 500 to about 1500 cps, or about 700 to about 1200 cps, while having a high solid content, and exhibiting a relatively low viscosity characteristic, excellent adhesive properties can have, and when used, it is possible to have excellent processability for various adhesion objects.

According to an embodiment of the present invention, the monomer mixture for the emulsion polymerization includes a (meth)acrylic acid ester-based monomer having 1 to 14 carbon atoms.

Specific examples of these monomer compounds include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate ) 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, lauryl (meth) acrylate, etc. may be , but is not limited thereto. In addition, these may be used alone or in mixture of two or more, which may be referred to as a first monomer.

In addition, the monomer mixture for preparing the acrylic emulsion resin further includes other monomers in addition to the above-described (meth)acrylic acid ester-based monomer.

Examples of additional monomers include allyl ester monomers, vinyl ester monomers, and unsaturated nitriles. Specifically, vinyl acetate, vinyl butanoate, vinyl propionate, vinyl laurate, vinyl pyrrolidone, acrylonitrile, meta and acrylonitrile, but is not limited thereto. In addition, these may be used alone or in mixture of two or more, which may be referred to as a second monomer.

According to an embodiment of the present invention, the second monomer may be used in an amount of about 1 to about 20 parts by weight based on 100 parts by weight of the first monomer, and in order to realize excellent adhesive properties, preferably about 5 to about 15 parts by weight. It may be used in parts by weight, or from about 10 to about 15 parts by weight.

And, the monomer mixture further includes an unsaturated carboxylic acid-based monomer in addition to the above-mentioned monomers. As the unsaturated carboxylic acid-based monomer, maleic anhydride, fumaric acid, crotanic acid, itaconic acid, and (meth)acrylic acid may be used alone or in combination of two or more, which may be referred to as a third monomer.

According to an embodiment of the present invention, the third monomer may be used in an amount of about 1 to about 5 parts by weight based on 100 parts by weight of the first monomer. may be used in an amount of about 2 to about 3 parts by weight.

When the content of the second and third monomers is too small, the cohesive force is lowered, so that transfer may occur during peeling. If the content is too large, the adhesive force may be reduced.

In addition, the crosslinking agent is a component added to reinforce cohesion, and may be a compound including 5 to 15 repeating units of alkylene oxide and having an acrylate group or a vinyl group at the terminal thereof. The number of alkylene oxide repeating units means the average number of alkylene oxides included in the crosslinking agent used. If the alkylene oxide repeating unit is too small in the crosslinking agent, the prepared pressure-sensitive adhesive becomes stronger than necessary, which may cause a problem that the initial adhesive strength is lowered. This is not preferable because the adhesive properties are lowered.

Specific examples of the crosslinking agent include polyethylene glycol diacrylate, polypropylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylpropane triacrylate, and tripropylene, which are organic crosslinking agents. Glycol diacrylate, 1,3-butanediol diacrylate, pentatritol triacrylate, 3-trimethoxysilyl propyl methacrylate, vinyltrimethoxysilane, divinylbenzene, etc., and aluminum acetylacetonate as an inorganic crosslinking agent , zinc acetate, zirconium carbonate, and the like, and more specifically, polyethylene glycol diacrylate and polypropylene glycol diacrylate, but are not limited thereto. In addition, these may be used alone or in combination of two or more.

According to an embodiment of the present invention, the crosslinking agent may be included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the total monomer mixture.

The emulsifier may serve to generate initial fine particles in the emulsion polymerization reaction of the resin, and is used to control the size of the particles and increase the stability of the particles.

Emulsion polymerization is a polymerization method that uses a water-soluble polymerization initiator to emulsify in water together with an emulsifier. Generally, it is divided into anionic emulsifiers, cationic emulsifiers and nonionic emulsifiers, and in order to supplement stability, etc. , a mixture of several types is also used.

Conventionally, a large amount of an emulsifier was used to ensure reaction stability in emulsion polymerization, but in this case, a large amount of agglomerates were generated, and there was a problem in that adhesion properties were significantly reduced.

As described above, the present invention uses a monomer mixture of a specific combination, and a nonionic emulsifier containing a dialkylene glycol alkyl ether compound is used here, and even if only a relatively small amount of the emulsifier is used, polymerization stability can be improved, the generation of aggregates can be minimized, and thus excellent adhesive properties can be realized.

The above-described dialkylene glycol alkyl ether-based compound, structurally both ends of the molecule exhibit an appropriate level of hydrophilicity and hydrophobicity, and have an appropriate overall length, so that the reactivity in emulsion polymerization can be improved, and the distance between the formed particles is constant. It serves to improve the three-dimensional stability.

As such a dialkylene glycol alkyl ether compound, a dialkylene glycol alkyl ether compound containing an alkylene group having 2 to 5 carbon atoms and an alkyl group having 5 to 15 carbon atoms, preferably, 2 or 3 carbon atoms. and a dialkylene glycol alkyl ether-based compound containing an alkylene group of and an alkyl group having 10 to 15 carbon atoms, and most preferably, diethylene glycol dodecyl ether and the like may be used. When the molecular length of the dialkylene glycol alkyl ether used as the emulsifier becomes too long, it cannot function as an emulsifier, so a large amount must be used or a problem of reduced reactivity may occur. Because the affinity of the polymer is too high, it cannot function as an emulsifier, and thus there may be a problem in that it cannot maintain stability after polymerization.

According to an embodiment of the present invention, the emulsifier may be included in an amount of about 0.01 to 1.0 parts by weight based on 100 parts by weight of the total of the monomer mixture, preferably about 0.02 parts by weight to about 0.7 parts by weight or about 0.6 parts by weight more than about 0.03 parts by weight. may be included in less than a part. When the above range is satisfied, it is preferable to maintain proper polymerization stability and at the same time realize excellent adhesive properties and cohesion.

In addition, in the case of the emulsion polymerization, an anionic emulsifier may be further used together with the above-described nonionic emulsifier.

Examples of the anionic emulsifier include sodium alkyldiphenyloxide disulfonate; sodium polyoxyethylene alkyl ether sulfates, including sodium polyoxyethylene lauryl ether sulfate and the like; sodium dialkyl sulfosuccinates, including sodium dioctyl sulfoxinate and the like; and the like.

In addition, these may be used alone or in mixture of two or more, and when used in combination with the above-described nonionic emulsifier, it may be more effective in terms of polymerization reaction stability and particle size control.

According to an embodiment of the present invention, the anionic emulsifier may be included in an amount of about 0.1 to about 1 part by weight, preferably 0.1 to 0.5 parts by weight, based on 100 parts by weight of the monomer mixture. When used in the above range, it is possible to properly maintain polymerization stability, and at the same time realize excellent adhesive properties and cohesion.

And, according to an embodiment of the present invention, as an initiator for the polymerization in the polymerization reaction, a persulfate of ammonium or alkali metal, a peroxide such as hydrogen peroxide may be used.

The initiator may be included in an amount of about 0.1 to about 5 parts by weight, preferably 0.5 to 3 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-mentioned 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 provide polymerization stability, for example, sodium bicarbonate, sodium carbonate, sodium phosphate, sodium sulfate, sodium chloride, etc., However, the present invention is not limited thereto. In addition, these may be used alone or in combination of two or more.

On the other hand, according to an embodiment of the present invention,

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

A) as a monomer component

a1) a (meth)acrylic acid ester-based first monomer having 1 to 14 carbon atoms;

a2) at least one second monomer selected from the group consisting of an allyl ester-based monomer, a vinyl ester-based monomer, a monomer containing a cyano group, and a monomer containing an amine group, and

a3) unsaturated carboxylic acid-based third monomer

A monomer mixture comprising: and B) a crosslinking agent; and C) mixing an emulsifier to prepare a pre-emulsion, a second step;

A third step of mixing the emulsion of the first step and the pre-emulsion of the second step in the presence of an initiator, and conducting emulsion polymerization,

The C) emulsifier includes a dialkylene glycol alkyl ether-based compound;

A method for preparing an acrylic emulsion pressure-sensitive adhesive composition is provided.

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. As the emulsifier, an anionic emulsifier may be used alone, or an anionic emulsifier and the above-described 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, the above-described first, second, and third monomers, a crosslinking agent and an emulsifier 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-described diethylene glycol alkyl ether-based nonionic emulsifier may be used in any one or more stages 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 0.001 to about 0.02 parts by weight relative to 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 0.5 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 5 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 are then subjected to a warming polymerization process in the presence of an additional polymerization initiator, through which the remaining monomers are polymerized.

At this time, the polymerization initiator may be added in an amount of about 0.001 to about 0.02 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 75 to about 85.

The manufacturing method of such an acrylic emulsion pressure-sensitive adhesive composition is divided into an emulsion manufacturing process and a pre-emulsion manufacturing process, and thereafter, it can be proceeded by a simple method of mixing the pre-emulsion with the emulsion, so that the conventional high-solids, low-viscosity acrylic emulsion adhesive Process stability and productivity can be improved compared to methods for preparing the composition.

On the other hand, in the pre-emulsion preparation process described above, a chain transfer agent may be used. The chain transfer agent serves to introduce homopolymers, which are polymers composed of only one type of monomer, into micelles, and may include sodium carbonate, sodium methylallyl sulfonate, n-dodecyl mercaptan, etc., but the present invention The present invention is not necessarily limited thereto.

And, in one embodiment of the present invention, after the polymerization step, the step of adjusting the pH may be further performed, at this time, the pH may be adjusted to be about 6 to about 9, preferably about 7 to about 8. there is.

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 hydroxide, chloride, or carbonate of a monovalent or divalent metal, inorganic substances such as carbonate, ammonia or organic amines and the like may be used.

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

The adhesive sheet is FINAT TEST METHOD NO. The initial adhesion according to 9 may be about 17 N/in, or about 17 to about 19 N/in.

And, the pressure-sensitive adhesive sheet, FINAT TEST METHOD NO. The 90 degree peel force according to 2 may be about 7 N/in, preferably about 7 to about 9 N/in.

In addition, the said adhesive sheet, FINAT TEST METHOD NO. The cohesive force according to 8 may be about 750 minutes or more, preferably about 900 minutes or more, and more preferably about 1000 to 2000 minutes.

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>

acrylic emulsion Adhesive composition preparation

Example One

220 g of water and 10 g of 30 wt% sodium polyoxyethylene lauryl ether sulfate (hereinafter referred to as S-POELES) were placed in a 3L glass reactor equipped with a thermometer, stirrer, dropping funnel, nitrogen inlet tube and reflux condenser, and the inside of the reactor was stirred while stirring. After replacing with nitrogen, the temperature was raised to 80 under a nitrogen atmosphere and maintained for 60 minutes (first step).

Separately, 220 g of butyl acrylate, 657 g of 2-ethylhexyl acrylate, 70 g of vinyl acetate, 30 g of acrylonitrile, 20 g of acrylic acid and 2 g of polyethylene glycol 400 diacrylate, 1 g of n-dodecyl mercaptan, and In a mixture of 2 g of diethylene glycol dodecyl ether (hereinafter, DEGDE), 10 g of 30 wt% sodium polyoxyethylene lauryl ether sulfate, 5 g of 60 wt% sodium dioctyl sulfosuccinate (hereinafter, S-DOSS), sodium carbonate A solution consisting of 3 g, 3 g of sodium methylallyl sulfonate and 300 g of water was added and mixed with a stirrer to prepare a cloudy free emulsion (second step).

5 g of a 10 wt% ammonium persulfate solution was added to the glass reactor containing the emulsion and dissolved by stirring for 10 minutes. Here, 140 g of the pre-emulsion and 10 wt% aqueous solution of ammonium persulfate were uniformly added continuously for 4 hours, and then 5 g of 10% aqueous solution of ammonium persulfate was further added (step 3). The temperature was raised to 80 and maintained at this temperature for 1 hour, then cooled to room temperature to prepare an acrylic emulsion pressure-sensitive adhesive composition, and 28wt% of an aqueous ammonia solution was added to adjust the pH to about 7 to about 8.

Example 2-8, Reference example 1, 2, and comparative example 1-3

With the components and contents shown in Table 1 below, an acrylic emulsion adhesive composition was prepared in the same manner as in Example 1, except that the time of addition of diethylene glycol dodecyl ether was adjusted.

division DEGDE
(parts by weight) S-POELES
(parts by weight) S-DOSS
(parts by weight) Step 1 Step 2 Step 1 Step 2 Step 1 Step 2 Example One - 0.2 0.3 0.3 - 0.3 2 - 0.05 0.3 0.3 - 0.3 3 - 0.5 0.3 0.3 - 0.3 4 - 0.2 - 0.3 - 0.3 5 - 0.2 0.5 0.3 - 0.3 6 0.2 - 0.3 0.3 - 0.3 7 0.2 - - 0.3 - 0.3 8 0.2 - 0.5 0.6 - 0.3 9 - 0.03 0.3 0.3 - 0.3 10 - 0.6 0.3 0.3 - 0.3 comparative example One - - 0.3 0.3 - 0.3 2 - - - 0.3 - 0.3 3 - - 0.5 0.3 - 0.3 Content relative to 100 parts by weight of the monomer mixture

Adhesive sheet manufacturing

The acrylic emulsion pressure-sensitive adhesive composition was applied on a silicone-coated release paper, and dried in an oven at 120 for 1 minute to have a dry thickness of 20 μm. This was laminated with paper to make a paper label, and cut to a size of 1 inch - 100 mm to prepare a paper label specimen.

<Experimental example>

For the pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet prepared in Examples and Comparative Examples, experiments were performed according to the following method, and the results are summarized in Table 2 below.

aggregate content measurement

100 g of the acrylic emulsion pressure-sensitive adhesive composition was filtered through a 74 μm standard sieve, and the aggregates left on the sieve were thoroughly washed with distilled water, and then dried at a temperature of 110 or less. The dried residual amount, that is, the dry weight of the aggregates left on the sieve was measured, and the aggregate content was calculated in ppm units using the following formula.

Agglomerate content (ppm) = {(dry weight of agglomerate (g)) / (sample 100g)} ? 10000

Particle size measurement

The particle size of the prepared emulsion acrylic pressure-sensitive adhesive composition was measured using a particle meter (Nicomp, CW380).

Initial adhesion test

FINAT TEST METHOD NO. 9 was measured.

The pressure-sensitive adhesive sheet was made into a ring shape and contacted for 5 seconds without applying pressure to the glass surface, followed by peeling at a rate of 300 mm/min using a TA Texture Analyzer. (Unit: N/in)

peel force test

FINAT TEST METHOD NO. 2 was measured.

The pressure-sensitive adhesive sheet is placed on a glass plate, and a 2 kg roller is reciprocally attached thereon at a speed of 300 mm/min, aged at room temperature for 20 minutes, and then 90 degrees at a speed of 300 mm/min using a TA Texture Analyzer device. It was measured while peeling. (Unit: N/in)

cohesion test

FINAT TEST METHOD NO. 8 was measured.

The pressure-sensitive adhesive sheet was attached to a stainless steel surface (SUS 304) so that the attachment surface was 1*1 inch, and after leaving it for 20 minutes, a weight of 1 kg was hung on the end of the sheet and the time for the weight to fall was measured. (Unit: minutes)

division Aggregate content
(ppm) particle size
(nm) initial adhesion
(N/in) 90˚ peeling force
(N/in) cohesion
(minute) Example One 290 210 17.7 7.8 1500 2 590 250 17.5 7.7 1450 3 180 200 18.0 7.8 1090 4 310 320 18.2 8.0 1930 5 300 170 17.3 7.7 1010 6 350 220 17.5 7.7 1430 7 330 300 18.1 7.5 1020 8 310 200 17.1 7.3 920 9 920 270 17.1 7.0 850 10 230 180 17.5 7.3 780 comparative example One 2100 290 16.7 6.8 800 2 3900 380 16.3 6.7 570 3 1210 210 16.5 6.5 730

Referring to Table 2, it can be seen that the acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention can maintain polymerization stability during polymerization, thereby reducing the occurrence of aggregates and implementing excellent adhesive properties.

In the acrylic emulsion pressure-sensitive adhesive composition according to the comparative example, a large amount of aggregates are generated in the polymerization process, such as the aggregate content exceeds about 1000 ppm, and it can be seen that the adhesion properties such as initial adhesion, peeling force, cohesive force, etc. are very deteriorated, especially In Comparative Example 3 and the like, even though a relatively large amount of the emulsifier was used, the adhesive properties were not improved.

In contrast, the acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention has an average particle diameter of about 170 to about 320 nm, is formed relatively evenly, and the content of aggregates is about 1,000 ppm or less, or about 180 to about 590 ppm level, , at a level of about 180 to about 350 ppm, except in Example 2, it can be clearly seen that the polymerization stability is very excellent. In addition, according to this, it can be clearly confirmed that the adhesion properties such as initial adhesion force, peel force, cohesive force are very excellent compared to the comparative example.

Claims (13)

A) as a monomer component
a1) a (meth)acrylic acid ester-based first monomer having 1 to 14 carbon atoms;
a2) at least one second monomer selected from the group consisting of an allyl ester-based monomer, a vinyl ester-based monomer, a monomer containing a cyano group, and a monomer containing an amine group, and
a3) an unsaturated carboxylic acid-based third monomer;
A monomer mixture comprising;
B) a crosslinking agent; and
C) emulsion polymerization in the presence of a nonionic emulsifier containing a dialkylene glycol alkyl ether compound, comprising copolymer particles,
Acrylic emulsion adhesive composition.
According to claim 1,
The number average particle diameter of the copolymer particles is 150 to 400 nm, the acrylic emulsion pressure-sensitive adhesive composition.
According to claim 1,
The content of aggregates having a particle size of 74 μm or more is less than 1000 ppm, an acrylic emulsion pressure-sensitive adhesive composition.
According to claim 1,
A viscosity of 500 to 1500 cps, an acrylic emulsion pressure-sensitive adhesive composition.
According to claim 1,
The first 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 ( 1 selected from the group consisting of meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, isobornyl (meth) acrylate, and lauryl (meth) acrylate More than a species, an acrylic emulsion pressure-sensitive adhesive composition.
According to claim 1,
With respect to 100 parts by weight of the first monomer, the acrylic emulsion pressure-sensitive adhesive composition comprising 1 to 20 parts by weight of the second monomer.
According to claim 1,
The third monomer is at least one selected from the group consisting of maleic anhydride, fumaric acid, crotanic acid, itaconic acid, and (meth)acrylic acid, an acrylic emulsion pressure-sensitive adhesive composition.
According to claim 1,
An acrylic emulsion pressure-sensitive adhesive composition comprising 1 to 5 parts by weight of the third monomer based on 100 parts by weight of the first monomer.
According to claim 1,
The nonionic emulsifier, an acrylic emulsion pressure-sensitive adhesive composition comprising a dialkylene glycol alkyl ether compound containing an alkylene group having 2 to 5 carbon atoms and an alkyl group having 5 to 15 carbon atoms.
According to claim 1,
With respect to 100 parts by weight of the monomer mixture, the acrylic emulsion pressure-sensitive adhesive composition comprising 0.01 to 1.0 parts by weight of the nonionic emulsifier.
According to claim 1,
The emulsion polymerization, which proceeds in the presence of the nonionic emulsifier and the anionic emulsifier, acrylic emulsion pressure-sensitive adhesive composition.
write; and
A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed by the acrylic emulsion pressure-sensitive adhesive composition according to claim 1 on at least one surface of the substrate.
Dispersing the emulsifier in a solvent to prepare an emulsion, the first step
A) as a monomer component
a1) a (meth)acrylic acid ester-based first monomer having 1 to 14 carbon atoms;
a2) at least one second monomer selected from the group consisting of an allyl ester-based monomer, a vinyl ester-based monomer, a monomer containing a cyano group, and a monomer containing an amine group, and
a3) unsaturated carboxylic acid-based third monomer
A monomer mixture comprising: and B) a crosslinking agent; and C) mixing an emulsifier to prepare a pre-emulsion, a second step;
A third step of mixing the emulsion of the first step and the pre-emulsion of the second step in the presence of an initiator, and conducting emulsion polymerization,
The C) emulsifier, including a dialkylene glycol alkyl ether compound;
Method for producing an acrylic emulsion pressure-sensitive adhesive composition.